Time between recall visits and residual probing depths predict long-term stability in patients enrolled in supportive periodontal therapy.

Abstract

To relate the time between recall visits and residual periodontal probing depths (PPDs) to periodontal stability in patients enrolled in supportive periodontal therapy (SPT). Retrospective data on residual PPDs from 11,842 SPT visits were evaluated in SPT patients at the Medi School of Dental Hygiene (MSDH), Bern, Switzerland, 1985-2011. A residual PPD-based algorithm was developed to compute SPT intervals with no expected change of residual PPD. A total of 883 patients aged 43.9 (±13.0)years and 55.4% (n=489) being females were identified. Linear mixed model analysis yielded highest statistically significant impact on PPD change with time between SPT visits, presence of residual PPD ≥4mm, and bleeding on probing (p<0.0001). Patients returning for SPT five times consecutively earlier than computed presented mean % PPDs ≥4mm of 5.8% (±3.9) compared with patients returning later (19.2%, ±7.6) (p<0.0001). Additionally, patients attending >50% of their SPT visits earlier versus later demonstrated increased periodontal stability after 5years (p=0.0002) and a reduced frequency of tooth loss (0.60, ±0.93 versus 1.45, ±2.07) after 20years (p<0.0001). To reach and maintain periodontal stability during SPT, individual quantitative data from comprehensive residual PPD profiles may contribute to the improved planning of SPT intervals.