Prosthetic rehabilitation of edentulous patients after surgical management of oral cancer is difficult and therefore often avoided. However, adequate prosthetic rehabilitation is a pivotal factor for patients to regain oral function . In terms of the masticatory rehabilitation of these patients, the application of a removable prosthesis unsupported by implants may be difficult or even impossible because of the postsurgical anatomical alteration . The benefits of implant-supported prostheses have been recognized for several years . Dental implants may improve denture retention and stability without unnecessary loading of the vulnerable mucosa. Function, comfort, esthetics, and eventually quality of life can be improved . Two different options for oral rehabilitation using dental implants exist. One of these is the fixed prosthesis supported by implants, which does not involve any contact with the oral mucosa, thereby preventing frictional ulcers. The other option is an implant-supported overdenture, which allows improved oral hygiene . Barão et al.  reported that patients with implant-supported overdentures exhibited a higher degree of stress on the supporting mucosa than those with fixed implant-supported prostheses. In those with fixed implant-supported prostheses, the prosthesis is completely supported by the implants, with no mucosal contact; therefore, fixed implant-supported prostheses limit the degree of mechanical irritation to the soft tissue.
Based on the clinical and histological findings, our case was considered to be an intermediate-grade mucoepidermoid carcinoma. Because wide local surgical excision is critical in the treatment of this tumor, we performed entire resection of the alveolar ridge, also considering her age and esthetic concerns. Loss of the alveolar ridge led to severe masticatory dysfunction. In the present case, the patient refused further surgical intervention following surgical removal of the gingival carcinoma, and we adopted an implant-supported overdenture because of its relative simplicity, ease of self-maintenance, and affordability. According to the literature, in patients with malignancies involving the lower region of the oral cavity, a minimum of four implants is needed to achieve maximal implant support for the prosthesis and to relieve the vulnerable underlying soft tissues [10, 11]. We inserted an implant-supported overdenture on a gold bar retainer splinting four implants. However, the patient was not satisfied with this prosthesis because of the mucosal pain and discomfort that developed over time. In such cases, prosthetic loading of atrophic mucosa is often not well tolerated. As such, we proposed replacement with an implant-fixed prosthesis. Initially, the patient elected not to proceed with this option because of the additional economic burden. However, the patient eventually opted for rehabilitation with a fixed implant-supported prosthesis, as this provided the psychological advantage of a prosthesis that felt similar to the natural teeth. In this case, an implant-supported overdenture, which was provided to rehabilitate the edentulous mandibular region after marginal mandibulectomy for treatment of gingival carcinoma of the mandible, was replaced by an implant-fixed prosthesis.
Pjetursson et al.  performed a systematic review of the survival and complication rates of implant-fixed prostheses after a mean observation period of at least 5 years. They concluded that implant-fixed prostheses are a safe and predictable treatment method with high survival rates. However, biological and technical complications were frequent in their review (33.6 %). To minimize the incidence of complications, dental professionals should make great effort to choose reliable components and materials for implant-fixed prostheses, and patients should undergo a well-structured maintenance protocol after treatment. In the present case, professional teeth cleaning with individual instruction every 3 months improved the patient’s oral hygiene. Maintenance care may have motivated the patient to improve her oral home care regimen. This case report indicates that occasionally, even after definitive therapy has been completed, the clinician must re-evaluate and sometimes alter the direction of treatment to provide the best possible outcome for the patient. In conclusion, we have herein reported a case illustrating our long-term clinical experience and the concept of switching therapy.