Evaluation of two quantitative analysis methods of optical coherence tomography for detection of enamel...

We aimed to evaluate in the same study two quantitative methods for quantification of incipient caries in human dental enamel by using optical coherence tomography (OCT): the optical attenuation coefficient and the area under the A-scan signal, and to compare their results with those obtained from microhardness analysis.

One hundred and sixty samples were obtained from 40 sound human third molars, which had their crowns sectioned. Simulated caries were created by a pH cycling method. OCT measurements were performed on the samples, before and after the induced demineralization. We determined the total optical attenuation coefficient from the OCT signal in each site and evaluated the sensitivity and specificity of this approach to the detection of the demineralization. Also, the areas under the OCT curves (AUC-OCT) and those from sectional microhardness tests (AUC-MH) were compared.

Both the analysis of the optical attenuation coefficient and the AUC-OCT were adequate to efficiently distinguish sound and demineralized samples with sensitivity of 0.93 and specificity of 0.96. The AUC-MH and the AUC-OCT data presented linear relationship and correlation of 0.99.

Both methods for signal analysis from OCT allowed detection of demineralization with good performance. The AUC-OCT approach enables obtaining a linear relation with the microhardness results, for a quantitative assessment of mineral loss in human teeth.