Effects of Occlusal Splints on Temporomandibular Disorders and Well-Being Among Fibromyalgia and Bruxism Patients: A Quasi-Experimental Study

Background: The purpose of this study was to investigate the effect of occlusal splints on temporomandibular disorders (TMDs) and well-being in patients with fibromyalgia and bruxism. This experimental study assessed the impact of Michigan-type occlusal splints on TMDs and well-being in fibromyalgia and bruxism patients and healthy individuals. Methods: This quasi-experimental study assesses the impact of an intervention on TMD symptoms and overall well-being in patients with fibromyalgia and bruxism. A total of 266 participants were divided into three groups: bruxism with fibromyalgia (ABFG, n = 37), sleep bruxism with fibromyalgia (SBFG, n = 53), awake bruxism without fibromyalgia (ABG, n = 45), sleep bruxism without fibromyalgia (SBG, n = 85), and a healthy control group (HG, n = 46). All participants received a rigid acrylic occlusal splint and counseling on behavioral changes. Pre- and post-treatment questionnaires measured various variables, including jaw function (JFLS-8), anxiety (GAD-7), oral health impact (OHIP-14), well-being (WHO-5), sleep quality (PSQI), and symptoms such as bruxism, TMJ pain, headaches, and jaw locking. Results: The study demonstrated that occlusal splints significantly improved various outcomes in patients with bruxism and fibromyalgia. For the ABFB, significant reductions were observed in JFLS-8, GAD-7, OHIP-14, and PSQI and increases in WHO-5 scores (p < 0.001). Similar improvements were noted in the SBFB. The ABG group showed significant changes in JFLS-8, OHIP-14, and WHO-5, but not in GAD-7 or PSQI. Furthermore, SBG exhibited significant improvements across all measures except WHO-5. Patients in the HG showed only slight changes in PSQI. Additionally, significant reductions in the prevalence of TMJ pain, headaches attributed to TMJ, and jaw locking were noted across the bruxism groups. Conclusion: This study finds that occlusal splints significantly enhance symptoms of TMD and enhance overall well-being, especially in patients with fibromyalgia. Significant improvements were observed in JFLS-8, GAD-7, OHIP-14, PSQI, and WHO-5 scores, alongside a marked reduction in the prevalence of TMJ pain, TMJ-related headaches, and jaw locking. This highlights occlusal splints as an effective therapeutic option for managing both physical and psychological symptoms in fibromyalgia patients. However, the benefits for healthy individuals were minimal, suggesting a need for further research on long-term effects and treatment optimization.