Evaluation of Etching Times to Determine the Penetration Depth of Resin Infiltration on Artificially Demineralised Teeth: An In-vitro Experimental Study

Introduction: The evolution of caries management has shifted towards minimally invasive approaches, with resin infiltration emerging as a promising treatment for non cavitated carious lesions. Resin infiltration is a minimally invasive treatment for early enamel lesions, but its effectiveness depends on optimal etching. Current protocols lack consensus on the ideal etching time for maximum resin penetration. This study evaluates how varying etching durations affect infiltration depth in demineralised enamel, aiming to improve clinical outcomes and refine evidence-based guidelines for non invasive caries management. Aim: To evaluate the effectiveness of resin infiltration by varying etching times and assessing the material’s penetration depth in enamel. Materials and Methods: This in-vitro experimental study was conducted Department of Paediatric and Preventive Dentistry, Guru Nanak Institute of Dental Sciences and Research, Kolkata, West Bengal, India, from January 2017 to December 2018. It involved 40 premolars extracted for orthodontic purposes that had sound enamel. The samples were divided into four groups, with the control group etched for two minutes as recommended by the manufacturer, and the experimental groups etched for one, three, and four minutes (R1-R4), respectively. Artificial lesions were created using a caries demineralisation solution. The resin infiltration process involved etching with Hydrochloric acid (HCl) gel { Infiltration Concept (ICON®) }, (ICON® Etch), drying the lesions with ICON® Dry (ethanol), and then applying ICON® infiltrant. The treated teeth were sectioned, stained with Sodium Fluorescein dye, and analysed using a fluorescent microscope. The results were tabulated and statistically evaluated using paired t-tests, with a significance level set at p-value<0.05. Results: Etching the teeth for four minutes (p-value=0.002) prior to resin infiltration resulted in the deepest penetration of the material, thus being more efficacious in arresting the progression of caries in comparison to three minutes (p-value=0.044), two minute and one minute (p-value=0.002) etching times. It also showed four minute etching time to have greater penetration of the material into the lesion. Conclusion: According to the results obtained, two minute etching, used as the control, was adequate but less effective than the three and four minute groups, and the one minute etching was the least effective. This finding highlights the importance of optimising the etching time for improved resin infiltration outcomes in the management of non cavitated carious lesions.