However, she was not satisfied with the prosthesis; she experienced denture discomfort and developed a decubital ulcer in the tongue flap area, and she gradually ceased use of the denture. The patient was followed for more than 10 years on a regular basis to examine recurrence or metastasis of the gingival carcinoma. Mild erythema and swelling of the mandibular and implant-surrounding mucosa secondary to stimulation during mastication were found (Fig. 7a), and contact with the opposing teeth resulted in wear of the prosthetic screws (Fig. 7b). In this case, the opposing occlusion involved the natural teeth, and the bone loss around the implants was negligible during the 15 years of follow-up (Fig. 8). We had previously proposed replacing the overdenture with an implant-fixed prosthesis; however, at that time, the patient elected not to proceed with this option because of the additional economic burden. Eventually, however, the patient opted for rehabilitation with a fixed implant-supported prosthesis. The patient was not willing to undergo extensive surgical intervention, including preprosthetic surgery and placement of additional implants. Therefore, we elected to replace the implant-supported overdenture with an implant-fixed prosthesis in May 2010.

After the impressions were taken, the implant-fixed prosthesis was fabricated with a cantilever design comprising two dental units. The mandibular prosthesis was then inserted in February 2011, and the final occlusion was verified and adjusted (Figs. 9a,b). The prosthesis was attached to the implants using prosthetic screws. The screw holes were filled with a dental temporary material overlaid with light-curable composite resin. The patient was highly satisfied with the improvement in oral rehabilitation as a result of the new prosthesis. She was instructed on brushing techniques and reviewed every 6 months. Neither dental plaque nor calculus beneath the prosthesis was detected, and there was no mucosal erythema or bone loss around the implants (Fig. 9c), which remained healthy almost 4 years after insertion of the final prosthesis.