PROFESSIONAL DENTISTRY PRESENTS...
AESTHETICS NOW 2019 Edition
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Contents...
S4S Foreword..................................................................................3
(A) Case report 2; Normal Crest....................................................28
A Literature Review of Bleaching Tray Design and Efficacy......3
(B) Facially generated smile assessment (‘Face-White-Pink’)...28
Bleaching Tray Design....................................................................3
(B) Crown lengthening surgery......................................................29
Reservoirs or No Reservoirs?...........................................................4
(B) Aim of surgery............................................................................29
Dosing Dots......................................................................................4
(A) Summary....................................................................................31
Gingival Contouring or Straight Extension?.................................4
References.......................................................................................31
Tray Material....................................................................................5
Conclusion.......................................................................................5
References.......................................................................................6
Chapter 3 Tooth whitening and bleaching treatment for under 18s and sensitivity issues.........................................................32
Chapter 1 Predictable gingival surgery for the general dentist - Dr Ken Harris - Part 1: Pre-operative smile assessment.........................................................................8
(A) Legal situation...........................................................................32
(A) Psychological trauma..............................................................34
(B) Brown and yellow staining.......................................................35
(A) Gingival aesthetics...................................................................8
(B) Coronal defects........................................................................35
(B) The ‘gummy smile’....................................................................8
(B) Molar incisor hypomineralisation (MIH)...................................36
(B) The irregular smile......................................................................10
(B) Hereditary factors......................................................................36
(B) Can we help?............................................................................10
(B) Traumatised/non-vital teeth....................................................37
(A) Full gingival smile assessment..................................................12
(B) Systemic diseases......................................................................37
(A) 1. Gingival exposure.................................................................12
(A) Tray design for under-18s.........................................................38
(B) Lips (high lip line).......................................................................13
(A) Managing sensitivity from bleaching treatment...................38
(B) Teeth (short clinical crown)......................................................13
(A) Extended tray vs non-extended.............................................39
(B) Gingivae (gingival overgrowth)..............................................13
Further reading................................................................................40
(B) Premaxilla overgrowth (dento-alveolar extrusion)................15
(B) Vertical maxillary excess...........................................................15
(B) Combination cases...................................................................16
(A) Facially generated smile assessment (‘Face-White-Pink’)...16
(A) 2. Comparative gingival anatomy.........................................17
(B) Anatomy of the gingival complex..........................................17
(B) Connective tissue......................................................................17
(B) Junctional epithelium...............................................................17
(B) Gingival sulcus...........................................................................18
(B) Biologic width............................................................................18
(B) Kois classification.......................................................................18
(B) ‘Bone sounding’........................................................................19
(B) Normal crest..............................................................................19
(B) High crest...................................................................................20
(B) Low crest....................................................................................20
(A) 3. Gingival papillae & embrasures.........................................20
(A) 4.Gingival scallop.....................................................................21
(B) White lesions...............................................................................35
(A) Gummy smile assessment........................................................22 (B) Biologic width............................................................................23
(A) Kois classification......................................................................24
(A) Case report 1; High Crest.........................................................24
(B) Gummy smile assessment........................................................25
(B) Facially generated smile assessment (‘Face-White-Pink’)...26
(B) Crown lengthening surgery......................................................26
(B) Osseous surgical steps..............................................................26
(B) Post-op instructions...................................................................27
(B) Aim of surgery............................................................................27
(A) Smile aesthetics........................................................................44
(B) Perioral ‘smokers’ lines..............................................................44
(B) Thin upper lip..............................................................................44
(B) Protrusive or dimpled chin........................................................44
(B) Smile curvature..........................................................................46
(B) Excessive gingival display and dental camouflage.............46
(A) Long-term management and safety.....................................47
Chapter 5 Anterior restorations under scrutiny..................................50
(A) Characteristics of the sample population.............................51
(B) Restorations in incisor teeth, overall........................................51
(B) Restorations in incisor teeth with respect to patient.............51
(B) Influence of dentist factors (gender and age).....................52
(B) Patient’s state of oral health....................................................52
(B) Influence of tooth position.......................................................53
(B) Other factors..............................................................................53
(A) Other factors.............................................................................55
References.......................................................................................56
(A) Facially generated smile assessment (‘Face-White-Pink’)...22
(A) Pharmacology and physiology..............................................42
Chapter 2 Predictable gingival surgery for the general dentist - Dr Ken Harris - Part 2...............................................................22
References.......................................................................................48
References.......................................................................................21
Chapter 4 Facial aesthetics in dentistry.................................................42
Chapter 6 Psychology, orthodontics & aesthetic dentistry.........58
(A) Personality and smiles..............................................................59
(A) Patient perceptions..................................................................59
(A) Case report...............................................................................60
(A) Orthodontic diagnosis..............................................................62
(A) Discussion...................................................................................65
References.......................................................................................65
2
S4S Foreword A LITERATURE REVIEW OF BLEACHING TRAY DESIGN AND EFFICACY Everatt M, D, FOTA and Bretton, D, J. BDS. June 2018
Tooth whitening is very common practice in dentistry today, made famous by celebrities in the 1980s, and was initially thought to have been discovered by accident by a group of dentists using peroxide to treat gum disease (Kurthy, 2016). The UK tooth whitening industry is believed to be worth over £40m, as more consumers seek the white, healthy smiles endorsed by many celebrities. (National Smile Month, 2018). Market research shows that 99.2% of us believe our smiles are an important social benefit (Hexa Research, 2017), whilst a further study found that 48% of adults believe a person’s smile is the most memorable feature upon first meeting (Salemi, 2013). Haywood (2003) suggests that the efficacy of whitening is greatly improved when the Hydrogen Peroxide level is around 6%, and custom-made dental trays are used to hold the gel close to the teeth for a period of around 2 hours. Carey (2014) also supports this approach, concluding that hydrogen peroxide and carbamide peroxide tooth whitening is safe and effective. He felt that “home based bleaching (following manufacturer’s instructions) results in less tooth sensitivity than in-office bleaching.” Cosmetic Dentist, Dr Zase (2009) lists sensitivity and compliance as the two main problems associated with tooth whitening. The whitening procedure could help reduce sensitivity, whereas tray design can directly help improve compliance. It is therefore important to consider the design and use of custom-made bleaching trays to achieve the optimal results in a timely and safe manner.
Bleaching Tray Design Bleaching Tray designs have been debated amongst dental professionals over the years, with many opinions formed on the basis of very little scientific evidence to support any particular design. Many assumptions are made and logic used in the absence of science when discussing the specifics of tray design. There are several technical specifications used, such as: scalloped margins, straight cut margins, extension beyond the gingiva, and reservoirs. The process of thermoforming is also debated; Mizuhashi and Koide (2017) found that vacuum formed appliances maintained material thickness, whilst pressure formed appliances obtained a better fit. Model thickness can also affect the fit of the finished tray. Due to the morphology of the oral tissues and dentition, it is difficult to provide a standardised model size in which to form the tray. Therefore, material thickness can vary from model to model. Mizuhashi and Koide (2017) also noted that the marginal fit of the pressure formed appliances was significantly improved by pressure forming appliances.
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Reservoirs or No Reservoirs? Matis et al (2002) showed that there was little difference in results in terms of shade difference when comparing trays with and without reservoirs. Despite there being minor shade differences when using a colorimeter, the shade difference was below the threshold of visual differentiation. It would appear that the importance of using reservoirs is linked to how well the margins are sealed. Trays that are scalloped are inevitably more flexible and will allow more bleach to escape the tray, therefore requiring a larger amount of bleach present in a reservoir. There are clinicians, such as Kurthy (2016), who advocate the use of a reservoirs and finishing the tray exactly at the gingival margin. The margin for error from the impression stage to the dental laboratory finishing the trays is high. Further anecdotal evidence suggests that the hand trimming and finishing process deforms the thermoformed tray, leading to a tray that is not as well sealed at the peripheral margins. Haywood (2008) also states: “reservoirs are not needed to bleach; they merely reduce the tightness of the tray. Teeth bleach just as quickly without the reservoir as they do with.”
Dosing Dots A relatively new method introduced in the tray design are ‘Dosing Dots’ (S4S, 2018) or ‘dimples’ (Chan, 2018). Not to be confused with reservoirs, these small areas in the trays are designed to help the patient add the correct amount of gel to each tooth and not overload the tray. Overloading the tray can lead to sensitivity, non-compliance and gingival irritation (Zase, 2009). Dosing dots are therefore recommended, to reduce the risk of complications associated with home tooth whitening.
Gingival Contouring or Straight Extension? Theory may suggest that gingival contouring or scalloping could reduce the amount bleach having mucosal contact, however there appears to be no cited references to the benefits to scalloping trays. One could argue that by closely following the gingival margin with a scalloped designed tray, the surface area covered is less and therefore leads to less mucosal irritation, although this theory is not supported by any literature. To the contrary, Curtis et al (1996) demonstrated in a group of fifty-two patients that there was no soft tissue damage in any of the sample group as a result of the bleaching regime. To further support that the extension of the bleaching tray beyond the gingival margin has no effect on efficacy or sensitivity, Morgan et al (2015) demonstrated in their group of twenty subjects that there was no statistical difference in how effective the bleaching was, nor did the extended or nonextended trays cause anymore or any less sensitivity. There appears to be a lack of clinical evidence to support gingival contouring. Scalloping is only needed with higher concentrations of peroxide. According to Haywood (2008), considering the 2013 laws in the UK that restricted the use of higher concentration ‘in office’ bleaching, the need for scalloped trays is no longer an issue in terms of gingival contact. Research by Cowley (2012) compares the fit and retention of thermoplastic retainers in the
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different design of finishing, these being; scalloped, straight cut at the gingival zenith, and a straight cut 2mm beyond gingival zenith. The best retention was found in the appliances finished 2mm beyond gingival margins, with those finished at the gingival margin the poorest. Although the materials cannot be compared like for like, finishing with a straight line cut will increase the stability of any thermoformed appliance. This means that the bleach will likely remain in contact with the tooth surface longer, possibly increasing the efficacy of the bleaching material. To further support the benefits of cutting the trays straight in a line 2mm above the gingival margin, Cowley (2012) also suggests that the appliances should: “be more comfortable than before, because there will be less risk of them impinging on the unattached marginal gingiva”. With the current literature stating that there is no benefit in using reservoirs, it would appear counter effective to have gingivally trimmed trays. Trays with a straight cut margin of approximately 2mm beyond the margin will give better stability (Cowley, 2012). The additional flexibility that comes with scalloping a tray can also be problematic in bruxism patients, as the tray is more prone to bending and emitting bleach in comparison to straight cut trays.
Tray Material There are several materials that are commonly used for bleaching trays, with 1 or 1.5mm soft Ethylene-vinyl acetate (EVA) being the most common. In recent years, there has been an introduction of material designed for use in bleaching. A foam lined tray, for instance, was introduced, with the notion that the foam would have an advantage in holding the bleach over standard trays. However, Haywood et al (1993) proved there was no difference in the clinical results. Manufacturers have introduced a material that has a firmer feel to standard EVA material, commercially available as a ‘Bleach Tray Material’, with the majority of the manufacturers offering 1.5mm semi-rigid as the most popular type for bleaching.
Conclusion In conclusion, this review has highlighted that there is only a limited number of clinical studies available discussing tooth bleaching. Furthermore there are even less studies to support bleaching tray designs in relation to their effect on treatment. Further studies should consider trays designs in relation to compliance alongside the efficacy of the whitening gels. With the limited clinical evidence, a conclusion can be drawn that a bleaching tray should have some specific design features, whilst other features appear to be operator-led, without having any proven clinical benefit other than it being accepted by the clinician and patient as acceptable. There is no evidence to show that reservoirs improve shade reductions, and there is little evidence to support their use other than in trays that are trimmed gingivally to aid the seal. Scalloping would also appear to be counterproductive in terms of patient comfort and tray stability. An optimal tray design should have a good peripheral seal around the gingival margin, be trimmed straight just beyond the gingival margin to improve seal and stability, and
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provide comfort and, therefore, increased compliance for the patient. Although there is no published data to support ‘Dosing Dots’ or ‘dimples’ on the labial surfaces, it appears to be a useful tool in demonstrating to patients how much bleach to administer per tooth.
