Effect of Increasing Low-Intensity Pulsed Ultrasound and a Functional Appliance on the Mandibular Condyle in Growing...

Area of Science:

• Orthodontics and Dental Biomaterials
• Regenerative Medicine and Tissue Engineering

Background:

• Functional appliances are used to treat mandibular deficiencies in growing individuals, but their efficacy is debated.
• Low-intensity pulsed ultrasound (US) is a noninvasive method shown to stimulate cartilage and bone formation.
• Previous studies suggest 20 minutes of US application is effective.

Purpose of the Study:

• To test if increasing low-intensity pulsed US application from 20 to 40 minutes daily enhances mandibular condylar growth in growing rats.
• To evaluate the combined effect of functional appliances and low-intensity pulsed US on mandibular growth.

Main Methods:

• Fifty-four Sprague Dawley rats were divided into six groups: control, 20-min US, 40-min US, functional appliance, functional appliance + 20-min US, and functional appliance + 40-min US.
• Low-intensity pulsed US was applied daily for 28 days.
• Mandibles were analyzed using morphometric, histomorphometric, and micro-computed tomographic methods.

Main Results:

• The 20-minute US group showed significant increases in most measured variables compared to control and other groups (P < .05).
• The functional appliance + 40-min US group exhibited the least favorable results.
• The 20-minute US application, alone or with a functional appliance, improved mandibular growth, including bone microarchitecture and cell proliferation/hypertrophy.

Conclusions:

• Daily 20-minute low-intensity pulsed US positively affects mandibular growth in growing rats, both independently and when combined with functional appliances.
• Increasing US application to 40 minutes daily did not yield superior results and showed less favorable outcomes.
• Further research with extended observation is needed to assess long-term effects and bone stability.