Impact of periodontal maintenance frequency on inflammatory and structural parameters: A propensity score-matched...

To determine the causal efficacy of supportive periodontal care (SPC) frequency on inflammatory and anatomical periodontal outcomes using a propensity score-matched analysis.

This retrospective cohort study utilized electronic health records from a multi-center dental data repository. Adult patients with periodontitis and at least one year of follow-up were classified into two maintenance cohorts based on their average recall interval: Frequent Maintenance (≤4.5 months) and Infrequent Maintenance (≥5.5 months). Propensity score matching (1:1) was performed to balance baseline covariates, including age, gender, diabetes, smoking status, and baseline disease severity (PPD and CAL), resulting in a matched sample of 1,500 patients. The primary outcomes were the annualized rates of change in PPD and Bleeding on Probing (BOP). Secondary outcomes included changes in clinical attachment level (CAL), furcation involvement, and tooth mobility.

Patients in the Frequent Maintenance group demonstrated significantly greater annual reductions in PPD (-0.19mm vs. -0.12mm; p<0.001) and BOP (-8.97% vs. -4.38%; p<0.001) compared to the Infrequent group. This represented a two-fold greater reduction in inflammatory burden for frequent attendees. However, no statistically significant differences were observed between groups regarding the improvement of acquired periodontal defects, including furcation involvement (p=0.15) and tooth mobility (p=0.57).

Frequent SPC provides a robust biological benefit by significantly reducing gingival inflammation and pocket depth but does not independently reverse acquired defects like furcation involvement or tooth mobility. These findings support a risk-based maintenance approach where visit frequency targets inflammation, while structural stability requires distinct therapeutic expectations or interventions.