References Carey, C, M. (2014) ‘Tooth Whitening: What We Now Know’, The Journal of Evidence Based Dental Practice, 14 (1), pp. 70-76. Chan, W. (2018) WY10 - Products - Perfect Trays, Available at: http://www.wy10.com/perfecttrays.html [Accessed: 23rd May 2018]. Cowley, D, P. (2012) Effect of Gingival Margin Design on Retention of Thermoformed Orthodontic Aligners, Las Vegas: University of Nevada. Curtis J, W, J., Dickinson, G, Downey, M, Russell, C, Haywood, V, Myers, M, & Johnson, M, (1996), ‘Assessing the effects of 10 percent carbamide peroxide on oral soft tissues’, Journal Of The American Dental Association (JADA), 127, 8, pp. 1218-1232, CINAHL Complete, EBSCOhost, viewed [22 May 2018]. Haywood, V, Leonard, R, and Nelson, C (1993) ‘Efficacy of foam liner in 10% carbamide peroxide bleaching technique’, Quintessence International, 24( 9), pp. 663-666. Haywood, V,B. (2003) Frequently Asked Questions About Bleaching, Available at: http://www. vanhaywood.com/uploads/articlespage/CE%201-Haywood.pdf [Accessed: 7th April 2018]. Haywood, V,B. (2008) ‘The “Bottom Line” on Bleaching 2008’, Inside Dentistry, pp. 2 [Online]. Available at: http://www.vanhaywood.com/uploads/articlespage/2008Bottom%20Line%20 on%20Bleaching.pdf[Accessed: 6th June 2018]. Hexa Research (2017) Teeth Whitening Products Market Size Worth USD 7.40 Billion By 2024, Available at: https://www.prnewswire.com/news-releases/teeth-whitening-products-marketsize-worth-usd-740-billion-by-2024-hexa-research-645998863.html[Accessed: 8th April 2018]. Kramer, M. (2016) The latest trends in cosmetic dentistry, Available at: https://www.raconteur. net/lifestyle/the-latest-trends-in-cosmetic-dentistry [Accessed: 9th April 2018]. Kurthy, R. (2016) The Myth Of Bleaching Lights And Lasers. [Online]. Available at: https:// en.calameo.com/read/005254607511df4b76906 [Accessed: 12th April 2018]. Matis, B, A., Hamdan, Y, S., Cochran, M, A., and Eckert, G, J. (2002) ‘A clinical evaluation of a bleaching agent used with and without reservoirs’, Operative Dentistry, 27, pp. 5-11.
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Mizuhashi, F, and Koide, K. (2017) ‘Formation of vacuum- formed and pressure- formed mouthguards’, Dental Traumatology, 33(4), pp. 295-299 [Online]. Available at: https://0onlinelibrary-wiley-com.serlib0.essex.ac.uk/doi/epdf/10.1111/edt.12337 (Accessed: 23rd May 2018). Morgan, S, Jum’ah, C, C, and Brunton, P. (2015) ‘Assessment of efficacy and post-bleaching sensitivity of home bleaching using 10% carbamide peroxide in extended and non-extended bleaching trays’, BDJ, 18(), pp. 5729–582 [Online]. Available at: http://0-www.nature.com. serlib0.essex.ac.uk/articles/sj.bdj.2015.391 [Accessed: 22nd May 2018]. National Smile Month (2018) Single adults leading growth in UK’s illegal tooth whitening industry, study finds, Available at: http://www.nationalsmilemonth.org/single-adults-leadinggrowth-uks-illegal-tooth-whitening-industry-study-finds/ [Accessed: 7th April 201]. Salemi, V. (2013) New Survey Shows Smiling Is Best Way to Make First Impression, Available at: http://www.adweek.com/digital/new-survey-shows-smiling-is-the-best-way-to-make-a-firstimpression/ [Accessed: 8th April 2018]. S4S (UK) Limited (2018) Teeth Whitening, Available at: https://s4sdental.com/teeth-whitening/ [Accessed: 23rd May 2018]. Zase, M. (2009) Bleaching: Preventing Common Problems, Available at: http://www. dentistrytoday.com/management/1389-bleaching-preventing-common-problems [Accessed: 23rd May 2018].
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Chapter 1 PREDICTABLE GINGIVAL SURGERY FOR THE GENERAL DENTIST - DR KEN HARRIS Part 1: Pre-operative smile assessment
Traditionally, dentists have modified gingival anatomy for restorative reasons, gaining access to sound tooth tissue subgingivally for margin placement, or to expose more clinical crown for greater crown retention or to create a ferrule for post crowns. Less often, to date, dentists have shown little inclination to alter gingival anatomy for purely aesthetic reasons. Modern patients are increasingly aware of gingival discrepancies, often seeking advice from their regular dentist first. As clinicians we need to know if we are able to carry out gingival tissue adjustments predictably in practice, or if the aesthetic problem is something which would need referral or perhaps even significant maxillofacial surgery.
(A) Gingival aesthetics Gingival aesthetic problems may be divided into two major areas, being either a facially apparent skeletal cause or a localised, purely dental cause.
(B) The ‘gummy smile’ Often produced by a facial or skeletal anomaly, the gummy smile affects the entire smile, and diagnosis depends upon the amount of gingivae exposed when smiling. Often the gummy smile exhibits all the principles of classical gingival anatomy, but despite this, 2.0 mm or more gingivae visible in a full smile is deemed unacceptable1. Maxillo-facial surgery is often the only true solution, but patients with gummy smiles often adopt a ‘defensive’ lip position when smiling in order to reduce excessive gingival display. Early assessment is important as in these cases as maxillo-facial surgery may be the only solution.
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(B) The irregular smile The rules of comparative gingival anatomy are well established with symmetry either side of the midline being key. Irregular gum heights visible in the smile may have localised dental causes, hence a full assessment of the ‘irregular smile’ is indicated to evaluate whether any asymmetry could be treatable by localised crown lengthening procedures (Figure 1).
(Figure 1) Irregular smiles reveal irregular gum heights in the smile
(B) Can we help? We need to consider smile design in terms of the big picture (face), the teeth (white) and the gingival display (pink), as dental aesthetics involves more than just the teeth. The classical proportions of an ideal smile in relation to teeth such as golden proportion are well established, and in seeking to fulfil these principles, too many dental photographs are of the lips retracted type, focussing almost exclusively on the teeth. However, such photographs provide little clue how the teeth look in the face, so are of little diagnostic value when treatment planning for aesthetics. We need full face photography to help prevent errors of orientation, amongst others.
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Three photos are required: The lips slightly apart in repose, or ‘MMMM’ The ‘social smile’ The widest smile possible, traditionally described as the ‘EEEE’ smile. Using these we can ascertain whether the face and lips are symmetrical, the upper central incisor edges are correctly positioned in the face and decide if the correct amount of gingival tissue is displayed. Each of these variables can have an impact upon the perfect smile.
(A) Full gingival smile assessment 1. Gingival exposure (gummy smile) 2. Comparative gingival anatomy (symmetry) 3. Gingival papillae and gingival embrasures (black triangles) 4. Gingival scallop; (rounded or flat).
(A) 1. Gingival exposure When diagnosing a ‘gummy smile’ the cause may be skeletal rather than dental, but not always, so we need to consider the following:
• Lips • Teeth • Gingivae • Premaxilla • Maxilla • Combination.
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(B) Lips (high lip line) Measured from the base of the nose, a female lip is usually 20-22 mm and male 22-24 mm, but some lips can be very short indeed. The range of lip mobility measured from rest up to widest smile is usually around 8 mm but may vary dramatically. Equally, an irregular lip revealing excess gum may be due to anatomical variation or lips may be scarred as a result of trauma. Lip abnormalities may be treated surgically or nonsurgically with Botox.
(B) Teeth (short clinical crown) A central incisor is around 10 mm long, however, anatomically shorter teeth due to accelerated wear or erosion, coupled with compensatory passive eruption can increase the gingival display in the smile. Abnormal eruption patterns such as altered passive eruption can also contribute. Short teeth may be treated with crown lengthening surgery and/or reconstructed with direct or indirect restorations.
(B) Gingivae (gingival overgrowth) During growth, teeth will erupt until they contact the opposing teeth (except notably in class II malocclusions) whereupon eruption ceases. The dento-gingival complex (including crestal bone) follows along with the erupting teeth, and stabilises as tooth eruption stops. When skeletal growth finally stops, the gingival soft tissue margins stabilise to a position just coronal to the CEJ, with the bone a further 2.0-2.5 mm apical to the CEJ. However, in a small minority of cases, this tissue stabilisation does not occur, and the gingival soft tissue encroaches upon the clinical crown with the crestal bone settling very close behind, often covering the CEJ. This phenomenon, known as Altered Passive Eruption, produces teeth with short clinical crowns and excessive gingival display, and is particularly common in young people after orthodontics. This condition can be treated by surgically raising the crestal bone back to the ‘normal’ 2.5 mm apical to the CEJ, thereby allowing a conventional dento-gingival complex to reform and re-establish the biologic width. This procedure is often known as a ‘gum lift’ and can sometimes be performed without the need for restorations if cementum is not left exposed.
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(B) Premaxilla overgrowth (dento-alveolar extrusion) Without a cingulum contact in full closure, there is no anterior occlusal stability, and the upper and lower incisal edges will gradually over-erupt. Such ‘passive eruption’ will bring the gingival complex along with the teeth resulting in overgrowth of both upper and lower anterior skeletal segments. This premaxillary overgrowth is typically seen in class II division 2 malocclusions. This results in the classic ‘gull wing’ gingival pattern in upper anterior segments where the tissue crest of the upper centrals appears lower than the laterals (Figure 2). The main aesthetic issues occur in the upper jaw, although in extreme cases, the lower anterior segment is an aesthetic challenge too. This may be treatable with orthodontic intrusion in the early stages, with perhaps maxilla-facial surgery in extreme cases.
(Figure 2) The upper anterior segment can overgrow and display the classic ‘gull wing’ gingival pattern where the tissue crest of the centrals appears lower than the laterals
(B) Vertical maxillary excess In ideal facial proportions, the measurement from the glabella to the base of the nose should be roughly equal to that from the base of the nose to the inferior border of the chin. However, in some cases, the maxilla continues to grow down vertically, thereby increasing the measurement below the base of the nose. In extreme cases, the situation is dealt with by a Lefort 1 procedure coupled with mandibular advancement, obviously well outside of the capabilities of a general dental practitioner.
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(B) Combination cases In reality most patients exhibit varying degrees of each of the above, hence the need to diagnose the cause of the gummy smile before deciding whether treatment is possible in dental practice, whereupon the following protocol (courtesy of Dr John Kois) is useful.
(A) Facially generated smile assessment (‘Face-White-Pink’) If the gingival issues are dentally caused they can often be dealt with by crown lengthening surgery, and the subsequent approach is recommended:
o Establish incisal edge position (in the face) o Decide clinical crown length (white) o Position of post surgical gingival margin (pink).
Face Many patients have asymmetric features, and a portrait photograph will highlight this. A referral to a maxillo-facial surgeon may be offered at this point if appropriate.
White The second step in facially-generated smile design requires a decision of how much tooth should be visible. Establishing the correct upper incisal edge position in the smile is critical with variations due to age and sex being significant.
Pink The laws of smile design also apply to the gingival tissue both in terms of symmetry (irregular smile), and the amount of gingival display shown in a full smile (gummy smile). As in most technical exercises, a step-by-step protocol helps in the decisionmaking process, and when considering gingival aesthetics, it is wise to consider the following.
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(A) 2. Comparative gingival anatomy Symmetrical gingival anatomy is the key here, and crown lengthening (occasionally crown shortening; tissue grafting) is often indicated. The gingival heights of the central incisors should be level with the canines, with the gingival zeniths distal to their long axes. The zeniths of the lateral incisors should be in line with the long axes of the teeth and positioned 0.5.mm-1.0mm more coronally2. Modern technology now allows us to remove gingival soft tissue with ease, and when striving to create the perfect gingival framework for our porcelain, the temptation to remove a small amount of gum tissue around one maverick tooth is often difficult to resist. However, unless we are familiar with the anatomy of the gingival complex, it can be surprisingly easy to produce biologic width violations by such actions.
(B) Anatomy of the gingival complex Whenever alteration of the gingival tissue is planned, a full knowledge of the anatomy of the gingival complex is necessary for success. The dento-gingival complex runs coronally from the osseous crest of the sub gingival bone to the free gingival margin of soft tissue, and falls into three distinct areas with agreed average dimensions.
