Attached gingiva width: not an independent bone-loss driver in this 5-year cohort

Does the width of attached gingiva around dental implants actually protect the underlying bone? This retrospective study set out to answer a question that remains genuinely unsettled in implantology: whether an adequate zone of keratinized, attached mucosa independently reduces peri-implant marginal bone loss (MBL) over time.

The study retrospectively analyzed 330 implants placed in 107 patients, followed over a five-year period. Implants were stratified by attached gingiva width — below or at/above 2 mm — and MBL was assessed radiographically as the primary outcome. Secondary outcomes included plaque index, gingival index, probing depth, and attached gingiva width measurements. Crucially, the statistical approach used multivariable generalized estimating equations (GEE) regression, a method that appropriately accounts for the clustering effect of multiple implants within the same patient — a methodological step often neglected in studies of this kind.

In univariate analysis, implants with less than 2 mm of attached gingiva showed greater mean MBL (2.17 ± 2.28 mm) compared to those with 2 mm or more (1.64 ± 1.84 mm), a difference that reached statistical significance (p = 0.045). However, once confounding variables were introduced into the multivariable GEE model, this association disappeared. Attached gingiva width was not an independent predictor of bone loss. Smoking, by contrast, remained a significant independent risk factor regardless of adjustment.

Approximately 79.7% of implants had ≥2 mm of attached gingiva, and 45.8% showed less than 1 mm of MBL over the five-year observation period — figures suggesting a generally favorable sample, which may have limited the study's power to detect subtle effects of mucosal width.

The clinical message is measured but important. The long-standing assumption that a minimum 2 mm band of attached gingiva is necessary around implants to prevent bone loss is not supported as an independent effect in this dataset. Soft tissue width may matter for patient comfort, plaque control, and tissue resilience, but it does not appear to operate as a standalone driver of bone resorption. Smoking, on the other hand, consistently emerges as a modifiable systemic factor with a measurable negative impact on peri-implant tissue stability.

For clinicians, this study reinforces a more nuanced risk-stratification approach: augmenting keratinized mucosa around implants may still be indicated in specific anatomical or prosthetic contexts, but it should not be viewed as a substitute for rigorous assessment and management of patient-level risk factors — smoking cessation counseling foremost among them. The authors appropriately call for prospective, multicenter studies to confirm these findings in larger and more heterogeneous populations.