Our aim was to compare visuo-tactile and electrical conductance methods for detecting occlusal caries, in third molars of young Venezuelan adults.
Method:
25 third molars identified for extraction were examined intra-orally by visuo-tactile and electrical conductance (EC) means. After scoring, the teeth were extracted, cleaned and imbedded in acrylic and sectioned sagittally/mesio-distally in a low speed Isomet microtome. Slice thicknesses were between 150 and 300 µm. Each section was then examined microscopically under a light microscope by a calibrated examiner (FR).
Result:
Of the total number (25) of occlusal lesions identified, 64% were detected by visuo-tactile, 88% by biopsy and 100% by EC means. Diagnostic matrix analysis showed sensitivity and specificity of EC vs. biopsy examination of 1.00 and 0, respectively; with a positive predictive value (PPV) of 0.88. The sensitivity and specificity of EC vs. visuo-tactile examination were 1.00 and 0, respectively; with a PPV of 0.64. By comparison, visuo-tactile examination vs. biopsy examination showed a sensitivity of 0.68, specificity of 0.66, and PPV of 0.93. Correlation of visuo-tactile with EC readings using a proposed severity scale, found for sound sites detected by visuo-tactile means that only 0 % were truly sound, 55.6% were compatible with change beneath the enamel and 44.4% extended into superficial and deep dentin. When a caries lesion was detected by the visuo-tactile method, 31,2% of the lesions were compatible with change beneath enamel and 68.8% extended into dentin of which 37.5% extended deep into dentin.
Conclusion:
The EC method detects more caries lesions at a much earlier stage than can be obtained by visuo-tactile means.