A Comparative Study of Difficulty Prediction Indices in Lower Third Molar Surgery

In third molar surgery, it is important to take into account multiple clinical and radiographic variables that, grouped into indices and classifications, allow estimating the degree of surgical difficulty. The present study proposes to evaluate the efficacy and congruence of these indices. Material and methods: a cross-sectional retrospective study in 77 patients. 123 lower third molar surgeries were performed using the Pederson, WHARFE and Parant prediction indices; to know the efficacy of the classifications, a statistical analysis with measures of central tendency, association through chi-square test and tables of frequency distribution were used, as well as non-parametric tests when determining an asymmetric distribution in the data through the Kolmogorov and Kruskall-Wallis test. Results: Analyzing the correlation between the Pederson and WHARFE indices, a strong association of P = .906 (Gamma), P = .761 (Kendall’s Tau “C”) and P = .834 (Somers “D”) was found, accepting frequency correlation through chi-square test. X2 test (P = 0.000) was performed accepting association between the Parant and Pederson scale, as well as for the WHARFE and Parant scales, resulting positive with a strong intensity and a direct association with a P = 0.796 (Gamma). Discussion: The difficulty prediction indices evaluated in the present study proved to be congruent with each other, their predictions regarding the type of surgery performed allow estimate degrees of complexity, type of surgical procedure, approximate time and possible complications, thus improving treatment planning. Keywords: Third molars; degree of difficulty; surgical tooth extraction; prediction