Comparison of Maximum Mouth Opening Following Mandibular Bilateral Sagittal Splitting Ramus osteotomies in Class III Females Using Two Different Osteosynthesis Methods.

BACKGROUND Limitation of mouth opening is a common complaint following orthognathic surgery. OBJECTIVES This investigation reports on the progress of maximum incisal opening following orthognathic surgery and compares the impact of two different osteosynthesis methods on mouth opening in female patients with Class III dentofacial deformities. METHODS Forty cases of skeletal class III malocclusion were divided into twenty cases treated using the conventional single miniplate osteosynthesis method (P1) and twenty cases using the additional L-shaped miniplate osteosynthesis method (P2). No significant differences in preoperative clinical status were detected between the P1 and P2 group, and all patients were managed with elastics in the post-operative period. Independent mouth opening exercises were initiated seven days after surgery, and inter-incisal distance was measured as maximum mouth opening (MMO) at 1 week, 2 weeks, and 1, 2, 3, 6 months. Statistical analysis was performed in order to analyze differences in MMO between the P1 and P2 groups (Prism 7 GraphPad software, San Diego, CA). Values of P<0.05 were considered to be significant. RESULTS MMO significantly increased from 2 weeks after surgery in both groups. The MMO of P2 was significantly larger than that of P1 in all experimental periods after surgery. MMO was statistically improved in P2 at 2 months after surgery, while MMO in P1 was significantly smaller than the preoperative MMO, even at 6 months post-operative. A minimum MMO of 40 mm was achieved by all patients. CONCLUSION L-shaped miniplate osteosynthesis was more useful for early limitation of mandibular opening improvement than conventional single miniplate osteosynthesis.