Permeability of different groups of maxillary teeth after 38% hydrogen peroxide internal bleaching

Abstract

This study evaluated the influence of internal tooth bleaching with 38% hydrogen peroxide (H2O2) on the permeability of the coronal dentin in maxillary anterior teeth and premolars. Seventy teeth (14 per group) were used: central incisors (CI), lateral incisor (LI), canines (C), first premolars (1PM) and second premolars (2PM). Pulp chamber access and transversal sectioning at 2 mm from the cementoenamel junction were performed and the specimens were divided into 2 groups (n= 7): a) no treatment and b) bleaching with 38% H2O2. The bleaching agent was applied to the buccal surface and to the pulp chamber for 10 min. This procedure was repeated 3 times. The specimens were processed histochemically with copper sulfate and rubeanic acid, sectioned longitudinally, and digitalized in a scanner. The area of stained dentin was measured using Image Tool software. Data were analyzed statistically by ANOVA and Tukey's HSD test (alpha=0.05). There was statistically significant difference (p<0.001) among the untreated groups, CI (0.23 +/- 0.26) having the lowest permeability and LI (10.14 +/- 1.89) the highest permeability. Among the bleached groups, dentin permeability was increased in all groups of teeth except for 2PM. It may be concluded that bleaching with 38% H2O2 affected dentin permeability near the pulp chamber in maxillary anterior teeth and in first and second premolars.

Mineral Loss and Morphological Changes in Dental Enamel Induced by a 16% Carbamide Peroxide Bleaching Gel

“…Disruption of the enamel organic matrix results in loss of the crystalline material sketched out of this matrix, leaving zones of erosion intercalated with areas of intact enamel, resulting in a rough surface (16,17). The presence of nitrogen and oxygen molecules on bleached enamel surface, probably due to the interaction of peroxide with the enamel proteins, suggests that HP is able of dissolving the enamel organic matrix (3). The results of the present investigation may confirm this hypothesis, since reduction of Ca and P content was observed after bleaching, associated with increase of enamel surface roughness.…”

“…In this condition, there is an influx of saliva, which presents remineralizing ions such as fluoride, calcium and phosphates (18). However, at the moment of bleaching procedure, increase of enamel porosity allows HP penetration on deep enamel and consequently into the pulp chamber (2,3). A recent study demonstrated that even when applied onto remineralized enamel by fluoride, the 16% CP gel was still toxic to the odontoblast-like cells, with no significant difference from the non-fluoride treated enamel (24).…”

“…However, a number of studies demonstrated that bleaching gels with high concentrations of hydrogen peroxide (HP), such as those used for in-office tooth bleaching, could promote pulp cell damage (1). This undesirable adverse effect has been related to the ability of HP to disrupt the mineral structure of enamel (2), which allows HP diffusion to the subjacent dentin and pulp chamber (3). Therefore, at-home tooth bleaching technique has been considered as an interesting alternative for bleaching teeth without causing toxic effects to pulp tissue.…”

Shear bond strength of an orthodontic self‐etching adhesive after intracoronary bleaching

“…Hydrogen peroxide at a concentration of 35% was used in this study because it demonstrates a low molecular weight, high enamel/dentine penetration, and the capacity to alter the nature of pigment macromolecules . In addition, hydrogen peroxide demonstrates a higher efficacy than does carbamide peroxide (another commonly used whitening agent) at the same concentration.…”

Impact of 35% Hydrogen Peroxide on Color and Translucency Changes in Enamel and Dentin

“…15,17,18 However, high-concentration hydrogen peroxide is also used for immediate internal tooth bleaching. [19][20][21] This last approach was simulated in the present study seeking out to evaluate the effects of the same bleaching agent over the different tooth hard tissues. It is important to emphasize that the findings of present study for dentin can`t be extrapolated to external bleaching procedures.…”