Growth modification of the rabbit mandible using therapeutic ultrasound: is it possible to enhance functional appliance results?

Previous studies have shown that functional appliances can enhance mandibular growth when applied during the active growth period. However, besides patient compliance problems with bulky appliances and prolonged treatment demands, there is contradictory evidence that functional appliances have a significant long-term effect. Is there a method to enhance the growth response and improve the long-term success of functional appliances? Previous studies have also found that therapeutic ultrasound (US) can stimulate cartilage and bone growth. The objective of this study was to evaluate the effect of therapeutic US on condylar and mandibular growth in the rabbit model. Eight growing New Zealand male rabbits were chosen for this study. They received therapeutic US on one side of the mandible for 20 minutes/day for four weeks. Anthropometrical and histological evaluations revealed that US enhances mandibular growth by condylar endochondreal bone growth and consequently mandibular ramus growth. The significant results of this study support conducting a long-term study to evaluate the ultimate stability of the results obtained. Also, they suggest an extended research with a larger sample size and investigating the molecular basis of this stimulatory effect, together with forward posturing splints for optimal macroscopic and microscopic responses.