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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex Tae-Woo Kim*, Benedito Viana Freitas**

Abstract

Orthodontic mini-implants have revolutionized orthodontic anchorage and biomechanics by making anchorage perfectly stable. In the first part of this study, ‘gummy smile’ was defined and classified according to its etiologies. Among them, dentoalveolar type, a good indication for mini-implant treatment, was divided into three categories that will be presented in consecutive articles: a) Cases with vertical growth of upper anterior dentoalveolar complex (Cases 1, 2, 3), b) Cases with protrusion of anterior dentoalveolar complex (Cases 4, 5), and c) Cases with protrusion of upper anterior dentoalveolar complex and extrusion of upper posterior teeth (Cases 6, 7). Three cases with excessive vertical growth of upper anterior dentoalveolar complex will be presented. They were characterized with extrusion and retroclination of upper incisors, deep overbite, and gummy smile. The aim of this paper is to show the mini-implant useful at the anterior area to intrude incisors and gummy smile correction. Upper anterior mini-implant (1.6 x 6.0 mm) and a NiTi closed coil spring were used to intrude and procline the retroclined extruded incisors. Miniimplants can be used successfully as orthodontic anchorage to intrude anterior teeth.

Keywords: Mini-implants. Intrusion. Gummy smile. Segmented arch.

INTRODUCTION AND LiteraturE REVIEW Most of dentists define “gummy smile” as excess gingival display.1 But if they are asked to decide whether cases are “gummy smile” or not, their answers may not be unanimous. It is not simple to determine if one patient have gummy smile or not, because patients can pose their smile. In other words, the amount of upper incisor and gingival exposure chang-

es depends on the muscle activity. As a general guideline, in adolescents 3 to 4 mm of the maxillary incisor should be displayed at rest, and the entire clinical crown (with some gingiva) should be seen on smiling.2 Gummy smile can be divided in several categories according to its etiologic factors.3,4 When used as orthodontic anchorage, miniimplants provide orthodontists with a high

* Professor and Chairman, Department of Orthodontics, Seoul National University, South Korea. ** Head Professor of the Discipline of Orthodontics, Federal University of Maranhão. Visiting Professor at Seoul National University, South Korea.

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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex

potential for successful results while offering many different treatment options since they need not rely on patient compliance. Miniscrews are indicated for tooth intrusion as they allow practitioners to apply light and continuous forces, which can reduce apical resorption, often associated with intrusive movement.5,6 Creekmore and Eklund7 reported the use of a metal implant for the correction of deep overbite. They placed a vitalium screw below the anterior nasal spine and stretched an elastic as far as the upper central incisors. They succeeded in intruding these teeth by 6 mm and tipped them 25º buccally avoiding infection, pain or other screw-related complications.

However, the authors considered that it would be premature to disseminate the use of this technique. Kanomi8 reported that the intrusion of lower incisors in a patient with deep overbite was achieved by means of a screw measuring 6 mm in length and 1.2 mm in diameter.

Ohnishi et al9 also showed a clinical case with deep overbite treated using mini-implants for intrusion of the upper incisors. Intrusion also improved the patients’ gingival smile.

The effects of mini-implant intrusive biomechanics are still poorly understood. Currently, the available literature consists mainly of clinical case reports and a handful of studies on animals.

The literature clearly shows that teeth can be intruded successfully using mini-screws as anchorage but there is great variability regarding the amount of intrusion, load time, intrusive forces and their relation to root resorption, hindering its clinical application by ortodontists.5,7,10

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Short upper lip type - Short philtrum height.

Skeletal type - Vertical maxillary excess.

- Maxillary protrusion.

Dentoalveolar type - Excessive vertical growth and/or - Protrusion of upper anterior dentoalveolar complex.

This dentoalveolar type is a good indication of mini-implant treatment. The cases that will be presented in consecutive articles were classified as follows: 1) Cases with vertical growth of upper anterior dentoalveolar complex (Cases 1, 2, 3).

2) Cases with protrusion of anterior dentoalveolar complex (Cases 4, 5).

3) Cases with protrusion of upper anterior dentoalveolar complex and extrusion of upper posterior teeth (Cases 6, 7).

Cases with vertical growth of upper anterior dentoalveolar complex Cases with excessive vertical growth of upper anterior dentoalveolar complex usually show extrusion and retroclination of upper incisors, deep overbite, and gummy smile (Figure 1).

