Article

Treatment outcomes of archwise distraction osteogenesis in mandibular dentoalveolar retrognathia cases

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Abstract

The aim of this study was to describe the treatment of class II malocclusion by sagittal advancement of the alveolar bone in the symphyseal area using an intraoral archwise distractor device and to determine the effects of this method on the dentoalveolar complex. Fifteen patients (10 female, five male) aged 16–20 years with a class II division 2 malocclusion, characterized by mandibular dentoalveolar retrusion and a prominent chin, underwent archwise alveolar distraction in the anterior mandible. Lateral cephalometric radiographs were obtained before distraction (T0), after 6 weeks of consolidation (T1), and after debonding (T2). Linear and angular skeletal, dental, and soft tissue measurements were performed. Forty-seven parameters were measured for each of the 15 subjects on pre- and postoperative lateral cephalometric radiographs (T0, T1, and T2). The distraction protocol was successful in all patients. Skeletally, the mandible showed a clockwise rotation. B-point moved forward significantly (P < 0.05). Overjet decreased significantly (P < 0.001). The total profile angle was unaffected, and the improvement in the submental fold was highly significant (P < 0.001). The intraoral archwise distraction force that is applied through brackets and archwires is sufficiently effective for alveolar advancement. This procedure is simple and effective in the treatment of specific adult patients with a class II division 2 malocclusion, characterized by a prominent chin and severe mandibular dentoalveolar retrusion.

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Bu çalışmanın amacı, iskeletsel Sınıf II maloklüzyona sahip olan bireylerde Herbst ve Twin-Blok fonksiyonel apareyleri ile tedavi sonunda; psikososyal durum ve subjektif uyku kalitelerinde meydana gelen değişimleri değerlendirmektir. Çalışmamızda büyüme gelişimi devam eden alt çene geriliği olan, 30 birey (18 kız ve 12 erkek, ortalama yaş 13.5±0.5 yıl) Herbst ve Twin-Blok fonksiyonel apareyleri ile randomize olarak tedavi edilmiştir. 15 birey (6 kız ve 9 erkek, ortalama yaş 13.4±0.7 yıl) Sınıf I kontrol grubunu oluşturmuştur. İskeletsel Sınıf II ilişkiye sahip bireylere tedavi süreci başında ve sonunda, iskeletsel Sınıf I ilişkiye sahip bireylere ise bir defa; Rosenberg Benlik Saygısı alt ölçeği, Eleştiriye Duyarlılık alt ölçeği, Sosyal Görünüş Kaygısı Ölçeği, Çapa Anksiyete Skalası ve Pittsburgh Uyku Kalite İndeksi uygulanmıştır. Tedavi öncesi ve tedavi sonrası ölçümler arasındaki istatistiksel karşılaştırılmalar Wilcoxon testi ile gruplar arası karşılaştırmalar Kruskall Wallis H testi ile değerlendirilmiştir. Başlangıç değerlendirmelerinde iskeletsel Sınıf I hastaların benlik saygısının ve uyku kalitesinin Sınıf II hastalardan istatistiksel olarak anlamlı düzeyde daha yüksek olduğu bulunmuştur (p
Article
The interaction between form and function in the craniofacial region is a well-accepted fact in orthodontics. The aim of the present study is to objectively evaluate if mandibular sagittal symphyseal distraction causes an increase in the retroglossal airway size and hyoid position in a retrospective clinical study. The pretreatment (T0) and 3 months post-distraction (T1) cone-beam computed tomography images of 12 patients (mean age 17.1 years) were retrieved. The retroglossal airway volume and hyoid-mandibular plane distance, hyoid-C3 distance, sella-nasion-B point angle angle, lower incisor to mandibular plane, and Mandibular plane angles were measured using 3D medical imaging software. The average amount of distraction at the superior border of the bony transport segment was 6.2 mm and 4.4 mm at the inferior border. The changes in retroglossal airway volume (2943.2 mm), incisor to mandibular plane (6.5°), and mandibular plane (2.1°) were significant. The changes in hyoid-mandibular plane distance and hyoid-C3 distances were not significant. However, a downward repositioning in Hyoid position was observed along with the mandibular clockwise rotation. This study showed that symphyseal dentoalveolar distraction osteogenesis, as a complementary to orthodontic therapy, can affect the form and size of the pharynx. Therefore, the airway size should be one of the diagnostic and decisive factors for an ideal treatment planning.
