Abstract: Objective: This case reports the multidisciplinary diagnosis and treatment of an elderly patient with maxillary and mandibular dentition defect. Diagnosis and treatment: The oral and maxillofacial surgery, periodontal, endodontic, and prosthodontic treatments were carried out interleaved according to the requirements. During the disease prevention and control period, the hopeless teeth were extracted. For the teeth with chronic pulpitis and chronic periapical periodontitis, the root canal treatments or root canal retreatments were completed. Periodontal treatment and follow-up were done alongside the whole treatment process. During the functional and aesthetic recovery period, pre-restoration review was conducted first, and the design of removable partial denture was carried out to determine the fixed restoration scheme of the remaining teeth. Then, the pre-restoration treatment and fixed restoration of the remaining teeth were carried out. Finally, the maxillary and mandible removable partial dentures were completed, and regular review and follow-up were conducted during the maintenance period. Results: After multidisciplinary diagnosis and treatment, the periodontal maintenance and the awareness of oral health maintenance of the patient were significantly improved. Teeth extraction sockets healed well. The fixed prosthesis of the remaining teeth were completed, and the patient felt comfortable occlusion. No abnormalities were found in the follow-up examination. For teeth with caries, there was no secondary caries after resin filling treatment. For maxillary and mandible removable partial dentures, the retention were well, and the patient felt comfortable with the occlusal movement without interference. Conclusions: Multidisciplinary comprehensive diagnosis and treatment for elderly patients with oral diseases can help improve patients' compliance and awareness of oral health maintenance, and also achieve satisfactory treatment effect. If more missing teeth in elderly patients lead to unstable occlusal relationship, it is necessary to restore correct and comfortable occlusal relationship through occlusal reconstruction when necessary.

Key words: dentition defect, comprehensive dental care, occlusal reconstruction, elderly patients, overdenture