Dentin bond strength and nanoleakage of the adhesive interface after intracoronal bleaching

Abstract

This study evaluated dentin bond strength (BS) and nanoleakage of non- and pre-etched dentin immediately (T ,), 7 days (T ), and 14 days (T ) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non- and pre-etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72-h interval. Afterwards, pulp chamber dentin was prepared for the BS test at different evaluation times (n = 5): T , T , and T . Composite blocks were built on pulp chamber and sectioned in slices. Slices were reduced to an hour-glass shape with a cross-sectional area of 0.8 mm and submitted to microtensile BS test. Two additional specimens for each group were prepared for nanoleakage evaluation by transmission electron microscopy (TEM). Results were analyzed by ANOVA (two-way) and Dunnett's test (p < .05). BS decreased immediately after intracoronal bleaching for both sound and pre-etched dentin (p < .05). At T , the BS of non-etched bleached dentin increased for all groups, whereas the pre-etched SPe group presented BS similar to the Ce. Nanoleakage within the hybrid layer was perceptible immediately after bleaching, although a decrease in nanoleakage was observed for all groups at T . Adhesive restorations should be performed 7-14 days after bleaching, according to the bleaching agent used. Intracoronal bleaching should be performed preferably with sodium perborate if previous dentin etching is applied.

Clinical efficiency of a sodium perborate - hydrogen peroxide mixture for intracoronal non-vital teeth bleaching

“…The "unknown" group was comparable to both previous groups (p > 0.05). In all three groups, the minimum number of shade guide units was the same (3), but the "necrotic pulp" group exceeded the other two groups in the number of maximum achievable shade guide units during bleaching (14). Figure 1 shows a significant relationship between BE and patients' age.…”

“…In vitro studies of intracoronal bleaching focused on tooth fracture resistance, composition of calcium-silicate cements, their compressive strength, and bond strength to composite resin, adhesive bonding, orthodontic brackets www.srpskiarhiv.rs "Walking bleach" technique bonding to enamel and marginal integrity of temporary and permanent restorative materials following various intracoronal bleaching protocols [12][13][14][15][16].…”

Nanoleakage Evaluation of Nano-Filled Resin Composite using Different Adhesive Systems at Different Dentin Depth

“…Silver nitrate migrates easily in the interface due to its tiny sized diameter molecule. This small size and high reactivity to stain after binding tightly to any exposed collagen fibrils that are not enveloped by the adhesive resin makes the sliver nitrate the most appropriate agent to detect the nanoporosities within the hybrid layer (16) .…”

Hypericum perforatum L.: A Potent Antioxidant Source for the Treatment of Oxidized Dentin: An Experimental In Vitro Study

“…Deterioration of the immediate resin-dentin bond strength was probably due to free radicals remained within the bleached dentin structure, which inhibits resin polymerization and compromises bonding, as previously reported. [4][5][6][7] Numerous substrates either synthetic or natural (plant derived) have been tested regarding their free-radical scavenging/antioxidant efficacy against the free radicals exerted within bleached tooth structures. However, there still lacks a clinically adapted antioxidant treatment modality for oxidized tooth structures.…”

“…1,2 Research has shown that the oxidizing action of hydrogen peroxide not only affects stain molecules but also interacts with the organic and inorganic matrix of dentin. 2,3 Those interactions may result in some postbleaching clinical adverse effects, such as compromised bonding to oxidized dentin [4][5][6][7] or decreased fracture resistance. 3 Throughout the bleaching process, the breakdown of hydrogen peroxide results in the release of several reactive oxygen species, namely free radicals such as nascent oxygen, hydroxyl, hydroperoxyl, and superoxide radicals.…”