Evaluation of penetration effect of resin infiltrant using optical coherence tomography

Abstract Objective The aims of this in vitro study were to investigate whether optical coherence tomography (OCT) could analyze infiltration of resin infiltrant (RI) into early dental caries (EC), and to confirm the correlation between the results of OCT and confocal laser scanning microscopy (CLSM) for evaluation of RI infiltration into EC. Methods Sound bovine permanent teeth were used to produce sixty specimens by making two windows on the teeth. Each 20 specimens were demineralized for 20, 30, and 40 days, and the RI was treated on one of the windows. As a result, the images of the fifty-two specimens were taken by OCT and CLSM. The demineralized lesion depth (LDOCT and LDCLSM ) and the infiltrated depth of RI into lesion (IDOCT and IDCLSM ) obtained from the OCT and the CLSM were analyzed. The correlations between the LDOCT and the LDCLSM , and between the IDOCT and the IDCLSM , were analyzed by Pearson correlation and intra-class correlation. Also, Bland–Altman plot was constructed to assess the agreement between the IDOCT and the IDCLSM , and the IDOCT divided by refractive index of RI and the IDCLSM. Results The Pearson correlation coefficient and intra-class correlation of 0.75 and 0.83 (95% CI: 0.71–0.91) respectively were confirmed between the LDOCT and the LDCLSM ( p < 0.001), and 0.59 and 0.71 (95% CI: 0.50–0.84) respectively were observed between the IDOCT and the IDCLSM ( p < 0.001). The lower bias was confirmed in Bland–Altman plot between adjusted IDOCT and the IDCLSM than between the IDOCT and the IDCLSM. Conclusion The OCT was the promising quantitative evaluation method for RI penetrated into EC. Clinical significance The OCT would be used as a nondestructive and real-time evaluation method for RI penetrated into EC on clinical procedure.