Osteoarthritis of the temporomandibular joint (TMJ) is a degenerative joint disease that leads to morphological and functional changes in the TMJ. Clinically, it can be associated with crepitation, pain, and functional limitations. The following article describes a patient case who presented with the above. First, the function-specific diagnostic cascade is explained. Based on these examinations, the diagnosis of temporomandibular disorder (TMD) with the components of occlusopathy, myopathy, and arthropathy was performed. Initially, a conservative treatment approach was chosen, which led to pain elimination. A follow-up examination 3 months later revealed a severely altered occlusion with only one single static occlusal contact, necessitating further measures. The focus was on slowing down the degenerative changes in the TMJ, eliminating the inflammation of the left TMJ, and restoring functional occlusion. These treatment goals were achieved only through the additional use of a tooth-colored CAD/CAM occlusal splint. For this purpose, the jaw relation was digitally transferred from the conventional centric splint to the CAD/CAM occlusal splint. The patient case is an example of a combined digital-conservative treatment approach for complex TMD cases. Keywords: osteoarthritis, TMJ effusion, function-specific diagnostic cascade, conservative treatment, tooth-colored fully anatomical CAD/CAM occlusal splint, digital transfer of the jaw relation