Peri-implantitis and mucosal dehiscence: local factors you can still plan for

Most risk-factor work on peri-implantitis looks at the patient: smoking, periodontitis history, diabetes. The implant itself, and the site where it sits, get less attention, even though these are the variables the clinician can still change at the planning stage.

This cross-sectional study examined a randomly selected sample of Norwegian patients who had received implant therapy in 2014: 242 patients and 732 implants. Clinical and radiographic parameters were recorded, including soft-tissue phenotype, mucosal margin mobility, connection type, platform switching, emergence angle, implant location and presence of adjacent teeth. Because implants cluster within patients, the analysis used mixed-effects logistic regression. The outcomes were peri-implantitis and peri-implant soft-tissue dehiscence (PISTD).

Peri-implantitis was present at 8.7% of implants and PISTD at 25.0%. For peri-implantitis, the significant risk indicators were mucosal margin mobility, bone-level implants without platform switching, an emergence angle above 45°, anterior location and daily smoking. For PISTD, they were a thin soft-tissue phenotype, mucosal margin mobility, absence of adjacent teeth, peri-implantitis itself and an external connection.

The design is cross-sectional, so these are associations rather than proof of cause. Still, the authors point out that many of the factors identified are modifiable during treatment planning, and they call for particular attention to soft-tissue phenotype, connection design, platform switching and prosthetic emergence angle. The relationship between systemic and local risk factors, they add, still needs to be investigated.