ELECTRICAL CONDUCTANCE OF FISSURE ENAMEL IN RECENTLY ERUPTED MOLAR TEETH AS RELATED TO CARIES STATUS

Pit-and-fissure caries lesions contribute greatly to the caries incide nce in permanent molar teeth in children. To date, the diagnosis of oc clusal caries is still performed mainly by visual inspection, periodic ally aided by bite-wing radiography However, in detecting small occlus al carious lesions, these methods perform inadequately, especially in low caries prevalence populations or individuals. The use of electrica l conductance measurements (ECMs) has been evaluated to improve the di agnosis of small occlusal carious lesions. The aim of this study was t o monitor the electrical conductance of fissure enamel in recently eru pted molar teeth and to relate these measurements to the caries status . 50 children aged 5-15 years, having first or second permanent molars that were not exposed to the oral environment for more than 6 months, participated in the study. The diagnostic systems evaluated were visu al inspection and ECMs. Following baseline data recording, diagnostic measurements were repeated three times within 18 months. Data were col lected at predefined sites in the fissures. 18 months after baseline r ecording, 179 sites at 60 molar teeth in 27 children were judged to re quire a sealant based on visual inspection. After removal of carious t issue, two examiners jointly decided on the status of decay as per the criteria: O = no caries or caries limited to enamel, and 1 = caries i nvolving dentine. The sensitivity of ECM continued to increase with ti me after a slight initial dip, whereas the specificity continuously in creased after baseline measurements as a result of the decreasing amou nt of false-positive diagnoses. ECMs obtained after each 6-month inter val from sites that developed caries were significantly higher than th ose from sites that remained caries free (all p < 0.02). Furthermore, ECMs obtained from sites that exhibited dentinal caries upon validatio n were significantly higher than those obtained from sites that showed no caries or caries limited to enamel on validation (p < 0.001). The areas under the receiver operating characteristic curves of visual ins pection and ECMs were 0.67 and 0.77, respectively, a difference that w as not statistically significant (p > 0.05). It was concluded from thi s study that ECMs can aid the detection of fissure caries in recently erupted molar teeth. The results imply that an ECM value of 6.5 can be considered as the cut-off between no caries or caries limited to enam el and dentinal caries. Furthermore, ECMs can be used to predict the p robability that a sealant or a sealant restoration will be required wi thin 18-24 months after eruption.