Decision of Surgery According to Relation of Roots of Lower Third Molar to Inferior Alveolar Canal in Different Winter Classes of Impaction Depending Only on Orthopan-tomogram. Surgical prospective from a Retrospective Radiographic Study

Abstract

Background and objectives: The proximity of inferior alveolar canal to roots of lower third molar is one of the serious challenges facing surgeons during extraction of that tooth. There are different types of this relation, mainly: away, in direct contact and crossing the canal. The aim is to evaluate the relation between roots of lower third molar and inferior alveolar canal, in Winter classification of impaction of impaction to decide whether to do surgery or to ask for Cone Beam Computed Tomography first. Methods:Orthopantomographs f 206 cases were retrospectively evaluated: the presence of impaction; applying Winter classification; studying roots, numbers; and their relation to the canal (away from, in direct contact and crossing). Results: One hundred and twenty-four cases were with lower third molar impaction; mean age (29.5 ± 6.2); mesioangular was the most common type of impaction. In general, 24 (19.5%) cases were away; 51 (40.5%) cases were with a direct contact; 49 (39.5%) cases were crossing the canal. In mesioangular im- paction the common relations were in direct contact and crossing the canal. There was large difference in prevalence of single-rooted and two-rooted teeth, with being two-rooted the common one, there were no significant differences in their relation to the canal. Two divergent rooted teeth majority were in direct contact with the canal. Conclusions: Our results showed that just 19.7%, regarding the relation to inferior alveolar canal are safe to do surgery without radio- graph, the rest has the risk of endangering the nerve and 40% needs computed tomography.