Shallow vestibular depth as a risk indicator for peri-implantitis: a retrospective analysis of 336 implants.

OBJECTIVE: This retrospective cross-sectional study aimed to evaluate the relationship between vestibular depth (VD) and peri-implant soft tissue parameters, marginal bone loss (MBL), and peri-implant disease status. MATERIALS AND METHODS: A total of 336 implants from 65 patients (27 males, 38 females) who had at least one implant restored prosthetically and whose implants had been in function for at least 1 year were examined at the Department of Periodontology, Faculty of Dentistry, Dicle University. Demographic and clinical data (age, gender, smoking, oral hygiene, implant function duration) were recorded. In the clinical evaluation, VD, keratinized mucosa (KM) width and phenotype, and periodontal/peri-implant parameters (modified plaque index (mPI), modified gingival index (mGI), probing pocket depth (PD), bleeding on probing (BOP), gingival recession, and suppuration) were recorded. Implants were divided into two groups based on VD: shallow VD (≤ 4 mm) and adequate VD (> 4 mm). The primary endpoint was the presence (yes/no) of peri-implantitis at the implant level according to clinical and radiographic criteria, reported as prevalence in the study population. Radiographic bone loss was measured on panoramic radiographs. The VD groups were compared using the Mann–Whitney U and χ² tests; within-patient clustering was accounted for using GEE logistic regression. FINDINGS: A total of 336 implants from 65 patients were evaluated. VD ≤ 4 mm was detected in 26.5% of implants, and > 4 mm in 73.5%. According to clinical diagnosis, 39.9% of implants (n = 134) had peri-implant health, 34.5% (n = 116) had peri-implant mucositis, and 25.6% (n = 86) had peri-implantitis. In the shallow VD group, mPI, mGI, BOP, PD, gingival recession, radiographic bone loss, and suppuration were found to be higher than in the adequate VD group in exploratory bivariate analyses (all p < 0.05). In the multivariate GEE analysis, VD ≤ 4 mm was independently associated with peri-implantitis (OR = 2.405; 95% CI: 1.233–4.690; p = 0.010). Additionally, the odds of peri-implantitis were increased in those with implant duration of 5–10 years (OR = 4.026; p = 0.044), and the maxillary anterior region showed a lower likelihood of peri-implantitis compared to the mandibular posterior region (OR = 0.409; p = 0.026). CONCLUSION: Shallow VD was associated with gingival recession, MBL, and the presence of peri-implantitis, along with higher plaque accumulation and soft tissue inflammation. The findings suggest that adequate VD, as a component of the peri-implant phenotype, may be associated with the maintenance of peri-implant health. In particular, in shallow vestibules with a KM width < 2 mm and a thin mucosal phenotype, approaches such as vestibuloplasty and/or soft tissue augmentation may be considered in selected cases to support plaque control. CLINICAL SIGNIFICANCE: Our findings suggest that evaluating VD as part of the peri-implant phenotype may help identify conditions that make maintaining hygiene difficult in areas with shallow vestibules and facilitate discussion of mucogingival approach options in selected cases.