Neurosensory and functional evaluation in distraction osteogenesis of the anterior mandibular alveolar process

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.

Anterior Mandibular Segmental Distraction Osteogenesis: A Case Report

Introduction:

Skeletal Angle Class I patients with a severe dental Class II malocclusion are characterized by an unfavourable anterior-posterior relationship between the anterior dentoalveolar area and the skeletal base. Orthodontic alignment posing various treatment difficulties and surgical correction with bilateral sagittal split osteotomy may result in a compromised facial profile. Hence, anterior mandibular segmental distraction osteogenesis has been proposed as an alternative treatment modality for solving facial esthetics, anterior tooth crowding and an unfavourable relationship between the anterior dentoalveolar area and the skeletal base in skeletal Angle Class I patients with a severe dental Class II malocclusion. Limited skeletal relapse with predictable soft tissue changes have been documented in long-term studies. Thus, anterior mandibular segmental distraction osteogenesis seems to be a valuable and predictable surgical method for correction of selected cases of skeletal Class I patients with a severe dental Class II malocclusion.

Case report:

The purpose of this case report is to present the treatment of a 57-year-old female with a skeletal Angle Class I relation and a severe dental Class II malocclusion. Anterior mandibular segmental distraction osteogenesis as well as discussing the current knowledge about this treatment modality.

Conclusion:

The present case report illustrates that establishment of a harmonious relationship between the maxillary and mandibular arch in patients with a skeletal Angle Class I relation and a severe dental Class II malocclusion using anterior mandibular segmental distraction osteogenesis seems to be a predictable and applicable surgical method for selected cases and General Dental Practitioners, orthodontics and maxillofacial surgeons must have knowledge of this treatment modality.

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.