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Purpose: The purpose of this study was to investigate mandibular stability after lengthening the mandible by means of distraction. Materials and Methods: Fifty patients (mean age, 14.7 years; range, 11.2 to 37.3 years) with Angle Class II mandibular hypoplasia were treated by bilateral distraction osteogenesis to lengthen the mandible. Patients were divided into a high-angle group, with a high mandibular angle (sella/nasion-mandibular plane [SN-MP] > 38degrees), and a normal-to-low mandibular angle group (SN-MP less than or equal to38degrees). Clinical measurements and standardized cephalometric radiographs were taken just before operation; postdistraction at time of removal of the distraction devices, and 6 months and I year postoperatively. Analysis was performed by means of angle measurements: sella/nasion-maxilla point A (SNA), sella/nasion-mandibular point B (SNB), and SN-MP. Results: Eight of 14 high-angle patients showed a degree of relapse (57%), and only 3 of 36 patients showed relapse in the low/normal-angle group (8.3%). Conclusion: it can be concluded that high-angle patients are still at risk of relapsing and that distraction osteogenesis cannot prevent relapse in cases with a high mandibular plane angle. For low-angle patients, however, distraction is a safe and predictable procedure. (C) 2004 American Association of Oral and Maxillofacial Surgeons.
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The purpose of this study was to evaluate two different groups of patients who underwent bilateral sagittal split osteotomy for mandibular advancement. One group demonstrated no relapse, whereas a second group had documented relapse. The following questions were asked: 1) What factors contribute to relapse? 2) At what site in the mandible is movement seen? and 3) During what period does movement occur? A retrospective lateral cephalometric serial analysis was performed on 50 patients at multiple time intervals. Criteria for a candidate include 1) mandibular advancement surgery with rigid fixation, with or without genioplasty, 2) no maxillary surgery, and 3) relapse of 25% or more of the advancement. Of the 50 patients analyzed, 13 (26%) showed relapse of 25% or more and served as the relapse group. Twelve patients showed no relapse and served as the comparison group. Multiple-regression analysis for the relapse group showed that magnitude of advancement, increasing gonial arc and changing mandibular plane significantly accounted for 84.9% of the variance observed in relapse (P less than .001). Repeated-measures ANOVA showed that the majority of relapse occurred in the first 6 weeks after surgery (68%, P less than .05). Results of a paired t test showed that a significant change occurred in all the linear and angular measures except SN-AR-GO (P less than .05).
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Relapse continues to be a potential problem with use of the sagittal split osteotomy to advance the mandible. In an effort to isolate predictive factors, the records of 235 patients were analyzed to determine the pretreatment facial morphology, the amount of advancement, the amount of relapse, and the duration of relapse. No relationship was found between any of the measures of facial morphology and relapse. However, the amount of advancement, the amount of relapse, and the duration of relapse all were found to be strongly related. It was found that all patients shared a similar facial morphology, and thus no influence of facial form on relapse would be expected from this group. The relationships between advancement and relapse could be attributed to neuromuscular adaptation, which would be more prolonged and more extensive in instances of greater advancement, and thus give rise to relapse of greater extent and duration. It is therefore suggested that mandibular advancements of greater than 10 mm be fixed more rigidly and for a greater length of time than those of lesser magnitude.
Article
Fifty-one patients who underwent mandibular advancements with or without genioplasties were rigidly fixated with three, 2-mm bicortical screws per side. Radiographs were digitized preoperatively, immediately postoperatively, at 6 weeks, at 6 months, and at a subsequent long-term follow-up period. Location of the cephalometric landmarks, referenced to a vertical reference line (in millimeters), was used as the dependent variable. An overall inspection of the data shows that rigidly fixated mandibular advancements were very stable. The average case showed further advancement of pogonion from 6 weeks to the long-term follow-up period. However, relapse was noted in several cases. Factors that could be used as predictors of relapse were examined. Results indicated that magnitude of advancement was the only factor that successfully predicted relapse, accounting for 37.9% of the variance in the sample. Anatomic changes found to accompany such advancement are as follows: (1) when pogonion comes forward, anterior facial height and mandibular plane decrease while the proximal segment rotates forward, and (2) the maxillary central incisors flare and the mandibular incisors upright during this time period. A small degree of relapse as assessed at pogonion occurred during the first 6 weeks, followed by an advancement from 6 weeks to the longest time interval after the surgical procedure. However, these directional movements were not statistically significant.
