Red fluorescence threshold for assessing the lesion activity of early caries

Abstract

Purpose: The aim of this study was to determine a red fluorescence threshold for differentiating active from inactive non-cavitated carious lesions. Methods: Using the Nyvad criteria, 30 human teeth with non-cavitated carious lesions were divided into active lesions (15 teeth) and inactive lesions (15 teeth). Using the blue light of a quantitative light-induced fluorescence-digital camera, the red fluorescence of the lesions was measured as the ΔR value. By live/dead bacterial staining, bacterial viability was calculated as the RatioG/G+R. The ΔR and RatioG/G+R of active and inactive lesions were compared. The relationship between ΔR and RatioG/G+R was also analyzed. The ΔR threshold was determined for the classification of lesion activity, and its validity was tested. Results: The mean ΔR of active lesions was 1.85 fold higher than that of inactive lesions (p < 0.001), and the RatioG/G+R of active lesions was 1.97 fold higher than that of inactive lesions (p < 0.001). There was a significant positive correlation between the ΔR and the RatioG/G+R in non-cavitated carious lesions (p < 0.05). The ΔR threshold for the differentiating non-cavitated carious lesions by activity status was 37.55, and the sensitivity and specificity were both 83.33 %. Conclusions: A red fluorescence threshold for categorizing non-cavitated carious lesion activity based on microbial metabolic activity was determined. Accurate evaluation of the activity status of non-cavitated carious lesions will assist in diagnosis and treatment planning for patients with dental caries. © 2020 Elsevier B.V.