Association between attached gingiva width and peri-implant marginal bone loss: a five-year retrospective study

The role of keratinized mucosa surrounding dental implants in maintaining peri-implant tissue health remains controversial. This study aimed to investigate the relationship between attached gingiva width and peri-implant marginal bone loss.

A total of 107 patients with 330 dental implants were retrospectively evaluated over a five-year follow-up period. The primary outcome was peri-implant marginal bone loss (MBL), while secondary outcomes included plaque index (PI), gingival index (GI), probing depth, and attached gingiva width. MBL was assessed radiographically and implants were grouped according to attached gingiva width (< 2 mm or ≥ 2 mm). Statistical analyses included chi-square tests, independent samples t-tests, and multivariable generalized estimating equations (GEE) regression to account for clustering of implants within patients.

Among the implants examined, 79.7% had an attached gingiva width of ≥ 2 mm, while 45.8% exhibited less than 1 mm of MBL. In the multivariable GEE analysis, attached gingiva width was not independently associated with peri-implant bone loss after adjustment for clustering and confounding variables, whereas smoking remained a significant independent predictor. Although mean MBL was greater in implants with < 2 mm of attached gingiva (2.17 ± 2.28 mm) than in those with ≥ 2 mm (1.64 ± 1.84 mm) in univariate analysis (p = 0.045), this association was not confirmed after multivariable adjustment.

Within the limitations of this retrospective study, attached gingiva width alone may not represent an independent determinant of peri-implant bone loss. Patient-related factors, particularly smoking, may play a more substantial role in peri-implant tissue stability. Further prospective multicenter studies are needed.