Bite forces before and after surgical correction of mandibular prognathism.
OBJECTIVE
The purpose of this investigation was 1) to compare morphologic parameters and voluntary bite forces between controls and a sample of patients with mandibular prognathism before surgical correction, and 2) to examine how these patients' bite forces adapt after treatment.


METHODS
Twenty-four prognathic patients were compared with 24 controls before and up to 3 years after mandibular setback surgery. Measures of skeletal morphology and maximum isometric bite force were made on all subjects over time. Statistical analysis compared the controls, the patients before surgery, and the patients after surgery.


RESULTS
Surgical shortening of the mandible averaged 4.1 mm, bringing most skeletal measures into the normal range. Before surgery, the jaw muscle mechanical advantages for patients were significantly smaller than for controls; surgery did not significantly change this relationship. Before surgery the patients had maximum isometric bite forces that were significantly less than those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 to 3 years.


CONCLUSIONS
The results of this study suggest that correction of mandibular prognathism by mandibular setback surgery produces some significant functional benefits.
Ellis
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E
University of Texas Southwestern Medical Center, Division of Oral and Maxillofacial Surgery, Dallas 75235-9109, USA.
Throckmorton
G S
GS
Sinn
D P
DP
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D001732:Bite Force; D002508:Cephalometry / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000503:physiopathology* / Q000601:surgery; D011378:Prognathism / Q000503:physiopathology* / Q000601:surgery