OBJECTIVES: To evaluate the bleaching efficacy of an over-the-counter, non-hydrogen peroxide at-home gel based on phthalimidoperoxycaproic acid (PAP) combined with papain and bromelain, compared with a 10% carbamide peroxide (CP) gel and a negative control. Gel pH and enamel effects were also assessed. METHODS: ) differences were calculated. Gel pH was measured hourly for 6 hours using a calibrated microelectrode. Enamel micromorphology was examined by SEM. Data were analyzed using two-way repeated measures ANOVA (α = 0.05). RESULTS: values than both PAP and control from day 7, with progressive increases. No differences between the 3- and 6-hour protocols for either the PAP or CP groups were detected. PAP maintained an alkaline pH, whereas CP showed slightly acidic values. No relevant enamel alterations were observed. CONCLUSIONS: The PAP gel produced a bleaching effect after 14 days, independent of application time, although less effective than 10% CP. Both gels showed no detectable enamel surface damage.
Jiménez‐Díez et al. (Tue,) studied this question.