Changes in mandibular mobility after different procedures of orthognathic surgery

Area of Science:

• Orthodontics
• Oral and Maxillofacial Surgery
• Skeletal Biology

Background:

• Orthognathic surgery aims to correct skeletal discrepancies, but potential impacts on mandibular mobility require investigation.
• Understanding treatment effects on jaw function is crucial for patient outcomes.

Purpose of the Study:

• To evaluate the short- and long-term effects of four distinct treatment modalities on mandibular mobility in adult Class II and Class III patients.
• To compare the influence of orthodontic treatment, LeFort I osteotomy, mandibular advancement, and two-jaw surgery on jaw movement.

Main Methods:

• Prospective study of 63 adult patients with Class II and III malocclusions.
• Four treatment groups: orthodontic treatment alone, LeFort I osteotomy, mandibular advancement, and two-jaw surgery/mandibular set-back.
• Measurement of maximum mouth opening, protrusion, and lateral excursions at pre-operative and multiple post-operative time points.

Main Results:

• Orthodontic treatment, LeFort I osteotomy, and two-jaw surgery did not permanently affect mandibular mobility.
• Temporary decreases in mobility were observed in LeFort I osteotomy and two-jaw surgery groups.
• Mandibular advancement surgery resulted in permanent reductions in mandibular mobility (P ≤ 0.001).
• Recovery of mobility in surgical groups was generally limited to 3-14.5 months.

Conclusions:

• Mandibular advancement surgery poses a risk of permanent reduction in mandibular mobility.
• LeFort I osteotomy and two-jaw surgery, particularly in Class III therapy with rigid fixation and condyle position maintenance, allow for rapid recovery of pre-operative mobility levels.
• Reduced mobility after orthognathic surgery may be more pertinent to Class II therapy.