ELECTRONIC DIAGNOSIS OF OCCLUSAL CARIES IN-VITRO - ADAPTATION OF THE TECHNIQUE FOR EPIDEMIOLOGIC PURPOSES

Most studies on electronic diagnosis of occlusal caries have involved taking site-specific conductance measurements. Airflow around the elec tronic caries monitor probe removes superficial moisture and the condu ctance measurement reflects the caries status of that part of the fiss ure beneath the probe tip. This is an appropriate technique for a clin ician to use to monitor caries status, and it could be adapted for use in epidemiological studies and clinical trials. The present work inve stigated an alternative technique using a jelly as a contact medium ov er the entire fissure system so that the probe might record the overal l caries status of the tooth reflecting the worst affected site. Readi ngs were taken on 96 extracted teeth with dye-coloured jelly acting as a contact medium. Readings were repealed on 32 teeth. Histological va lidation of caries status was carried out by visual examination of ser ial sections through each tooth to note the deepest lesion. The sensit ivity and specificity of the overall electronic caries monitor reading s were calculated for all lesions and dentine lesions only using selec ted resistance cut-off points and presented as a series of Receiver Op erating Characteristic (ROC) curves. The optimum sensitivity and speci ficity values were, for all lesions: 61% and 86%, and for dentine lesi ons: 76% and 76% respectively. The reproducibility of the readings was acceptable (Kappa values for all lesions= 0.76, for dentine lesions=0 .55). The technique warrants further study as an overall reading may b e more appropriate for epidemiological and clinical trial use.