AN OBSERVATIONAL STUDY ON THE EFFECTS OF BETEL NUT CHEWING ON MASTICATION MUSCLES AND THE DEVELOPMENT OF TRISMUS

Abstract

Background: Betel nut (areca nut) chewing is a common habit in many Asian countries and is associated with several oral health disorders, including oral submucous fibrosis (OSMF), muscle stiffness, and trismus. Prolonged chewing may adversely affect the muscles of mastication, leading to restricted mouth opening and impaired oral function. Objective: To investigate the effects of betel nut chewing on mastication muscles and its role in the development of trismus among adult individuals. Methods: A cross-sectional observational study was conducted on 120 participants, comprising 60 chronic betel nut chewers and 60 non-chewers. Participants aged between 21 and 80 years were assessed using the Maximum Mouth Opening (MMO) test and the Vertical Three-Finger Test (Ruler Test). Data were analyzed using descriptive statistics and the Mann–Whitney U test to compare oral function between the two groups. Results: The mean age of participants was 41.49 ± 21.71 years. Betel nut chewers demonstrated significantly reduced oral function compared to non-chewers. The mean MMO was lower among chewers (2.18 cm) than nonchewers (2.93 cm). Similarly, the mean Ruler Test score was lower in chewers (30.94 mm) compared to nonchewers (45.65 mm). Mann–Whitney U analysis revealed statistically significant differences in both MMO (U = 674.000, p < 0.001) and Ruler Test scores (U = 170.000, p < 0.001) between the groups. Male participants were more likely to be habitual betel nut chewers than females. Conclusion: Chronic betel nut chewing is significantly associated with reduced mouth opening, impaired mastication muscle function, and an increased risk of trismus. Early identification of oral functional limitations and awareness programs aimed at reducing betel nut consumption may help prevent long-term oral health complications.