Mandibular adaptations following total maxillary osteotomy in adolescent monkeys

Area of Science:

• Craniofacial surgery
• Orthodontics
• Primate research

Background:

• Surgical repositioning of the maxilla (Le Fort I osteotomy) is a common procedure in treating midface discrepancies.
• Understanding the subsequent effects on mandibular growth is crucial for optimizing treatment outcomes.
• Adolescent growth phases are particularly sensitive to surgical interventions.

Purpose of the Study:

• To investigate craniofacial growth and remodeling of the mandible after superior anterior surgical repositioning of the maxilla.
• To assess the adaptive changes in mandibular growth in adolescent Macaca fascicularis monkeys.

Main Methods:

• Utilized stereometric and conventional cephalometry with tantalum implants in adolescent monkeys.
• Monitored growth for up to 24 months postoperatively.
• Analyzed cephalometric head films at monthly intervals.

Main Results:

• Both maxilla and mandible exhibited harmonious growth, but with significant changes in amount and direction compared to controls.
• Mandibular growth (condylion to menton, condylion to gonion, gonion to menton) reduced by 36-60% in experimental animals undergoing autorotation.
• Anterior dental-alveolar-symphyseal height showed a 75% less increase compared to controls.

Conclusions:

• Superior anterior maxillary repositioning significantly modulates mandibular growth.
• The mandible demonstrates adaptive remodeling in response to surgically altered maxillary environments.
• Occlusion and function likely play key roles in mediating these adaptive mandibular changes.