JOS - European Journal of Oral Surgery

JOS European journal of oral surgery

Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale

2 ISSUE 2 VOL.

October 2011

ISSN 2037-7525

CASA EDITRICE ARIESDUE

ITALIA PRESS EDIZIONI

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European journal of oral surgery Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale www.ejos.eu

European journal of oral surgery

Editor-in-chief

Publisher

Prof. Franco Santoro (Italy)

ARIESDUE SRL

ITALIA PRESS EDIZIONI

Via Airoldi, 11 22060 Carimate (CO) +39 (0)31.79.21.35 +39 (0)31.79.07.43 www.ariesdue.it info@ariesdue.it

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Editorial Director Prof. Carlo Maiorana (Italy)

Associate Editors

ISSN: 2037-7525

Prof. Piero Balleri (Italy) Prof. Pascal Valentini (France)

Editorial Board Dr. Giovanni Battista Grossi (Italy) Prof. Alan Herford (USA) Prof. Fouad Khoury (Germany) Prof. Jaime A. Gil (Spain) Prof. Massimo Simion (Italy) Prof. Anton Sculean (Switzerland) Prof. Tiziano Testori (Italy) Prof. Nicholas Toscano (USA) Prof. Leonardo Trombelli (Italy) Dr. Istvan Urban (Hungary)

DIRECTOR Dino Sergio Porro EDITORIAL STAFF Angela Battaglia: a.battaglia@ariesdue.it Cristina Calchera: farma@ariesdue.it Simona Marelli: doctoros@ariesdue.it MARKETING & ADVERTISING Barbara Bono: b.bono@ariesdue.it Paola Cappelletti: p.cappelletti@ariesdue.it Franco De Fazio: f.defazio@ariesdue.it WEB & GRAPHIC DESIGN Michele Moscatelli: grafica@ariesdue.it Simone Porro: simone@ariesdue.it Cover image courtesy of Giampiero Gasperini

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JOS VOL.2 N.2 2011

Pagina Pubbl A4 marted每每 30 agosto 2011 14.16.43

European journal of oral surgery

Issue 2 Volume 2 October 2011

page 39

Small volume Cone Beam CT in the evaluation of impacted mandibular third molars

page 45

Vertical ridge augmentation with a titanium reinforced e-PTFE membrane. Report of a case

page 51

Surgically-assisted rapid palatal expansion and orthodontic treatment in preparation for Le Fort 1 and sagittal split osteotomy surgery

35

JOS VOL.2 N.2 2011

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In armonia con la natura

European journal of oral surgery Official journal of the SocietĂ Italiana Specializzati in Chirurgia Odontostomatologica ed Orale

European journal of oral surgery

Editor-in-chief

Prof. Franco Santoro SISCOO President

Editorial Dear colleagues, The weak financial situation we are passing through often leads patients to give up with sophisticated dental rehabilitations, particularly when implant placement is required.

Parallelly to this situation, some dental clinics are proposing implant treatments at a very cheap price, but most of the times this attractive proposal is not coupled to an adequate clinical standard.

Maybe it is time to change mind a little bit by taking into consideration the possibility to tender the patients, who do not have liquid assets to face complex treatments, alternative therapies as a temporary solution. In this way these patients will be able to postpone the sophisticated rehabilitation, anyhow without giving up function and aesthetics, waiting for clearer skyes.

I take this opportunity to invite all of you to submit your clinical contributions to JOS for a possible publication: it does not really matter if you are faculty members or free practioners. JOS is growing fastly, but it needs the support of all its readers and fans.

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JOS VOL.2 N.2 2011

Manuscript Preparation

European journal of oral surgery ISSN: 2037-7525 www.ejos.eu

Guidelines for Authors Manuscript Submission Manuscripts can be uploaded in the “Manuscript Submission” section of the journal’s website http://www.ejos.eu or sent in a CD to the publisher: Ariesdue Srl via Airoldi, 11 - 22060 Carimate (Co) Italy e-mail: farma@ariesdue.it as a PC Word (doc) file with tables and figure legends at the end of the document. Figures should be supplied separately.

• Manuscripts should be typed in a 12-point font and double-spaced; their length should range from 6,000 to 18,000 digits for Case Reports and from 10,000 to 25,000 digits for Monographs. The number of visual components (images and tables) should not exceed 18.

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• References: References should be limited to those specifically referred to in the text, cited numerically, in order of appearance in the text and listed according to the following style (Vancouver style): Journals: 1. Del Fabbro M, Testori T, Francetti L, Taschieri S, Weinstein R. Systematic review of survival rates for immediately loaded dental implants. Int J Periodontics Restorative Dent 2006;26:249–264.

Submission Letter

Books:

A Submission Letter must be signed by all authors and supplied as a separate pdf file along with the manuscript.

1. Tarnow DP, Cho S-C, Wallace SS, Froum SJ. Effect of surface morphology on implant survival in the grafted maxillary sinus. In: Jensen OT (ed). Bone Graft, ed 2.

Chicago: Quintessence; 2006. p.223–227.

Figures

Publishers ARIESDUE SRL

ITALIA PRESS EDIZIONI

Via Airoldi, 11 22060 Carimate (CO) +39 (0)31.79.21.35 +39 (0)31.79.07.43 www.ariesdue.it info@ariesdue.it

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JOS VOL.2 N.2 2011

Monograph

Small volume Cone Beam CT in the evaluation of impacted mandibular third molars Davide SigurtĂ * Giovanni Battista Grossi* Sandro De Nardi

*University of Milan, School of Dentistry Dental Clinic Ospedale Maggiore IRCCS CĂ Granda Milan (Italy) Director: Prof. Franco Santoro Department of Implantology

Aim:

This was to assess the accuracy of small volume CBCT in the visualization of the inferior alveolar canal and of the anatomic variations of the mandibular third molar as well as to evaluate their mutual relationships compared to conventional radiographs.

Key words: cone beam CT, third molar surgery, inferior alveolar nerve injury.

Materials and methods: In this observational study the shape and position of 104 third molars and their relationship to the inferior alveolar canal were examined with Accuitomo 3D. Results:

The inferior alveolar canal was clearly visible in all examinations, its course was mostly buccal. In 51% of cases a direct contact between nerve and root vas observed.

Discussion:

Small volume cone beam CT showed its potential in providing images with high definition. The understanding of the exact position of the IAC can modify the surgical approach.

Conclusion: The use of small volume cone beam CT for the preoperative evaluation of impacted third molars at risk of nerve injury is suggested.

