IMPROVEMENT OF MAXIMUM OCCLUSAL FORCES AFTER ORTHOGNATHIC SURGERY

Purpose: A number of studies have reported that maximum voluntary bite forces increase after orthognathic surgery, This study determined rat es of longterm improvement in bite forces and looked for both sex-rela ted differences in improvement and for any differences among surgical procedures. Patients and Methods: The study tested 117 patients before surgery and between 6 months and 3 years after surgery, At each trial , unilateral maximum voluntary bite force was measured at four differe nt tooth positions using a standard transducer. Forty-three control su bjects were similarly tested. The rate of increase in maximum bite for ce was calculated separately for male and female patients in various g roups of patients and the controls. Results: The patients had signific antly lower maximum bite forces than the controls before surgery and f or as long as 2 years after surgery, Within 6 months after surgery, pa tients' bite forces were already greater than their presurgical forces . Patients generally showed steady improvement in bite force thereafte r, with male patients improving more quickly than female patients, The re were no clear differences among surgical procedures. Conclusions: A ny temporary reduction in maximum voluntary bite force disappears less than 6 months after orthognathic surgery, Orthognathic surgery improv es patients' bite forces, but this improvement may be gradual, requiri ng many months.