[Symphyseal bone distraction (part 2): which protocol in 2018? A systematic literature review]

The aim of this systematic literature review is to propose a clinical protocol in 2018 by comparing therapeutic efficacy and undesirable effects of the technique.

Searches were made on Pubmed/Medline and Cochrane for randomized clinical trials and case series involving mandibular symphyseal distraction over the past 20 years with a patient sample greater than or equal to 10.

Of the 92 articles, 25 met the inclusion criteria. A controlled trial was selected, but no randomized trial. The other studies were all case series, 16 retrospective and 8 prospective. Dental crowding over 7 mm, with or without compensation, is an indication for mid-symphyseal distraction. Pre-surgical orthodontic treatment ensures root divergence between the mandibular incisors. Tooth-borne devices are recommended in first intention. Surgical intervention (ambulatory) under local anesthesia and intravenous sedation is considered. The latency period before activation of the jack is 6 days. Activations are performed by the orthodontist and subsequently by the patient at a rate of 1 mm per day, with four activations daily. Orthodontic movements are resumed two weeks after activations are discontinued. The distractor is removed within two to three months after installation.

Although the main features of the mid-symphyseal distraction protocol were drawn up essentially in the light of expert opinion, they still need to be refined by controlled trials.