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

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.