Method:
Ninety one exfoliated primary second molars were obtained from 9 to 11 year old children at or close to time of exfoliation and scored for caries lesions by visual-tactile means and then by biopsy examination. Visual-tactile scoring was done by a single calibrated examiner (MM) using Radike (1972) criteria as modified by Acevedo et al. (2005). The extent of caries progression was then determined by biopsy, each tooth was imbedded in a clear acrylic cylinder and sectioned horizontally and mesio-distally with a diamond disc and slow speed Isomet microtome. Thickness of slices obtained was between 150 and 200 µm. Biopsy by visible light and microscopic examination of the slices was done by a calibrated examiner (FR). Teeth without any caries by visual-tactile inspection followed by biopsy comprised one group of analyses. A second group with caries by visual-tactile inspection followed by biopsy was also done.
Result:
Teeth (91) showing no occlusal caries lesions in situ by visual-tactile means, upon biopsy showed 55% of them with enamel lesions, 41% with dentinal caries close to the dentinal-enamel junction and 4% lesions clearly in the dentin. After exfoliation, 78 of the teeth still showed no caries detectable by visuo-tactile means and when biopsied showed 56.4% already carious in the enamel, 39.8% with lesions reaching the dentinal-enamel junction and 3.8% extending into dentin.
Conclusion:
The results showed that caries lesions in occlusal sites can reach into dentin and yet not be indicated or visible clinically by mirror or probe methods (or x-ray) routinely used presently for caries detection clinically.