The effect of different surface preparation procedures on the depth of penetration of the resin infiltration technique in teeth with artificial caries lesions: A confocal microscope study

This study aimed to evaluate the effect of different etching cycles applied to artificially enamel lesions on the penetration depth of the resin infiltrant. Enamel samples of 4x4x3mm3 were prepared from the buccal surface of 50 bovine teeth. Samples were kept in demineralization solution for 21 days to create artificial enamel lesions. The samples were randomly divided into five groups (n=10). 15% hydrochloric acid (HCl) gel was applied to each group. Acid etching application time: Group 1; 2 min, Group 2; 2x2 min, Group 3; 3x2 min, Group 4; 4x2 min and Group 5; 5x2 min. The resin was stained with Rhodamine B, the lesion was stained with Sodium Fluorescein and the samples were visualized with a confocal laser scanning microscope (CLSM). The lesion, penetration, and erosion depth (µm) were calculated and the data were analyzed statistically. The mean lesion depth was 108.87 ± 2.96. The highest penetration depth (75.59 ± 9.42) and the lowest penetration depth (37.27 ± 8.36) were obtained from Group 5 and Group 1, respectively (p<0.05). A mean of 22.54 ± 2.35 enamel erosion was detected in a total of five samples. In this study, it can be concluded that the repeated etching cycle increases the depth of resin penetration while causing negligible depth of erosion on the enamel surface.