The Effects of Nanohydroxyapatite with and without Low-Power Laser and Cold Atmospheric Plasma on Enamel Remineralization: in vitro Study.

Background: Remineralizing early enamel lesions in primary dentition remain a significant challenge in dentistry, requiring innovative approaches to enhance enamel repair.

Purpose: This study aimed to evaluate the efficacy of a commercially available nanohydroxyapatite paste (Nano P), alone and in combination with air dielectric barrier discharge cold atmospheric plasma (CAP) and a 940-nm diode laser, on enamel remineralization.

Materials and method: In this in vitro study, 105 intact anterior primary teeth were randomly assigned into one control and six experimental groups: (I) control, (II) Fluoride varnish, (III) Nano P, (IV) Nano P + dye + laser, (V) Nano P + laser, (VI) CAP, and (VII) Nano P + CAP. Caries-like lesions were induced by demineralization. Microhardness was evaluated before and after demineralization and 4 weeks post-remineralization with pH cycling. Data analysis was conducted using one-way ANOVA (α=.05) and Tamhane's Post-Hoc test, with effect sizes determined by Cohen's d test and Hedges' g correction. The percentage of recovery of the enamel microhardness was calculated.

Results: Initial and secondary microhardness were similar across groups (p Value >.05). Post-remineralization, significant differences were observed (p< 0.05), with the highest microhardness in the Nano P+ laser group, followed by Nano P+ dye+ laser, Nano P+ CAP, Nano P, fluoride varnish, CAP, and the control. Pairwise comparisons showed significant differences between all pairs except Nano P+ laser and Nano P+ dye + laser (p= 0.7, Effect size=0.4).

Conclusion: Nano P combined with a laser, followed by Nano P with plasma, and Nano P alone significantly increased microhardness more than fluoride or plasma, suggesting these combinations as effective alternatives for enamel remineralization in primary teeth.