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Sigurtà D, Grossi G.B. and De Nardi S. Characteristics of Accuitomo 3D

Introduction Surgical removal of impacted wisdom teeth is a common procedure in oral and maxillofacial surgery.

Inferior alveolar nerve (IAN) injury is a rare but unpleasant complication after mandibular third molar (M3) extraction, with a frequency that varies from 0.5% to 5% according to authors (1-3).

The factors that can lead to a nerve lesion are many (patients age, surgeon’s experience, surgical technique, type of anaesthesia) but the proximity of the inferior alveolar canal (IAC) to the third molar is surely the most relevant one.

The surgical damages can be reduced with a precise evaluation of patient anatomy, by means of which the surgeon could be able to decide if the tooth has to be removed and how to operate.

The panoramic radiography (OPT) is widely used in this field in order to see the shape and position of M3: it shows the overlap of the roots and the IAC, and to recognize the signs of anatomical proximity such as darkening of the root, loss of the cortical line, diversion of the canal, deflection of the roots and narrowing of the roots. Nevertheless it has been demonstrated that these signs, as test of nerve damage, have a high specificity but a low sensitivity (4). As all projective radiological images, OPT presents the limits due to the superimposition of structures lying in different planes and has a limited accuracy regarding number and morphology of the roots. In contrast, Computed Tomography (CT) can give us a 3D view of the anatomy, but this exam requires high financial costs and gives the patients, typically adolescents or young adults, an elevated radiation exposure. Finally, the advent of Cone Beam Computerized Tomography (CBCT) (5,6) reduced exposition and costs and provided a widely used examination in oral and maxillofacial regions (7) for many diseases (8). In particular, the CBCT units designed for the analysis of small volume (4-6 cm) fields of view (FOV) (9) have their elective indication in the study of impacted teeth.

These devices can produce images in different planes characterized by a high definition of the details and are able to supply precise information about shape and relationships of the anatomic structures; in particular, IAC, multiple roots and thin apices are clearly visualized.

The aims of this study were on the one hand to analyze the diagnostic potential of small volume CBCT in the visualization of the M3 and IAC; on the other hand to evaluate the anatomic variations of these structures

X Ray beam Tube voltage Focal spot size Field of view Voxel size Exposure time Radiation dose Patient position

Cone Beam 60/80 kV 0.5 x 0.5 mm 4x4 cm / 6x6 cm 0.125 x 0.125 x 0.125 mm 18 sec 20 µS /43 µS sitting

TABLE 1

and their mutual relationships, for risk evaluation and surgical procedure adaptation.

Materials and methods The radiographic unit used for this study was Accuitomo 3D (Morita Mfg. Corp, Kyoto Japan), which works with the patient in sitting position, with a 360° rotation of the gantry and a FOV of 6 cm (Table 1). The software reconstructs a rough volume and axial, coronal (frontal), sagittal (lateral) panoramic and cross-sectional images.

Patients’ dose is very low as compared to conventional CT: according to the recommendation of the International Committee for Radiological Protection (ICRP), the effective dose is 43 µSv (9), which is equivalent to 3.1 digital panoramic radiographs or 5.2 days of natural background radiation (Table 2).

The study population was composed of all the patients referred to a private office of oral and maxillofacial radiology in Milan (Italy), for a CBCT evaluation of lower third molars, from January to July 2011. Only the cases that showed an overlap of the IAC and M3 in the sagittal images were included in the study sample, therefore all patients who did not present a situation of risk of nerve damage were excluded.

A total of 104 wisdom teeth (54 right, 50 left) were examined in 74 patients (29 males, 45 females) aged between 16 and 71 years (mean 31.7) (Table 3).

The CBCT images were assessed through the special software programme. Axial, sagittal and coronal images were analysed. Slices thickness was 1 mm. The distances between the IAC and M3 roots were measured in the coronal images. For each CBCT exam the

FOV

4x4 cm

6x6 cm

Effective dose (µSv) Digital panoramic equivalent N° of days of natural background

20 1.4 2.5

43 3.1 5.2

TABLE 2 Radiation dose for Accuitomo 3D (from Scarfe et al., 2009).

JOS VOL.2 N. 2 2011

40

Monograph Patients

74 in total; males 29 (39%); females 45 (61%); mean age 31.7 y

Third molars

104; right 54 (52%), left 50 (48)

CBCT findings

Overlap in lateral view: partial 63 (61%); total 41 (39%) Type of retention according to Wolf and Haunfelder: vertical 46 (44), mesial 44 (42%), distal 5 (5%), horizontal 9 (9%) Vertical position of M3 crown: Class A: 37 (35%), Class B: 60 (58%), Class C: 7 (7%) A-P position of M3 crown: Class 1: 98 (94%); Class 2: 6 (6%) Root configuration of M3: single root 7 (7%), 2 roots 55 (53%), 3 roots 3 (3%), fused roots 37 (35%), bud 2 (2%) Course of IAN in relationship to M3 roots: inferior 37 (36%), buccal 39 (37%), lingual 21 (20%), inter-root 6 (6%), intra-root 1 (1%) Distance between IAN and M3 root: direct contact 51 (50%), maximum distance 3.8 mm, average distance 0.6 mm Bone characteristics between IAN and M3: absence of bone 51 (50%), only cortical bone 34 (33%), cancellous and cortical bone 19 (18%) Length of bone dehiscence: range 0.5–7 mm, mean 4 mm Anatomical modifications of canal and root: no modification 73 (70%), narrowing of the canal 27 (26%), diversion of the canal 3 (3%), grooving of the root 1 (1%)

TABLE 3 Summary of descriptive statistics.

following elements were considered.

• M3 vertical position. Class A: M3 cusps at the level of patient’s occlusal plane. Class B: M3 cusps between the occlusal plane and the cementumenamel junction of the second molar (M2-CEJ).

Class C: M3 cusps below the (M2-CEJ).

• M3 antero-posterior position . Class 1: M3 crown totally anterior to the mandibular ramus. Class 2: less than half M3 crown inside the mandibular ramus.

Class 3: more than half M3 crown inside the mandibular ramus.

• Type of retention. Vertical; mesial; distal; horizontal; transversal (according to Wolf and Haunfelder).

• Root configuration. Number of roots; fused roots.

• Course of IAC in relation to M3 roots. Buccal; lingual; inferior; inter-root (IAC between apically open roots); intra-root (IAC inside apically closed roots).

