Phthalimidoperoxycaproic Acid (PAP) Versus Peroxides and Impact on Dental Enamel After Whitening Treatment: An In Vitro Study

Phthalimidoperoxycaproic acid (PAP) emerges as a promising alternative non-peroxide bleaching agent to hydrogen peroxide (HP), offering similar efficacy with potentially less enamel damage. This in vitro study aimed to evaluate and compare the effects of 37.5% HP, 35% carbamide peroxide (CP), and PAP on dental color, enamel surface microhardness, and morphological integrity. Fifty-seven extracted human maxillary incisors were randomly assigned to three groups (<i>n</i> = 18). Thirteen teeth per group were used for color evaluation, four for microhardness, and one for surface morphology analysis. Each group received three whitening sessions (three applications per session) according to the manufacturers' instructions. Color was assessed before and one week after each session using a spectrophotometer. Lightness increased by 7.19 units (HP), 7.11 (PAP), and 4.43 (CP). ΔWI_D was 4.48 (HP), 4.16 (CP), and 8.82 (PAP). All agents produced an "excellent" bleaching effect (ΔE₀₀ index); only PAP achieved "excellent" values with the ΔWI_D index at the end of the study. PAP produced fewer morphological changes on the enamel surface and less reduction in microhardness compared to the untreated control than the other agents evaluated. PAP emerges as an effective alternative for dental bleaching, offering significant color improvement while ensuring minimal alterations to enamel morphology.