HISTOLOGICAL VALIDATION OF ELECTRICAL-RESISTANCE MEASUREMENTS IN THE DIAGNOSIS OF OCCLUSAL CARIES

Diagnosis of occlusal caries is difficult from visual and radiographic examination. The use of electrical resistance measurement has been de scribed previously and reported to be a potentially sensitive alternat ive technique. This is possibly due to the decreased resistance of car ious pits and fissures. The aim of this study was to validate a protot ype electrical caries monitor for the diagnosis of caries in pits and fissures in vitro using a microfocal radiographic technique. Thirty di screte sites were investigated in 10 extracted molar teeth. Electrical resistance measurements were recorded at each site and thick sections (approximately 0.65 mm) prepared for microfocal radiography. Microfoc al radiography indicated that six sites were sound, 10 had enamel cari es and 14 dentine caries. At a resistance value of 2.2 M Omega, below which a site was regarded as carious and above which it was regarded a s sound, electrical resistance measurements proved sensitive (92%) and specific (100%). Quantification of mineral content indicated that min eral loss in enamel may influence resistance measurement more than les ion depth.