• Distance between IAC and M3 roots. The minimum distance in coronal view.

• Bone characteristics between IAC and M3. Any bone tissue (direct contact); cortical bone tissue; cortical and spongy bone.

• Length of the cortical defect. The length of the direct contact.

• Anatomical modifications of IAC and root. Narrowing of the IAC; diversion of the IAC; grooving of the root; no modification.

and the crown anteriorly to the border of the ramus (98%). Two separate roots (54%) or fused roots (36%) were the most frequent shapes. The IAC was well visible in all the exams. Sometimes, in the coronal images, it could be confused with other radiolucent areas, but in these cases too it was easily recognizable in the sagittal views (Fig. 1-3).

In our experience the IAC was more frequently on the buccal (37%) than in the lingual side (20%). In only a few cases the course was in inter-root (Fig. 3, 4) or intra-root (Fig. 5).

In 5% of cases, the IAC was in direct contact with the M3 roots: the maximum length of direct contact was 7 mm, the average cortical defect was 4 mm (Fig. 6).

Conversely, in 49% of cases there was cortical or cortical and cancellous bone between IAC and roots: the maximum thickness was 3.8 mm (Fig. 7).

The narrowing of the IAC was the most frequent

Results The results are summarized in Table 3.

Most of the teeth studied were in vertical (46%) or in mesial (44%) retention, with the cusp tips positioned between the occlusal plane and the M2-CEJ (58%)

FIG. 1 Where is the canal? It is just below the apex, but the presence of spongy radiolucent spaces does not allow a sure identification in the coronal view.

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SigurtĂ D, Grossi G.B. and De Nardi S.

FIG. 2 Same case as figure 1: in the sagittal image the canal is clearly identifiable and, by means of this datum, it can

be easily localized in the coronal view too. In the axial it appears distal to the apex.

FIG. 3 Axial, sagittal and coronal CBCT images showing the inter-root position of the canal. Tooth 48 has three

separated roots; there is not bone between them and the neurovascular bundle. The canal shows a little flattening and diversion. An area of osteosclerosis is present over the third molar crown. In the coronal image the translucent oval area between the IAC and the inferior cortex looks like the canal. In such a situation, without the aid of the other projections it would be impossible to distinguish the real position of the nerve.

FIG. 4 Axial, coronal and sagittal CBCT images showing the inter-root position of the IAC. Tooth 48 has two separated roots and the canal runs in between.

FIG. 5 In the axial, coronal and sagittal CBCT images the canal appears totally surrounded by the third molar roots (intra-root position). The tooth has three apically closed roots. The picture shows a diversion of the canal, but not a narrowing. The IAN is in direct contact with the roots and any bone tissue is visible in between through a length of seven millimetres. A large radicular cyst of the second molar is easily appreciable.

anatomical modification (26%). There were only three cases of diversion of the IAC and one grooving of the root.

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FIG. 6 The coronal CBCT image shows the direct contact between the root and the IAN. A minimum flattening of the canal is appreciable.

Monograph

FIG. 7 Same patient of figure 6, right side. The coronal CBCT image shows the presence of cortical and spongy bone between the root and the IAN. Measures are taken in the coronal image in which the two structures appear closer. At the level of the apex the lingual bony cortex is perforated. In such a case the risk of lingual cortex fracture, lingual nerve impairment and root dislocation must be considered.

Discussion The present study confirms the high diagnostic potential of small volume CBCT, which is able to provide images characterised by a high quality of the details.

The interpretation of the pictures and the identification of little structures, such as IAC cortex and fine radicular apices, are easy. The morphology of teeth with more than two roots, which is difficult to evaluate with conventional radiography owing to the superimpositions, is clearly detectable with the small volume Cone Beam CT (Fig. 3-5; 8-10).

CBCT images provide a reliable insight of bucco-lingual relationships between tooth and IAC, which cannot be achieved with panoramic radiography. Moreover,

FIG. 8 The curved shape of the root is well visible in

sagittal CBCT image. The axial view shows the proximity to the lingual cortex.

according to the study of Tantanapornkul (10), carried out with the same radiologic unit used in this work, CBCT in this particular anatomical field is more accurate than conventional CT. In 51% of cases a direct contact of the IAC and M3 roots was shown with a subsequent possibility of IAN exposition during removal. Susarla and Avery (11) refer that cortical defects of 3 mm or more were associated with an increased risk of intraoperative IAN visualization. Moreover, the incidence of postoperative

FIG. 9 The sagittal CBCT image shows the angulation of the mesial root apex. In the coronal view the dehiscence of the canal and the mesial apex in direct contact with IAN is clearly visible. In such a case all surgical manoeuvres that push the apex downwards and laterally must be avoided. The area of osteolysis between 37 and 38 and the caries of 37 are clearly visible.

FIG. 10 Sagittal and axial CBCT images show the resorption of the distal root of tooth 37.

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Sigurtà D, Grossi G.B. and De Nardi S. quality of the images, the high diagnostic potential and the low radiation exposure of small volume CBCT, the authors suggest the use of this diagnostic tool before the removal of M3 whenever a conventional radiographs shows any signs of a close relationship to the IAC.

References 1. Robert RC, Bacchetti P, Pogrel MA. Frequency of trigeminal nerve injuries following third molar removal. J Oral Maxillofac Surg 2005;63(6):732-6.

2. Queral-Godoy E, Valmaseda-Castellón E, Berini-Aytés L, GayEscoda C. Incidence and evolution of inferior alveolar nerve lesions following lower third molar extraction. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99(3):259-64.

3. Nakayama K, Nonoyama M, Takaki Y, Kagawa T, Yuasa K, Izumi K, Ozeki S, Ikebe T. Assessment of the relationship between impacted mandibular third molars and inferior alveolar nerve with dental 3-dimensional computed tomography. J Oral Maxillofac Surg 2009;67(12):2587-91.

FIG. 11 Axial and coronal CBCT images show the lingual course of the nerve. The canal is narrowed, flat, in direct contact with the root and compressed between the tooth and the lingual cortex that appears resorbed. In such a case if the root is luxated lingually the risk of compression of the nerve is high.

4. Susarla SM, Dodson TB. Preoperative computed tomography imaging in the management of impacted mandibular third molars. J Oral Maxillofac Surg 2007;65(1):83-8.

5. Zöller JE, Neugebauer J. Cone Beam Volumetric Imaging in dental, oral and maxillofacial medicine. Berlin: Quintessence Publishing Co. Ltd; 2008.

