Malocclusion complexity as an associated factor for temporomandibular disorders. A case-control study.

Objective: To evaluate the association between temporomandibular disorders (TMD) and malocclusion complexity using the Index of Complexity Outcome and Need (ICON) levels. Methods: A prospective, cross-sectional, case and control study was done. Cases and controls were matched in a one-to-one relationship (179 subjects each). The Research Diagnostic Criteria was used to evaluate the presence of TMD, and the ICON was used to quantify malocclusion complexity. A binary logistic regression (p < 0.05) was used to identify associations between variables. Results: TMD presence was associated with gender and malocclusion complexity (p < 0.05). The largest proportion of controls were in the lowest three levels of ICON complexity, while most cases were in the three highest levels (p < 0.001). Higher malocclusion complexity indicated a greater TMD risk. Conclusion: The results indicate that TMD is associated with malocclusion complexity. As malocclusion complexity increases, so do the odds of presenting with TMD.