Reproducibility and agreement of clinical diagnosis of occlusal caries using unaided visual examination and operating microscope

To assess the reproducibility of clinical diagnosis of occlusal caries using unaided visual examination and examination with an operating microscope (16 x magnification) and to determine the agreement between these 2 methods. Three experienced dentists used unaided visual examination and an operating microscope to grade, according to a standard caries rating scale, a total of 299 occlusal surfaces in 112 subjects (mean age 28.3 years, standard deviation 0.5 years), during several examination sessions. Intraobserver and interobserver reproducibility was calculated, and agreement in diagnosis of the same teeth by different methods was also determined. The level of intraobserver agreement for the 2 modes of clinical diagnosis was substantial, as indicated by kappa values; however, there was substantial interobserver variability with both techniques. Agreement in clinical diagnosis between the 2 techniques was 62.5% for observer 1 (kappa = 0.483), 65.4% for observer 2 (kappa = 0.531) and 63.5% for observer 3 (kappa = 0.508) (p = 0.001). Intraobserver agreement with the operating microscope and with unaided visual examination was roughly the same, but interobserver agreement was low with both techniques. For some surfaces, the diagnosis made by a particular observer with unaided visual examination differed from that made with microscopic examination. The diagnoses differed most frequently for surfaces that were scored as sound with unaided visual examination.