(B) Connective tissue The first 1.0 mm or so, coronal to the crest of the bone, consists of connective tissue which is attached via collagen fibres to both the crestal bone and the cementum of the tooth (Sharpey’s fibres). This is a very strong attachment and cannot be breached without causing pain to the patient.
(B) Junctional epithelium The middle1.0 mm or so consists of the junctional epithelium which exhibits a weak hemidesmosomal attachment to enamel. This attachment is easily breached by the periodontal probe, and also damaged by gingival retraction cord. However, it rapidly regenerates, often within six days and consequently is rarely permanently damaged3.
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(B) Gingival sulcus The gingival sulcus, perhaps 0.5 -1.0 mm, which is not attached to tooth at all, is the most coronal area. This sulcus depth is measured with periodontal probes during periodontal therapy; however, it is traditionally difficult to record with any accuracy, particularly as the dento-gingival complex is often inflamed, and the base of the sulcus fragile as a result.
(B) Biologic width Knowledge of the above dimensions helps us to ascertain the biologic width which consists of the connective tissue attachment and the junctional epithelium, but not the sulcus. Biologic width will inevitably reform if altered by ill judged gingival surgery or infringed by injudiciously placed restoration margins. Gingival soft tissue is seductively easy to alter, but improving gingival anatomy by arbitrary removal of gingival soft tissue without reference to underlying crestal bone risks violating biologic width. Excised soft tissue may well grow back, often within months, as violated biologic width seeks to re-establish itself hence negating any short-term aesthetic improvements. Since the 1960s it has been widely accepted that biologic width is 2.04 mm but later research has suggested this measurement is an average, and not the same for everybody hence strict rules are difficult to formulate4. When placing dental restorations, the convention states that there needs to be 2.5 mm of distance between any restoration margin and the crest of the underlying gingival bone; the margin should be just sitting within the sulcus. Any closer than 2.5 mm risks infringing ‘biologic width’ resulting in classical red tissue margins around our restorations.
(B) Kois classification Dr. John Kois in Seattle has proposed a more detailed classification of biologic width describing three categories based upon the position of the sub gingival crestal bone relative to the free gingival margin (in healthy gingivae) prior to any treatment5.
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(B) ‘Bone sounding’ The position of the bony crest is located by ‘bone sounding’ whereby the periodontal probe is forced, under local anaesthetic, into the sulcus, (Figure 3) through both the junctional epithelium and the connective tissue until it contacts the crestal bone. Kois suggests bone levels should be recorded mid-facially and interstitially. The interstitial measurement is usually around 1.5 mm greater than midfacial to account for the gingival scallop.
(Figure 3) The position of the bony crest is located by ‘bone sounding’ whereby the periodontal probe is forced, under local anaesthetic, down through the sulcus
(B) Normal crest In 85% of the population the bone is found mid-facially 3.0 mm apical to the gingival margin, and 4.5 mm interstitially. In these cases the anatomy of the gingival complex remains quite stable and will readily re-establish itself if altered. Biologic width is therefore easily infringed if soft tissue is removed without also removing the bone beneath by the same amount.
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(B) High crest In 2% of the population the bone mid-facially is found just beneath the gingival crest, often a result of aberrant eruption patterns. When planning to raise the gingival level by even a small amount, it is mandatory to carry out osseous surgery to avoid biological width infringement. The aim is to surgically change ‘high crest’ into ‘normal crest’.
(B) Low crest When the mid-facial bone is more than 3.0 mm apical to the gingival crest, the final tissue position after surgery cannot be predicted with any accuracy as the tissue will ultimately settle 3.0 mm from the crestal bone, but when? Predictability is improved if soft issue is removed before restorative treatment to change ‘low crest’ into ‘normal crest’. The fact that 13% of the population exhibit this classification introduces an unwelcome degree of unpredictability to proceedings. ‘Low crest’ has also been described as ‘thin’ gingival biotype.
(A) 3. Gingival papillae & embrasures Open gingival embrasures (black triangles) (Figure 4) are always unacceptable aesthetically to patients. Reduction of black triangles requires knowledge of Tarnow’s classic work, and the ability to manipulate both the hard and soft gingival tissue6. Excellent laboratory communication is mandatory when aiming to provide correctly positioned interstitial contact points in our restorations.
(Figure 4) Open gingival embrasures (black triangles) are unacceptable to even the undemanding patient
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(A) 4.Gingival scallop The classical gingival scallop is around 1.5 mm from papilla to papilla. A flatter scallop, often a result of gingival recession is deemed unattractive1 (Figure 5). Maverick tooth position or toothbrush abrasion may contribute to a deeper scallop which also causes concern. Orthodontics or tissue grafting can be of use in such situations, but a flat scallop remains a challenging problem. We need to be aware of all the aspects which impact upon a smile when we assess the patient’s suitability for treatment, and not just the teeth. The ‘gummy smile assessment’ can help decide whether a surgical referral is indicated. If not by following the ‘face-white-pink’ process, coupled with detailed knowledge of patients’ individual gingival anatomy, we should be able to predictably alter gingival levels in practice as required. (Adapted from an article in the International Journal of Cosmetic Dentistry with permission.)
(Figure 5) The classical gingival scallop is around 1.5 mm from papilla to papilla. A flatter scallop, often a result of gingival recession is deemed unattractive
References 1. 3. 4. 5. 6.
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Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent 1984; 51: 24-28.2. Chu SJ, Tan JHP, Stappert CFJ, Tarnow DP. Gingival zenith positions and levels of the maxillary anterior dentition. J Esthet Restor Dent 2009; 21: 113-120. Tarnow DP, Stahl SS, Magner A. Human gingival attachment response to subgingival crown placement. J Clin Perio 1986:13: 563-569. Gargiulo AW, Wentz FM, Orban B. Dimensions & relations of the dentogingival junction in humans. J Periodontol 1961; 32: 261-267. Kois JC. Altering gingival levels: the restorative connection. Part 1: biologic variables. J Esthet Dent 1994; 6: 3-9. Tarnow DP, Magner AW, Fletcher P. The effect of distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontol 1992; 634: 995-996.
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Chapter 2 PREDICTABLE GINGIVAL SURGERY FOR THE GENERAL DENTIST - DR KEN HARRIS Part 2
The rules of smile design are well established, and apply equally to gingival anatomy1 as well as the teeth themselves,2 consequently when providing cosmetic dental treatment, we often need to alter gingival anatomy. The first stage is to assess the big picture, using a ‘gummy smile assessment’ to decide whether maxillofacial surgery and a referral is required or whether simple crown lengthening surgery can be carried out within the dental practice. If so, the next stage is to use a ‘facially generated smile assessment’ (‘face-white-pink’) to assess whether we can produce the ideal result or at least determine where the patient is willing to compromise.
(A) Gummy smile assessment When diagnosing a ‘gummy smile’, 2.0 mm or more visible gum in a full smile is deemed unacceptable,3 we initially need to know if the cause is skeletal requiring significant surgery beyond the remit of dental practice, or a manageable localised dental cause. The first step is to carry out a ‘gummy smile assessment’ of lips, teeth, gingivae, premaxilla and maxilla.
(A) Facially generated smile assessment (‘Face-White-Pink’) If the gingival status is caused by localised dental issues the following ‘facially generated smile assessment’ is carried out to determine if simple crown lengthening surgery will solve the problem.
1. Establish incisal edge position (in the face) 2. Choose clinical crown length (white) 3. Decide position of post-surgical gingival margin (pink).
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Face Step one is to decide the position of the incisal edge position in the face; ideally horizontal, and usually between 50-75% of the inter-labial distance in the ‘EEEE’ smile. Females generally show more teeth than males and the young show more than older patients. White Central incisors are 10-11 mm long, and occasionally short teeth may need lengthening. However, once the incisal edge position is decided the only way to lengthen teeth is to raise the gingival level. Pink Soft tissue margins are easily altered, and it is tempting to improve the gingival anatomy by arbitrary soft tissue removal. However, unless we are familiar with the anatomy of the gingival complex it can be surprisingly easy to produce biologic width violations by such actions.
(B) Biologic width This comprises the distance from the base of the sulcus to the crestal bone, but sulcus depth, and consequently biologic width, is notoriously difficult to record. Equally, the free gingival margin can vary dramatically, in relation to the crestal bone, and therefore cannot be used as an accurate reference either. Kois has attempted to bring some consistency to the problem by classifying patients into three groups (Figure 1) depending on the relationship of the sub gingival crestal bone to the free gingival margin4. The crestal bone position is located by ‘bone sounding’ under local anaesthetic and classified as follows, each with its own surgical guidelines.
(Figure 1) Dr John Kois describes three categories of gingival complex based upon the position of the sub gingival crestal bone (bony crest) relative to the healthy free gingival margin.
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(A) Kois classification Normal Crest; bone 3.0 mm subgingival, stable soft tissue. 85% Cannot alter soft tissue without altering the bone beneath by the same amount. High Crest; bone less than 3.0 mm subgingival, stable soft tissue. 2% Easy to violate biologic width (remove bone to change high crest to normal crest). Low Crest; bone greater than 3.0 mm subgingival, unstable soft tissue. 13% Gingival tissue often recedes stabilising 3.0 mm from underlying crestal bone. (remove soft tissue to change low crest to normal crest). When placing dental restorations, the convention states that there needs to be 2.5 mm of distance between any restoration margin and the crest of the underlying gingival bone. Restoration margins, conventionally sitting 0.5 mm within the sulcus, must not be placed closer than 2.5 mm or may infringe ‘biologic width’, so the aim of crown lengthening surgery is to raise the crestal bone to around 2.5 mm apical to any planned restoration margin.
(A) Case report 1; High Crest In a few patients (2%) the bone is found just beneath the gingival crest mid-facially, often a result of aberrant eruption patterns. For most patients, the gingival crestal bone stabilises around 2.5 mm apical to the cemento-enamel junction (CEJ). However, in a small minority of cases, the crestal bone encroaches upon the clinical crown even covering the CEJ in some cases. This phenomenon, known as Altered Passive Eruption (APE), produces excessive gingival display and teeth with short clinical crowns, particularly common in young people who have had fixed orthodontic treatment. The crestal bone lies just beneath the gingival crest in these cases, and when planning to raise the gingival level by even a small amount it is therefore necessary to raise the bone by a similar amount with osseous surgery if we wish to avoid biological width infringement. The young lady in this case was unhappy with her small teeth, but her main complaint was a gummy smile so an assessment was carried out to see if crown lengthening alone would suffice.
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(B) Gummy smile assessment Lips: Slight irregularity was apparent, but lips were normal length; 22 mm from base of nose, and exhibited average 6 mm mobility. (Figure 2) ACCEPTABLE
(Figure 2) Lips slightly irregular, but normal length; 22 mm with average 6 mm mobility. Anterior segment exhibited conventional gingival levels which discounted dento-alveolar excess.
Teeth: Central incisors were 2.0 mm short of the preferred 10.0 mm. UNACCEPTABLE Gums: Gingival overgrowth with significant exostoses. Bone sounding showed crestal bone to be just 1.0 mm subgingival. Diagnosis; ‘high crest’ caused by APE. UNACCEPTABLE Premaxilla: Anterior segment did not exhibit the classic ‘gull-wing’ gingival pattern of short central incisors compared to the laterals found in dento-alveolar excess. ACCEPTABLE Maxilla: Lower facial third measurably longer than mid third suggesting vertical maxillary excess, but given the option of significant facial surgery she agreed to accept the limitations of her condition. ACCEPTABLE (just about). A combination of causes contribute to this gummy smile, but following composite trial ‘mock up’ and the patient’s acceptance of compromise, it was felt this gummy smile could be dealt with by crown lengthening surgery alone, so a detailed smile assessment followed.
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(B) Facially generated smile assessment (‘Face-White-Pink’) Face: Her upper incisal edge was acceptably positioned at 60% of the inter-labial distance of ‘EEEEE’ smile. White: Her central incisors were short (8.0 mm) so needed to be lengthened by 2.0 mm to the preferred 10.0 mm. Pink: Her incisal edge position was correct so could not be lengthened in the smile. The extra 2.0 mm length would be found by raising the gingival level by 2.0 mm. Our aim was to have both central incisors with their incisal edges at the correct position in the smile (FACE), and following the proposed crown lengthening of all eight upper anteriors, they would both be 10 mm long (WHITE), with the gingival heights equal and balanced in the smile (PINK). Bone sounding suggested bone around 1.0 mm beneath the gingival crest, confirmed by raising a flap. Consequently ‘high crest’ due to APE was diagnosed.
