Low-level laser effect on mandibular distraction osteogenesis.

PURPOSE: The purpose of this study was to determine whether low-level laser (LLL) application during distraction osteogenesis could accelerate bone regeneration and decrease the length of the consolidation phase and thereby reduce potential patient morbidity.
MATERIALS AND METHODS: Nine adult female New Zealand white rabbits underwent bilateral mandibular corticotomies and placement of unidirectional distraction devices (KLS-Martin LP, Jacksonville, FL). Each rabbit served as its own internal control. After a latency of 1 day, distraction progressed bilaterally at 1 mm per day for 10 days. Immediately after each device activation, the experimental side, chosen randomly, was treated with real LLL (Laser Medical Systems, Hedehusene, Denmark) of 6.0 J x 6 transmucosal sites in the area of the distraction gap. Radiographs were taken presurgically, immediately postsurgically, and weekly until sacrifice, and the bone was analyzed using a semiquantitative 4-point scale (Bone Healing Score [BHS]). Three animals each were sacrificed at 2, 4, and 6 weeks postdistraction, and each hemimandible was prepared for histologic examination in a blinded fashion.
RESULTS: Ten millimeters of distraction was achieved in each rabbit bilaterally. Radiographically, the BHS was higher for the LLL-treated group at all time periods. Histologically, the area of new bone trabeculation and ossification was more advanced for the LLL-treated group, with less intervening fibrovascular intermediate zone in the bony regenerate, at all time periods. The formation of a complete inferior border occurred sooner in the treatment group than in the controls.
CONCLUSIONS: LLL accelerates the process of bone regeneration during the consolidation phase after distraction osteogenesis. The adjunctive use of LLL may allow a shortened period of consolidation and therefore permit earlier device removal, with the avoidance of morbidity associated with prolonged device retention.