Thin Gingival Phenotype Emerges as the Strongest Peri-Implant Risk Signal in a 968-Implant Cohort

Peri-implant mucositis and peri-implantitis remain among the most common biological complications of implant therapy, but how much patient-level versus implant-level factors each contribute is still debated. This retrospective study analyzed 968 dental implants placed in 199 patients between January 2015 and January 2023, recording demographic data, systemic conditions, smoking status, oral hygiene habits, implant-related parameters, clinical indices (plaque index, gingival index, probing depth, attached gingiva width, gingival thickness), and radiographic marginal bone loss. Peri-implant disease status was classified per the 2017 World Workshop criteria as health, mucositis, or peri-implantitis, and multivariable generalized estimating equations (accounting for multiple implants per patient) identified independent risk factors.

Of the 968 implants, 73.6% were peri-implant healthy, 17.9% had mucositis, and 8.5% had peri-implantitis. Four factors emerged as independently associated with both mucositis and peri-implantitis: smoking ≥10 cigarettes/day (odds ratio 2.55 for mucositis, 4.40 for peri-implantitis), inadequate tooth-brushing (OR 4.65 and 5.90 respectively), and — the strongest signal in the study — thin gingival phenotype (OR 4.22 for mucositis, and a striking OR 15.64 for peri-implantitis). Longer implant functional duration was an additional independent risk factor specifically for peri-implantitis (OR 1.57 per unit of time).

For everyday practice, this large, well-powered cohort reinforces a maintenance-focused message: patients who smoke heavily, brush inadequately, or present with a thin gingival phenotype around their implants are at substantially higher risk of biological complications, and thin phenotype in particular stands out as a strong, modifiable-at-treatment-planning-stage risk marker. The authors argue that peri-implant soft tissue assessment — including phenotype — and individualized risk stratification should be built into long-term implant maintenance protocols, not treated as an afterthought once problems appear. As with any retrospective design, causation cannot be proven, but the size of the cohort and the consistency of the associations make this a solid addition to the risk-factor evidence base for peri-implant disease.