Coincidence and Awareness of the Relationship Between Temporomandibular Disorders and Jaw Injury, Orthodontic Treatment, and Third Molar Removal in University Students

Aims: To determine whether there is an association between temporomandibular disorders (TMD) and a history of facial/jaw injury (FJI), orthodontic treatment (OT), or third molar removal (TMR) in university students, and to evaluate the students' awareness of a possible relationship between jaw pain or other TMD symptoms, FJI, OT, and TMR, and the presence of TMD. Methods: This cross-sectional study involved 1,381 Oporto District university students. The Portuguese version of the Research Diagnostic Criteria for TMD was used for TMD diagnosis. FJI, OT, and TMR histories were evaluated by questionnaire. Univariate associations between categorical variables were tested by using chi-square tests. Multivariate logistic regression was applied to predict independent factors associated with TMD. Results: Of the 1,381 students (mean age ± standard deviation [SD]: 21.7 ± 3.9 years), 39.3% had TMD, 23.2% had a history of FJI, 44.5% had undergone OT, and 26.2% had undergone TMR. Univariate analyses showed significant associations between OT and TMD (P = .044) and between TMR and TMD (P = .003). Multivariate regression analyses using FJI, OT, TMR, OT × TMR interaction, sex, and age in the first step showed TMR (Odds Ratio [OR] = 1.30; P = .041), sex (OR = 1.59; P = .001), and age (OR = 1.04; P = .013) as significant. A positive correlation between TMD and awareness of the relationship between jaw pain or TMD symptoms and a history of FJI or OT (P .001 and P = .002, respectively) was documented. Conclusion: TMR, female sex, and older age were risk factors independently associated with TMD. The results also suggest that patients' awareness of potential risk factors for TMD should be taken into account on an individual basis. Keywords: jaw injury, orthodontic treatment, RDC/TMD Axis I, third molar removal, university students