(B) Crown lengthening surgery Bone was therefore raised 2.0 mm to create ‘normal crest’ (3.0 mm subgingivally), leaving the CEJ a ‘normal’ 2.5 mm from the bony crest. It is worth mentioning that in many cases of APE (high crest) it is possible to raise the bone level without exposing roots hence without the need for restorations, a procedure known as a ‘gum lift’. However, in this case a further 2.0 mm of crown lengthening (4.5 mm in total) was needed to allow new margin placement 2.0 mm more apically without violating biologic width. The bulky exostoses would also be reduced and refined to create a more pleasing morphology.
(B) Osseous surgical steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
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Initial sulcular Incision with blade (Swan Morton 15) Raise full thickness flap (molar to molar) Re-model bony exostoses (7009 carbide bur 027; Brasseler) Remove excess bone by hand (Wedelstaedt Chisel ; Hu Friedy) Confirm 2.5 mm from planned restoration margin to new bone level. Refine the marginal bone shape (856 diamond bur 016; Brasseler) Relay flap and re-contour papillae with scalpel Suture; (Vicryl 5.0 or 6.0) Establish haemostasis and gingival position Re-contour entire tissue anatomy with electrosurgery.
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Medication: prophylactic ibuprofen; 400 mg pds starting 24 hours before surgery, continued 48 hours after surgery.
(B) Post-op instructions • • • •
No ‘lip lifting’ for 2 weeks Do not brush at all for 3 days Do not brush surgical area for 2 weeks Use Mouthwash (gently) B.D. for 2 weeks
• Resume normal diet when comfortable.
(B) Aim of surgery Crestal bone to be 2.5 mm apical to CEJ (if no restorations are planned) or from restoration margin (if restorations planned), with the margin 0.5 mm within the sulcus. Three months post-operatively healing was complete (Figure 3) and ten upper anteriors were prepared for porcelain restorations with the definitive margins placed 0.5 mm within the new gingival sulcus, and 2.5 mm coronal to the newly created crestal bone level thereby avoiding biologic width infringement. Six lower anterior veneers were provided earlier at the patient’s request. Three years following osseous gingival surgery and restoration placement there was little sign of recession or biologic width infringement (as planned) (Figure 4) with the smile still conforming to the ‘ideal’ facial proportions.
(Figure 3) Three months after osseous surgery
(Figure 4) Three years after significant osseous
the gingivae have stabilised and matured.
gingival surgery and restoration placement,
Provisionals are still present, and are now ready
there is little sign of recession or biologic
for definitive restorations.
width infringement.
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(A) Case report 2; Normal Crest In 85% of the population the bone is found mid facially to be 3.0 mm apical to the tissue margin, and 4.5 mm interstitially4. If our new restoration margins are moved apically, biologic width will be violated as the margin will be placed closer to the unaltered bone beneath. Hence, we cannot raise the soft tissue without also raising the crestal bone beneath by a similar amount. In this case a 24 year-old lady was referred to have two central incisor crowns replaced. She explained that her centrals seemed small and wished them to be longer, but was unsure how long.
(B) Facially generated smile assessment (‘Face-White-Pink’) She did not exhibit a ‘gummy smile’ so we carried out the ‘face-white-pink’ assessment.
Face: It was decided her face was symmetrical, but the incisal edge position could be lengthened by 1.0 mm.
White: Measuring the clinical crown length of the centrals revealed them both to be 8 mm (Figure 5) so 2.0 mm extra was needed for the preferred ‘age-appropriate’ 11 mm length.
Pink: However, as the incisal edge position was to be lengthened by only 1.0 mm to be correct in the face, the extra 2.0 mm would be found by raising gingival level.
The aim was to have both central incisors with their incisal edges 1.0 mm longer at the correct position in the smile (FACE), and following the proposed 2.0 mm crown lengthening, they would both eventually be 11 mm long (WHITE), with the gingival heights equal and balanced in the smile (PINK). Bone sounding revealed bone 3.0 mm beneath the gingival crest, so a ‘normal crest’ was diagnosed. Tempting as it may be to just remove some soft tissue, in order to alter gingival levels without violating biologic width the gum level cannot be raised in a ‘normal crest’ case without also raising the bone level by the same amount, so osseous crown lengthening was necessary in order to allow us to safely place the crown margins 2.0 mm more apically.
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(B) Crown lengthening surgery The soft tissue level of both upper central incisors was initially raised by 2.0 mm using electro-surgery. The old crowns were then removed and the restoration margins also needed moving 2 mm apically. Well-fitting highly polished provisional restorations were then fitted. This may appear to be a deliberate violation of biologic width as the new crown margins were now only 1.0 mm from the crestal bone beneath; however, osseous crown lengthening surgery was commenced immediately after the provisionals were fitted. The aim was to raise the bone to be 2.5 mm apical to the new restoration margin; the margins of the provisionals were used as the reference. A full flap was raised from the first premolar to first premolars (without relieving incisions) to expose the crestal bone, which was closer than 2.5 mm to the new provisional restoration margins thereby infringing biologic width. To re-establish ‘normal crest’ biologic width, crestal bone was carefully removed (ensuring the scalloped anatomy was not lost) positioning the bony crest 2.5 mm apical to the new provisional restoration margins and 3.0 mm from the free gingival margin. Crestal bone may ‘rebound’ after surgery, so removing an extra 0.5 mm at this stage is a sensible option. The flap was re-laid, sutures placed, and the patient given written instructions on how to care for the surgical site, which included no brushing or lip lifting for two weeks. After two weeks the sutures were removed and normal oral hygiene was commenced.
(B) Aim of surgery The aim was to create crestal bone to be between 2.0 mm and 2.5 mm apical to CEJ or planned restoration margin, with the margin 0.5 mm within the sulcus. Three months later the gingivae had stabilised, free gingival margin had re-established itself at 3 mm from the crestal bone and definitive crown preparations were completed with margins 2.5 mm coronal to crestal bone (crestal bone had actually regrown 0.5 mm) and 0.5 mm into the sulcus thereby leaving biologic width free from infringement. The two cord retraction technique moves soft tissue coronally, away from definitive restoration margins for ease of impression taking. Restoration margins may appear too coronal, but gingivae will resolve back to 3.0 mm from crestal bone once cords are removed. Trust the bone position and resist the temptation to move prep shoulder further apically.
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One year later the anterior gingivae conformed to conventional smile design proportions as planned (Figure 6), and around the restorations appear pink stippled and healthy. There was no significant recession nor any sign of biologic width infringement (as planned) (Figure 7).
(Figure 6) One year later the anterior gingivae conform to conventional smile design proportions, as planned.
(Figure 7) One year later the gingivae around the restorations appear pink stippled and healthy with no significant recession nor any sign of biologic width infringement, as planned.
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(A) Summary Once established that the gingival issues are produced by localised dental causes, it can be within the skill set of general dentists to provide simple and predictable crown lengthening surgery in the practice environment. (Adapted from an article in the International Journal of Cosmetic Dentistry with permission.)
References 1. Chu SJ, Tan JHP, Stappert CFJ, Tarnow DP. gingival zenith positions and levels of the maxillary anterior dentition. J Esthet Restor Dent 2009; 21:113-120. 2. Chiche GJ, Pinault A. Esthetics of Anterior Fixed Prosthodontics. Quintessence Publishing, 1994. 3. Tjan AH, Miller GD. The JG some esthetic factors in a smile. J Prosthet Dent 1984; 51: 24-28. 4. Kois JC. Altering gingival levels: the restorative connection. part 1: biologic variables. J Esthet Dent 1994; 6: 3-9.
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Chapter 3 TOOTH WHITENING AND BLEACHING TREATMENT FOR UNDER 18S AND SENSITIVITY ISSUES
There has been some confusion in recent years over the legality of tooth whitening and bleaching for patients under 18 years of age. Additionally, there have been questions over tooth sensitivity post-treatment. Here we provide an update on both issues. Discolouration of teeth is caused due to a range of reasons and the most important starting point in rectifying the matter is to establish the aetiology so that the correct procedures can be agreed and provided for the patient. Usually a dentist is the person best placed to diagnose this, although other dental care professionals such as dental hygienists and therapists can provided treatment under a dentist’s supervision. The legal situation over tooth whitening and bleaching can be confusing but the law is clear in at least some respects. Applying materials and carrying out procedures designed to improve the aesthetic appearance of teeth is the practice of dentistry, as governed by the Dentists Act 1984. This was confirmed by the High Court in May 2013 and anyone who practises dentistry illegally risks being prosecuted by the GDC in the criminal courts. A distinction should be made between ‘bleaching’ and ‘whitening,’ since many over-the-counter products make the claim of ‘whitening’ to rival dentists’ bleaching treatments. ‘Whitening’ is only removing surface stains, but ‘bleaching’ changes the inherent colour of the tooth.
(A) Legal situation Historically, the legal position in Europe relating to tooth whitening has been confusing but the relevant current legislation, the UK Cosmetic Product (Safety) (Amendment) Regulations 2012 states that:
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• Products containing or releasing over 0.1% hydrogen peroxide cannot be supplied
directly to the consumer
• Products containing or releasing between 0.1 and 6% hydrogen peroxide can only
be sold to dental practitioners
• Products containing or releasing between 0.1 and 6% hydrogen peroxide can
only be made available to patients following an examination by a dentist with the
first episode of treatment being provided by a dentist, or by a hygienist or therapist
under supervision of a dentist (i.e. within the same dental setting) after which they
can be supplied to the patient to complete the cycle of use
• Products containing or releasing over 0.1% cannot be supplied to persons under
18 years of age
• It is illegal to supply any product containing or releasing over 6%
hydrogen peroxide
• The restrictions set out above apply equally to internal tooth whitening treatments. Carbamide peroxide (CP) based whitening products are covered by the regulations as they release hydrogen peroxide when applied. Products containing 10% carbamide peroxide will release approximately 3.6% hydrogen peroxide. Therefore approximately 16.62% carbamide peroxide will release hydrogen peroxide at the legal limit of 6%. The ethical dilemma that this ruling created in relation to under-18s with discoloured teeth was that tooth whitening or bleaching is non-invasive whereas other, often more traditional, treatments using restorative dentistry are invasive and start a young person on the road to a need for life-long restorative treatment. For example, crowned teeth may lose vitality and this may be more significant for adolescent patients due to the larger pulps. Even less destructive treatment such as ceramic veneers has a finite life span with the most frequent complications being marginal discolouration and loss of marginal integrity. The signifi¬cance of these failures being compounded by the younger age of these patients. After representations from the dental profession, the General Dental Council provided a revised position statement stating that: ‘Products containing or releasing between 0.1% and 6% hydrogen peroxide cannot be used on any person under 18 years of age except where such use is intended wholly for the purpose of treating or preventing disease,’ thereby helping to solve the ethical dilemma.
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In general, tooth discolouration can be the result of the natural darkening of the teeth through ageing, extrinsic staining, genetically discoloured teeth, drug interactions such as tetracycline staining, trauma or caries, to mention just a few. In children and adolescents the causes are more usually due to enamel conditions, white lesions, white markings and white flecks, brown, orange and yellow staining, coronal defects, molar incisor hypomineralisation (MIH), hereditary factors, trauma or systemic diseases with dental effects (diseases of the liver, kidneys or haemorrhagic diseases).
(A) Psychological trauma One of the main reasons for treating discolouration in young patients is the psychological trauma that can follow from teasing and peer pressure to conform. Negative self-image due to a discoloured tooth or teeth can have serious consequences on adolescents such that treating the discolouration may aid in preven¬tion of bullying and associated or resulting mental health conditions such as depression and suicide. In addition, underlying enamel quality or quantity defects commonly associ¬ated with the discolouration renders the classification of disease appropriate. Generally the combination of bleaching using custom tray-applied 10% carbamide peroxide is the basis for successfully treatment. A close fitting, non-reservoir, custom tray is recommended for these patients to minimise the amount of bleaching material. This is due to the additional urea having benefi¬cial cariostatic effects and an antibacterial effect which have been shown to improve gingival scores. Furthermore carbopol, a slow oxygen releasing agent present in 10% CP, results in a steady slow release of oxygen making the process sustainable through the night. Haywood has recommended commencing bleaching in adolescent patients at ages 10–14, however, this should still be assessed on an individual basis. A range of enamel conditions result in discol¬ouration and can be effectively treated with bleaching. These include but are not limited to amelogenesis imperfect, post traumatic opacities, idiopathic opacities, chronological hypomineralisation and white markings or puffs on the lines of enamel maturation.
