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.