Abstract
Background: Specular reflection can be used to quantify dental erosion, and might also provide similar results for caries. This study assessed the possibility of using specular reflection intensity (SRI; quantitative lesion activity assessment) to measure the progression of initial enamel caries lesions. Methods: Two hundred native enamel specimens and flat ground enamel specimens (n=100 each) were subjected to a 4-species biofilm caries model during 2, 4, 6, 8, and 10 weeks (n=20 each), to induce ‘active’ enamel caries lesions. Afterwards, to induce ‘inactive’ lesions, all specimens were continuously remineralized and brushed twice daily for 2, 4, 6, 8, and 10 weeks. Change in specular reflection intensity (%SRI), visual caries detection (ICDAS) and visual caries severity assessment were performed for all active lesions and during the remineralization phase. Scanning electron microscopy (SEM) images were taken for qualitative analysis. Results: For active lesions, %SRI dropped from 100% to about 80% in native enamel, and to about 15% in polished enamel. Remineralization/brushing increased %SRI in native enamel, but not in polished enamel. The comparison with visual caries scores yielded a better linear relationship of %SRI with early enamel lesion where caries was induced for up to 6 weeks. Conclusion: The use of the optical reflectometer for the assessment of caries lesion activity seemed to work better for early caries lesions and for polished specimens.