Mandibular symphyseal distraction osteogenesis with stepwise osteotomy in adult skeletal class III patient

Facial improvement after mandibular midline distraction and surgically assisted rapid maxillary expansion

This case report describes the retreatment of a 49-year-old woman with severe crowding in the mandibular incisor region and tapered maxillary and mandibular arches. Treatment consisted of mandibular midline distraction and surgically assisted rapid maxillary expansion to increase arch length. The need for proper presurgical orthodontics is described, and the complications during treatment are discussed. The results of treatment, including the superimposition of 3-dimensional facial scans, are presented. The treatment approach we used is typically indicated for patients with previous extractions of all first premolars who develop significant crowding after treatment. Surgical planning in 3 dimensions and the use of a 3-dimensional designed surgical osteotomy guiding wafer should improve the predictability of this treatment approach.

Two-step transport-disk distraction osteogenesis in reconstruction of mandibular defect involving body and ramus

One-step transport-disk distraction osteogenesis (TDDO) is effective for repairing segmental mandibular defects. The authors studied whether it was effective for reconstructing angled large mandibular defects using a two-step TDDO procedure in seven patients suffering from neoplasm. In the two-step TDDO procedure, the first distraction (horizontal distraction) was initiated immediately after mandibulectomy, aimed at restoring the mandibular body. It was followed by the second distraction, which was obliquely vertical and aimed at restoring the height of the ramus. The distraction rate was set at twice 0.4mm/day. The treatment lasted for 14-18 months. The horizontal distraction length ranged from 48 to 55mm, and the vertical one from 33 to 43mm, with full ossification in the distraction area. No obvious shift of mandible, malocclusion or mouth opening limitation was observed. Patients had a regular diet and spoke clearly. In conclusion, the two-step TDDO is still an option for the reconstruction of large angled mandibular defects when patients are prudently selected, despite the long treatment period required.

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Facing a dental crowding, the orthodontist has several therapeutic options. If maxillary expansion is often used, mandibular orthodontic expansion is proscribed because of its tendency of inefficiency and relapse. Mandibular symphyseal distraction osteogenesis allows to remove this proscription. This therapeutic protocol consists in a pre-surgery orthodontic preparation phase followed by surgery (symphyseal osteotomy and placement of the distraction device), a latency period (five to seven days), then an activation period (most of the time 1 mm/day in two steps) followed by a consolidation period (three months) during which the orthodontic treatment can be resumed. Skeletal and alveolar expansion corrects dental crowding. This surgical technique is versatile, minimally invasive, and stable with time. Major indications are hypoplastic symphysis, anterior crowding, relapse of orthodontic treatments and some syndromes. This method can also be an answer to aesthetic concerns or an alternative for treatment of dental crowding. Face à un encombrement dentaire, l'orthodontiste dispose de plusieurs options thérapeutiques. Si au maxillaire, l'expansion est fréquemment utilisée, l'expansion mandibulaire orthodontique est proscrite, car inefficace et récidivante. La distraction symphysaire permet de lever cet interdit. Ce protocole thérapeutique comprend : une préparation orthodontique pré-chirurgicale, une chirurgie (ostéotomie symphysaire et pose du distracteur), une période de latence (cinq à sept jours), puis une période d'activation (le plus souvent 1 mm/j en deux fois) suivie d'une période de consolidation (trois mois) pendant laquelle le traitement orthodontique peut être repris. L'expansion basale et alvéolaire corrige l'encombrement dentaire. Cette technique est polyvalente, peu invasive et stable dans le temps. Ses indications majeures sont l'hyposymphysie, l'encombrement incisif, la récidive de traitements orthodontiques et certains grands syndromes. Cette méthode peut aussi être proposée pour répondre à des préoccupations esthétiques ou comme alternative aux traitements classiques de l'encombrement dentaire.