6. Scarfe WC, Farman AG. What is cone-beam CT and how does it work? Dent Clin North Am 2008;52(4):707-30.

neurological disturbances is increased in case of intraoperative visualisation of the nerve (3, 12). On the contrary, in 49% of cases there was some cortical or cortical and cancellous bone between nerve and roots with a maximum thickness of 3.8 mm. This datum means that in 1 out to 2 cases of overlap in lateral projection, such as in panoramic radiograph, the two structures are not in proximity. This study too confirms that the panoramic evaluation often overestimates the risk, by giving the suspect of a close proximity that in the reality does not exist.

In our sample the IAC position resulted to be more common in the buccal side than in the lingual, in agreement with Lübbers (13). However, there is a large discrepancy between the various authors regarding these data. Gaemina and coworkers (11) found that the lingual position is the most common (49%), furthermore the neurovascular bundle is more frequently exposed if lingually positioned. In that work the nerve was lingually positioned in all cases of injury.

A precise knowledge of the exact course of the IAC may modify the surgical approach, showing where it is safer to remove bone and in which direction luxate the roots (14) (Fig. 11).

Conclusion Given the great variability in the course of the IAC, in morphology and number of roots, considering also the

JOS VOL.2 N. 2 2011

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7. Angelopoulos C. Cone beam tomographic imaging anatomy of the maxillofacial region. Dent Clin North Am 2008;52(4):731-52.

8. Guttenberg SA. Oral and maxillofacial pathology in three dimensions. Dent Clin North Am 2008;52(4):843-7.

9. Scarfe WC, Levin MD, Gane D, Farman AG. Use of cone beam computed tomography in endodontics. Int J Dent 2009; 2009:634567. Epub 2010 Mar 31.

10. Tantanapornkul W, Okouchi K, Fujiwara Y, Yamashiro M, Maruoka Y, Ohbayashi N, Kurabayashi T. A comparative study of cone-beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Oral Surg Oral Med Oral Pathol Radiol Endod 2007;103(2):253-9.

11. Susarla SM, Sidhu HK, Avery LL, Dodson TB. Does computed tomographic assessment of inferior alveolar canal cortical integrity predict nerve exposure during third molar surgery? J Oral Maxillofac Surg 2010;68(6):1296-303.

12. Ghaeminia H, Meijer GJ, Soehardi A, Borstlap WA, Mulder J, Bergé SJ. Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography.

Int J Oral Maxillofac Surg 2009;38(9):964-71.

13. Lübbers HT, Matthews F, Damerau G, Kruse AL, Obwegeser JA, Grätz KW, Eyrich GK. Anatomy of impacted lower third molars evaluated by computerized tomography: is there an indication for 3-dimensional imaging? Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111(5):547-50.

14. Ghaeminia H, Meijer G J, Soehardi A, Borstlap WA, Mulder J, Vlijmen OJ, Bergé SJ, Maal TJ. The use of cone beam CT for the removal of wisdom teeth changes the surgical approach compared with panoramic radiography: a pilot study. Int J Oral Maxillofac Surg 2011;40(8):834-9.

Case report

Vertical ridge augmentation with a titanium reinforced e-PTFE membrane.

Report of a case Filippo Fontana Maurizio Fimmanò Frederick Berardinelli University of Milan, School of Dentistry, Dental Clinic Ospedale Maggiore IRCCS Ca’ Granda Milan (Italy), Director: Prof. Franco Santoro

Aim:

The aim of this case report is to evaluate effectiveness and reliability of a surgical procedure for vertical crestal bone regeneration through Guided Bone Regeneration (GBR) in mandibular bone atrophy.

Case report: Vertical bone augmentation was performed with an e-PTFE membrane combined to a mixed bone autograft and xenograft. Implants were inserted at the same time of bone regeneration (one step procedure). The results were stable and esthetically acceptable, thanks to a correct diagnosis. This is, in fact, a prerequisite, along with an adequate tratment plan and a constant commitment from both the treatment team and the patient, for the attainment of good results over time. Guided Bone Regeneration can be considered a successful and predictable technique for vertical ridge augmentation in the lower jaw.

45

Key words: Alveolar ridge augmentation, guided bone regeneration, barrier membrane.

JOS VOL.2 N.2 2011

Fontana F., Fimmanò M. and Berardinelli F.

Introduction The placement of titanium dental implants is a widespread method for the rehabilitation of edentulous areas in the jaws (1). However, implant positioning is not possible in cases of alveolar bone resorption ending with a massive, vertical and horizontal, crestal modification. In these situations, bone regeneration is the only possibility to allow implant prosthodontic techniques.

The correct positioning of an implant is a keypoint for the final biomechanical and esthetic outcome.

In the last decade Guided Bone Regeneration (GBR) has proved to be a very effective and predictable technique for vertical bone augmentation. The rationale of this technique includes the use of a membrane in order to create a protected space where the blood clot and the bone graft can be stabilized, thus allowing new bone formation by preventing epithelia and connective cells to migrate inside.

In 1991 Schmid (2) first proved GBR effectiveness by inserting implants on upper crestal rabbit bone. Similar outcomes were soon after reported on rats (3) and dogs (4-6). In 1994 Simion (7) was the first author to clinically and histologically demonstrate the possibility of vertical crestal bone augmentation in humans. He used a titanium reinforced expandedpolytetrafluoroethylene (e-PTFE) membrane for covering the implants, and obtained a 4 mm vertical ridge bone augmentation.

The following clinical and histological studies on humans (811) proved that filling the space below the membrane with autogenous, homologous, heterologous or mixed bone graft could dramatically help bone regeneration.

The technique reliability and predictability were further confirmed by a retrospective study by Simion on 123 dental implants (12). The Author’s conclusions were that implants inserted in regenerated bone behave in the same way as those placed in native bone.

The aim of this case report is to evaluate effectiveness and reliability of vertical crestal bone regeneration

JOS VOL.2 N.2 2011

through Guided Bone Regeneration (GBR) in mandibular bone atrophy.

Case report A 55-year-old, nonsmoking female patient, in good systemic and periodontal health, presented to our institution with a bilateral atrophic edentulous ridge in the posterior mandible.

The remaining mandibular teeth were: 4.3, 4.2, 4.1, 3.1, 3.2 (Fig. 1).

The surgical sequence was scheduled as follows.

• Flap design and recipient site preparation.

• Membrane positioning.

