Long-term outcomes of dental implants in oncologic patients reconstructed with fibula free flaps

Background : Dental rehabilitation with conventional prostheses after microvascular jaw reconstruction could result often unsuccessful because of the altered oral anatomy and the lack of adequate dentition for fixation. Although the efficacy and long-term safety of osseointegrated implants have been documented in atrophic patients, their outcomes in the oral cancer population remain unclear.Aim: to evaluate the long-term clinical outcomes and the survival and success rates of implants placed in patients who underwent mandibular or maxillary reconstruction with a fibula free flap; to investigate the relationship between implant prognosis and therapeutic variables.Materials and Methods: Between 1998 and 2015, 21 patients underwent maxillary or mandibular resections for benign or malignant oral tumors and simultaneous microvascular reconstructions with fibula free flaps. 20.8 (8u201338) months after the reconstructive surgery 108 dental implants were placed. Eighteen patients received a fixed prosthesis while three received an implant-supported overdenture. Clinical data as the probing pocket depth, the presence of suppuration and bleeding on probing and the occurrence of hyperplastic tissue formation were collected from medical records and implant bone loss was measured on radiographs to determine survival and success rates. The possible influence of radiation therapy, the reconstructive technique and the use of soft tissue grafts as prognostic factors were determined. To statistically analyze the results Kruskal-Wallis test and Fisher test were used. For the survival analysis, Kaplan-Meier curves and Log-rank test were employed.Results: The mean follow-up after implant insertion was 90.2 (20u2013204) months. The implant survival and success rate was respectively 97.2% and 95.4% at the 12-month follow-up, 86.5% and 73.5% at 60 months, and 79.3% and 64.7% at 120 months. Implant failure was more common in patients that had implants placed after they underwent radiation therapy (p = 0.001) versus those who did not. Peri-implant probing depth measures ranged from 2 mm to 9 mm (mean 3.8u00b12 mm). Peri-implant bone loss ranged from 0.5 mm to 8.1 mm (mean 2.2u00b11 mm) at the 10-year follow-up. Peri-implant bone loss values were higher in case of fibular distraction (p=0,04). Peri-implant hyperplasic tissue was identified in 20.3% of the surviving implants at the 10-year follow-up and its presence impacted the rate of peri-implant bone loss (p=0,001). Connective tissue and skin grafts positively influenced both survival and success of implants and reduced the risk of peri-implant hyperplastic tissue formation.Conclusion:The overall implant survival rate was acceptable. However, a relevant number of implants was identified as unsuccessful at a long-term follow-up. The use of soft tissue grafts can be considered a reliable procedure to significantly improve the long-term outcomes.