Incidence of tooth loss and associated risk factors in patients during periodontal maintenance therapy in a School of Dentistry.

Aim: The aim of this study was to investigate patient- and tooth-level factors that may predict tooth loss and periodontitis progression in patients who have undergone at least 5 years of periodontal maintenance.

Materials and methods: In this retrospective cohort study, 135 patients were examined after active periodontal therapy (APT) and periodontal maintenance for 5.09-8.65 years (mean 6.16 ± 0.74 years). Regression models were applied to identify risk factors associated with tooth loss and disease progression.

Results: Stage IV periodontitis (incidence rate ratio [IRR] = 4.61; 95% confidence interval, CI [2.97-7.18], p < .001), the presence of ≥5 sites with probing pocket depth (PPD) ≥5 mm at the end of APT (IRR = 2.04; 95% CI [1.32-3.20], p < .01), and residual PPD ≥7 mm at the end of APT (odds ratio [OR] = 3.01; 95% CI [1.14-7.94], p < .05) were risk factors for tooth loss. Residual PPDs of 5 mm (OR = 2.02; 95% CI [1.20-3.40], p < .01) and 6 mm (OR = 2.41; 95% CI [1.22-4.76], p < .05) at the end of APT were risk factors for disease progression. Above 3 mm, each 1 mm increase in maximum PPD/clinical attachment loss was associated with an increased risk of tooth loss and disease progression.

Conclusions: Stage IV periodontitis is associated with an increased risk of tooth loss. Teeth with PPD ≥5 mm at the end of APT are at risk of periodontitis progression or tooth loss.

Keywords: periodontal maintenance; periodontitis; risk factors; supportive periodontal therapy.