• Bone graft.

• • • •

Suture.

Pre- and post-operative care.

Membrane removal.

Implant insertion.

Flap design and recipient site preparation The surgery started with a full thickness crestal incision within the keratinized mucosa of the edentulous ridge (Fig. 2,3). The incision extended intrasulcularly to one mesially adjacent tooth. Two vertical releasing incisions were made buccaly at the distal and mesial ends of the crestal incision.

The buccal and palatal full thickness flaps were elevated to gain a wide access for both membrane and implant placement.

A continuous periostal releasing

FIG. 1

The orthopantomograph shows bilateral atrophic edentulous ridge in the posterior mandible. The residual alveolar crest is at least 5 mm, thus allowing implant placement simultaneously to vertical bone regeneration in both sides.

FIG. 2

Intraoral view of the defect in the posterior right mandible. The anatomic condition requires vertical ridge augmentation to allow implant placement.

FIG. 3

Buccal and lingual full thickness flaps elevation and curettage of the bone surface from all remaining connective tissue and periostium.

46

Case report incision at the base of the buccal flap was made, connecting the mesial and distal vertical incisions in order to obtain, at the end of the surgery, a completely tension-free suture.

In the lower jaw particular care must be taken to avoid any lesion to the mental nerve and not to damage the vascular plexus of the floor of the mouth. Moreover, the lingual flap must be reflected beyond the mylohyoid insertion of the omohyoid muscle, in order to be coronally advanced. No periostal incision is performed in the palatal flap in the upper jaw. The flaps must be carefully managed to avoid any soft tissue trauma or perforation that could lead to membrane exposure during the healing period. After the flaps have been released, curettage of the bone surface is essential to remove all remaining connective tissue and the periostium that could jeopardize the regenerative procedure.

Membrane positioning In order to vertically augment the bone crest with the GBR technique, a titanium reinforced e-PTFE membrane (Gore-Tex, WL Gore) is necessary. The authors suggest the use of a TR9W or a TR6Y type, depending on the amount of bone to regenerate. The better performance of non–resorbable membranes compared to resorbable ones is due to their enhanced space making capabilities, controlled time of barrier function and lack of resorption process (Fig. 4). The surgeron must bend and trim the membrane to adjust it in the ridge and considering the width and height of the area to regenerate. To avoid any interference during the healing process, the membrane should not reach the periodontal ligament of the adjacent teeth and should overlap the residual crestal bone by at least 3 to 4mm.

Stainless steel miniscrews (6 to 12 mm in length) are used as tenting screws to support the membrane.

They are positioned in the residual bone and left to protrude for the required height. However, when the residual bone height is at least 6 mm and primary implant stability can be achieved, the implants are inserted simultaneously to membrane positioning. Implants are

left to protrude 3 to 7 mm from the cortical bone, thus acting as miniscrews (Fig. 5).

Several drill holes must be made on the cortical bone to ensure bleeding, and thus the blood clot, necessary for bone formation.

Once positioned in the recipient site, the membrane is lingually stabilized with fixation mini-screws in the mandible, and with titanium tacks in the upper maxilla. A particulated bone graft is then placed on the bone crest under the partially fixed membrane and covered with it to achieve optimal adaptation. The membrane is gently pulled buccally and fixed at its mesial and distal buccal border.

Bone graft In 1994 Simion introduced the use of GBR technique for vertical ridge augmentation in humans. Filling the space under the membrane with a bone graft resulted in improved bone formation (Simion et al., 1998; Tinti et al., 1996).

Autogenous bone grafts, harvested from both intra-oral and extra-oral donor sites, are considered to be the gold standard in bone regeneration (Burchardt, 1983; Simion et al., 1998; Tinti et al., 1996). However, in order to reduce the disadvantages

associated with autogenous bone harvesting, some authors suggested the use of combination grafts to add the scaffold properties of a bone substitute to the osteogenetic and osteoinductive properties of the autografts (Misch and Dietsh, 1993; Tidwell et al., 1992; Yildirim et al., 2001).

Even though in the literature no information is available about mixing an autogenous bone graft with a xenograft in vertical ridge augmentation, evidence emerging from clinical results suggests a 1 to 1 ratio of autograft and deproteinized bovine bone.

Moreover, the use of this combination always avoided a major surgery for autogenous bone harvesting, subsequently leading to a less invasive procedure and less post-operative discomfort of the patient.

The autogenous bone graft is usually harvested from the mandibular ramus and the mental symphysis with trephine burs. The collected bone is then particulated using a bone mill (Quetin) and finally mixed with deproteinized bovine bone (Bio–Oss, Geistlich).

Sutures Membrane exposure during the

FIG. 4 Titanium-

reinforced e-PTFE membrane fixed with 2 miniscrews. Several drill holes must be made on the cortical bone to ensure enough bleeding.

Autograft harvested from the mandibular ramus mixed with deproteinized bovine bone is placed under the membrane over the defect.

FIG. 5

The membrane is gently pulled buccally and fixed with 2 miniscrews.

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Fontana F., Fimmanò M. and Berardinelli F. FIG. 6

Suturing consists of two lines of closure.

Horizontal mattress sutures with U stitches and interrupted sutures.

FIG. 7

A drawing of the suture technique.

FIG. 8

Suture removal after 15 days.

FIG. 9

Lateral view after 8 months of healing.

healing period is the main complication in vertical ridge augmentation with GBR procedures, therefore the suturing technique is essential for tissue healing (Fig. 6, 7) Sutures should just keep the soft

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tissue flaps in position. Therefore, before suturing, the surgeon must clinically evaluate the coronal extension of both flaps: they should overlap each other at least 10 mm.

Suturing consists of two lines of

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closure: horizontal mattress U stitches must be applied first to ensure proper flap apposition with the connective tissue surfaces, facing each other at least 3 mm.

Subsequently, interrupted sutures are used between the horizontal mattress and to close the vertical incisions. Sutures are removed after 12 to 15 days (Fig. 8, 9). The choice of a suitable suturing material is also very important. The authors suggest the use of an ePTFE nonabsorbable monofilament (Gore Tex suture, WL Gore).

Pre and postoperative care The surgical procedure requires an aseptic operating room.

Presurgical preparation of the patient consisted of a chlorhexidine digluconate 0.2% mouthrinse (Corsodyl, GlaxoSmithKline) for 2 minutes and an extraoral scrub with a povidone-iodine solution (Betadine, Viatris). A sedative premedication with diazepam (2030 gtt, Valium-2, Roche) was administered before surgery.

