## 4 Discussion  
The treatment for patients suffering from a clicking joint, including DDwR with intermittent locking, is dictated primarily by the presence of pain or dysfunction and leads to a more favorable mechanical TMJ load [26; 27; 28; 29; 30]. Non-surgical options are proposed for the treatment and include a combination of spliting with physical therapy [31; 32]. Currently, occlusal splint rehabilitation is the standard method to treat disc displacement with reduction. Types of occlusal splints include the stabilization splint, modified Hawley splint, and repositioning splint. Outdated evidence shows that the occlusal stabilization splint is effective in patients with DDwR, and occlusal appliances are the most common therapy, even though there are no guidelines to provide specific recommendations to support clinical practice and decisions. Furthermore, there is often a discrepancy between the findings [33; 34; 35; 36; 37; 38; 39; 40]. In DDwR, the treatment objectives are multiple: the restoration of muscle-articular balance proprioception and recovery of the relation of the condyle with a disc. However, clinical responses to available therapies remain variable and unpredictable, making it difficult to select patients who could benefit from these types of treatments [39]. Furthermore, there is currently no conclusive evidence that biomechanical conditions cause the healthy disc to become a disc with problems, such as TMJ displacement without reduction [40; 41; 42; 43; 44; 45]. Modified mandibular splint therapy as a term was also used in literature by researchers; however, the protocols used were different from the ones presented in this paper [24; 46]. In a recent study, modified mandibular splint therapy was evaluated for TMD. For that research, the authors aimed to present an MOS splint with a specific treatment regimen, and improvements in joint sounds were assessed as an outcome [24]. As a result, they reported that a modified mandibular splint can be used to treat reciprocal clicking of the TMJ effectively. Furthermore, the study did not use any magnetic resonance imaging examination for evaluation, which was one of the major limitations [24]. In this present study, different from that, MOS therapy was tested for DDwRwIL, and MRI images were used for evaluation. Another study by [PERSON] et al. reported outcomes of MOS to treat bruxism and related cranio-mandibular-myofasical pain in post-traumatic stress disorder patients [46]. However, their MOS appliance was different from the one used in this work,  
Figure 8: TMJ locking frequency at different timelines for comparison of 3 testing groups (Block score shows results of TMJ locking evaluations \". (In the last 30 days, 1—less than three episodes of TMJ locking; 2—three to 15 episodes of TMJ locking; 3—more than 15 episodes of TMJ locking”). (The horizontal bars just indicate no significant difference (nsd) among the 3 groups at baseline, and significant difference (*) between baseline and subsequent assessments for each group). as it was a thicker mandibular splint. In conclusion, they reported that MOS therapy provided an effective therapy for reducing nocturnal pain and bruxism symptoms in such patients [46]. Various designs of appliances are utilized for the management of TMD, including stabilization splints (Michigan Splints) and anterior repositioning appliances (such as Tanner appliances, Fox appliances, or centric relation appliances) [47; 48; 49]. Mostly, these appliances are made of hard acrylic, which looks like orthodontic retainers in design. The aim of such therapies is to provide a temporary and ideal occlusion, minimize abnormal muscle function, and protect teeth from clenching [47; 48; 49; 50; 51; 52]. On the other hand, the purpose of the anterior positioning appliances is more concentrated on the improvement of the disk-condyle relationship with joint function by repositioning the mandible and condyle anteriorly [49].