Effects of repeated etching cycles using 15% hydrochloric acid on enamel loss and relative attenuation coefficient in resin infiltration.

BACKGROUND: Resin infiltration is used to mask enamel opacities and the recommended etching cycles are three. However, anecdotal evidence suggests that favorable esthetics outcomes can be obtained by increasing the etching cycles. AIM: To determine the incremental and total enamel loss when enamel surfaces are exposed to multiple etching cycles and to assess the relative attenuation coefficient after multiple etching cycles and resin infiltration treatment. METHODS: Ninety extracted sound human premolars teeth were divided into 9 groups (n = 10); with each consecutive group having one additional etching cycle up to 9 cycles. The teeth were scanned with optical coherence tomography and enamel loss and attenuation coefficient were measured with MATLAB software. Enamel loss (one-way ANOVA, p ≤ 0.05) and attenuation coefficient (two-way ANOVA, p ≤ 0.05) were statistically analyzed. RESULTS: There was a significant total enamel loss of more than 33% found at the 7th etching cycle and more. There was no statistically significant difference in the incremental mean depth of penetration of resin between various etching cycles (F(8, 134) = [2.016], one-way ANOVA, p = 0.185). CONCLUSION: This study recommends that etching should not be repeated more than seven cycles to prevent excessive enamel loss. Following eight etching cycles, resin infiltration penetration appears approximately equal to that of healthy enamel.

Esthetic Effects and Color Stability of Resin Infiltration on Demineralized Enamel Lesions: A Systematic Review.

Aims and Objectives: The aim of this study was to systematically review the ability of resin infiltration to conceal demineralized enamel lesions to normal enamel translucency and to maintain color stability. Materials and Methods: A literature search of PubMed, MEDLINE, Web of Science, and Scopus databases and a manual search of articles from 2009 to 2021 for randomized controlled trials (RCTs) and clinical efficacy trials (nonrandomized) were performed. Methodological quality and risk of bias (RoB) of included papers was assessed using Cochrane Collaboration Risk of Bias Tool 2.0 for RCTs and ROBINS-I (Risk Of Bias In Non-randomized Studies of Interventions) tool for nonrandomized studies. Results: A total of 352 titles and abstracts were reviewed. Eight RCTs and three clinical efficiency studies were included in this review. The masking effects of the demineralized enamel lesion were reported immediately after resin infiltration, and the color stability of this material was up to 24 months, with no adverse effects noted. For RCTs, four studies were classified as "some concerns" and four were as "low RoB." For nonrandomized studies, all of the studies presented an overall moderate RoB. Conclusion: Resin infiltration achieves the best esthetic outcomes compared with microabrasion and remineralization therapy. Color stability was achieved with this material for up to 24 months and no adverse effects were noted. Factors contributing to the esthetic outcomes of the resin include the elimination of the hypermineralized surface layer, the homogeneity of the resin itself, and polishing after resin infiltration. Longitudinal follow-up and improved control of confounding variables should characterize future high-quality systematic reviews.

The Penetration Depth of Resin Infiltration Into Enamel: A Systematic Review.

Aims and Objectives: Studies on resin infiltration and its penetration capability are becoming the focus of emerging dentistry. The depth of resin penetration could be a key determining factor in creating a diffusion barrier and in the success of infiltration. The aim of this review article was to evaluate the penetration depth of commercially available resin infiltration in early caries lesions and to identify factors that influence the penetration capability of resin infiltration. Materials and Methods: A literature search was performed in four databases (PubMed, Science Direct, Scopus, and Web of Science) and manual searching from 2009 to December 2022. Eligibility criteria included in vitro studies pertaining to factors affecting the penetration depth of resin infiltration into the enamel. The risk of bias assessment was done by using checklist for reporting in vitro studies (CRIS). Results: The initial search resulted in a total of 297 studies. Twenty-nine were assessed for eligibility, and 23 were selected in the qualitative synthesis. According to the CRIS guidelines, all of the studies were classified as moderate risk of bias. The penetration of resin infiltration is influenced by the enamel surface treatment with hydrochloric acid, formulations containing triethylene glycol dimethacrylate (TEGDMA), the addition of ethanol, penetration time, duration of penetration time, saliva contamination, caries activity, and type of tooth. The hypermineralized surface layer needs to be removed for better resin perfusion. Conclusion: The key to optimal resin infiltration depends on the enamel surface treatment with hydrochloric acid and application technique, infiltration duration, formulation of TEGDMA and ethanol in the resin composition, as well as the type and caries activity of involved teeth. Resin infiltration has superior penetrability compared to fissure sealant, casein phosphopeptide-amorphous calcium phosphate nanocomplexes, flowable composite, adhesive and fluoride varnish. Resin penetration depth may be a critical factor in forming a diffusion barrier and the effectiveness of infiltration in halting the progression of caries.

Repeated Etching Cycles of Resin Infiltration up to Nine Cycles on Demineralized Enamel: Surface Roughness and Esthetic Outcomes-In Vitro Study.

Resin infiltration (RI) is used to mask enamel opacities. There are three recommended etching cycles. However, anecdotal evidence suggests that favorable esthetics outcomes can be obtained by increasing the etching cycles. This study aimed to evaluate the effects of repeated etching cycles during RI application on esthetic changes and surface roughness of demineralized enamel at multiple treatment stages. Artificial demineralization was prepared on the buccal surface of ninety sound extracted premolars. The teeth were divided into nine groups (n = 10); with each consecutive group having one additional etching cycle up to nine etching cycles. Resin infiltrant was performed twice, first for 3 min (Resin 1) and again for 1 min (Resin 2). Surface roughness and esthetic changes were assessed using a profilometer (Ambios XP-200) and Minolta spectrophotometer, respectively, at baseline (sound enamel), etching, resin 1, resin 2, 7 days, and 28 days post resin applications. Data were analyzed with two-way ANOVA (p < 0.05). There was a significant interaction between the different stages and various groups of etching cycles on surface roughness, F(48, 126) = 3.48, p < 0.001. There was a significant interaction between the different stages and various groups of etching cycles on color changes, F(4, 126) = 1.177, p = 0.045. The surface roughness of demineralized enamel infiltrated with RI was less than that of sound enamel (baseline). There is a significant difference in color changes between resin 1 and resin 2 (p < 0.05). After five etching cycles, RI improved the esthetic of the color of teeth similar to the baseline. Surface roughness and color changes remained constant for 28 days. RI can be considered an effective and predictable treatment option for the restoration of early enamel lesions owing to its better surface characteristics and reliable masking effects. The color stability and surface roughness stay unaltered for up to 28 days.