Local anaesthesia consisted of articaine 4% and epinephrine 1:100000 (Citocartin 100, Molteni Dental). The patient underwent antibiotic treatment with amoxicillin and clavulanic acid (Augmentin, GlaxoSmithKline) starting 1 day before surgery and then twice a day for 1 week. The patient also received a non-steroid anti-inflammatory drug starting 1 hour before the surgery and twice a day for 1 week. Chemical plaque control was ensured with chlorhexidine 0.12% mouthrinses twice a day, in order to reduce bacterial contamination of the wound. The patient followed monthly recalls. Radiographic examination was done at the end of the surgery and at membrane removal (Fig. 10).

Membrane removal The titanium-reinforced e-PTFE membrane is a non resorbable membrane, therefore a second surgery is required. These e-PTFE membranes should remain completely submerged and in place for 6 to 8 months, that is the optimal time frame clinically required for bone regeneration to occur (Becker and Becker, 1990; Buser et al., 1990).

Case report FIG. 10

Orthopantomography after bilateral bone regeneration with fixing miniscrews, “pole� miniscrews and titanium mesh membrane.

FIG. 11

Two fullthickness flaps were elevated buccally and lingually to localize and to remove the miniscrews and the membrane.

FIG. 12

A layer of connective tissue-like soft tissue layer was present upon the vertically regenerated bone.

Membrane removal started with a crestal incision and mesial and distal vertical releasing incisions (Fig. 11). Two full-thickness flaps were then elevated buccally and lingually to localize and to remove the mini-screws (or the tacks in the upper jaw). The membrane was gently dissected from the bone.

Usually a connective tissue like soft tissue layer is present upon the vertically regenerated bone. It is about 1 mm thick and it can be used to apically position the buccal flap in order to augment keratinized mucosa (Fig. 12, 13).

Implant insertion Implants can be positioned with a simultaneous or with a staged approach. When the residual bone crest is high enough to allow primary implant stability (>= 6 mm), fixtures are inserted at the time of the vertical regenerating procedure.

Therefore, healing abutment connection coincides with membrane removal (Fig. 14-18).

In the staged approach, implants are positioned at membrane removal after at least 6 months of submerged membrane healing.

Discussion and conclusion FIG. 13

The regenerated area has the clinical aspect and the stiffness of native bone.

The mini tenting screws were almost submerged.

FIG. 14

Three parallel pins after implants insertion.

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The case reported above illustrates a vertical crestal bone regeneration by means of guided bone regeneration which had stable and esthetically acceptable results (13).

A well-planned therapeutic design, and the efforts and persistence of both the treatment team and the patient are essential for a successful treatment outcome, as this may require multiple surgeries and log healing periods.

Vertical ridge augmentation by means of GBR has proved to be a successful and predictable procedure, when non resorbable membranes are associated to a filling material, but this surgical technique is the most technicallysensitive among all GBR procedures. Therefore, a proper surgical technique and the skill of the surgeon represent crucial factors for a successful and predictable bone regeneration.

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Fontana F., Fimmanò M. and Berardinelli F. FIG. 15

Implants on site, occlusal view.

study in the rabbit. Clin Oral Implants Res 1991;2(4):199-202.

3. Linde A, Thoren C, Dahlin C, Sandberg E. Creation of new bone by an osteopromotive membrane technique: An experimental study in rats. Int J Oral Maxillofac Surg 1993;51:892897.

4. Jovanovic SA, Schenk RK, Orsini M, Kenney EB. Supracrestal bone formation around dental implants: An experimental dog study. Int J Oral Maxillofac Implants 1995;10:23-31.

FIG. 16

Control orthopantomography.

5. Jensen OT, Greer RO, Johnson L, Kassebaum D. Vertical guided bonegraft augmentation in a new canine mandibular model. Int J Oral Maxillofac Implants 1995;10:335-344.

6. Renvert S, Claffey N, Orafi H, Albrektsson T. Supracrestal bone growth around partially inserted titanium implants in dogs. Clin Oral Implants Res 1996;7:360-365.

FIG. 17

During implants reopening connective graft is compulsory to create a wide enough strip of keratinized adherent gingiva.

FIG. 18

One month of fealing after the connective palatal graft.

7. Simion M, Trisi P, Piattelli A. Vertical ridge augmentation using a membrane technique associated with osseointegrated implants. Int J Periodontics Restorative Dent 1994;14:497-511.

8. Simion M, Jovanovic SA, Trisi P, Scarano A, Piattelli A. Vertical ridge augmentation around dental implants using a membrane technique and autogenous bone or allografts in humans. Int J Periodontics Restorative Dent 1998;18(1):8-23.

9. Simion M, Fontana F, Rasperini G, Maiorana C. Vertical ridge augmentation by e-PTFE membrane and a combination of intraoral autogenous bone graft and deproteinized anorganic bovine bone (Bio-Oss). Clin Oral Implants Res. In press.

10. Tinti C, Parma-Benfenati S, Polizzi G. Vertical ridge augmentation:What is the limit? Int J Periodontics Restorative Dent 1996;16:221-229.

11. Parma-Benfenati S, Tinti C, Albrektsson T, Johansson C.Histologic evaluation of guided vertical ridge augmentation around implants in humans. Int J Periodontics Restorative Dent 1999;19(5):424-437.

References 1. Albrektsson T, Dahl E, Enborn L et al.

Osseointegrated oral implants. A Swedish multicenter study of 8139

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consecutively inserted Nobelpharma implants. J Periodontol 1988;59:287296.

2. Schmid J, Hammerle CH, Stich H, Lang NP. Supraplant,a novel implant system based on the principle of guided bone generation. A preliminary

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12. Simion M, Jovanovic SA, Tinti C, Benfenati SP. Long-term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation. A retrospective study on 123 implants with 1-5 year follow-up.

Clin Oral Implants Res 2001;12(1):35-45.

13. Anitua E. Plasma rich in growth factors: preliminary results of use in the preparation of future sites for implants. Int J Oral Maxillofac Implants 1999;14(4):529-535.

