Alloplastic replacement has become a valid treatment for TMJ endstage disease. The Alkayat and Bramley pre-auricular approach combined with the submandibular incision are the current surgical approaches for TMJ surgery. The present study shows a modified approach using intraoral endoscopic assistance. A female patient affected by jaw osteomielitis with condylar detachment was treated with total left TMJ alloplastic replacement combined with a right TMJ arthroplasty. No subamandibular incision was performed and, subsequently, the risks for permanent or temporary damage to the marginalis mandibulae nerve and surgical submandibular scar were avoided. Postoperative CT-Scan evidenced a good prosthesis position. No complications occurred after two years of follow-up.