Association between Parafunctional Habits and Temporomandibular Disorders among Sohag University Medical Students: A Cross-Sectional Study

Background: Parafunctional oral habits previously suspected to contribute in temporomandibular disorders (TMD). These habits such as clenching, grinding, gum chewing, and nail or lip biting may increase the load on the temporomandibular joint and aggravate symptoms.Methods: A cross-sectional study was conducted among Sohag University medical students by using Fonseca's anamnestic index (FAI). A total of 1130 students completed the questionnaire. Participants were classified into no, mild, moderate, and severe TMD. The questionnaire also included questions about parafunctional habits. Chi-square test used to compare distribution of TMD categories across different habits.Results: The mean age of participants was 22.82 ± 2.96 years; 54.3% were females. Overall, 66% had some degree of TMD. All studied parafunctional habits showed significant associations with higher TMD severity (p < 0.001). For example, students who reported clenching or grinding during sleep had higher percentages of moderate (40%) and severe TMD (10%) compared with those who denied the habit (moderate 12.3%, severe 1.7%). Similar results were observed with gum chewing, nail biting, lip biting, and object biting.Conclusion: Parafunctional habits are strongly associated with increased prevalence and severity of TMD among medical students. Early identification and preventive strategies may help reduce the burden of TMD in young populations.