Effects of modifications of complete mandibular dentures on the electrical activity of masticatory muscles in edentulous patients: an interventional analytical clinical study.

Background: To assess whether two modifications of complete mandibular dentures (relining and restoration of the vertical dimension of occlusion, VDO) affect the electrical activity of the masseter and temporal muscles, bite force, and oral health-related quality of life in edentulous individuals. Materials and Methods: Fifteen complete denture users were included. Evaluations of quality of life (Oral Health Impact Profile for Edentulous-OHIP-EDENT), bite force, and electromyography of the masseter and temporal muscles were performed at five different times: T1-original dentures; T2-after 18 days of using the relined mandibular denture; T3-after 18 days following the definitive restoration of the vertical dimension of occlusion; and T4 and T5-30 and 100 days after using the new dentures. A one-way analysis of variance (ANOVA) (time) was performed for each muscle's electromyography data and the bite force of each region. For the OHIP-EDENT, descriptive analysis (frequency of responses "never," "sometimes," and "always") for each question was followed by a non-parametric two-way Friedman ANOVA (p < 0.05). Results: There was no statistically significant difference between the time points for the electrical activity of the masseter and temporal muscles and bite force. The OHIP-EDENT showed that patients perceived less (or no) food retention under the mandibular denture and better fitting at T2, T3, T4, or T5 compared to T1. Additionally, at T2, patients reported more comfort while eating food and overall comfort with their dentures than at T1. At T3, patients reported difficulty chewing some foods, discomfort while eating, and uncomfortable dentures compared to T2. Conclusion: Relining the complete mandibular denture increased masticatory comfort, while the definitive restoration of the VDO caused discomfort for the patients. The modifications made before rehabilitation did not significantly alter the values of the electrical activity of the masseter and temporal muscles, as well as the bite force.