Functional Evaluation of the Behavior of Masticatory Muscles in Zygomaticomaxillary Complex Fracture: A Prospective Study.

AIMS: The purpose of this study is to functionally evaluate the behavior of the masticatory muscles (masseter and temporalis) following zygomaticomaxillary complex (ZMC) fractures by assessing bite force, electromyography (EMG), and mandibular movements.

MATERIALS AND METHODS: Group I consisted of 20 patients with unilateral ZMC fractures who were treated surgically with one-, two-, or three-point fixations at the frontozygomatic, infraorbital, or zygomaticomaxillary buttress region as per clinical and radiological assessments. Group II control group included 20 normal patients. The muscle activity was functionally evaluated before and after the surgery for a period of 6 months. The evaluation consisted of bite force measurement, EMG analysis of masseter and temporalis muscles, and measurements of mandibular movements.

RESULTS: There was an increase in bite force and EMG activity throughout the evaluated postoperative period, but at the end of 6 months, the values were still below the control levels for majority of the patients. Maximum mouth opening increased considerably after the surgery.

CONCLUSION: According to bite force and EMG, the masticatory musculature returned to near normal levels by the 3rd month after the surgery.

CLINICAL SIGNIFICANCE: Management of fractures of the zygoma by open reduction and fixation raises the question of the location of fixation points owing to the action of masseter and temporalis on the ZMC. This study supports the current clinical concept of minimized fixation in treating ZMC fractures.