Modulating the Optical Properties of Initial Caries Lesions Through Low-Viscosity Resin Infiltration: A Spectrophotometric Evaluation

Objectives: Initial caries lesions (ICLs) are the earliest manifestation of dental caries, characterized by subsurface porosity that affects enamel’s optical properties while maintaining its surface integrity. Resin infiltration is a minimally invasive approach to managing these lesions by penetrating and sealing pores with low-viscosity resin, potentially modifying their visual appearance. In order to provide a quantifiable, objective assessment of this optical behavior, this study aimed to evaluate the modulation of color coordinates and VITA Classical shade transitions within the initial lesions immediately following infiltration with Icon Smooth Surface (DMG, Hamburg, Germany). Materials and Methods: Forty-nine extracted human premolars with naturally occurring proximal ICLs (subsurface demineralization) were selected. Lesions were assessed for fluorescence level using 655 nm laser fluorescence (DIAGNOdent pen). Reflectance spectrophotometry (SpectroShade Micro) was employed to record color coordinates in the CIELab and CIELCh spaces, alongside VITA Classical shades, before and after resin infiltration. Results: The infiltration procedure resulted in a statistically significant increase in b* (yellowness) and subsequent C* (chroma) parameters (p < 0.05). VITA Classical shade guide analysis showed an insignificant shift in color distribution according to value (p > 0.05). Conclusions: The present exploratory study provides quantitative insights into the immediate color-modifying effects of a resin infiltration procedure on natural initial proximal caries lesions, complementing the existing literature with objective CIELab/CIELCh and VITA Classical measurements. The p-values should be interpreted as descriptive indicators of potential trends rather than definitive statistical proof. Further research with larger cohorts and long-term follow-up is needed to validate the durability and clinical relevance of these esthetic outcomes.