Evaluation capability of surgical difficulty in the extraction of impacted mandibular third molars: a retrospective study from a post-graduate institution.

The first aim of the present study was to analyze if any correlation exists between the post-graduate's and the tutor's difficulty evaluation of the same tooth to be extracted. Secondly, the study aimed to verify whether, and possibly which, anatomical/topographic characteristics of the impacted lower third molar influence the post-graduate's difficulty evaluation. Thirdly, patient's age and gender were studied for any influence either on the post-graduate's and tutor's extraction difficulty evaluation or on surgical time. Lastly, the possible effect of the post-graduate's difficulty evaluation on the incidence of surgical accidents was also studied. Eighty-four impacted mandibular third molars have been retrospectively reviewed. For each molar, pre- and operative information have been collected. The Pearson's Product Moment Correlation, the general linear model with backward stepwise procedure, the variance analysis and the logistic regression were used for inferential statistics. Correlation between the post-graduate's and tutor's difficulty evaluation of each lower third molar to be extracted as well as between difficulty evaluation and operative time were statistically significant. Tooth position, impaction depth and relationship with the inferior alveolar nerve influenced operative times. Pre-surgical difficult degree had a positive significant effect on accident occurrence. The pre-operative post-graduates' difficulty evaluation did not differ from their post-operative evaluation although their judgement differed from that given by the tutor and did not correlate with the operative time. Lower third molar extraction difficulty seems to be influenced by some topographic factors such as tooth position, impaction depth and relationship between inferior alveolar nerve and impacted tooth.