RESUMO
Mandibular third molar impaction is a major problem in modern dentistry. The incomplete eruption of third molars remains a serious problem in dentistry, primarily because of its high incidence and clinical consequences.The purpose of this study was to relate the impaction of third molars to individual patterns of facial growth, as well as to the gonial angle. A group of 100 subjects with impacted mandibular third molar and a group of 75 subjects whose lower third molars had erupted. Both formed part of a cross-sectional study on prediction of impaction. There was at least 2 degrees difference between two groups. The mean value for gonial angle in erupted cases was 126 +/- 6 which is not so different from the standard ranges in the literature. Gonial angle can be used as one of impaction indices. Less value of gonial angle is in association with impacted third molar compared with erupted teeth