Femtosecond Laser-Activated Chitosan for Biomodification of Caries-Affected Deep Dentine: A Structural Microhardness and Laser-Induced Breakdown Spectroscopy (LIBS) Kinetic Analysis

Abstract

Deep carious dentine is highly vulnerable to acid-induced mineral loss and subsequent mechanical breakdown. This study evaluated five distinct surface conditioning approaches on artificial caries-affected human dentine (N = 40, n = 8/group): Group 1, standalone sub-ablation 750 nm femtosecond laser; Group 2, standalone sub-ablation 830 nm femtosecond laser; Group 3, combined 750 nm laser conditioning with a 2% chitosan hydrogel; Group 4, combined 830 nm laser conditioning with a 2% chitosan hydrogel; and Group 5, topical application of 2% chitosan gel alone. Experimental photoactivation was executed using a sub-ablation average power of 300 mW for 5 minutes. Surface microhardness (VHN) and raw elemental peak intensity by Laser-Induced Breakdown Spectroscopy (LIBS) tracking Calcium (317 nm) and Phosphorus (558 nm) were quantified across baseline, post-demineralization, and post-treatment intervals. Mixed-model analysis revealed highly significant main effects for both treatment stages (p Conclusion: The synergistic combination of a 750 nm near-infrared femtosecond laser operating under a non-destructive sub-ablation threshold and a concentrated 2% chitosan gel effectively biomodifies deep carious dentine by maximizing structural surface microhardness and Calcium recovery.

Abstract as supplied by the indexing source. © the authors / publisher.