Comparative analysis of laser activated radical free bleaching agent on surface morphology and calcium phosphate content of enamel

Conventional peroxide-based bleaching agents can cause adverse effects such as post-operative sensitivity, gingival irritation, and morphological changes of the enamel surface due to the release of free radicals. This has led to the search for safer bleaching agents. Phthalimidoperoxycaproic acid (PAP+) produces a bleaching effect without releasing free radicals, resulting in less erosive effects on enamel. Additionally, laser-activated bleaching has been found to enhance bleaching efficacy while causing minimal alteration to surface morphology. The purpose of this in-vitro study is to analyse the effect of laser irradiation and PAP + on the surface morphology and Calcium and Phosphate content of enamel during bleaching treatment.

Forty samples of extracted human premolar were divided into one control (Group I) and four experimental groups (n = 8), Group II was treated with 35% HP, Group III was subjected to 35% HP followed by diode laser irradiation, Group IV was treated with PAP+, Group V was treated with PAP + followed by diode laser irradiation. The samples were then subjected to SEM and EDX analysis.

SEM analysis revealed moderate to severe alterations in Group II. Group V displayed the least surface alteration compared to the control group. EDX analysis showed significant alterations in elemental composition across all experimental groups. However, Group V exhibited higher level of Ca and P compared to other experimental groups.

PAP + combined with laser activation yielded lesser alterations on surface morphology and Ca and P content compared to peroxide-based agents thereby offering a safer and more efficacious approach for tooth bleaching endeavours.