A sample of thirteen patients who had sustained subcondylar fractures were evaluated for mandibular asymmetry. They were compared with a set of age and sex matched control patients with no history of fracture. The comparison was done cephalometrically by analysis of posterior-anterior radiographs. The purpose of the study was to determine if there was an increase in mandibular asymmetry in the subcondylar fracture patients over the control patients and to determine the location of the change.
On each radiograph 53 measurements were taken; of these there were 17 sets of bilateral measurements. Each set of bilateral measurements was analyzed in three ways:
- A ratio of the two measurements was determined.
- A difference of the two measurements was determined.
- The absolute value of the difference of the two measurements was determined.
Statistical comparisons with the paired control patients were done using only the patients with unilateral fractures, only the patients with bilateral fractures and a group of all the fractures combined. The subcondylar fracture patients were divided into two groups based on the length of follow up and a comparison of short versus long term follow up was done. Due to the age difference in the length of follow up groups, the nonfractured patients were compared according to age for a control. Finally, the longer term follow up fracture patients were compared with the older control patients. The Student's T test was used to analyze differences between groups.
The results show no significantly greater asymmetry of the mandible in the subcondylar fracture group as compared with the nonfractured group except when the older control patients were compared with the longer term follow up fracture group. In these groups, their was greater difference in the length of the mandibular body (as viewed on a PA radiograph) in the fracture group. In the comparison of the subcondylar fracture patients divided according to follow up time more indications of mandibular asymmetry is seen in the patients with the longer follow up. The differences are in the cant of the antegonial plane with respect to the zygomatic plane, the absolute value of the difference from Z point to the antegonial notch point, the absolute value of the difference from Z point to the genial tubercles, the absolute value of the difference in the molar-jaw width and the absolute value of the difference in the lengths of the condyle from condylion to the antegonial notch point. The results indicate that with increased follow up time, there may be an increase in mandibular asymmetry in patients with a history of subcondylar fracture. Further investigations would be necessary before this could be stated with absolute certainty.
Stanton S. Appleton
J. Milford Anholm
Michael J. Fillman
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Mandibular Fractures; Facial Asymmetry
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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Gregory-Anderson, Crystal, "The Effects of Subcondylar Fracture on Mandibular Symmetry" (1988). Loma Linda University Electronic Theses, Dissertations & Projects. 1302.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives