Objective: To verify horizontal jaw relations using anatomical marks on a cast and evaluate the efficiency and accuracy of the test on checking the horizontal relation.
Methods: A total of 200 patients with a loss of posterior occlusion were recruited. After casts were made and the horizontal jaw relation was recorded, the pterygomaxillary notch and retromolar pad were identified bilaterally on the maxillary and mandibular casts. On each cast, a vertical line was drawn to bisect the anatomical landmarks and the distance between the two vertical lines was measured. Using the result of the wax try-in appointment and the corresponding measurements, a diagnostic test was conducted. A receiver operating curve was created and the maximum horizontal distance between bisecting points that still obtained correct jaw relations was determined to be a criterion. The accuracy of the test to verify horizontal jaw relations was evaluated.
Results: The area under the curve of the receiver operating curve was 0.833 (P < 0.05). With a maximum Youden index, the d value threshold was 1.0 mm. Using 1.0 mm as a criterion to check the horizontal relation, the sensitivity of the test was 0.76 and the specificity was 0.93. The kappa value for different researchers was calculated to be 0.79 (P < 0.05). The intraexaminer 1 reliability gave a kappa value of 0.76 (P < 0.05), and intraexaminer 2 gave a value of 0.81 (P < 0.05).
Conclusion: The test for verifying the accuracy of horizontal jaw relations is reliable. If horizontal distance is measured as greater than 1.0 mm at the jaw relation record appointment, the recorded horizontal jaw relationship may be wrong and need to be reexamined.