Association between Clinical and Photoimaging Scores for Gingivitis

Both inter and intra-examiner reproducibility are essential considerations when conducting clinical gingivitis studies, in part the result of the subjective nature of the indices commonly used. Any progress towards greater objectivity would be advantageous. Objectives: The purpose of this study was to determine a) the reproducibility of an experienced gingivitis examiner when using the Modified Gingival Index and b) the correlation between gingivitis scores from clinical measures and from high quality digital images taken of those sites. Methods: The study protocol was reviewed and approved by the IRB's of both participant universities. The examiner had been trained and calibrated. Thirty male and female participants were each examined clinically on 2 separate occasions within the same day, and gingivitis recorded for the facial surfaces of the 12 anterior teeth, using the Modified Gingival Index (MGI). Independently, 3 digital images were taken of the anterior teeth on 2 occasions on the same day, using a FujiFilm FinePix S1Pro, 5.0 megapixel camera and data recorded on CD. On a separate day, the examiner read the MGI scores from the randomized images on a computer screen. Agreement between direct measurements, between repeated photo measurements, and between both direct and photo measurements were determined for site-specific and computed indices.Results: For the repeat clinical indices, ICC values were >0.90, with 76% site measurements identical, and for the repeat photo measurements, ICC's were generally between 0.85 and 0.90. ICC values between direct clinical and photo measurements were 0.70 – 0.80. Conclusions: The high correlation between repeat clinical measures and also between photo image measures, together with the agreement between these two measures, provide encouragement for developing digital imaging methodology, in an attempt to introduce greater objectivity in gingivitis studies and clinical trials.