Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review

Area of Science:

• Orthodontics
• Craniofacial Growth

Background:

• Class II malocclusion is characterized by a deficient mandible.
• Functional appliances are used to stimulate mandibular growth.

Purpose of the Study:

• To systematically review the scientific evidence on the effectiveness of functional appliances in increasing mandibular length in Class II subjects.

Main Methods:

• A comprehensive literature search was conducted using the Medline database (1966-2005).
• Included studies were randomized clinical trials (RCTs) and controlled clinical trials (CCTs) with untreated Class II controls.
• 22 studies met the inclusion criteria for final analysis.

Main Results:

• Two-thirds of the studies reported a clinically significant increase in mandibular length (>2.0 mm) with functional appliance treatment.
• Treatment during the pubertal peak showed greater mandibular growth enhancement.
• The Herbst appliance (0.28 mm/month) and Twin-block appliance (0.23 mm/month) were most efficient.

Conclusions:

• Functional appliances can effectively enhance mandibular growth in Class II patients.
• Timing of treatment during the pubertal growth spurt is crucial for optimal results.
• Specific appliances like Herbst and Twin-block show significant efficiency in promoting mandibular elongation.