A Comparative Study of Different Bleaching Agents on the Morphology of Human Enamel: An in vitro SEM Study

Abstract

The purpose of the study was to compare two different commercial bleaching agents, Opalescence with Colgate Platinum, and 30% phosphoric acid used as aggressive agent on the morphology of human enamel. Materials and methods:Ten freshly extracted, noncarious, human maxillary central incisors extracted for periodontal reasons were used in this study. The labial surface of the disinfected teeth were polished using a polishing paste with the help of rubber cup and a slow speed handpiece. Each tooth was sectioned at cement-enamel junction and the crown was separated into four specimens, all taken from labial surface. Group 1 was treated with Colgate Platinum for 7 hours, group 2 with Opalescence for 7 hours, group 3 was treated with 30% phosphoric acid for 30 seconds and group 4 was untreated and used as control. After the treatment period, the specimens were washed with normal saline and stored in sterile bottle and sealed. Photomicrographs obtained from the scanning electron microscopy (SEM) after surface treatments were examined for no alteration, slight alteration, moderate alteration and severe alterations. Results:The specimens treated with commercial bleaching agents revealed no enamel surface morphologic alterations compared to control group. The specimen treated with phosphoric acid showed severe alterations. Conclusion:Ten percent carbamide peroxide evaluated in this study does not etch tooth enamel or alter enamel surface morphology as do conventional etching techniques.Clinical relevance: Carbamine peroxide is a safe and effective tooth whitening agent even when used for extended period of time. The enamel surface remains smooth which reduces caries due to plaque collection.

In Vitro Re-Hardening of Bleached Enamel Using Mineralizing Pastes: Toward Preventing Bacterial Colonization

“…As expected, the subgroups 1b (enamel + Perfect Bleach Office+) and 2b (enamel + Perfect Bleach) showed that the bleaching agents cause changes on the enamel structure with a reduction of the hardness number, especially using the professional whitening agent at 35% hydrogen peroxide which was obviously more aggressive than the home whitening at 16% carbamide peroxide (which corresponds to 6% hydrogen peroxide). According to the literature, this study undoubtedly confirmed that teeth whitening procedures led to enamel alterations [49][50][51]. In particular, the oxide-reduction of the peroxides seems to be related to demineralization and dissolution of the organic dental matrix (protein) [5,16,52]; although the organic component represents a minor part of the enamel structure (1%), its action is essential for its integrity since it glues the mineral crystals of the enamel together, preventing micro-hardness loss [53].…”

Effect of Vital Bleaching on Micromorphology of Enamel Surface: an in Vitro Study

“…In contrast to the results of the present study, Uthappa et al, 32 Engle et al, 33 Faraoni-Romano et al, 34 Basting et al, 35 Cobankara et al 36 and Nucci et al 37 reported, by using SEM analysis, no morphological changes in the enamel surface after the application of 10% carbamide peroxide bleaching. Fatima 38 reported mild changes in surface micro-morphology of enamel, likewise Titley et al 39 observed a slight increase in surface roughness, whereas Gurgan et al 40 reported no modification of surface roughness.…”

Comparison of Bleaching Products With Up to 6% and With More Than 6% Hydrogen Peroxide: Whitening Efficacy Using BI and WID and Side Effects – An in vitro Study

“…An explanation might be that lower concentrations of HP, due to the longer exposure time, resulted in similar whitening effects like the products with higher concentration. High concentrated HP whitening products have been well investigated regarding enamel damage (Uthappa et al, 2012; Coceska et al, 2016), also have different remineralization methods (Kemaloglu et al, 2014; Coceska et al, 2016). However, in the present study most notably the pH, ranging from 5.0 to 8.5, and the exposure time seem to influence enamel surface morphology.…”