Long term dental implant survival and bone level changes with special emphasis on radiation therapy after free fibula flap reconstruction – a retrospective study

OBJECTIVES: This study aimed to investigate the long-term survival of dental implants in patients after ablative resection of the maxilla or mandible and consecutive reconstruction with microvascular free fibula flaps (FFF). MATERIALS AND METHODS: Patients treated with a FFF reconstruction of the mandible/maxilla and dental implant insertion were included. Implant survival and the influence of age, gender, radiotherapy, and localization were evaluated. Moreover, mesial and distal bone resorption was recorded. Implant survival was assessed using Kaplan-Meier methods and Cox regression, while bone loss was analyzed with linear mixed models. Multiple testing was adjusted by Scheffé's method; significance was set at p < 0.05. RESULTS: In total, 53 patients with 257 implants were evaluated. The mean observation period was 64 months. The cumulative survival rate was 98.4% at 1 year, 95.7% after 3 years, and 91.8% at 5 years. After five years, adjuvant radiotherapy was associated with reduced implant survival (73.8%) and significantly increased distal bone loss (p = 0.009). Moreover, native bone (mesial: 3.2 ± 0.6; distal 3.2 ± 0.8) demonstrated significantly greater bone loss compared with fibula bone (mesial: 2.6 ± 1.6; distal 2.8 ± 1.7). CONCLUSION: Adjuvant radiotherapy results in a markedly reduced implant survival and a significantly greater marginal bone (distal) loss after five years. CLINICAL RELEVANCE: Dental implants reveal higher survival in fibula bone after mandibular/maxillary reconstruction with microvascular FFF when irradiation was performed prior to reconstruction with a FFF and in patients without irradiation.