Peri-implant parameters in head and neck reconstruction: influence of extraoral skin or intraoral mucosa.

Objective: This study is designed to assess dental implants supporting overdentures in edentulous patients with operated head and neck malignancies using parameters to detect peri-implant disease.
Material and Methods: Thirty-four implants supporting overdentures in 34 oral cancer patients were examined. Clinical parameters [plaque index, probing depth, bleeding on probing (BOP), origin of peri-implant soft tissue, and amount of irradiation] were recorded, and microbiological identification of periodontal pathogens was carried out by DNA-DNA hybridization. To identify yeast species, the samples were cultivated on Sabouraud agar plates and subsequently identified by API 20C AUX plates. An implant site showing BOP, probing pocket depth (PPD)>or=5 mm and radiographic vertical bone loss was considered to have peri-implant disease.
Results: Colonization by periodontal pathogens was found on 15 implants, while yeast species were found in 14 cases. Using a univariate analysis, none of the investigated parameters (microbiologic sign, detection of yeast, origin of peri-implant soft tissue and irradiation) were significantly correlated to signs of peri-implant disease. In the multivariate analysis, yeast [odds ratio (OR) 12.32, P=0.033] and periodontal pathogen (OR 9.88, P=0.046) were significant predictor variables for peri-implant disease. Yeasts were less frequently detected around implants placed in re-vascularized skin flaps if irradiation was set as a confounder (P=0.019).
Conclusions: With respect to the pilot study nature of the study peri-implant soft tissue origin and irradiation had little influence on the development of peri-implant disease. Yeast and periodontal pathogen were explanatory variables for the development of peri-implant disease. Considering the effect of irradiation on the prevalence of yeast, yeast was less frequently observed in peri-implant soft tissue of the skin. Based on these data, future studies on the role of yeast and soft tissue in peri-implant disease should be encouraged.