IADR Abstract Archives
Enamel Surface Changes Observed in Gel vs. Light Activation Whitening
Objectives: Observational study to detect microstructural enamel surface changes of gel-based versus light activation whitening.
Methods: Six human extracted mandibular incisors in distilled water were assigned to one of six groups: CON = control, PE = 35% phosphoric etch, CP = 16% carbamide peroxide gel, HP = 25% hydrogen peroxide (Philips Zoom!® gel), HP+LA = HP plus light activation (Philips Zoom! WhiteSpeed©, medium intensity), and RELACP = HP+LA with ReliefACP© gel (Philips). PE was applied for 30 seconds, CP for 4 hours/day x 7 days, HP, HP+LA and RELACP for 1 hour with gel replacement every 15 minutes, and ReliefACP applied for 30 minutes to RELACP post-whitening. Color analysis was obtained using Olympus Crystaleye Spectrophotometer with L, a, b values averaged over 3 trials per condition both before and after treatment. Crown body overall color difference (DE) was calculated subtracting post-treatment L,a,b values from pre-treatment L,a,b values (standard). Post-treatment samples were imaged using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) to determine structural morphology of the enamel surface changes.
Results: All whitening conditions demonstrated color differences compared to CON (Table 1). SEM images showed spot-like enamel changes in HP compared to CON, but CP did not. HP+LA demonstrated homogenous enamel microstructural changes compared to CON, but RELACP application showed morphological improvement from HP+LA.
Conclusions: Gel-based and light activation whitening alters quantitative color, but SEM qualitative imaging demonstrates changes of depressions and porosities in enamel microstructure. However, ReliefACP treatment reduced enamel surface degradation, although a study with an increased sample size is needed to determine preliminary data significance.
Methods: Six human extracted mandibular incisors in distilled water were assigned to one of six groups: CON = control, PE = 35% phosphoric etch, CP = 16% carbamide peroxide gel, HP = 25% hydrogen peroxide (Philips Zoom!® gel), HP+LA = HP plus light activation (Philips Zoom! WhiteSpeed©, medium intensity), and RELACP = HP+LA with ReliefACP© gel (Philips). PE was applied for 30 seconds, CP for 4 hours/day x 7 days, HP, HP+LA and RELACP for 1 hour with gel replacement every 15 minutes, and ReliefACP applied for 30 minutes to RELACP post-whitening. Color analysis was obtained using Olympus Crystaleye Spectrophotometer with L, a, b values averaged over 3 trials per condition both before and after treatment. Crown body overall color difference (DE) was calculated subtracting post-treatment L,a,b values from pre-treatment L,a,b values (standard). Post-treatment samples were imaged using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) to determine structural morphology of the enamel surface changes.
Results: All whitening conditions demonstrated color differences compared to CON (Table 1). SEM images showed spot-like enamel changes in HP compared to CON, but CP did not. HP+LA demonstrated homogenous enamel microstructural changes compared to CON, but RELACP application showed morphological improvement from HP+LA.
Conclusions: Gel-based and light activation whitening alters quantitative color, but SEM qualitative imaging demonstrates changes of depressions and porosities in enamel microstructure. However, ReliefACP treatment reduced enamel surface degradation, although a study with an increased sample size is needed to determine preliminary data significance.
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