A RELIABILITY COMPARISON OF SUBMENTOVERTEX AND ZONOGRAPHIC METHODS OFHORIZONTAL CONDYLAR ANGLE ESTIMATION

Objective. The objectives of this retrospective clinical study were, f irst, to compare submentovertex radiography and zonographic temporoman dibular joint orientation programs: that use the Scanora imaging syste m with respect to the reproducibility with which the angulation of the horizontal condylar axis may be determined and, second, to assess the level of agreement between the 2 methods. Study design. Submentoverte x radiographs and zonographic projections of 16 joints (8 patients) we re evaluated. Two raters independently determined the horizontal angul ation of each condyle 3 times using each method. Horizontal condylar a ngle measurements differing by no more than 5 degrees were considered to be in agreement. Statistical analyses were performed with a repeate d-measures analysis of variance, sign tests, and Wilcoxon signed rank test. Results. No significant difference was found in the 3 measuremen ts between the 2 raters (P = .9122) or between the raters adjusted for method (P = .5093). A significant difference was found between method s (P = .0001). Intrarater agreement values were 81% and 88% for the su bmentovertex method and 75% for each rater for the zonographic method. Interrater agreement was 94% for each method. Intermethod agreement w as 50% for one rater and 81% for the other. Conclusions, The submentov ertex and zonographic methods of determining the horizontal condylar a ngulation demonstrated consistency and reliability both within and bet ween the raters. However, the zonographic method did not agree with th e submentovertex method. This finding does not imply that the zonograp hic method is not a clinically acceptable technique for the determinat ion of the horizontal condylar angulation when subsequent tomographic projections are made on the same unit with the same head-positioning d evice.