Masticatory behavior and chewing difficulties in young adults with temporomandibular disorders

BACKGROUND: Difficulties and limitations on masticatory function are among the main reasons why patients with temporomandibular disorder (TMD) seek care. OBJECTIVE: To evaluate the masticatory behaviour and perception of chewing difficulties in adults with mild TMD of recent onset, considering the presence of malocclusion. METHODS: Eighty-one young adults were divided into groups according to the presence of TMD and malocclusion: Non-TMD Normal Occlusion (n = 18), Non-TMD Malocclusion (n = 22), TMD Normal Occlusion (n = 18) and TMD Malocclusion (n = 23). TMD was assessed using the TMD Research Diagnostic Criteria and volunteers also answered questionnaires regarding their perception about jaw functional limitation and difficulty to chew foods of different textures. Masticatory and swallowing behaviours were assessed using the Orofacial Myofunctional Evaluation with Scores (OMES) protocol. Chewing time and chewing frequency taken to ingest the test-food were also obtained. Two-way-ANOVA was used to analyse the TMD, occlusion and TMD × occlusion interaction effects. RESULTS: Temporomandibular disorder effect was observed on vertical jaw mobility and jaw function limitation total scores, meaning that groups differed in the perception of opening limitation and mandibular limitation according to TMD status with a medium effect size. Also, more changes in chewing function (OMES-chewing score) and higher chewing frequency was observed in the presence of TMD (P < 0.05). Occlusion effect was only observed on OMES-swallowing score and no TMD × occlusion interaction effect was observed. CONCLUSION: Changes in chewing behaviour, frequency and perception of mandibular limitation was observed in the presence of TMD, pointing out the importance of functional evaluation when planning and establishing a treatment plan.