Article
The purpose of this article is to survey the Herbst bite-jumping method. An outline of appliance design and appliance construction is given. The effects of the treatment method on the dentofacial complex and on the masticatory system have been analyzed with the aid of dental casts, cephalometric roentgenograms, and electromyographic registrations from the masticatory muscles. The use and effectiveness of the Herbst appliance in the treatment of Class II malocclusions are exemplified by clinical cases, some of which were followed for 5 years after treatment. The Herbst appliance is most effective in the treatment of Class II malocclusions, provided it is used as indicated. Thus, the appliance must be limited to growing persons only. The treatment method should not be looked upon as a last resort to be used only when other treatment approaches have failed. Treatment prognosis is best in subjects with a brachyfacial growth pattern. Unfavorable growth, unstable occlusal conditions, and persisting oral habits after treatment are potential risk factors for occlusal relapses. As treatment with the Herbst appliance is performed during a relatively short period, the hard and soft tissues (teeth, bone, and musculature) would need some time for adaptation to the new mandibular position after the appliance is removed. Posttreatment retention as a routine with a removable functional appliance is therefore recommended.
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A retrospective recall study of forty patients was made to examine mandibular function after orthognathic surgery. Maximum maxillomandibular opening, protrusion, and lateral excursions were measured and compared with similar mandibular movements in a control group of patients of comparable age. Six months to 42 months after maxillary and mandibular osteotomies, the majority of patients demonstrated decreased maxillomandibular opening compared to the control group 54.8 mm (SD 4.7). The decrease was most dramatic in patients previously treated with sagittal split ramus osteotomies. The mean maxillomandibular opening after Le Fort I osteotomy to reposition the maxilla superiorly was 48.7 mm (SD 5.7); after bilateral intraoral vertical ramus osteotomies to retract the mandible it was 48.6 mm (SD 5.7); and after bilateral sagittal split ramus osteotomies to advance the mandible it was 35.1 mm (SD 6.7). The presence of mandibular hypomobility after orthognathic surgery and maxillomandibular immobilization may be due to pre-existing or surgically induced muscle or temporomandibular joint dysfunction. Our findings indicate the need for routine clinical assessment of mandibular function preoperatively and for a systematic regimen of muscular and occlusal rehabilitation postsurgically to normalize muscle function, condylar movement, and range of mandibular motion.
Article
The objective of this study was to retrospectively evaluate stability of mandibular advancement after bilateral sagittal split osteotomies were performed. Three different fixation and immobilization protocols were examined. Thirty-three patients were evaluated with preoperative, immediate postoperative, and long-term (mean, 13 months) lateral cephalometric radiographs. The patients were divided into three groups: group 1 (n = 10) had nonrigid internal fixation and 6 weeks of maxillomandibular fixation, group 2 (n = 12) had rigid internal fixation and immediate postoperative function, and group 3 (n = 11) had rigid internal fixation with maxillomandibular fixation for a mean of 14 days. Group 3 had the least amount of sagittal and vertical relapse. Differences in sagittal relapse were statistically significant between groups 1 and 3. Group 2 demonstrated greater sagittal relapse than did group 3, although the result was not statistically significant. This study suggests that the use of rigid internal fixation with a period of maxillomandibular fixation appears to be more stable than nonrigid internal fixation with maxillomandibular fixation or rigid internal fixation without maxillomandibular fixation.
Article
Distraction osteogenesis as per Ilizarov was used to lengthen the canine mandible. In this study, physiological and ultrastructural examination of the inferior nerve was performed. Mandibular body corticotomies were performed, and the mandible was distracted 7 mm. The animals were killed 4 weeks after the distraction was completed. Bone formed within the distraction gap in all dogs. There was no statistically significant difference in the jaw-jerk voltage between control and experimental sides. There was a significant difference between the distracted and control nerves in only one area of one nerve.
