Abstract

Purpose: The purpose of this study was to validate the newly proposed periodontal disease index "PerioQuotient (PQ)" based on a periodontal disease symptoms questionnaire developed by brainstorming and the Delphi method by the 32nd Executive Committee of the Korean Academy of Periodontology. Materials and Methods: A total of 135 subjects were recruited. Age, gender, and clinical indices of periodontal disease were measured. Periodontitis stage was determined, and an 18-question questionnaire was administered. The internal consistency and validity of the questionnaire were examined using Cronbach's alpha and principal component analysis. Receiver operating characteristic (ROC) analysis, area under the curve (AUC), sensitivity, and specificity were investigated to assess the diagnostic test performance of the questionnaire. Results: The mean age of the 135 subjects was 48.8 ± 17.1 years (male 77 (57.0%), female 58 (43.0%)). The average response to the 18 questions was 7.4 ± 3.1. Reliability testing of the PQ-18 showed that the Cronbach's alpha was 0.68. The original PQ-18 had an AUC of 0.806 (95% CI: 0.709-0.903). Sensitivity was 0.76, and specificity was 0.77. Applying weighting factors according to Firth’s logistic regression analysis to the answers increased the AUC to 0.964 (95% CI: 0.934-0.993). Sensitivity was 0.893, and specificity of 1.0 was achieved. Conclusion: The PQ-17, excluding Question 15 ("No scaling for two years"), was shown a valid and reliable tool for the diagnosis of periodontitis. The PQ index presented in this study achieved high sensitivity, specificity, and AUC, suggesting its potential use as a diagnostic tool for periodontal disease status assessment. (J Korean Dent Assoc 2026; 64(6): 185-191)