Innovation in anterior mandibular alveolar distraction osteogenesis: Introduction of a new bone-borne distraction device and first clinical results

Front-block technical note: dental and bone borne distractors

Orthognathic surgical technique of segmental osteogenesis distraction of the anterior mandible alveolar process (front-block) was introduced by Triaca and al. in 2001 [2] including lower incisors. The technical note describes distraction process used both, dental-borne distractor and bone-borne distractor. A genioplasty plate was used as a bone-borne distractor. The main point here is that distraction depends on two distraction vectors, a dental one and an alveolar one. It provides good stability and controlled segmental osteogenesis translation and allows sufficient alveolar segmental transport without loading the teeth too heavily.

Nasopharyngoscopic Analyses through Anterior Maxillary Distraction Osteogenesis for Adolescent Patients With Cleft Palate

Anterior maxillary distraction osteogenesis (AMDO) is a novel technique for correcting hypoplastic maxilla by sagittal expansion of the maxilla. Recent reports suggest that AMDO does not have an effect on fragile velopharyngeal function in patients with cleft palate. Furthermore, no studies have evaluated the impact of AMDO on velopharyngeal function.We adopted AMDO to correct severe hypoplastic maxilla in adolescent patients with cleft palate and evaluated its impact on velopharyngeal space and function in 8 patients aged 12 to 21 years who underwent AMDO from 2006 to 2014. All the patients had received treatment for cleft palate; however, they still exhibited marginal velopharyngeal insufficiency. The mean activation of the distractor was 10.9 ± 0.9 mm.We determined changes in velopharyngeal closure ratio and closure pattern via nasopharyngoscopy. Additionally, skeletal changes were evaluated using lateral cephalograms.The mean horizontal advancement in the cephalogram obtained 1 year after the distraction was +6.4 mm. Nasopharyngoscopic examination revealed that no deterioration of velopharyngeal gap had occurred after AMDO in all 8 patients. The velopharyngeal closure pattern changed from coronal to circular in 1 patient.Our results indicate that AMDO achieved correction of hypoplastic maxilla without deterioration in velopharyngeal gap and function. Therefore, AMDO is an effective and optimal approach for correcting hypoplastic maxilla especially in patients with fragile velopharyngeal function, such as those with cleft palate.

Treatment outcomes of archwise distraction osteogenesis in mandibular dentoalveolar retrognathia cases

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.

Gingival recessions of lower incisors after proclination by orthodontics alone or in combination with anterior mandibular alveolar process distraction osteogenesis

OBJECTIVES

The aim of this study was to longitudinally compare periodontal conditions in consecutive patients who had orthodontic treatment with proclination of lower incisors either by orthodontics alone or in combination with anterior mandibular alveolar process distraction osteogenesis (DO).

MATERIALS AND METHODS

Nineteen patients had orthodontic treatment with DO, 18 with extraction of lower premolars (Ex), and 18 without extractions (Nonex). Lateral cephalograms were used to evaluate lower incisor proclination, while study casts and intraoral photographs were used to evaluate labial and lingual gingival recessions before (T1) and at an average of 4.5 years (T2) after treatment.

RESULTS

No differences in labial recessions on lower incisors were present between the patient groups despite greater lower incisor proclination in the Nonex and DO groups. The Ex group showed no new development of lingual recessions in contrast to the Nonex (eight sites; two subjects) and DO groups (seven sites; three subjects). Severe lingual recessions (increased ≥1 mm) were more present in the Nonex group (five sites; two subjects) compared to the Ex group (no sites). Proclination of lower incisors of 10° or more either by orthodontic tooth movement or displacement of the whole alveolar process increased the risk of lingual gingival recessions 17 times. This was not the case with labial gingival recessions.

CONCLUSIONS

Orthodontic or surgical proclination of lower incisors beyond a 10° limit increases the risk of inducing lingual gingival recessions.

CLINICAL RELEVANCE

During orthodontic treatment, with or without DO, one should avoid proclining lower incisors more than 10° to decrease the risk of gingival recessions.

[Front Block distraction]

The contribution of the segmental osteotomies in the ortho-surgical protocols is no longer to demonstrate and found a new lease of life thanks to the combination with the bone distraction techniques. The osteotomy of Köle, initially described to close infraclusies, and then used to level very marked curves of Spee has more recently been used to correct anterior crowding. This support is therefore aimed at patients with an incisor and canine Class 2 but molar Class 1 with an isolated mandibular footprint. With minimal orthodontic preparation we can create in two weeks bilateral diastemas that will then be used to align the incisivocanin crowding without stripping or bicuspid extractions. Dental orthodontic movements can be resumed one month after the end of the distraction. This technique is therefore likely to avoid bicuspid extraction and replace some sagittal osteotomy advancement by correction of the overjet. It also helps to correct a incisors labial or lingual tipping playing on differential activation of the cylinders and the distractor. This segmental surgery can be combined with Le Fort 1 surgeries with correction of the transverse and associated meanings, but in a second time, to a mandibular advancement and/or a genioplasty.

Anterior alveolar segmental osteodistraction with a bone-borne device: clinical and radiographic evaluation

PURPOSE

Anterior alveolar osteodistraction is a common method for enlargement of the dentoalveolar process, and bone-borne distraction devices are hypothesized to avoid the risk of dental tipping and periodontal impairment during distraction. The aim of this study was to objectify this thesis and to determine the reliability of bone-borne osteodistraction of the anterior alveolar process.

PATIENTS AND METHODS

The study group consisted of 18 consecutive patients who underwent anterior alveolar segmental distraction with a bone-borne distraction device for the treatment of dental crowding or alveolar retrusion from 2008 through 2011. Clinical and radiologic changes within the apical base and dentoalveolar process were analyzed after bone-borne distraction osteogenesis. All measurements were carried out using cone-beam computed tomography.

RESULTS

Surgery and the postoperative period were uneventful in all patients. Mean alveolar movement was 8.2° ± 2.4°. Skeletal movement was 97.6% and absolute dental tipping was 2.4%. A mean change in the occlusal plane of 1.9° ± 1.1° was verified. The apical base enlargement showed a mean of 7.9 ± 1.4 mm, and the dentoalveolar arch a mean increase of 12.7 ± 2.1 mm. Within the distraction zone, a mean vertical bone loss of 3.5 ± 0.7 mm and a mean horizontal bone loss of 3.9 ± 0.8 mm were seen. After orthodontic gap closure, both were clinically irrelevant, with no need for additional bone grafts. Periodontal impairment (gingival recessions of 1 mm) was observed in 7 patients but affected only the teeth bordering the vertical osteotomy line.

CONCLUSIONS

Bone-borne anterior alveolar osteodistraction is sufficient for enlargement of the apical base and the dentoalveolar arch of the mandible. Skeletal movement of the alveolar segment was predictable and dental tipping was clinically irrelevant. This technique presents further indications and approaches in orthognathic surgery.