In this clinical study, pre- and post-rehabilitation changes in intraborder mandible movements, chewing cycles, masticatory efficiencies, and borders of the chewing area of patients with unilateral muscular disorders (MD) (n=20) or unilateral disc derangement disorders (DDD) (n=20) of temporomandibular disorder (TMD) were observed and compared with healthy individuals with full dentition (n=20) (48 female, 12 male; mean age: 28). The MD patients received stabilization splints and the DDD patients, anterior positioning splints for six weeks. Symptoms, such as muscle pain, TMJ pain, headache, chewing difficulty, and maximum mouth opening, showed significant improvements after splint therapy for both MD (p=0.000) and DDD (p=0.000) patients, but lateral excursion and protrusion were not significantly changed (p>0.05). Chewing efficacy and chewing cycles improved significantly (p<0.05) in both the MD (p<0.05) and DDD (p<0.05) groups, but only the MD group was comparable to the control group after treatment. Pre- and post-rehabilitation chewing cycles along the frontal plane on both sides in the MD group were similar to the control group. Considering the majority of the improvements in the diagnostic measures, patients with MD and DDD may benefit from occlusal splint therapy.