Gingival inflammation assessment by image analysis: measurement and validation

AIM: Gingival inflammation may be caused by injury or plaque-related diseases and reduction in inflammation can be a useful indicator of gingival recovery. There has been little research on development of non-index methods to measure gingival condition. The aims of the study were to investigate the reliability of the measurement of changes in gingival redness and swelling, using image analysis, and to compare this approach with an established method for assessing gingival overgrowth [J Clin Periodontol 28 (2001) 81]. METHOD: Twenty volunteers with gingival inflammation were recruited and digital images were taken. Duplicate measurements were made on the first visit by two examiners. At a subsequent visit following periodontal treatment, second images were taken. Gingival changes were determined by assessing redness and tooth surface area visible between the level of the inter-proximal papillae and the gingival margin. Tooth area measurements were compared with the established gingival overgrowth method. RESULTS: The method showed excellent reliability for both intra- and inter-examiner measurements of 0.968-0.998 and 0.769-0.947, respectively, according to the classification by Donner and Eliasziw of the Fleiss coefficient of reliability (repeat measures taken during the patients' first attendance). High correlation was found for gingival encroachment when compared with the established gingival overgrowth method. CONCLUSION: This technique proved a reliable method for investigating changes in gingival redness. High correlation was found for gingival encroachment when compared with an established method.