Case report

Surgically-assisted rapid palatal expansion and orthodontic treatment in preparation for Le Fort 1 and sagittal split osteotomy surgery Giovanna Perrotti* Michele Izzo* Laura De Vecchi* Aldo B. GiannĂŹ** Massimo Del Fabbro***

Department of Health Technologies, University of Milano, IRCCS Istituto Ortopedico Galeazzi, Milano, Italy *Section of of Pre-Surgical Orthodontics, Dental Clinic **Professor, Head of Section of Maxillofacial Surgery ***Researcher, Section of Oral Physiology

Background: This article reports the treatment of a 15-year old male patient with anterior open bite and a severely narrowed upper dental arch. The young patient complained of occlusal and masticatory dysfunction due to the anterior open bite and difficulties in breathing normally through his nose.

Case report: A posterior crossbite was present on both sides. For the correction of the posterior cross-bite, a surgically assisted rapid maxillary expansion and a presurgical straight wire multibracket tooth alignment was applied. The treatment plan included Le Fort I osteotomy and mandibular setback with a sagittal splitting ramus osteotomy. The total treatment time was 36 months, including five months of post-surgical observation.

After treatment, a stable occlusion was achieved with a Class I molar relationship and a complete open-bite closure. The patient referred remarkable improvements in breathing.

Conclusion: Surgically assisted rapid maxillary expansion and Le Fort 1 osteotomy can be regarded as a safe and effective approach for the treatment of skeletal divergence. Long-term observation of the maxillary arch width after retention is of the utmost importance for the maintenance of a successful treatment outcome.

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Key words: rapid palatal expansion; sagittal split osteotomy; open-bite.

Perrotti G. et al.

Introduction Genetic factors have a role in the aetiology of skeletal hyperdivergence associated with anterior open-bite.

The growth pattern of the maxillary base usually follows a forward and upward trend leading to an increase in the anterior vertical dimension at the expenses of the posterior vertical dimension. This results in a reduction of the posterior space available for dentoalveolar eruption (1,2), whereas mandibular growth follows a rotational pattern along the condylar axis resulting in mandibular postero-rotation. The greater this movement, the shorter the ascending branch of the mandibular bone. The result of this diverging movement is an increase in the skeletal vertical dimension.

Vertical maxillary excess may involve a maxillary component associated with this mandibular posterorotation.

Some cases of skeletal divergence develop a correct molar Class I occlusion with overjet and overbite parameters within the normal range, obtained by significant vertical maxillary compensation that causes a ‘gummy smile’, often accompanied by labial incompetence.

Differential diagnosis between dentoskeletal open-bite and long face syndrome is based on the different stages of dentoalveolar compensation. In the former case, compensation does not develop, as the divergence of the occlusal planes follows skeletal divergence.

The aetiology of open bit often also involves bad habits such as prolonged finger or lip sucking and mouth breathing, aggravating factors that, when expressed on a highlyreceptive substrate, worsen the disease (3,4).

Skeletal diagnosis A 15 year-old male subject was referred to the Galeazzi Institution with the aim to obtain a normal occlusion and correct skeletal relationship (Fig. 1).

The patient simply asked to obtain a normal bite with teeth in contact, to be able to breathe normally through his nose and to close his lips without

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FIG. 1b

Right side.

FIG. 1a

Pre-treatment lateral photograph with Ricketts cephalometric tracing.

FIG. 1c

Front side.

FIG. 1d

Left side.

difficulty.

The patient showed the typical adenoid face, nasal voice, labial incompetence and dental open-bite, which resulted in relational difficulties. He had a Class II malocclusion with greatly reduced transverse diameters, and a severely ogival palate. This generated a reduction in volume of the nasal fossae and consequently reduced nasal patency, forcing the subject to breathe through his mouth.

The mandibular plane and gonial angle were greater than normal and had caused extensive mandibular postero-rotation. The ascending branch, however, was adequately sized: a favourable prognostic factor when it comes to surgical anterorotation. The occlusal planes were cephalometrically divergent and caused an open bite beyond the first premolars (Fig. 2).

The facial analysis confirmed the skeletal cephalometric data: the

52

convex profile and increased vertical dimension caused an open nasolabial angle and labial incompetence, while the soft-tissue pogonion was set back from the true vertical line (TVL).

The chin-neck angle was favourable for surgical rotation.

On a frontal view, the vertical maxillary excess and the transverse deficiency caused a slight protrusion of the sclera and the smile line showed the severe dentoskeletal open bite and gummy smile. The interzygomatic distance was reduced and the gonial angles were underpronounced on account of the mandibular postero-rotation.

Dental diagnosis • Molar Class II occlusion.

• Reduced transverse diameters.

• Medium - high teeth crowding.

Case report • Anterior open-bite.

• Midlines corresponding with skeletal midlines.

• Poor periodontal health due to a combination of factors: the patient’s poor oral hygiene, the result of mouth breathing and the absence of dental occlusion, which impaired the tongue’s cleaning effect on teeth.

The aim of the treatment plan was to threedimensionally reposition the maxillary and mandibular bones, rotate the occlusal planes in order to close the open bite, allow nose breathing and harmonize the facial tissues.

The cosmetic and functional expectations of the young patient were, of course, quite high. He was very motivated and very keen to cooperate in any possible way since the start of the treatment.

FIG. 3a

Intraoral photograph of the upper arch with palatal expander in situ.

FIG. 2

Pre-treatment Ricketts cephalometric tracing, the patient is a Class II malocclusion and had a skeletal severe anterior open bite.

FIG. 3b

Treatment plan In the treatment plan the following steps were scheduled: • surgically-assisted rapid palatal expansion; • presurgical orthodontic treatment using multibracket appliances on both dental arches; • maxillary and mandibular osteotomy surgery; • post-surgical orthodontic treatment; • post-treatment orthodontic retention; • craniofacial physiotherapy; • routine oral hygiene recalls.

SURGICALLY-ASSISTED RAPID PALATAL EXPANSION This approach was chosen due to the significant height of the palatal vault, that implied a reduction in air space and lack of room for dental alignment along the arch.

The surgical option was chosen despite the fact that the patient was 16 years old when the appliance was placed and there was a technical possibility that expansion could be obtained without performing an osteotomy (5-9).

A Haas-type Rapid Expander anchored by 4 bands was cemented onto the first molars and first premolars (Fig. 3). The operation was performed under general anaesthesia. The central screw was

Intraoral photograph of the upper arch after surgically-assisted rapid palatal expansion.

activated in the operating room with 8 full turns, equal to 2 mm.

Three days after surgery, screw activation was repeated for a total of 11 mm.

Weekly recalls were scheduled to check the extent of expansion reached, and the healing of both the vestibular suture and the postoperative swelling. The screw was then sealed using composite resin.

