Maxillary third molar: Patterns of impaction and their relation to oroantral perforation

Abstract

Purpose: The objectives of this study were to examine 1) the patterns of the impacted maxillary wisdom tooth and 2) the proximity of the impacted maxillary wisdom tooth to the maxillary sinus in relation to oroantral perforation during the removal of a maxillary wisdom tooth. Materials and Methods: This retrospective study reviewed the clinical records and dental pantomograms of patients who underwent the removal of maxillary wisdom teeth under general anesthesia over a 6-month period. Using a modified version of the Archer classification of impacted maxillary wisdom teeth, types of impaction were classified according to depth, angulation of impaction, and proximity to the floor of the sinus. Clinical records showed the occurrence of oroantral perforation. Results: In total, 845 maxillary wisdom teeth were removed; 66.8% were by routine extraction and 33.2% were removed surgically. The most common type of impaction was vertical followed by mesioangular. Most impacted teeth were at the level between the occlusal and cervical level of the adjacent second molar. Only 7 of the 278 excised wisdom teeth produced an oroantral perforation. Only 0.9% of all cases with a close sinus approximation showed an oroantral perforation. Statistical analysis with the Fisher exact test showed statistically significant associations of depth of impaction (P