This kind of case could be treated well with the Burstone’s Segmented Arch Technique.11 It would be used “one-piece intrusion arch” for the retroclinated and extruded upper incisors (Figure 2). In this technique, high-pull headgear and precision lingual arch are used to counteract the adverse reactions like extrusion of upper molars. But the mini-implants mechanics (Figure 3) can treat the retroclined and extruded incisors very efficiently without an extrusion of upper molars and it does not need the patient’s cooperation. This mini-implant technique was modified from the method reported by Creekmore and Eklund7 (Figure 3).

After placing a 1.6 x 6.0 mm mini-implant (Jeil Med Co, Seoul, Korea) without drilling,

Etiology and classification • Dento-gengival type - Deficient gingival recession, which is revealed by a short clinical crown.

• Muscular type - Hyperactivity of the elevator muscle of the upper lip.

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FigurE 1 - Cases showing excessive vertical growth of upper anterior dentoalveolar complex. A) Case 1 (10y 6m/ male, Class II, div 2).

B) Case 2 (12y, male Class I). C) Case 3 (26y 5m, male/ Class II div. 2).

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FigurE 2 - A) Burstone’s one-piece intrusion arch. B) One-piece intrusion arch is very efficient to intrude and procline the retroclined and extruded incisors without extruding molars.

Case 1 was treated with non-extraction for two years. His gummy smile and deep overbite was treated well with a mini-implant (Figure 3, 4A, 5). For accelerating the mandibular growth, twin-blocks were used. Case 2 was treated with non-extraction for three years (Figure 6). His gummy smile and deep overbite was also improved very well with the same mechanics (Figure 3). Case 3 was treated by intrusion of upper incisors with a mini-implant and by a mandibular advancement surgery (Figure 7).

a NiTi closed coil spring was applied immediately over a 0.019 x 0.025-in stainless steel box wire (Figure 3). The mini-implant and the upper portion of NiTi closed coil spring was covered by a flap. The covered mini-implant was not discomfort to patients and it was preferred to a headgear and a lingual or transpalatal arch. After using this mechanics, three cases showed upper incisors that were intruded and proclined (Figure 3B and 4) as one-piece intrusion arch was used (Figure 2A).

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FigurE 3 - A) 1.6 x 6.0 mm mini-implant (Jeil Med. Co., Seoul, Korea) and NiTi closed coil spring to intrude and procline the retroclined extruded incisors. B) Intraoral photos of Case 1. C) Upper central incisors intruded and proclined as one-piece intrusion arch made with 0.019 x 0.025-in stainless steel box wire was used to prevent impingement of gingival tissue.

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FigurE 4 - Superimposition of tracings before treatment and after intrusion and proclination of upper incisors. A) Case 1: After using mini-implant for 6 months (Figure 3). Upper incisors were intruded and proclined like the movement by one-piece intrusion arch (Figure 2). B) Case 2: After 1 year, upper incisors were intruded and proclined with a lot of growth. C) Case 3: After 1 year and 2 months, this case also showed upper incisors were intruded and proclined. Mandibular retrognathism was treated by advancement surgery.

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FigurE 5 - Case 1 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared after debonding. B) Profile was improved by using Twin-Block. C) Before treatment. D) After debonding.

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FigurE 6 - Case 2 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared. B) After debonding, his profile had not changed. C) Before treatment. D) After debonding, this case was also treated with non-extraction.

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FigurE 7 - Case 3 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared by an intrusion of upper incisors with a miniimplant, which made the superior impaction surgery of maxilla not necessary. B) His retrognathic mandible was improved by mandibular advancement surgery. C) Before treatment. D) After debonding.

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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex

DISCUSSION In the past, molar extrusion was the most common treatment to correct deep overbite.

However, the intrusion of anterior teeth became possible with the introduction of the sectional arch wire technique by Burstone. However, this method requires patient compliance in the use of high-pull headgear and other appliances. Lately, mini-implants have been used for treating of Angle Class II, division 2 malocclusions with deep overbite. This procedure is simple and does not require patient compliance. Although concrete evidence is still lacking to prove that treatments involving incisor intrusion are more stable over time, we can now intrude anterior teeth free from the past restrictions when molar extrusion was the only option for treating deep overbite.