Article
Experience using distraction osteogenesis for limb lengthening has shown the importance of appliance orientation. Although successful results of mandibular lengthening using osteodistraction have been reported, optimal orientation of the distractors relative to the mandible has not been determined. The purpose of this study was to evaluate the biomechanical effects of linear distractors placed parallel to the body of the mandible or parallel to the axis of distraction. A two-dimensional model of the human mandible was generated for computer simulation of mandibular osteodistraction. Linear distractors were then analyzed based on their orientation, either parallel to the body of the mandible or parallel to the axis of distraction. In addition, two types of distraction osteogenesis procedures for mandibular reconstruction were analyzed: 1) bilateral mandibular lengthening, and 2) bilateral mandibular lengthening in combination with midline mandibular widening. Distractors oriented parallel to the body of the mandible caused a lateral displacement of the posterior components of the distraction devices and a reduction of the midline distraction gap during mandibular lengthening. These effects were eliminated when the device was oriented parallel to the axis of distraction. Midline symphyseal widening created axial rotation of the mandibular condyles regardless of the orientation of the distractors. Distraction appliances must be oriented parallel to the axis of distraction to prevent adverse biomechanical effects during bilateral mandibular lengthening. Additional ramus osteotomies, using hinged devices for angular correction, may be necessary to compensate for rotational movements of the mandibular condyles secondary to midline osteodistraction.
Article
Although orthognathic surgery has now become a routine part of oral and maxillofacial surgery practice, the complexity of such surgery together with the detailed planning involved makes it a difficult area of surgery to follow in the literature. The plethora of literature on the subject of complications in orthognathic surgery makes it essential to devise a simple classification of complications so that comparative studies can be identified and grouped together for more meaningful interpretation. The aim of this article is to present a brief and coherent overview of the main complications associated with orthognathic surgery for the purpose of establishing a simple classification of complications for future reference.
Article
Dysfunction of the inferior alveolar nerve indicated by various degrees of numbness of the lower lip and chin is one of the few drawbacks of sagittal split osteotomy (SSO) of the mandible. Although it has been recorded throughout the history of this technique its true aetiology is poorly understood. In this study of 496 SSOs, we have evaluated possible correlations between neurosensory dysfunction and several variables that have been implicated, such as the age of the patient, mandibular movement, type of split technique and osteosynthesis, degree of intraoperative nerve encounter, and surgical skill. Nerve dysfunction developed after 200/496 SSOs (40%). The patient's age had a significant influence on the recovery of the neurosensory function. Intraoperative nerve encounter such as nerve manipulation correlated with dysfunction to a much lesser degree than expected. Surgical skill seemed to influence the recovery of neurosensory function after SSO, which is often referred to as a technique-sensitive procedure. We suggest that the dissection of the soft tissue on the medial aspect of the mandibular ramus might be partly responsible for nerve dysfunction of the lower lip and chin after SSO of the mandible.
Article
This report describes the application of an intraoral device for treatment of malocclusions characterized by mandibular deficiency and the surgical technique for its placement. In an office setting, 5 retrognathic patients underwent mandibular lengthening via distraction osteogenesis with an intraoral tooth-borne distraction device. Under local anesthesia and sedation, mandibular corticotomies, mobilization, and placement of the distractors were performed. Preoperative, intradistraction, and postoperative dental casts, photographs, and cephalometric radiographs were used to analyze the results. In 3 of the 5 cases, distraction occurred along the planned vector. The remaining 2 cases showed opening rotations of the mandibular anterior segment along with the advancement. This study documents that the mandible and the dental arch can be lengthened successfully using this technique.
Article
This article describes a nonextraction therapy for patients with anterior tooth crowding in the mandible or with an unfavorable relation between the anterior dentoalveolar area and the skeletal base. The method involves the gradual repositioning of the dentate segment by use of distraction osteogenesis. The method was applied in 25 patients. Indications comprised skeletal Class II patients with crowding, Class I patients with crowding, and Class III patients requiring decompensation before orthognathic surgery. A special hinge-joint bone plate was developed to allow the rotation of the anterior bone segment into the desired position. The gradual repositioning was achieved with orthodontic appliances. The procedure was successful in all patients. The typical advancement at the incisal edge was 2 to 5 mm. This method represents a new approach for nonextraction therapy in the mandible. It requires no soft or hard tissue grafting and results in favorable tissue conditions at the distraction site.