The rapid expander was worn for 6 months.

PRESURGICAL ORTHODONTIC TREATMENT WITH A MULTIBRACKET APPLIANCE The orthodontic treatment aiming at dental alignment started before the palatal expansion in the lower arch. The extraction option was taken into consideration during planning, but it was later decided that the arches could be prepared using orthodontic techniques to

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maintain the number of teeth and check the periodontal risk, especially in the lower incisors.

The Straight-wire technique was used, with pre-angled brackets and Ni-Ti archwire progression in the early phases, by fitting a fullthickness 0.17 X 0.25 steel arch-wire.

Transverse relapse was controlled at the initial phase, after the first rapid palatal expansion, and later while using a rigid palatal splint. The splint and transpalatal bar were maintained during the second surgical phase.

ORTHOGNATHIC SURGERY The surgical repositioning of the bone bases was performed with a Le Fort I osteotomy with 9 mm anterior and posterior vertical impaction, combined with extensive resection of the cartilaginous and bone nasal septum, in order to avoid secondary dislocations.

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Perrotti G. et al.

FIG. 4b

Right side.

his self-confidence.

Cephalometric and cosmetic analysis confirmed that the goals set had been achieved: this means the attainment of a skeletal I Class and an Angle I Class. The line of the profile is straight.

Our young patient reported an improvement in airways patency.

The significant vertical and sagittal skeletal displacements were welltolerated in terms of neuromuscular compensation and tendency to relapse.

The two-year follow up confirmed the stability of the case.

Discussion FIG. 4a

FIG. 4c

Post-treatment lateral photograph with Ricketts cephalometric tracing.

Frontal side.

FIG. 4d

Left side.

The mandibular osteotomy allowed to disengage the temporomandibular joint from the lower arch. This allowed the mandibular arch to follow the whole upward vertical movement of the maxilla, bringing the teeth into occlusion.

The mandibular ramus was then bilaterally stabilized, to avoid loss of its physiological inclination.

The last step of the procedure was the osteotomy of the mental symphysis, with a 4-5 mm advancement to achieve better cosmetic results and an improved profile (10-11).

RETENTION After the finishing procedures, the fixed appliance was removed. The patient was given an Essix retainer in the upper jaw to wear during the day and a removable appliance to wear at night, to maintain transverse stability.

Moreover the lower incisors were splinted together at the lingual side.

A removable appliance was fitted to maintain correct occlusal relationships (12).

The patient was encouraged to improve labial competence with myofunctional exercises.

POST-SURGICAL ORTHODONTIC TREATMENT Eight weeks after surgery, following routine check-ups and occlusal splint treatment, another orthodontic phase was undertaken to correct occlusal stability and intercuspidation. (Fig. 4).

Results

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Good balance was obtained between the soft tissues, bone and teeth, improving the patient’s appearance, breathing and masticatory function, joint stability and, undoubtedly, also

54

The combination of orthodontic and surgical treatment made it possible to achieve the targets set: expansion of the transverse maxillary diameter and control over the skeletal vertical dimension.

After the first surgically-assisted rapid palatal expansion and dental alignment procedures were performed, a rotation of the occlusal plane was achieved by mandibular anterorotation.

From a skeletal viewpoint there was a vertical maxillary excess, despite having achieved a molar I Class occlusion and closure of the anterior open bite during the first phase of treatment.

As illustrated in detail, the second surgical stage modified the skeletal pattern in order to obtain a better balance between soft tissues, skeletal components and occlusion with a significant improvement in the facial harmony. In other words, if a maxillary osteotomy is performed, the mandible autorotates with a condylar fulcrum.

This movement normally changes too much the inclination of the ramus so that condylar problems and instability may occur. For this reason, when the vertical upward movement of the maxilla is greater than 4-5 mm, it is always advisable to perform mandibular osteotomy.

This justified our decision to perform a two-staged surgical approach.

Transverse relapse factors also have to be considered. The first expansion operation favoured the presence of 2 conditions: the first,

Case report removable retainer appliance was also stimulated by the higher, palatal posture of the tongue, which is able to keep the lips completely closed. In a short period of time it has been obtained the relaxation of the mental muscle. The patient had obtained complete nasal breathing, due to wider palatal vault, reduction of nasal resistance and improvement of nasal breathing.

However not all patients increase the nasal breathing after maxillary expansion because of the habit of oral breathing. In our case the autorotation of the mandible obtained the complete muscular closure of the lips and consequently a complete nasal breathing (Fig. 6).

Conclusion

FIG. 5a

Comparison between pre-treatment and post-treatment lateral photographs.

Good stability of the neuromuscular system, occlusion and nasal function were obtained.

The combination of surgicallyassisted palatal expansion and maxillary and mandibular osteotomy can provide satisfactory results. The two step procedure has the benefit to increase and lower the maxillary vault, creating an anatomical situation that could decrease the level of difficulty at the second surgical intervention.

However, further clinical studies are required to confirm the effectiveness of this treatment approach.

FIG. 6

FIG. 5b

Comparison between pre-treatment and post-treatment lateral photographs.

of an orthodontic nature, allowed dental alignment without extractions, the second, of a surgical type, made it possible to expand and impact the maxilla, reducing the risk of excess strain on the palatal mucosa (Fig. 5a-b).

Moreover the first surgery improved airways patency, which helped the patient breathing through his nose and contributed to conditioning the neuromuscular tissues prior to the

Pre-treatment (black line), after surgically-assisted rapid palatal expansion (pink line) and posttreatment (blue line) Ricketts cephalometric tracings. Look at mandibular anterorotation and vertical dimension reduction after surgically-assisted rapid palatal expansion.

corticotomy and mandibular rotation.

This latter factor may have contributed to the satisfying result achieved and to the neuromuscular maintenance of occlusal stability.

During the mandibular anterorotation procedure, the elongation of the suprahyoid muscles was slight and labial competence was easily maintained.

Transverse stability assisted by the

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Perrotti G. et al. orthodontic expansion of the maxilla.

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8. Koudstaal MJ, Poort LJ, van der Wal KG., Wolvius EB, Prahl-Andersen B, Schulten AJ. Surgically assisted rapid maxillary expansion (SARME): a review of the literature. Int J Oral Maxillofac Surg 2005;34:709-714.

9. Altug Atac AT, Karasu HA, Aytac D. Surgically assisted rapid maxillary expansion compared with orthopedic rapid maxillary expansion. Angle Orthod 2006;76:353-359.

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