The effect of keratinized mucosa on the severity of peri-implant mucositis differs between periodontally healthy subjects and the general population: a cross-sectional study

Abstract Objective The study aims to investigate the effect of reduced keratinized mucosa (KM) and other risk indicators on the severity of peri-implant mucositis in (i) the general population, (ii) in periodontally healthy patients, and (iii) in periodontally healthy patients without a history of periodontitis. Materials and methods Anamnesis and the following clinical parameters were taken: mucosal-index, bleeding on probing, local plaque index, oral hygiene-index, and width of KM. Mucositis severity score was determined for each implant. Multi-level and subgroup analysis was performed on the patient and implant level. Results Six hundred twelve implants in 130 patients were analyzed. Subgroup analysis showed significant associations between KM < 2 mm and the severity score in (ii) periodontally healthy patients ( p = 0.014) and in (iii) patients without history of periodontitis ( p = 0.017). Secondary outcome showed higher severity scores for patients with insufficient oral hygiene or without residual teeth ( p ≤ 0.001), in maxillary implants ( p = 0.04), and for the number of implants per patient ( p ≤ 0.001). Conclusion Within the limits of the study, one may conclude that a reduced width of KM is a risk indicator for the severity of peri-implant mucositis in periodontally healthy patients and patients without a history of periodontitis. Clinical relevance The results indicate a band of ≥ 2 mm KM to reduce the severity of peri-implant mucositis in periodontally healthy patients.