Article
Osteogenic distraction has been used for decades to lengthen limbs and now attention is focused upon its use within the craniofacial skeleton. This paper addresses distraction of the mandible. It is proposed that mandibular osteogenic distraction could be a possible adjunct to the orthodontic treatment of those adult patients with skeletal anomalies, who would benefit from combined orthodontic/orthognathic treatment. Three consecutive cases from one unit are presented, where adult patients with severe Class II division 1 malocclusions have undergone orthodontic treatment combined with mandibular osteogenic distraction, instead of conventional bilateral sagittal split osteotomies.
Article
Distraction osteogenesis is a technique used to lengthen the shortened mandible. However, the long term stability of the distracted mandibular bone is not known. The aim of this study was to assess if the sheep mandible relapses following lengthening, and to assess the quality of distracted bone up to 1 year post lengthening. Twenty-four sheep had bilateral external mandibular distractors applied, with three sheep as controls. Titanium marker screws were positioned both proximal and distal to the distraction zone in all sheep. Following a 5 day latency period, the interdental gap was distracted 1 mm/day for 20 days, with a subsequent 20 day consolidation period. Ante-mortem serial X-rays were used to assess for relapse by measuring the distance between the screws. The animals were sacrificed at either 3, 6, 9 or 12 months post-distraction. At post mortem, the distance between the screws was re-measured. The distracted bone was assessed mechanically and histologically. The mean mandibular lengthening obtained was 13.2 mm. There was no relapse of the mandible over 12 months. The distracted bone had attained the strength and stiffness of undistracted bone by 6 months post-distraction (p < 0.05). Histological evaluation revealed significant amounts of lamellar bone by 6 months post-distraction. No relapse occurred for 12 months post distraction lengthening. The bone formed following distraction was stable and of good quality. These findings lend support to the use of distraction osteogenesis in clinical practice.
Article
This study investigated the changes in the inferior alveolar nerve after mandibular lengthening with different rates of distraction. Bilateral mandibular corticotomies were performed in 8 goats. The mandibles in 6 goats were lengthened 10 mm using a custom-made distractor with 2 different rates of distraction (1 mm/d [n = 3] and 2 mm/d [n = 3]); the other 2 nondistracted mandibles served as a control. The goats with distracted mandibles were killed at 2 weeks after completion of distraction. The inferior alveolar nerve specimens from all animals were harvested and processed for histologic and ultrastructural evaluation. The mandibles were lengthened successfully in the distracted animals. Morphologic changes in the inferior alveolar nerves were observed when compared with the nondistracted controls. Moreover, signs of nerve degeneration, such as demyelination, axonal swelling, axoplasmic darking, and decrease in the number of axons, were more extensive and prominent in those nerves distracted at a rate of 2 mm/d. Degenerative changes in the inferior alveolar nerve occur after mandibular lengthening by distraction osteogenesis. The distraction rate of 1 mm/d appears to be tolerable and safe for the inferior alveolar nerve, but rapid distraction may cause serious degeneration.
Article
The purpose of this study was to verify the influence of tooth movement on tooth roots and periodontal tissues when teeth were moved into mature, well-organized, and mineralized regenerate bone created after distraction osteogenesis compared with immature, fibrous, and less-mineralized bone. Six 15-month-old male beagles underwent 10 mm of bilateral mandibular distraction osteogenesis. After 2-week (group 1) and 12-week (group 2) consolidation periods, third premolars were moved distally into the regenerate bone with 100 g of orthodontic force for 12 weeks. Simultaneously, second premolars were also moved distally as controls. After completion of tooth movement, the experimental animals were killed, and their tissues were harvested for histological evaluation. When premolars in groups 1 and 2 were compared, group 1 showed higher rates of tooth movement until the eighth week of experimental tooth movement (P <.05). The amount of tooth movement was significantly greater in group 1 than in group 2 or in the control teeth (P <.05). In group 1, we observed considerable root resorption extending into the dentin, and the thickness of the dentin became approximately half that of the controls at the compression side adjacent to the distraction gap. This root resorption extended from the cementoenamel junction to the root apex. In group 2, root resorption on the compression side reached the dentin, but the root resorption was less than in group 1. These results indicated that heavy force and early orthodontic tooth movement are not recommended when teeth are moved through regenerated bone created by distraction osteogenesis, to avoid tipping and severe root resorption.
