Periodontal risk score: Initiation and model validation for 6,762 teeth

Tooth-level prognostic systems are valuable tools for treatment planning and risk assessment of periodontally involved teeth. Recently the Miller-McEntire prognosis index was found to outperform comparable systems. However, it had some limitations. The present study aimed to develop and evaluate the prognostic performance of a modified version that addresses most limitations of the previous model called the periodontal risk score (PRS).

Data were retrieved retrospectively from patients who received surgical and non-surgical periodontal treatment at a university setting. Data on medical history and smoking status at baseline and the last maintenance visit were collected. Both univariate and multivariate Cox proportional hazard regression models were used to analyze the prognostic capability for predicting tooth loss due to periodontitis (TLP) risk.

A total of 6762 teeth (281 patients) were followed up for a mean period of 22.6 ± 6.34 (10-47.6y) years. The PRS was successfully able to stratify the risk of TLP at baseline when the three different classes of association were compared for anterior and/or posterior tooth loss. After controlling for maintenance, age, and sex, the index showed an excellent predictive capacity for TLP with a Harrell C-index of 0.947.

The periodontal risk score (PRS) displayed excellent predictive capability for anterior as well as posterior tooth loss due to periodontitis. This system was able to predict long-term tooth loss with a very high accuracy  in a population treated mainly by dental students and periodontics residents. The use of this/similar prognosis system is advisable as a means to establish tooth prognosis.