Effect of Different Treatment Modalities on Masseter Inhibitory Reflex in Patients with Sleep Bruxism: A Case-Control Study

Background: Sleep bruxism (SB) is a parafunctional oral habit that is frequently related to sleep arousals. The masseter inhibitory reflex (MIR) causes reflex inhibition of voluntary contractions of the elevator muscles induced by intense peri- or intraoral mechanical or electrical stimulations. This study aimed to investigate the changes in MIR of patients with SB, and the effect of different treatment modalities on MIR. Methods: In this case-control study, ۱۰۰ individuals were randomly assigned to four groups (n=۲۵) of conservative treatment (G۱), occlusal splint treatment (G۲), low-level laser therapy (LLLT) treatment (G۳); and control (G۴). The MIR was tested in all participants before and one month after treatment.  Results: All MIR components of the patients had longer right and left SP۱ and right and left SP۲ latencies (P=۰.۰۱۷, P=۰.۰۴۳, P<۰.۰۰۱, and P=۰.۰۴, respectively), and shorter right and left SP۱ and right and left SP۲ durations (P=۰.۰۲۱, P=۰.۰۲۱, P<۰.۰۰۱, and P<۰.۰۰۱, respectively) as compared to the control group. The right SP۱ and SP۲ latencies were prolonged in G۳ versus G۱ and G۲ (P=۰.۰۲۶ and P<۰.۰۰۱, respectively); whereas, the left SP۲ latency was prolonged in G۲ compared with G۱. The right and left SP۲ duration was not significantly different among the three treated groups. The left SP۱ duration was not significantly different among the three treated groups. Gender had no effect on MIR parameters. Conclusion: SB patients had an abnormal MIR response. LLLT was the most effective compared to other treatment modalities.

کلیدواژه ها:

Bruxism ، Masseter Muscle ، Low-Level Light Therapy ، Sleep