With this new treatment, we have succeeded in intruding upper incisors and enhancing gingival smile using only mini-implants and sectional arch wires.

Gingival smile can be divided into various categories according to etiological factors. Dentoalveolar gingival smile occurs due to excessive incisor eruption in relation to the upper lip. Dentogingival smile is related to abnormal tooth eruption, gingival hyperplasia or lack of gingival recession, as evidenced by a short height crown. Gingival smile of skeletal origin occurs on account of excessively vertical maxillary growth and requires orthognathic surgery.

A short upper lip is also a frequent cause of gingival smile.3,4 Muscular gingival smile is caused by overactivity of the upper lip levator muscle.

Finally, gingival smiles can be caused by a combination of these factors.

All patients shown in this article had dentoalveolar gingival smile. Only the central incisors were extruded and the posterior teeth were in normal position vertically. In this category, if extruded teeth are intruded, as in such cases, both the overbite and the gingival smile can

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be corrected effectively. This method was first introduced by Creekmore and Eklund7 and recently reported by Ohnishi et al.9 These patients were treated with a sectional arch on the anterior teeth, which were connected to a mini-implant inserted between the incisors by means of a closed NiTi spring.

This procedure provides some advantages such as no subsequent extrusion, which can lead to a rotation of the mandible in a clockwise direction, opening the mandibular plane and worsening the patient’s pattern.

Conclusion The use of mini-implants in the anterior region was effective for the intrusion of upper incisors and therefore the gingival smile was corrected in all cases. These intrusion movements were obtained easily and without patient compliance. Patients did not complained of discomfort caused by the mini-implants. Mini-implants can be successfully used as anchorage for the intrusion of anterior teeth.

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ReferENCES 1.

Robbins JW. Differential diagnosis and treatment of excess gingival display. Pract Periodontics Aesthet Dent. 1999 Mar;11(2):265-72; quiz 273.

2. Sarver DM, Proffit WR, Ackerman JL. Evaluation of facial soft tissue. In: Proffit WR, White RP, Sarver DM. Contemporary treatment of dentofacial deformity. Mosby; 2003. cap.

4, p. 92-126.

3. Monaco A, Streni O, Marci MC, Marzo G, Gatto R, Giannoni M. Gummy smile: clinical parameters useful for diagnosis and therapeutical approach. J Clin Pediatr Dent. 2004 Fall;29(1):19-25.

4. Burstone CJ. Deep overbite correction by intrusion. Am J Orthod. 1977 Jul;72(1):1-22.

5. Carrillo R, Rossouw PE, Franco PF, Opperman LA, Buschang PH. Intrusion of multiradicular teeth and related root resorption with mini-screw implant anchorage: a radiographic evaluation.

Am J Orthod Dentofacial Orthop. 2007 Nov;132(5):647-55.

6. Sameshima GT, Sinclair PM. Predicting and preventing root resorption: part II. Treatment factors. Am J Orthod Dentofacial Orthop. 2001 May;119(5):511-5.

7.

Creekmore TD, Eklund MK. The possibility of skeletal anchorage. J Clin Orthod. 1983 Apr;17(4):266-9.

8. Kanomi R. Mini-implant for orthodontic anchorage. J Clin Orthod. 1997 Nov;31(11):763-7.

9. Ohnishi H, Yagi T, Yasuda Y, Takada K. A mini-implant for orthodontic anchorage in a deep overbite case. Angle Orthod.

2005 May;75(3):444-52.

10. Ohmae M, Saito S, Morohashi T, Seki K, Qu H, Kanomi R, et al.

A clinical and histological evaluation of titanium mini-implants as anchors for orthodontic intrusion in the beagle dog. Am J Orthod Dentofacial Orthop. 2001 May;119(5):489-97.

11. Burstone CJ. Deep overbite correction by intrusion. Am J Orthod. 1977 Jul;72(1):1-22.

12. Shroff B, Lindauer SJ, Burstone CJ, Leiss JB. Segmented approach to simultaneous intrusion and space closure: Biomechanics of the three-piece base arch appliance. Am J Orthod Dentofacial Orthop. 1995 Feb;107(2):136-43.

Submitted: September 2008 Reviewed and accepted: April 2009

Contact address Benedito Viana Freitas Avenida da Universidade, qd. 2, nº 27 - Cohafuma CEP: 65070-650 - São Luís / MA E-mail: beneditovfreitas@uol.com.br

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