Article
In this study the literature dealing with experimental cranio-facial distraction osteogenesis (DO) was reviewed. A PUBMED search (National Library of Medicine [NCBI] revised 1 April 2001) from 1966 through December 2000 was conducted. Key words used in the search were: distraction, lengthening, mandible, mandibular, maxilla, maxillary, midface, midfacial, monobloc, cranial, cranio-facial, maxillofacial. This search revealed a total of 120 experiment-orientated articles that were all analyzed in detail in this study. The purpose of the experimental study, animal model, animal growth status, type of distraction, type of surgery, distraction rate and rhythm, latency and contention period, amount of lengthening, relapse, complications and nature of the distraction device were analyzed. This review revealed that a total of 1207 animals were used in seven different animal models for research on cranio-facial DO: 54 using dogs (45.0%), 25 using rabbits (20.8%), 18 using sheep (15.0%), 11 using minipig (9.2%), seven using monkeys (5.8%), four using rats (3.3%) and one using a cat model (0.8%). Based on the results of this study, an attempt was made to provide biological DO parameters and guidelines for future research on experimental cranio-facial DO related to the appropriate animal model.
Article
Bilateral sagittal split osteotomy (BSSO) and distraction osteogenesis (DO) are the most common techniques currently applied to surgically correct mandibular retrognathia. It is the responsibility of the maxillofacial surgeon to determine the optimal treatment option in each individual case. The aim of this study was to review the literature on BSSO and mandibular DO with emphasis on the influence of age and post-surgical growth, damage to the inferior alveolar nerve, and post-surgical stability and relapse. Although randomized clinical trials are lacking, some support was found in the literature for DO having advantages over BSSO in the surgical treatment of low and normal mandibular plane angle patients needing greater advancement (>7 mm). In all other mandibular retrognathia patients the treatment outcomes of DO and BSSO seemed to be comparable. DO is accompanied by greater patient discomfort than BSSO during and shortly after treatment, but it is unclear whether this has any consequences in the long term. There is a need for randomized clinical trials comparing the two techniques in all types of mandibular retrognathia, in order to provide evidence-based guidelines for selecting which retrognathia cases are preferably treated by BSSO or DO, both from the surgeon's and the patient's perspective.
Article
The purpose of this study was to examine the effect of distraction osteogenesis surgery on the inferior alveolar nerve (IAN) and on the stability of the occlusion in patients undergoing mandibular osteotomy and advancement for correction of severe retrognathia. Five patients (4 women and 1 man) underwent vertical posterior body osteotomy or bilateral sagittal split ramus osteotomy with the application of a distraction device for advancement of the mandible of 10 to 14 mm. After a period of latency, each mandible was advanced 1 mm per day until the patient achieved a Class I occlusion. Distraction devices were removed after a suitable period of consolidation (4 to 11 months). IAN sensory function was evaluated by 2-point discrimination, response to painful stimulus, and moving brush stroke identification. Testing of the IAN was performed on all patients at 7 different time intervals: preoperative (T0), postsurgery and predistraction (T1), within 7 days after the end of distraction (T2), 3 months after T2 (T3), 6 months after T2 (T4), 9 months after T2 (T5), and 1 year after T2 (T6). The same surgeon performed all IAN testing. There were no instances of malunion or fibrous union. At the 1-year follow-up, all 5 patients showed no relapse of their advancement as assessed by their maintenance of a Class I occlusion. Radiographic analysis was not done to discern skeletal versus dental stability. All 10 IANs were intact after the initial surgery. As time progressed, all 10 nerves showed improvement of function as measured by 2-point discrimination, response to painful stimulus, and moving brush stroke identification. At 1 year postsurgery, all 10 nerves showed function consistent with or very near presurgery levels. Stable mandibular advancements of 10 mm and greater can be successfully accomplished by distraction osteogenesis without producing significant damage to the IAN.
Skeletal and dental stability of segmental distraction of the anterior mandibular alveolar process. A 5.5-year follow-up
  • Joss
Operation der prognathie und mikrogenie
  • Hofer