Accuracy of digital photographs for assessing inflammatory gum disease in epidemiologic studies

Background Incorporating gum disease assessment into epidemiologic studies would facilitate investigations of disease etiology. Objective We evaluated the accuracy and inter-rater reliability of experienced dental health professionals' visual assessments of digital photographs to determine inflammatory gum disease. Methods Raters viewed anonymized photographs of the teeth and gums of 30 adult patients and were asked to distinguish “healthy” gingiva from “gum disease” and to assess disease severity. Frequency, percentage, and cross-tabulation statistics were used to perform diagnostic calculations including sensitivity, specificity, and overall accuracy. Fleiss' Kappa, with a 95% confidence interval, was used to test for interrater reliability amongst the four raters. Cohen's Kappa was then calculated for each potential pairing of the four raters. Results The accuracy of determining active inflammatory gum disease from digital photographs ranged from 76.7% to 96.7% (mean 85.9%) across the four raters. Sensitivity ranged from 70% to 95% (mean 82.5%), and specificity ranged from 80% to 100% (mean 92.5%). However, inter-rater reliability for disease severity was only fair, with Fleiss's Kappa for gingivitis and periodontitis 0.25 (0.00–0.51) and 0.28 (0.03–0.54), respectively. Conclusion Our findings show that digital photographs could be useful for assessing inflammatory gum disease in epidemiologic studies of inflammation-mediated chronic systemic diseases.