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(B) White lesions White spot lesions have numerous aeti¬ologies, some are chronologic in nature and appear as white lines that follow deposition of enamel such as amoxicillin or high temperature defects. Bleaching treatment whitens the surrounding or background enamel of the white lesion, which reduces the contrast of the defect. It has also been suggested that elevation of salivary pH and flow rates following carbamide peroxide application may alter the refractive index of the white spot by promoting remineralisation. Isolated white blemishes can be effectively treated but this may need to be followed by microabrasion or resin infiltration for completeness. Original white spots may become more noticeable during bleaching treatment due to the bleaching material penetrating the weakest part of the enamel first, which is often the white spot. This commonly occurs during the first few days and is referred to as the ‘splotchy stage’ of bleaching. The patient should be encouraged to persevere with the bleaching treatment to allow time for the bleaching material to dissipate equally throughout the enamel and allow efficient lightening of the background. White spots that are present following com¬pletion of bleaching treatment may become less noticeable two weeks post treatment, as oxygen dissipates from the tooth and espe¬cially the white spot defect.
(B) Brown and yellow staining Isolated yellow and brown stains result from numerous aetiologies such as fluorosis. Brown stains can be removed 80% of the time by bleaching alone and as such, should be the first line of treatment for such conditions. Cases where bleaching does not completely remove brown staining should utilise additional microabrasion and bonding procedures.
(B) Coronal defects These can present as discrepancies in tooth shape, size, position, proportion, shade and number. Bleaching often forms an integral part in management of aesthetics and can reduce the need for invasive restorations. This perfectly justifies the use of bleaching, bonding and orthodontics as compared to the use of porcelain veneers and crowns. Additionally, the use of bleaching to lighten the value of a tooth, can reduce the requirement for reduction required for indirect restorations to mask discolouration. This enables the use of more translucent, multi-chromatic restorations,
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thus improving the outcome. Validation of bleaching in such circumstances is particularly noted in severe tetracycline discolouration. Bleaching material can also improve the longevity of restorations in the anterior region, which may be failing due to exposure of restorative margins or due to discoloura¬tion of underlying tooth structure. Although bleaching materials have no effect on porcelain, they can successfully penetrate and bleach tooth structure beneath porcelain veneers. Further restorative treatment should be delayed for at least two weeks following the completion of bleaching as bond strength to composites is reduced by 25–50% during bleaching before returning to normal. This results from oxygen, in the enamel because of the bleaching material, inhibiting the set of resin tags in etched enamel. Over a two-week period, the oxygen dissipates out of the enamel thus returning bond strength to normal. Oxygen present in enamel can also lead to incorrect shade taking and thus, shade taking should also be delayed by at least two weeks and up to six weeks in cases when exact shade matching is at a premium.
(B) Molar incisor hypomineralisation (MIH) MIH lesions often present as demarcated enamel opacities ranging in colour from creamy white to yellow/brown. It is well documented that children with MIH may suffer from a reluctance to smile or a lack of confidence due to the appearance of their teeth and thus may require treatment early to prevent this. Bleaching has been reported to produce some improvement in MIH patients, especially with the yellow brown discoloured defects. Teeth affected by MIH show inflamma¬tory changes within the pulp and as a result, sensitivity is more common among this group of patients and thus prior sensitivity prevention is required.
(B) Hereditary factors Several hereditary conditions can lead to white blemishes and white discolouration of teeth some of which can be generalised and bleaching has been shown to be success¬ful in the minimal invasive treatment of these, especially amelogenesis imperfecta and dentinogenesis imperfecta. This is extremely beneficial for such patients as preservation of existing enamel is crucial in such conditions. Sensitivity may also be an issue for patients with hereditary defects and adequate sensitivity prevention is required.
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(B) Traumatised/non-vital teeth Discolouration associated with trauma or loss of tooth vitality can be very severe and range in colour from yellow, black, brown, purple and grey. Haemorrhage of the pulp is the most common cause of discolouration due to blood entering the dentinal tubules and then decomposing causing a deposit of chromo¬genic blood degradation products. These can also result from pulp necrosis. Calcific metamorphosis may also result in discolouration and is commonly seen as early as three months after traumatic tooth injury. It is characterised by the deposition of hard tissue within the root canal space and a yellow discolouration of the clinical crown. Discolouration may result from iatrogenic induced causes following treatment of the non-vital tooth. These include: . Root canal cement or gutta percha in the coronal portion of the access cavity . Remnants of the pulp and pulp horns following access cavity preparation60 . Combining sodium hypochlorite (even at low concentrations) and chlorhexidine irrigation which may result in formation of brownish-red precipitates. It is essential that iatrogenic causes are appropriately identified and managed before commencing with bleaching treatment. Discoloured teeth with a history of trauma should undergo vitality testing and if no previous radiographs have been taken, appro¬priate radiographic assessment should be undertaken to ensure appropriate treatment is undertaken prior to and post bleaching. A single discoloured tooth which retains vitality, for example in calcific metamorphisis, should not have elective root canal treatment undertaken. These patients should rather be provided with a ‘single tooth’ bleaching tray and bleaching agent applied externally, solely to the targeted discoloured tooth. This is because externally applied bleaching material diffuses readily through teeth and uniformly changes dentine shade throughout, regardless of depth.
(B) Systemic diseases Numerous systemic diseases can lead to discol¬ouration including but not limited to premature birth and low birthweight, diseases of the blood and neonatal kidney and liver disease. The discolouration experienced as a result of systemic disease is most likely to be intrinsic in nature and, as such, requires prolonged bleaching. Antibiotics used to treat systemic infec¬tions, such as amoxicillin, ciprofloxacin and tetracycline can also lead to discolouration of teeth, the latter sometimes requiring up to six months of prolonged custom tray-applied 10% CP bleaching to ensure a satisfactory effect. Professional Dentistry
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All risks and benefits associated with bleaching must also be discussed before commencing treatment and consent appro¬priately obtained. It should be expressed that further restorative treatment may be required post bleaching, for example microabrasion, resin infiltration and composite bonding where large enamel surface defects exist.
(A) Tray design for under-18s Although there were initially concerns that wearing beaching trays could impede tooth eruption, current orthodontic opinion is that this is not the case and they can be safely used for the short time required for bleaching. The best tray design for under-18s would be vacuum formed, custom made, non-reservoir, close fitting trays made from 0.35 mm soft acrylic. Some clini¬cians prefer to scallop the tray to avoid any soft tissue contact of the bleaching material with the gingiva. However, extreme care is needed in the tray fabrication to avoid jagged edges which may discourage compliance. There is a greater chance of leakage of material if not well made, so only a minimum of bleaching material should be inserted into the tray. Reservoirs or spacers have been shown to be unnecessary. A non-scalloped tray design tends to seal better against the soft tissue, and be more com¬fortable to wear. Although it would allow the 10% carbamide peroxide to contact the tissue, the CP material is made to contact tissue. The original intent of 10% CP was as an oral antiseptic for wound healing of soft tissue, so generally there is no negative consequence for tissue contact. Custom trays should be worn for a minimum of two hours under parental supervision. Either daytime or overnight wear is accept¬able, however, as CP can remain active for up to ten hours, overnight use is recommended for maximum benefit. In general children with malformed or dis¬coloured teeth are very motivated to remove the defect and are keenly compliant especially under parental supervision.
(A) Managing sensitivity from bleaching treatment Sensitivity from bleaching treatment is common and this must be explained to all patients before undertak¬ing treatment. In the majority of bleaching patients, history of sensitivity is the greatest predictor for sensitivity during treatment and as such a detailed sensitivity history is required on initial patient examination. Prevention may be in the following forms:
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• Brushing with a desensitising toothpaste containing potassium nitrate for two
weeks before commencing treatment and during bleaching treatment
• Wearing of the bleaching tray without bleaching agent for two nights
before treatment
• Wearing of bleaching trays with desensitis¬ing agent for two nights before
treatment. Ideally this would be potassium nitrate con¬taining, however, other
products such as ACP-CPP may be beneficial. Regardless of product used, it is
essential this is sodium lauryl sulphate (SLS) free, as SLS may result in
gingival irritation
• Alternating nights between bleaching agents and desensitising agents. This
can be balanced with the degree of sensitivity, e.g. in severe cases, one night of
bleaching may be followed by three nights of desensitising agent use
• Using a low concentration bleaching agent, for example a 5% bleaching agent.
This is beneficial as bleaching sensitivity is concen¬tration dependant
• Using a bleaching agent containing potassium nitrate and fluoride. If sensitivity is experienced during treatment, two approaches can be undertaken. A passive approach could be taken, whereby the frequency of application of CP or wearing time is reduced. Alternatively, an active approach, employing the use of desensitising agents either in the custom tray or applied during brushing (as described in prevention). Sensitivity resulting from wearing of the bleaching tray alone, as mentioned previously, is commonly associated with the mechanical pressure of an improperly fitting tray, from occlusion on the tray, and is more common with harder bleaching trays. It is therefore essential that an accurate impression is made and a soft tray is used to prevent or alleviate the tray associated sensitivity.
(A) Extended tray vs non-extended To test the issue of tray design and sensitivity one study aimed to compare the effect of extended margin and conventional bleaching trays on tooth bleaching and tooth sensitivity. Twenty subjects (18–56 years) were investigated in a split arch design clinical study that was conducted in a general dental practice. Each subject received a custom made bleaching tray and 10% carbamide per¬oxide gel. The bleaching trays had the borders extended 5 mm beyond the gingival margins on the right side and finished just at the gingival margin on the left side. Shade change and
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tooth sensitivity were the primary outcomes studied and analysed in this study. The shade of the six upper and lower anterior teeth was assessed using a value-ordered shade guide before, one week and two weeks after treatment. Sensitivity was selfassessed using a visual analogue scale (VAS) at the end of the first and second weeks of the study. At the end of week two, the mean shade change was 5.01 and 5.10 for teeth covered by extended and non-extended tray design, respectively. The mean VAS sensitivity scores for teeth covered by extended and non-extended tray design were 0.96 and 0.66 respectively. There was no significant sta¬tistical difference between the two designs at any assessment point with regard to shade change and sensitivity (p >0.05). It can be concluded that an extended tray design confers no superior effect in terms of the whitening outcome achieved or in reducing levels of sensitivity. Thus, both tray designs can be used depending on a dentist’s personal preference.
Further reading Greenwall-Cohen J, Greenwall L, Haywood VB, Harley K. Tooth whitening for the under-18-year-old patient. Br Dent J 2018; 225: 19-26. Haywood VB, Sword RJ. Tooth bleaching questions answered. Br Dent J 2017; 223: 369-380. Morgan S, Jum’ah AA, Brunton P. Assessment of efficacy and post-bleaching sensitivity of home bleaching using 10% carbamide peroxide in extended and nonextended bleaching trays. Br Dent J 2015; 218: 579-582.
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STEP 1
Advantages for the Clinician
Anesthetizing the attached gingiva
• When anesthetic solution is delivered into cancellous bone, excellent pulpal anesthesia is obtained, even in patients with irreversible pulpitis or hypersensitive teeth.
STEP 2 Perforating the cortial plate
• Intraosseous Anesthesia saves valuable time because there is no delay between injection and effect. Work on the tooth can commence in less than 30 seconds after the injection.
STEP 3
Advantages for the patient
Inserting the injection-needle in the perforation
• The patient experiences minimal pain during the dental procedure itself, and on leaving the dental office there will be no balooning of soft tissues and a much lessened feeling of numbness.
