Long-term Effectiveness of Occlusal Splint Therapy Compared to Placebo in Patients with Chronic Temporomandibular Disorders

PURPOSE: The aim of this study was to compare long-term effectiveness of stabilization splint (SS) with that of placebo splint (PS) in chronic TMD patients and to investigate differences in treatment outcomes based on diagnostic subgroups [disc displacement (DD)/myofascial pain (MP)]. MATERIALS AND METHODS: Thirty-four female participants, diagnosed with chronic TMD, were classified in groups: one provided with SS and other with PS and were followed for six months. Treatment outcomes included spontaneous pain [visual analogue scale (VAS)], self-perceived quality of life (OHIP-14), pain-free maximal mouth opening (MCO), maximal mouth opening (MMO), level of perceived stress (PSS), characteristic pain intensity [graded chronic pain scale (GCPS)], and functional jaw limitation [jaw functional limitation scale (JFLS)]. RESULTS: Baseline characteristics did not differ significantly between the two groups (p>0.05). After six months of treatment the changes in spontaneous pain and OHIP-14 scores differed significantly between treatment groups (p=0.004, p=0.02 respectively), with greater reduction in SS compared to the PS group. Pain-free maximal mouth opening did not change significantly over time, however MCO values differed significantly between the two treatment groups, with greater overall values in the SS compared to the PS group (p= 0.046), as well as between TMD subgroups, with greater overall values in MP compared to DD patients (p= 0.03). In the SS group, significant difference in JFLS categories was found between baseline and after 6 months of treatment in all except emotional and verbal expression (mastication p=0.00015; vertical jaw mobility p=0.00018). No such changes in JFLS categories were observed in the PS group. CONCLUSIONS: During 6-month period, SS was more effective than PS in reducing spontaneous pain and improving self-perceived quality of life and functional limitations of the lower jaw. Moreover, significantely higher values of pain-free mouth opening were observed in patients treated with stabilization splint. While placebo might be partly responsible for improving the symptoms of TMD, it seems that itcannot maintain a continual long-term positive therapeutic effect.