The influence of anatomical, pathophysiological and other factors on periodontal healing after impacted lower third molar surgery. A multiple regression analysis.

A multifactorial approach has been used to identify some predictors of postoperative intrabony defects (IBD) on the distal surface of the adjacent second molar (M2) after impacted lower third molar (M3) surgery. The material consisted of 215 lower third molar removals, performed on 144 persons (age range 16-53 years; mean 27.2 years). The postoperative examination took place 2 years after impaction surgery and included both clinical and radiographic variables. Statistically significant (5% significance level) predictors of IBD found in stepwise multiple regression analyses were: (1) preoperative intrabony defect M2 distal; (2) age at the time of surgery; (3) size of contact-area M3/M2; (4) root resorption M2 distal; (5) probing dept distal surface of adjacent first molar postoperatively; (6) pathological follicle M3. The regression model with IBD as regressand produced a total R2 of 0.45. When the regressand was the difference between IBD and the preoperative intrabony defect, the regression analysis explained 62% of the variance (R2 = 0.62). These regression models explained the variance in terms of the size of the remaining postoperative intrabony defect as well as in terms of periodontal healing after impacted lower third molar surgery.