CONTACT DETAILS United States:
U.K. or Republic of Ireland:-
Fairfax Dental Inc., 2937 SW 27 Ave, Suite 102, Miami, FL 33133. Tel: 305-476-7180 Fax: 305-476-7183 E-mail: fairfax@stabident.com
Fairfax Dental Ltd., Hill Place House, 55a High Street, London SW19 5BA Tel: 020-8947-6464 Fax:020-8947-2727 Email: fairuk@stabident.com
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Chapter 4 FACIAL AESTHETICS IN DENTISTRY
Botox has become a familiar term in dental circles in recent years as the popularity of the techniques of its use for facial aesthetics has grown. Here we look at recent updates and developments. A smile is an essential human characteristic in communication and social interaction. As a central aspect of dental care, the smile has for many years concentrated on the teeth alone as the important element. More recently the focus has shifted to include the lips and facial appearance so as to provide an overall impact in what has come to be known as smile design and the delivery of non-surgical facial aesthetics (NSFA). This is a growing field in aesthetic medicine that is practised by a range of clinicians including doctors, dentists and registered prescriber nurses and is an industry estimated to be worth over £3 billion in the UK alone. Central to this wider brief has been the application of the substance commonly referred to as Botox which is botulinum neurotoxin A (BT-A) a commercially available preparation of a neu¬rotoxin produced by the bacterium Clostridium botulinum. When injected into muscle tissue, BT-A induces a semi-permanent inhibition of muscle fibre contraction. Such prepa¬rations of BT-A were initially approved for a number of medical indications; more recently, the effect of the drug has been harnessed for cosmetic applications in the upper face, in the reduction of age-associated rhytids (wrinkles), and is well-established as a safe and effective clinic-based treatment1.
(A) Pharmacology and physiology Neuromuscular transmission is usually achieved when the neurotransmitter acetylcholine is transported to presynaptic terminals (the nerve endings) in membrane vesicles which fuse with the cytoplasmic membrane leading to release of the neurotransmitter into the neuromuscular junction. This is the process which administra¬tion of botulinum toxin blocks. From here it diffuses across the synaptic gap to bind with the nicotinic cholinergic receptors on the postsynap¬tic membrane of the muscle surface. The effect of preventing neurotransmission at motor nerve endings is to temporarily denervate and hence relax the muscles local to the injection site2.
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It is not yet known how the toxin is metabo¬lised or otherwise eliminated from nerve endings. Indeed, there remain some consider¬able gaps in knowledge of the mechanism for absorption, distribution, metabolism and elimination of the toxin. However, it has been postulated that the toxin binds irreversibly to the synaptic nerve endings, and is then metabo¬lised over the following months. It is likely that the protein degrades and is removed by the body and the pharmacological effects then cease. There is no evidence of muscular atrophy following repeated botulinum toxin injections over long periods of time, but there have been incidences of resistance by antibody develop¬ment. Certainly, with botulinum toxin treat¬ments being so common, it follows that with greater numbers of treatments the number of incidents of immunity should rise but has been reported to be rare. There is also no evidence of hypersensitivity developing but potential behavioural modification whereby the patient learns to avoid ‘undesirable’ facial movements may occur. The therapeutic scope of the toxin is quite varied as it has been used cosmetically since 1989. In facial aesthetic treat¬ments the toxin works by causing weakening of the underlying muscle which exhibits habitual contraction, causing relaxation and thus flattening of the overlying skin. The use of botulinum toxin for treatment of facial rhytides is ‘off-label’ (an unlicensed but well accepted use) aside from glabellar lines and thus should be explained to the patient at point of consent. Paresis of the muscle generally occurs after 3–4 days post-injection, and is clinically evident for approximately 2–3 months, after which there is gradual return of muscle function. It has other non-cosmetic indications including migraines and hyperhidrosis. Botox is most commonly supplied in vac¬uum-dried form, and one vial can contains 50, 100 or 200 units (u). Reconstitution of the vial is necessary before administration. Manufacturer recommendations for the 100 units involve reconstitution of the entire vial with 2.5 ml of sterile 0.9% sodium chloride solution for injection, to produce a concentra¬tion of 4u/0.1 ml.11 The reconstituted solution should be used within 24 hours of opening; during this time, the reconstituted vial must be stored at a temperature of 2 - 80C. The drug is administered using a tuberculin syringe with smallgauge needle, or other equivalent equipment.
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(A) Smile aesthetics (B)Perioral ‘smokers’ lines Perioral rhytids, known colloquially as ‘smoker’s lines’, are a result of contraction of the lips to maintain a closed posture. These present as superficial skin wrinkles radiating outward from the vermillion border. Smokers’ lines tend to occur in patients where active lip pursing is required (for example, musicians or chronic smokers), or where lips are pursed in the resting state. Abnormal incisor inclination or position may theoretically produce this requirement of muscle contraction for lip competence, and this requires diagnosis before BT-A injection to avoid potentially incompetent lips. The orbicularis oris muscle can be easily identified by palpation, while asking the patient to purse the lips. Injections should be placed peri-orally, approximately 5 mm concentric to the vermillion border, at a depth midway between the outer surface and inner mucosa of the lip. A similar distribution of injections and dose of BT-A is utilised as for lip lengthening. The philtrum and commissural areas should be approached with caution to avoid flattening of the Cupid’s bow or spread of toxin into the risorius muscle.
(B) Thin upper lip A thin upper ver¬million or short clinical lip length may be a presenting complaint, or a consequence of orthodontic/orthognathic treatment. A functional loss of lip length may occur as a result of the resting contraction of the innermost portion of orbicularis oris, causing an inversion of the lips. In these cases small, concentrated doses of BT-A have been injected superficially along the vermillion border of both lips to increase the show of vermillion. As with smokers’ lines, care should be taken to avoid injections within the philtrum region. Additionally, excessive lip lengthening reduces tooth show and may produce an ‘aged’ appearance so low doses should be administered to avoid adverse aesthetic changes. Doses of up to 2 u, across four injection points across the vermillion border, have been reported to provide a significant pseudoeversion and increase in lip length.
(B) Protrusive or dimpled chin Chin shape and symmetry can have a marked effect on overall facial harmony, and is a major determinant of facial shape. An aesthetic, youthful chin in women is small and narrow, with a single point of light reflection. From a lateral profile, the female chin should contribute relatively less to the total soft tissue profile than in men,
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contributing to a convex mean facial profile. The aesthetic male chin by contrast is broad, large, can be dimpled, and relatively more protrusive, contributing to a straighter facial profile.
A complete assessment of chin aesthet¬ics should involve evaluation of the skeletal, dental, and soft tissue contributions to lower face morphology or dysmorphology. A com¬prehensive assessment is necessary, to predict both the impact and success of soft tissue mod¬ification with BT-A. Class I dentofacial patients are generally suitable for BT-A treatment of mentalis; class II or III patients are better served with a comprehensive orthodontic or surgical approach. While the clinical approach is similar, three indications exist for injection of BT-A into the broad, thick mentalis muscle: • Deep labiomental fold due to soft tissue relationships. The labiomental fold refers
to the visible depression that exists between the lower lip and the chin, and is best
observed on profile view. Labiomental fold depth is highly dependent on occlusal
vertical dimension and lower face height, and is normally 4 mm in men and 6 mm
in women. A prominent chin or lower lip can alter the labiomental fold and this
can be a presenting complaint of the patient
• Excessive muscular soft tissue prominence of the chin. Presence of a strong
mentalis muscle can produce a broad, prominent, masculine chin, and is
associated with an unaesthetic, aged appearance in women
• Presence of mentalis rhytids, or ‘Peau D’Orange’ chin.
For a reduction in soft tissue prominence or deep labiomental folds, a high dose (5–10u) is recommended, to produce a slow atrophy of the muscle. Injections placed deep into the muscle, near the origin of the muscle at the anterior mandible, may reduce risk of inadvertently injecting into more superficial muscles of expression. Post injection massage is sometimes suggested to help promote spread of toxin throughout the large muscle. Reduction of the size of mentalis may take one to two months before the desired effect is noted. For removal of rhytids, total doses reported have varied from 3–6 u and methods described are single, more superficial injections in each band of the mentalis. The muscle should be palpated before injection and injection points should be aimed toward the lowest portion of the muscle. This is to prevent toxin spread to the orbicularis oris, which can result in lower lip incompetence. Injecting too laterally may cause inadvertent paralysis of the depressor anguli oris muscle, and potentially create facial asymmetry.
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(B) Smile curvature The bilateral depressor anguli oris (DAO) muscles are responsible for lowering the corners of the mouth, contributing to the ‘mouth frown’ facial expression. The presence of hyperfunctional DAO muscles can cause an unaesthetic lowering of the corners of the mouth, and secondary rhytids in the area can produce an aged appearance. Some individuals activate the DAO muscles while smiling, which can flatten the upper and lower lips. The aesthetic maxillary arch should form a convex shape, with the central incisors at the lowest point in the arc, with progressive elevation of the incisal edges of the lateral incisors followed by the canines. An aesthetic lower lip should match this arc. Successful soft tissue modification to produce a more consonant smile is therefore dependent on having correctly positioned maxillary incisors. To identify the DAO muscles, instruct the patient to pull the corners of the mouth downward. The muscle will be palpable inferior and lateral to the oral commissures. Particular care should be taken to identify this muscle, to avoid accidental injection into the orbicularis oris, buccinator, or mentalis muscles. As with all toxin injections, but of particular importance to DAO treatment, palpation and correct identifi¬cation of the muscle and its anatomy is essential before commencing injections. Branches of the facial vein can be easily perforated in this region, causing significant haematoma of the lower face. Spread of toxin to surrounding muscles can lead to marked asymmetry and loss of oral function, and so care should be taken when approaching this area. If the DAO muscles are overparalysed, patients may experience obvious difficulties with mastication and food packing in the lower vestibule, despite a good cosmetic result. A dose of 2–5 u BT-A is suitable for this area, at moderate depth, injected in two points diagonally along the direction of muscle fibres.
(B) Excessive gingival display and dental camouflage Excessive gingival display, or ‘gummy smile’ has been previously defined as an exposure of greater than 3 mm of gingiva on smiling which appears to be of greater predominance in women than men, who tend to have a lower smile line. A number of anatomic factors are of influence including lip length, crown length, vertical maxillary excess, and oral muscular behaviour. Use of BT-A is indicated when perioral muscle hyperfunction is responsible for the gingival display, but may be used to mask other causes of gummy smile. Techniques used for reduction of excessive gingival display can also be used to camouflage defective temporary or permanent prosthodontic restorative margins, irregularities in the gingival contours, and gingival black triangles in the maxillary arch.
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Common practice in the management of gummy smile with BT-A has been a single injection into the ‘Yonsei point’, a surface landmark area lateral to the ala where the levator labii superioris, levator labii superioris alaeque nasi, and zygomaticus minor converge. Generally, a dose of 2–5 u at this point has been sufficient to cause improvement in the appear¬ance of a gummy smile.
(A) Long-term management and safety Procedures involving BT-A for smile modifica¬tion require a comprehensive understanding of regional anatomy of the lower face. BT-A is technique sensitive and is associated with several complications and adverse outcomes. It is difficult to achieve a perfect result and managing patient expectations is a key component of the cosmetic practitioner. However, when used for cosmetic rather than therapeutic purposes, complications are generally mild and short-lived. Common adverse outcomes include asymmetry, over-correction, under-correction and perioral droop. More commonly, patients may be satisfied with the results at rest but dynamic results may be less satisfactory because of the secondary functional consequences of perioral muscle paralysis. There also exists the potential for more serious functional deficits involving the airway and processes of mastica¬tion and swallowing, when incorrectly applied to the orofacial region. Repeated use of BT-A for cosmetic purposes, even in cases of varying dosages, shows no increase in adverse outcomes, with no changes in safety profile. Appropriate administration by well-trained practitioners of BT-A should result in few undesirable side effects, and in the case of an adverse outcome these are usually mild. Careful case selection should be exercised when using BT-A for smile modification. Consideration should be given to the mental well-being of the patient, including their psychological stability, their expectations and fears of the treatment. It is important to assess muscle dynamism, balance, and symmetry before injection and when deciding on dosage site and depth, and postoperative review at two weeks it is essential to assess and appraise results of the treatment. In the past few years, public scandals in aesthetic medicine have prompted reactions by several bodies including the Government and Royal Colleges. With Health Education England (HEE) having recently released standards in education, it is clear that a shift in attitude towards training is imminent. With a large volume of dentists making up this NSFA workforce it is reasonable to consider the stance of undergraduate training and the relevance of the existing knowledge within dentistry in the context of the HEE standards. A recent paper surveyed all dental schools in the UK to establish the range of subjects taught within the curriculum, with particular
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reference to those relevant to NSFA3. The two largest aesthetic pharmacies were also contacted regarding numbers of registered dentists they serve. Twelve out of 16 dental schools responded with two-thirds of them not covering NSFA in their curricula. However, many dental schools cover related subjects including: facial anatomy/ material science/neuromuscular junction physiology (100%), anatomy of the ageing face (66%), pharmacology of botulinum toxin (25%) and ethical-legal implications of aesthetic dentistry/NSFA (50%/42% respectively). With the emergence and growth of such a large multi-disciplinary field it is crucial that dentistry is not left behind so that just as most dental schools have embraced the evolution of cosmetic dentistry and implantology, it would be prudent to consider that training standards around NSFA are reflected in both undergraduate curricula and appropriate post-graduate clinical training for dentistry. The dental practitioner should be aware of these broader implications of BT-A practised under the scope of dentistry. The General Dental Council (GDC) recognises that dental registrants may prescribe Botox, however, its use is not conÂŹsidered to be representative of the practice of dentistry so that guidance is recommend from relevant dental boards and indemnity providers.
