Objective: This article aims to describe a new technique for predicting the results of resin infiltration procedure in molar incisor hypomineralization lesions, named Infiltration Monitoring by Transillumination. The technique involves the use of transillumination together with ethanol application during the steps of lesion body opening and resin penetration. It provides color contrast that enhances the removal of the less porous surface layer and controls the effectiveness of resin infiltration within the lesion.Clinical Considerations: The clinical procedure presented illustrates the steps involved in the resin infiltration procedure for color masking of molar incisor hypomineralization lesions in anterior teeth, highlighting the use of transillumination both for monitoring the lesion body opening step and the resin infiltration process.Conclusions: The monitoring with transillumination during the ethanol test can assist the removal of the enamel external layer over the lesion, necessary to expose the inner porosity to be infiltrated, in a very precise and conservative way. In addition, it can effectively help to determine the moment when the infiltrant resin has fully penetrated the lesion.Clinical Significance: The Infiltration Monitoring by Transillumination technique offers the possibility to precisely control the infiltration procedure in molar incisor hypomineralization lesions, thereby improving the predictability of the esthetic outcome.

There are many suitable strategies for addressing caries, which is an ongoing worldwide problem. Although white spot lesions (WSLs) can be either remineralized naturally or treated with non- or micro-invasive strategies, their whitish and opaque appearance may persist.

Considering that a single passive application of hydrochloric acid (HCl) as a resin infiltration pretreatment can remove between 20 and 45 µm of enamel and cause etching that extends up to 2 mm beyond the white spot lesions (WSLs), it is plausible that its repeated and active applications could result in a greater amount of dental tissue being removed. Objective To evaluate the enamel surface loss and micromorphology after etching with 15% HCl using two application methods (passive-P and active-A) and varying numbers of applications (C-placebo – 120 s; 1x HCl – 120 s; 2x HCl – 120 s + 120 s; 3x HCl – 120 s + 120 s + 120 s). Methodology Bovine incisors with ≤0.3 µm initial curvature were randomized into eight groups (n=12) based on microhardness, followed by WSL simulation. A central window was etched according to experimental conditions, and surface loss was assessed using optical profilometry and micromorphology via scanning electron microscopy (SEM). Two-way ANOVA and Tukey's test were used for surface loss, and the chi-square test evaluated the association of experimental conditions with etching patterns (α=0.05). Results 1xP generated intermediate mean surface loss, positioned between the values observed for passive control (PC) and active control (AC), and those for 2xP and 3xP. Losses from active applications were significantly higher than passive ones and were increased by the number of applications. SEM showed Types II and III etching patterns and Type II was more frequent. There was no association between treatment and etching pattern. Conclusion Multiple and active HCl applications may raise concerns about removal of the remaining tooth structure, challenging the principles of minimal intervention dentistry.

This study evaluated the color change (ΔE₀₀) and penetration depth (PD) of white spot lesions (WSLs) infiltrated with the resin infiltrant (Icon^®) functionalized with methacrylate epigallocatechin-3-gallate (EGCG). To introduce polymerizable double bonds, EGCG was reacted with methacryloyl chloride (EM). Subsequently, the Icon resin infiltrant (I) was loaded with neat EGCG (IE) or EGCG–methacrylate (IEM) at 2 wt% each. WSLs were created on bovine enamel blocks and treated with I, IE, or IEM. Sound and untreated enamel surfaces were used as controls (C). Infiltrant PD (%) was determined by Confocal Laser Scanning Microscopy (CLSM, n = 12) analysis. For color change (ΔE₀₀) determination (n = 14), ΔL, Δa, and Δb, half of each sample was kept sound as a reference area. The color was determined with a spectrophotometer. Data were statistically evaluated (p = 0.05). Surface morphology was obtained as a qualitative response variable using 3D CLSM. PD (%) did not differ statistically for I, IE, and IEM (p = 0.780). Groups I and IEM showed similar performance on color change (ΔE₀₀) compared to the control group, while IE exhibited intermediate results, with no significant difference observed between the untreated, I, and IEM groups (p < 0.001). IEM promoted the masking of the WSL color without interfering with the PD.