Connective tissue forces from mandibular advancement.
OBJECTIVE
To quantify the connective tissue forces generated during surgical lengthening of the mandible.


METHODS
Sixty-three patients who had mandibular advancements by sagittal ramus osteotomy were used in this study. Prior to sectioning the rami, the overjet was recorded. After sectioning the rami, a spring-gauge was attached to the mandibular orthodontic wire and pulled anteriorly to determine how much force was necessary to bring the mandibular incisors into a Class I relationship with the maxillary incisors. Aggressive stripping of the perimandibular periosteum and connective tissues on the distal segment was then performed. The amount of force was again recorded.


RESULTS
The mean preoperative overjet in the 63 patients was 6 mm (range, 3 to 11 mm). The mean amount of force required to advance the mandible prior to stripping the tissues was 1,498 g compared with a mean of 787 g after stripping (P < .001). There were statistically significant correlations between the preoperative overjet and the prestripping and poststripping force levels (P < .001). There was also a significant relationship between prestripping and poststripping values (P < .001).


CONCLUSIONS
The results of this study indicate that orthopedic forces are generated by the perimandibular connective tissues following advancement by the mandible. The effect of these forces on the temporomandibular joint should be evaluated in future studies.
Division of Oral and Maxillofacial Surgery, University of Texas Southwestern Medical Center, Dallas 75235-9109.
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Ellis
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Sinn
D001862:Bone Resorption / Q000209:etiology; D003238:Connective Tissue / Q000503:physiopathology*; D003799:Dental Stress Analysis; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000601:surgery*; D008334:Mandible / Q000601:surgery*; D008335:Mandibular Condyle / Q000503:physiopathology; D010027:Osteotomy / Q000009:adverse effects; D013705:Temporomandibular Joint Disorders / Q000209:etiology