References
1. Delpachitra SN, Sklavos AW, Dastaran M. Clinical uses of botulinum toxin A in smile
aesthetic modification. Br Dent J 225: 502-506.
2. Wright G, Lax A, Mehta SB. A review of the longevity of effect of botulinum toxin in
wrinkle treatments. Br Dent J 224: 255-260.
3. Walker TWM et al. Can UK undergraduate dental programmes provide training in
non-surgical facial aesthetics? Br Dent J 222: 949-953.
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Chapter 5 ANTERIOR RESTORATIONS UNDER SCRUTINY
Although conservation of anterior teeth is undertaken to restore function, the result also has to be aesthetically acceptable to the patient. Consequently, restorations have developed to accommodate this necessity but which are best, last longest and are most effective? A series of papers in the British Dental Journal entitled The ultimate guide to restoration longevity in England and Wales has reported the analysis of, probably, the largest ever available data set of restorative treatment. It is derived from NHS General Dental Services patients obtained from all records for adults (aged 18 or over at date of acceptance) in the GDS of England and Wales between 1990 and 2006. The data consist of items obtained from the payment claims submitted by GDS dentists to the Dental Practice Board (DPB) in Eastbourne, Sussex. One of the papers examined the recorded intervals between placing a restoration in an incisor tooth and re-intervention on the tooth, and the time to extraction of the restored tooth1. Not only does this facilitate a means of assessing restoration survival to re-intervention but it also allows the analysis of restoration type on survival of the restored tooth to extraction. In other words, survival of the tooth rather than survival of the restoration per se. Since in incisor teeth, patients will be particularly interested in the appearance of their restorations and the overall aesthetics of their anterior teeth, compromised aesthetics may therefore be another reason (other than secondary caries, defective margins etc) why a restoration may be replaced/have a re-intervention. The purpose was therefore to investigate the survival of directplacement restorations, crowns and veneers in incisor teeth, by assessing: the time to re-intervention, and patient and dentist factors associated with this, and the time to extraction of incisor teeth restored with direct-placement restorations, crowns and veneers, and the factors which influence this.
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(A) Characteristics of the sample population More than three million different patient IDs and more than 25 million courses of treatment were included in the analysis, each of which includes data down to individual tooth level. Included were all records for adults (aged 18 or over at date of acceptance). Of these, 2,526,576 restorations involved incisor teeth.
(B) Restorations in incisor teeth, overall Resin composite restorations were the most frequently provided restorations (n = 1,747,379), while 286,795 glass ionomer restorations, 400,230 crowns and 57,955 porcelain veneers were included. When the survival of restoraÂŹtions in incisor teeth is examined with respect to time to re-intervention, it is apparent that, overall, 35% of restorations have survived at 15 years, with 44% having survived to ten years and 60% to five years. When the data are re-analysed with regard to time to extraction, it is apparent that 81% of restored incisor teeth have survived for 15 years, with 86% having survived to ten years and 93% to five years. When the data on the more commonly-used restoration types for incisor teeth are analysed with regard to re-intervention, it is apparent that crowns outperform other commonly provided restoration types by around fifteen percentage points at 15 years, with glass ionomer performing least favourably. Specifically, for the three most common restorations of incisor teeth, 48% of crowns have survived without a reintervention at 15 years, as have 33% of composites (Class II and Class IV), and only 25% of glass-ionomers. As for porcelain veneers, 41% have survived at 15 years. However, when the data are analysed with regard to time to extraction of the restored tooth, there is a different story. Crowns no longer represent the optimally performing restoration, since, at 15 years, resin composite restorations (overall) are performing about nine percentage points more favourably than crowns in terms of time to extraction of the restored tooth and veneers are performing optimally, with only 7% of teeth restored with a veneer being extracted at 15 years, compared with 25% of teeth which have received a crown and 16% of teeth which received a resin composite restoration.
(B) Restorations in incisor teeth with respect to patient age and gender When the data are analysed with regard to patient age and restoration survival to re-intervention, it is apparent that restorations in incisor teeth perform less well in older than in younger patients. A similar relationship can be seen between patient age
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and survival of incisor teeth to extraction. The analysis by restoration type was then repeated for different patient age groups and showed that veneers and crowns outperform all other restoration types in all age groups in terms of time to re-intervention. With regard to patient age and time to extrac¬tion of the restored tooth this indicates that the direct placement composite restora¬tion performs approximately ten percentage points better than a crown, with the teeth restored with a veneer performing best. In the under-40 age group, crowns represent the worst outcome to extrac¬tion of any treatment modality. As the patient groups get older, the relative performance of teeth restored with crowns starts to improve in terms of time of the restored tooth to extrac¬tion, but this is never better than veneers or direct-placement resin composite restorations. In other words, crowning of incisor teeth represents a relatively poor option in terms of time to extraction of the restored tooth. Throughout the analyses, teeth restored with a veneer perform better than any other in terms of time to extraction of the restored tooth. With respect to patient gender, there is, at 15 years, approximately three percentage points difference between male and female patients in survival to re-intervention on incisor teeth. When the data are examined in terms of time to extraction of the restored incisor tooth, it is apparent that restored teeth in female patients perform about four percentage points better than in male patients, equating to about four years’ difference in survival of the restored tooth.
(B) Influence of dentist factors (gender and age) Regarding dentists’ gender, there are no dif¬ferences in survival of restorations to reintervention in incisor teeth. When dentists’ age is examined, the indications are that restorations in incisor teeth placed by younger dentists outperform those placed by older dentists by up to six percentage points at 15 years. When time to extraction of the restored tooth is examined, the situation is similar in relation to dentists’ age, with restorations placed in incisor teeth by older dentists performing less well than those placed by dentists in the younger age groups.
(B) Patient’s state of oral health The patient’s history of dental treatment is a major factor in determin¬ing the likely survival of restorations to re-inter¬vention in incisor teeth. At fifteen years, this is between 64% for those with low annual expendi¬ture on dental treatment, and
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24% for those with high annual dental treatment fees. For time to extraction of the restored incisor tooth, the difference is approximately 23 percentage points between those with high annual treatment fees and those with low annual treatment fees, with the latter having restored teeth which perform more favourably. Looked at in terms of tooth loss, patients with high annual dental expenditure face the prospect of losing 27% of their restored incisor teeth within 15 years, compared with only 4% for patients with low annual dental fees.
(B) Influence of tooth position With regard to tooth position, there is a differ¬ence of six percentage points in survival of restorations in lower incisor teeth and upper incisor teeth, with restorations in lower incisor teeth performing better in terms of time to re-intervention. When individual incisor teeth position are examined it is apparent that, with regard to restoration survival, restorations in lower central incisor teeth perform better than those placed in lower lateral incisor teeth, with restorations in both these teeth per¬forming better than upper incisor teeth. With regard to survival to extraction with respect to individual incisor teeth, the results are less clear, with restored lower lateral incisor teeth performing worse and restored upper central incisor teeth performing better than the other two incisor teeth positions. Overall, in terms of time to extraction of the restored tooth, upper incisor teeth exhibit more favourable times to extraction than lower incisor teeth.
(B) Other factors Concerning the difference between teeth which were root filled on the same course of treatment as the restoration that has been placed, the indications are of about a five percent¬age point difference at 15 years in survival of restorations to reintervention, with restorations in teeth which have received root fillings performing less well. When time to extraction of the restored tooth is examined, the chart indicates about 13% difference at 15 years, this equating to about seven years, again with the root filled teeth performing less well. The results of the present work, in terms of time to re-intervention and time to extraction of the restored tooth, may initially appear to be con¬tradictory, given that the analysis confirms that, when an incisor tooth is restored with a crown, the time to re-intervention outperforms all other restoration types at all ages. However, when time to extraction of the restored tooth is examined, the picture is very different. For all age groups, crowning a tooth, as opposed to placement of a (direct-placement)
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composite restoration or a veneer, is indicative of a reduced lifespan of the crowned tooth, even though the crown performs better in terms of restoration survival to reinter¬vention than a direct placement resin-composite restoration, but not as well as a veneer. In other words, when the incisor tooth is crowned, there will be fewer re-interventions than with a direct-placement resin-composite restoration, but the lifespan of the tooth is compromised and it may be assumed that the crowned tooth is subject to a more catastrophic failure than one restored with resin composite or a veneer. Clinicians and patients should be aware of this. It is apparent, when the performance of veneers is examined, that these perform optimally throughout, which would tend to indicate that their more minimal preparation than a crown, which depends upon bonding the veneer to enamel which has been etched with phosphoric acid, does not compromise the strength of the restored tooth. In other words, the lesson is clear for all clinicians that maintaining the structurally stiff enamel layer of an incisor tooth rather than removing it (as is part of the crown preparation) helps protect the restored tooth from the need for early extraction. However, given that a veneer is often an elective restoration placed to enhance the appearance of the restored tooth, it should be questioned whether a 59% failure rate at 15 years represents a good treatment outcome. On the other hand, the lifespan of the tooth is compromised less by the placement of a veneer than any other restoration type, given that teeth restored with veneers have the best survival to extraction of any type of restora¬tion in anterior teeth. The reasons for this are a matter of surmise, but it is likely to be related to the substantially reduced preparation when compared with a crown and the maintenance of the enamel of the tooth, as discussed above. Compared with a full coverage (crown) restoration, the direct placement restoration has more factors which may fail, such as lengthy margins and caries, notwithstand¬ing the patient requesting replacement of the restoration because (s) he is unhappy with its appearance. In a text book from a bygone era, a crown has been considered to ‘protect’ and ‘strengthen’ underlying tooth substance, adding that ‘by completely enveloping the tooth, the crown holds together the portions weakened by the inroads of caries.’ However, when a tooth is prepared for a crown, there is a concomitant reduction of tooth substance, which, in respect of the results of the present work on incisor teeth would appear to indicate that the tooth is more likely to be extracted. However, it is retention of the (restored) tooth as opposed to survival of the restoration which may be considered to be most important.
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The reasons for crowning an incisor tooth in a young patient may only be surmised – in an anterior tooth it may be due to trauma or gross caries in a patient with high aesthetic demands. However, the results of this work indicate that an advisable approach is restoration of the incisor tooth with a direct placement restoration until the clinician considers that there is insufficient tooth substance remaining to retain a direct res¬toration. On the other hand, large carious cavities and/or a traumatic incident may have weakened the tooth to such an extent and a crown is considered by the clinician to replace a significant amount of lost tooth substance. The results of the present study indicate that this is now outmoded thinking and that restoration of the incisor tooth by a direct restoration is advisable if the longevity of the tooth is to be assured. Whatever the age of the patient, 15% of crowned teeth are lost in 15 years. It could be considered that this figure represents the irreducible risk in an incisor tooth when its tooth substance is removed.
