Occlusal Splint Combined With Granisetron Injection for Management of Myofascial Pain Related to Temporomandibular Disorders

The goal of this clinical trial is to evaluate whether a combination of occlusal splint therapy and granisetron injection into the masseter muscle is effective in managing myofascial pain related to temporomandibular disorders (TMD). The study will also compare this combination treatment to occlusal splint therapy alone and to occlusal splint therapy combined with lidocaine injection. The main questions this study aims to answer are: * Does adding granisetron injection to occlusal splint therapy reduce myofascial pain more effectively than occlusal splint therapy alone? * How does granisetron injection compare to lidocaine injection when combined with occlusal splint therapy? * Does the combination treatment improve mandibular movement and reduce joint clicking? * Are there any local or systemic side effects associated with granisetron or lidocaine injections? Researchers will compare three groups to evaluate treatment effectiveness: * Occlusal splint therapy alone * Occlusal splint therapy plus granisetron injection * Occlusal splint therapy plus lidocaine injection Participants will: * Wear an occlusal splint as part of their treatment * Attend follow-up visits after 1 week, 1 month, 3 months, and 6 months