The Color Masking Efficacy of Resin Infiltration, Casein Phosphopeptide-Amorphous Calcium Phosphate, and Fluoride Varnish on the Appearance of White Spot Lesions at Various Depths

Abstract

Background: Non-cavitated white spot lesions (WSLs) pose a concern because they are considered as the initial sign of enamel demineralization, and they present an esthetic issue due to their chalky opaque appearance. Methods to reduce the visibility of WSLs include topical applications of fluoride or casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) to arrest the activity of the initial caries lesion or through infiltrating low-viscosity resin into the subsurface porosities. There is limited research on the esthetic appearance after WSL treatment and color masking efficacy of these methods. Objectives: The aim of this study is to evaluate and compare the color masking effect of WSLs using resin infiltration (RI), CPP-ACP, and fluoride varnish (FV) and to determine the penetration depth after each treatment. Methods: Forty-eight sound extracted human molars were obtained after IRB approval. Teeth were divided into four main groups: RI, CPP-ACP, FV, and control. Teeth were sectioned in a mesiodistal direction into buccal and lingual surfaces. Then each of the main groups was subdivided into two groups (n=12) according to the depth of the WSL: deep buccal and shallow lingual. Teeth were subjected to demineralization solution to create the two lesion depths. VITA Easyshade® (Zahnfabrik, Bad Sackingen, Germany) was used for baseline color measurement (M1), after artificial WSL formation (M2), and following treatments and thermocycling (M3). In addition, visual shade selection by three blinded observers was done. Delta E (△E) was measured between M1 and M3 to determine the success of the methods. Penetration depth was determined using a scanning electron microscope (SEM). Energy dispersive x-ray spectrometry (EDS) was used for the elemental analysis. Statistical analysis was performed using a two-way analysis of variance (ANOVA) with interaction and Tukey HSD post -hoc test if the ANOVA demonstrated significant differences, both with a significance level of p<0.05. Results: All test groups in both lesion depths showed no statistically significant difference in color masking efficiency, as they did not exceed the clinically detectable threshold of (△E=3.7), whereas FV application in the shallow lesion depth did not mask the visual appearance of WSL (△E=6.14), with high significant difference (p<0.001) when compared with the other groups. SEM images revealed the presence of resin tags in the RI group and showed remineralization of the subsurface lesions in the CPP-ACP and FV groups. Conclusion: All treatments tested were effective in improving the esthetic appearance by masking the color of WSLs and would not be clinically visible.