Quantification and validation of predictive values of occlusal variables in temporomandibular disorders using a multifactorial analysis

Statement of problem. A consensus is lacking on the association between occ lusal variables and temporomandibular disorders (TMDs). Purpose. This study estimated the maximum potential power of occlusal varia bles to differentiate patients with TMD from asymptomatic normal adult subj ects. Material and methods. The occlusal characteristics in 2 sets of female pati ents with intracapsular TMD (1993, n = 257, and 1998, n = 124) differentiat ed into disk displacement and osteoarthrosis subdiagnoses were compared wit h asymptomatic: female controls (n = 51 and 47) with multiple logistic regr ession analysis. Significant variables and total contribution to the log li kelihood were compared with the predictive value of univariate analysis, in cluding sensitivity and specificity. Results. Occlusal factors in the females (1993, 1998) explained no more tha n 4.8% to 27.1% of the log likelihood. In comparison to the logistic regres sion analysis, univariate analysis was less predictive of patients with TMD , due to notably lower sensitivity. Patients with disk displacement were ma inly characterized by unilateral posterior crossbite and longer RCP-ICP sli des. Patients with osteoarthrosis n ere most consistently characterized by longer RCP-ICP slides and larger overjet, and in part to reduced overbite. Significant relative risk for disease (odds ratio > 2:1) was mainly associa ted with infrequent, more extreme ranges of occlusion measurements. Conclusion. Occlusal factors may be cofactors in the identification of pati ents with TMD, but their role should not be overstated. Some occlusal varia tion may be a consequence of rather than a cause for TMD. Single variables have more limited value and it takes sets of adverse variables to model TMD . Combinations of variables appear to be disease specific. Some extreme ran ges of occlusion were the domain of patients with TMD, but most patients we re within the normal ranges.