(A) Other factors Other factors can come into play to lead to extraction, such as periodontal problems. In this regard, there is limited evidence that loss of attachment occurs more in mandibular incisor teeth than in maxillary central incisors. This may therefore account for the fact that restora¬tions in lower incisor teeth have better survival time to re-intervention, but less good survival to extraction. A further factor may be involved: it may be considered that upper incisor teeth are at greater risk to traumatic injury than lower incisor teeth, especially in patients with certain occlusal classifications and/or a large overjet. An additional patient factor is their treatment need. There are dramatic differences in restoration performance among patients, with those with high treatment need having restorations which perform less well in either of the methods described in this work. This could be regarded as a ‘chicken and egg’ situation – which came first? Patients with high caries activity will, if they attend a dentist for treatment, require more restorations than those with low caries activity and may be more likely to attend more frequently because of the need for emergency appointments. Either way, their restorations perform less well, perhaps indicating that some of those patients with high treatment need/high caries activity do not mend their diet or improve their oral hygiene and therefore continue to require restorations. On the other hand, the patients with high caries activity will receive larger restorations, and these are likely to fail more readily than small restorations.
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Finally, when survival of restorations to re-intervention is examined with regard to the year of placement of the restoration, it is clear that there is very little variation over the course of the observation period. This implies year-on-year consistency of the findings, and hence suggests that the patterns found in this study may be expected to persist into future years.
Reference 1. Lucarotti PSK, Burke FJT. The ultimate guide to restoration longevity in England and
Wales. Part 9: incisor teeth: restoration time to next intervention and to extraction
of the restored tooth. Br Dent J 225: 964-975.
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Chapter 6 PSYCHOLOGY, ORTHODONTICS & AESTHETIC DENTISTRY
Conventional wisdom has it that ‘beauty is in the eye of the beholder’ but how professional is that eye and what is the personality of the ‘beauty’? We consider some of the factors affecting the perception of beauty and the interdisciplinary overlaps. We are accustomed to viewing smiles from directly in front of the person or patient and this is the aspect usually given by photographers, painters as well for example, as television presenters. But what if we consider sagittal and oblique smiling profile images when assessing facial aesthetics? A study used photographs from 80 patients, of whom 40 underwent orthognathic surgery and 40 underwent orthodontic treatment, including front, front smiling, profile, sagittal profile smiling, and oblique profile smiling images before and after treatment1. Thirty judges gave scores to these photographs based on their own aesthetic conception with a one-week interval for each category. The results demonstrated that the mean score change of evaluating facial attractiveness of patients who underwent orthognathic surgery was lower when adding sagittal or oblique smiling profiles before the treatment, whereas it was higher after the treatment. The results for the orthodontic treatment group were the opposite with a higher score before the treatment and a lower score after the treatment when sagittal or oblique smiling profiles were added. The authors concluded that oblique smiling profile and sagittal smiling profile is crucial in evaluating facial aesthetics for orthodontic treatment and orthognathic surgery and suggest that both be integrated in routine photographic assessment of facial attractiveness evaluation before and after treatment.
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(A) Personality and smiles Symmetric, aligned and luminous smiles are usually classified as ‘beautiful’ and aesthetic. However, smile perception is not strictly governed by standardised rules and personal traits and may influence the perception of non-ideal smiles. A study aimed to determine the influence of personality traits in the aesthetic preference for different strategically flawed smiles shown in photographs. Smiles with dark teeth, with uneven teeth, with lip asymmetry and dental asymmetry were put in order from 1 to 4 as a function of the degree of beauty by 548 participants, of which 50.7% were females with a mean age of 41.5 years (range: 16-89 years). Self-assessment and oral satisfaction were recorded on a Likert scale and personality was measured by means of extraversion, agreeableness, conscientiousness, neuroticism and openness. Of the four photographs with imperfect smiles, dental asymmetry was the most highly assessed in 63% of the sample, and the worst was lip asymmetry, in 43.7% of the sample. Some personality traits (above all conscientiousness and openness) were significantly correlated with the position assigned to the photographs with dental and lip asymmetry or with misaligned teeth. The extraversion, agreeableness and openness traits were correlated with the self-perceptions of oral health and aesthetics of the participants. Dental asymmetry seems to be better tolerated than lip asymmetry. Personality traits seem to be weakly but significantly correlated with the aesthetic preference and oral health values, conscientiousness and openness being the most relevant domains in this sense.
(A) Patient perceptions The ‘value’ that a patient or professional places on dental and facial aesthetics may be different according to the point of view of their training. A further study aimed to determine how sensitive dental specialists and laypeople are to maxillary incisor crowding. Computer technology was used to create a series of photographs of the incisors of a smiling woman viewed from the front, showing varying degrees of maxillary incisor crowding3. The incisors illustrated in the photos were ranked on a scale from perfect alignment to severely crowded and then rated by four groups of people: orthodontists, general dentists, laypeople with experience of orthodontic treatment, and laypeople with no history of orthodontic treatment. The orthodontists and the general dentists noted misalignment of one central incisor when the malalignment reached 1.5 mm, whereas the laypeople with or without experience of orthodontic treatment were sensitive to 2.0 mm of crowding. When the crowding reached 2.0 mm for one lateral incisor, it triggered the orthodontists
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to consider providing orthodontic treatment, whereas this degree of irregularity was ignored by the general dentists and laypeople. When both central incisors were misaligned, the orthodontists were sensitive to the fact at 2.0 mm of change, whereas the general dentists and the laypeople with experience of orthodontic treatment became sensitive at 3.0 mm and the laypeople with no history of orthodontic treatment were sensitive at 4.0 mm. When both lateral incisors were misaligned, the orthodontists noted the crowding at 3.0 mm, the general dentists at 4.0 mm, whereas both the laypeople with experience of orthodontic treatment and the laypeople with no history of orthodontic treatment ignored it. When the crowding of all maxillary incisors reached 4 mm, both the orthodontists and the general dentists were alerted to the fact, but both groups of laypeople were sensitive only to a total incisor crowding equal to 6.0 mm. Clearly, and as expected, orthodontists were more critical than other groups when evaluating the misalignment of the maxillary incisors. It appears that the central incisors play a more important role than do the lateral incisors when crowding impacts smile aesthetics. For all observer groups, it also appears that people are more sensitive to the misalignment of a single tooth than they are to the same level of crowding distributed over multiple teeth.
(A) Case report Within the mix of patient and professionals perceptions, the combination of different dental disciplines including orthodontics can have a positive effect on individual cases as this report illustrates. A 36-year old female complained of the persistent bonding failure of the veneers on her upper incisors. These had been made four years previously to mask the irregularity and discolouration of the upper incisors. While she was happy with the aesthetics of the veneers, she had become increasingly concerned regarding their regular bond failures (Figure 1).
Figure 1. Pre-treatment smile
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Her skeletal pattern was symmetrical and mildly class 2 with a lower face height which was slightly reduced as was the Frankfort-mandibular planes angle. The soft tissues were balanced, with competent lips and a high lip line, producing a smile which was somewhat gummy, with 2-4mm of gingival show extending to the buccal segments, combining with narrowness across the premolars to produce significant buccal corridor shadows. The TMJs were healthy and the oral hygiene and general dental condition were good. The labial surfaces of the upper incisors were well aligned, having been restored with porcelain veneers. The palatal aspects of these teeth were irregular confirming the underlying incisor crowding. The overbite was increased and complete to soft tissue, the retroclined upper incisors having over-erupted. The canines were partially class 2 on both sides. There was mild crowding of the lower incisors and a fairly marked curve of Spee, combining to produce uneven lower incisal edge wear. Class 2 division 2 relationships produce steep guidance in all excursions, and most patients function mainly in centric and protrusion. This, combined with stronger than average muscular forces associated with this malocclusion type, make the bonding problems with veneers in this case less than surprising (Figure 2 a, b). However, progression to full coverage restorations would have been highly destructive due to the underlying rotations of the incisors. It was at this point that reorganisation of the occlusion by orthodontic means was considered.
Figure 2a.
Figure 2b.
Palatal veneer margin
Palatal veneer margin
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(A) Orthodontic diagnosis Class 2 division 2 incisor relationship on a mild skeletal 2 base with an average lower face height and mild incisor crowding in both arches. The smile was somewhat gummy. The case was complicated by previous loss of 16 and 35, and by the camouflaging of upper incisor crowding with porcelain veneers which were unstable. Aims of treatment: • Reduce overbite • Decrease inter-incisal angle • Camouflage underlying skeletal discrepancy • Eliminate buccal corridor shadows • Harmonise occlusion for restoration of the upper incisors.
Treatment plan: • Extract 25 to balance 16 loss, improving the canine relationship as all upper
spaces close
• Upper and lower fixed appliances using rectangular wires to control incisor torque • 35 space to be kept and restored after orthodontic phase, lower arch expansion
being necessary to reduce overbite and camouflage skeletal discrepancy
• Fully bonded appliances to avoid the need for AB cover during appliance
fitting Routine use of 0.2% chlorhexidine mouth rinse prior to appliance adjustments
following BOS guidelines
• Fixed retainers to be fitted to support the upper and lower anterior teeth and kept
in place permanently provided hygiene allows it
• Removable retainers to be worn in both arches until the completion of the
restorative phase.
Treatment time was estimated at 2 years and the patient requested the use of aesthetic appliances, upper lingual fixed appliances offering particular advantages in this case. Lingual brackets with bite planes are highly effective at overbite reduction, and gave the additional advantage of avoiding bonding to tenuous veneers. In the lower arch she opted for the use of labial ceramic fixed appliances.
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These incorporated a bite plane which produced immediate disclusion and no bonding failures of the veneers occurred after appliances were bonded. Once initial upper arch alignment had been achieved, the lower arch was bonded with slot brackets. Once alignment had been achieved, rectangular stainless steel wires were fitted in both arches to allow space closure with 3-D control. Expression of these wires caused a change in upper incisor inclination and an opening of the contacts between the veneers. Nocturnal class 2 intermaxillary elastics were prescribed during space closure to correct the canine relationship and facilitate overbite reduction. As upper arch spaces were closed, the lower arch was expanded, slightly increasing the 35 space, and space for lower incisor alignment gained by their proclination. Such movement camouflages a skeletal 2 discrepancy, but as proclined teeth occupy more arch length, the canine relationship usually remains slightly class 2, as in this case (Figure 3).
Figure 3. Left side after space closure
As space closure neared completion the restorative dentist reviewed the occlusion and requested that the overbite be made incomplete. This would allow full coverage porcelain restorations to be created whilst minimising the amount of palatal tooth reduction. Bends were placed distal to 33 and 43 to achieve this. When the fixed appliances were removed, upper and lower lingual fixed retainers were bonded at the same appointment and upper and lower vacuum formed
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retainers were fitted for nocturnal wear to allow home bleaching with 10% carbamide peroxide. Significant reduction in the gumminess of the smile occurred during the orthodontic phase. It has been suggested that this might be due to changes in lip retraction resulting from palatal root movement. This was refined by surgical crown lengthening, excluding 22. Six months after the removal of fixed appliances, the upper incisors were prepared for full coverage crowns with the temporaries being joined to prevent orthodontic relapse. The all-ceramic crowns (Figure 4) were fabricated and cemented and a week later a fixed retainer was refitted, extending from 13 to 23 and utilising hydrofluoric acid etch and silane bonding agent (Figure 5).
Figure 4. Final restorations
Figure 5. Final fixed retainer
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(A) Discussion This case illustrates some of the compromises and risks associated with masking aspects of a significant malocclusion by restorative means only. Such an approach may well be preferred by the patient, but a discussion of its shortcomings and risks should form part of the consent process. Following an initial unstable restorative-only approach, orthodontic treatment produced an increase in the inter-incisal angle, overbite reduction, alignment, an increase in smile width and a reduction in the gumminess of the smile. This contributed to a greatly improved overall outcome. It should also be considered that once a restorative-only path is followed, subsequent orthodontic correction of other aspects of the malocclusion may be more difficult or impossible. The restorative dentist should be aware that the alternative of orthodontic treatment prior to restorative treatment can produce a range of improvements, and a far superior functional and aesthetic outcome in some situations. Where separate individuals provide these treatments, good communication and mutual understanding are essential to success.
References 1.
Yang X et al. Role of sagittal and oblique smiling profiles in evaluating
facial esthetics. J Craniofac Surg 2015; 26: 532-536.
2.
Montero J et al. The role of personality traits in self-rated oral health and
preferences for different types of flawed smiles. J Oral Rehabil 2016; 43: 39-50.
3.
Ma W et al. Perceptions of dental professionals and laypeople to altered
maxillary incisor crowding. J Orthod Dentofacial Orthop 2014; 146: 579-586.
4.
Huntley P. Orthodontics as an adjunct to restorative dentistry - an illustrative
case. Int J Cosmetic Dent 2011; 1(2): 40-44.
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