Analyzing the predictability of the Kwok and Caton periodontal prognosis system: A retrospective study

BACKGROUND: The aim of this study was to analyze the predictability of the Kwok and Caton periodontal prognosis system by investigating tooth survival within a 64-month period and to compare this to other well-established prognosis systems. METHODS: This retrospective study included the records of patients who had a minimum of two dental exams at least 12 months apart at a single University-affiliated Dental Center. Data including patients' age, sex, length of follow-up period, initial tooth prognosis, revised tooth prognosis, tooth type, and number of teeth lost at the latest exam were recorded. Descriptive analysis was used for data interpretation. RESULTS: A total of 4,046 teeth from 174 patients qualified for the study. Teeth with initial poorer prognosis had a higher chance of being extracted compared with those with a better initial prognosis. Tooth survival rate at the latest follow-up for those with an initial favorable, questionable, unfavorable, and hopeless prognosis was 97.9%, 90.7%, 62.5%, and 17.7%, respectively. Teeth initially assigned to a poorer prognosis category had a higher proportion that changed to a worse prognosis at the latest periodontal exam. CONCLUSIONS: The Kwok and Caton prognosis system can predictably determine tooth survivability within a 5-year period. The defined categories of this prognosis system are more reliable than that of other systems in the short-term. However, long-term (>5 years) prediction accuracy of this prognosis system needs further investigation.