Comparison of the Detection of Early Occlusal Caries in Extracted Human Permanent Molar Teeth by Electrical Conductance and Biopsy Means

Objectives: An in vitro study was performed to detect occlusal caries lesions of extracted permanent human molars by electrical conductance measurement with the Ortek ECD™ electronic device, and each tooth was sectioned and biopsied to validate and evaluate results.

Methods: Thirty-nine permanent molars were extracted. Thirteen were freshly erupted and had little opportunity to develop lesions. Twenty-six were in the mouth longer and likely to be carious. After extraction and storage in a mild disinfectant, each tooth was thoroughly rinsed with distilled water and positioned upright to enable its electrical conductance measurement. Electrical conductance was measured in pits and fissures of carious and non-carious permanent molars with an Ortek ECD. Crowns were sectioned horizontally producing 630 µm thick slices and examined individually for demineralization by light microscopy and photography. Tooth biopsy was analyzed to ascertain the degree of tooth demineralization.

Results: Visual examination by light microscopy and photography of the sections of non-carious and carious teeth were analyzed. Noncarious teeth showed no mineral loss and showed an electrical conductance score of 0.0 µA. In carious teeth, this score ranged from 0.3 to 3.0. A significant (p < 0.001) correlation coefficient (r) of 0.914 was obtained. Electrical conductance versus biopsy resulted in high values for sensitivity (100%) and specificity (93%). It showed a positive predictive value (PPV) of 96% and a negative predictive value (NPV) of 100% for electrical conductance versus biopsy.

Conclusions: Subject to in vivo clinical support, the Ortek ECD is likely to prove to be the best method for detection and evaluation of early occlusal caries.