Growth modification of the mandible with ultrasound in baboons: A preliminary report

Introduction: Growth modification for patients with skeletal Class II malocclusions due to mandibular deficiency is controversial. Low-intensity pulsed ultrasound (LIPUS) can modify mandibular growth in growing rabbits. Before applying this treatment to humans, we must study the effect on mandibular growth in higher animal models. The objective of this study was to evaluate the effect of LIPUS on mandibular growth in baboons. Methods: Fourteen juvenile male hamadryas baboons were divided into 2 groups of 7 each. One group received bite-jumping appliances (jumper group), and the other group did not (control group). In both groups, the left temporomandibular joint area received LIPUS (stimulated), and the right side served as the control (unstimulated). Four months after the start of treatment, the baboons were injected with 99-mTc methylene diphosphonate and killed. They were decapitated and scanned for bone growth by using a dual head gamma camera. The mandibles were dissected, sectioned into halves, and radiographed for anthropometric measurements. The condyles were harvested and processed for histological examinations. Results: LIPUS increased mandibular length and growth activity in all treated sides (P<.001), especially in the jumper group. Conclusions: LIPUS enhances mandibular growth in growing baboons, especially when combined with anterior mandibular jumping appliances.