## 4 Discussion
A recent meta-analysis evaluated the effectiveness of splint therapy in patients with temporomandibular disorders and reported moderate-quality evidence that splint therapy has a substantial effect on reducing pain among patients with TMDs [48]. Even though they are mentioned in the literature with successful outcomes, some limitations of the traditional approaches are being experienced clinically in terms of pain and TMJ movement restrictions, especially for DDwRwIL patients. The proposed protocol in this research is represented as an alternative to conventional treatments. Although not statistically significant, the results of this study showed a tendency for reduced scores in terms of pain and TMJ locking episodes. MRI studies evaluating treatment-dependent changes have documented disc displacement in \(\sim\)35% of asymptomatic patients, showing no long-term effect on snap [15; 33]. The purpose of a splint for DDwR of TMJ is to recapture the disc anteriorly and reposition the condyle downward; improve jaw function; correct the relationship between the glenoid fossa, articular disc, and condyle; reduce joint pain and sounds; prevent the development of the TMD [31]. The modified splint used in this study was designed to reduce pain and TMJ locks. MRI is the gold standard method for diagnosis of DDwRwIL, and research in this field should use this diagnostic tool, whenever possible, to confirm and check the outcomes, which is also one of the strong points of this study. Another strong point was the four-year follow-up period, which can be considered a long-term follow-up with control visits when compared to other research papers [48; 49; 50; 51; 52; 53; 54]. The outcomes of this study demonstrated no significant difference comparing the three groups. The TMJ locking frequency of the conventional treatment was slightly higher when compared to the other groups, but no significant difference was detected. All of the treatments seem to be efficient in reducing the pain score and the TMJ locking frequency from the baseline to the T1 timepoint. In the literature, there are various studies evaluating the outcomes of TMD treatments with splint therapy [48; 49; 50; 51; 52; 53; 54]. However, the number of randomized clinical trials is limited (54). The majority of the studies assess the outcomes such as pain, restriction in TMJ movements, and pain [48; 49; 50; 51; 52; 53; 54]. In a recent network meta-analysis of randomized controlled trials, the effectiveness of occlusal splint therapy was investigated for the management of temporomandibular disorders with forty-eight randomized studies. According to the results, there was a significant decrease in post-treatment pain intensity in arthogenous TMDs after anterior repositioning splints, counseling therapy with hard stabilization splints, mini-anterior splints, and hard stabilization splints alone, when compared to the control groups. Outcome variables were pain improvement, post-treatment pain intensity, improvement in mouth opening, and disappearance of TMJ sounds. Based on their results, they reported moderate to very low-quality evidence confirming the effectiveness of occlusal splint therapy in the treatment of TMDs [53]. The results of this present work, in accordance with the literature, highlight an obvious enhancement of the symptoms with successful results in splint therapy (both with conventional splints and MOS). These outcomes show that splint therapy is a successful treatment for DDwRwIL patients. One of the limitations of this study is that it included a small number of patients in groups. Further prospective studies with larger groups and longer follow-ups are needed in the literature to confirm these results. Within the limitation of the present study, the findings seem to encourage a non-surgical approach to temporomandibular joint disc displacement through both occlusal splint and reduction exercises.