The precision of the panoramic mandibular index

This study evaluates the precision of the panoramic mandibular index (PMI). Measurements were made by two observers on both of the left and right sides of the mandible on the radiographs taken from 41 young individuals and the inferior and superior PMI were calculated. Two weeks later the same observers repeated their measurements to assess intrarater reliability. Paired t-test, Pearson correlation coefficients and precision values were calculated to assess levels of association. There was a significant difference between the first rater's first and second measurements (intrarater repeatability) for both the inferior and superior PMI, while no significant difference was observed for the second rater. The intrarater and inter-rater precision values for the inferior PMI were calculated as 0.005319 and 0.005594 for the first rater and 0.005663 and 0.005594 for the second, respectively. The intrarater and inter-rater precision values for the superior PMI were similar for both observers, calculated as 0.002558, 0.002766; and 0.003046, 0.002766, respectively. The precision of both inferior and superior indices was not very good, but precision figures for the superior PMI demonstrated consistency almost twice better than those for the inferior PMI for both observers. The precision values for the PMI seem to be sufficient according to the results of this study, but they are still questionable and more studies need to be done on this aspect.