Demineralization and Hydrogen Peroxide Penetration in Teeth with Incipient Lesions

Abstract

The aim of this study was to evaluate the demineralization and hydrogen peroxide (HP) penetration in teeth with incipient lesions submitted to bleaching treatment. For analysis of HP penetration, sound and demineralized enamel/dentin discs were placed in artificial pulp chambers containing acetate buffer solution. After bleaching treatment, this solution was subjected for analysis of optical density by spectrophotometry and the disc surfaces were analyzed with scanning electron microscopy (SEM) and polarized light microscopy (PLM). The remaining discs were subjected for cross-sectional hardness analysis at different depths. Data were analyzed by repeated measures ANOVA and PLSD Fisher test (a=0.05). It was observed that previously demineralized teeth showed greater HP penetration (p<0.05). The bleaching treatment caused changes to a depth of 20 µm in sound enamel and up to 90 µm in demineralized enamel. SEM and PLM images revealed that the bleaching treatment caused superficial changes that were considerably more accentuated in previously demineralized teeth. It may be concluded that the enamel mineralization level influences HP penetration and the bleaching agent contributed to increase the demineralization depth.

Initial and pulp chamber concentration of hydrogen peroxide using different bleaching products

“…In the present study, the concentration of hydrogen peroxide found in the pulp chamber for 35% HP group was higher than other published studies [18,22,23]. Amounts of HP ranging from 1.22 to 6.22 µg was observed in the pulp chamber of teeth bleached with 35% hydrogen peroxide in other studies [18,22,23], while in the present study an average of 28.5 µg was detected for 35% HP group. These differences may be attributed to variations in the experimental design such as the type of dental substrate used (human or bovine), composition of the gels, experimental protocol, hydrogen peroxide delivery method and differences of cavity preparation.…”

Influence of different types of light on the response of the pulp tissue in dental bleaching: a systematic review

“…(1) studies that compared the effects of the bleaching gel on the pulp tissue with and without the use of light or heat; (2) in vivo and in vitro studies; and (3) studies published in English. The exclusion criteria were (1) studies comparing only the effects of bleaching gel without light or only bleaching gel with light and (2) duplicated studies.…”

“…Studies have shown that hydrogen peroxide (HP) in bleaching gels can cause morphological alterations in the dental surface, such as the reduction of the enamel hardness and increased roughness [1,2], in addition to histochemical alterations [3]. Furthermore, bleaching agents release reactive oxygen species (ROS) that reach the pulp tissue and cause cell damage [4,5].…”

Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols

“…In-office bleaching is a popular dental aesthetic treatment option because of its high success rate (1). Several methods and approaches have been described in the literature for bleaching vital teeth, such as different bleaching agents, concentrations, time of application and product presentation (2).…”