Roles of Thin Gingival Phenotype and Insufficient Keratinized Mucosal Width as Risk Indicators in Peri-Implantitis and Peri-Implant Mucositis

We aimed to explore the roles of thin gingival phenotype and insufficient keratinized mucosal width (KMW) as risk indicators in peri-implantitis and peri-implant mucositis. Patients (100 in total) planted with bone level implants and soft tissue level implants during January 2021 and October 2024 were retrospectively selected. They were allocated to a KMW ≥2 mm group (n=48) and a KMW <2 mm group (n=52) on the basis of KMW. The mSBI of the thick gingival phenotype was significantly decreased at 6 months and 3-4 years compared with that of the thin gingival phenotype in both groups, while significant increases in the mSBI at 6 months and 3-4 years were observed from the bone level implants in comparison to those from the soft tissue level implants (P<0.05). In the two groups, the mPLI of the thick gingival phenotype declined significantly at 6 months, 1 year, and 3-4 years in comparison to that of the thin gingival phenotype, whereas the bone-level implants presented significantly higher mPLI than the soft tissue level implants at 6 months and 1 year (P<0.05). The KMW ≥2 mm group had significantly smaller proportions of patients with peri-implant mucositis and peri-implantitis in the bone level implants and soft tissue level implants than the KMW <2 mm group (P<0.05). Thin gingival phenotype and insufficient KMW can be used as risk indicators for assessing the occurrence of peri-implantitis and peri-implant mucositis, for which targeted preventive and therapeutic measures can be taken.