Microleakage comparison of glass-ionomer and white mineral trioxide aggregate used as a coronal barrier in nonvital bleaching

Abstract

Objectives: There is some evidence that the pH at the root surface is reduced by intracoronal placement of bleaching pastes, which is known to enhance osteoclastic activity. Therefore, it is recommended that a protective barrier be used over the canal filling to prevent leakage of bleaching agents. Glass-ionomer (GI) is commonly used as a coronal barrier before nonvital bleaching. Because mineral trioxide aggregate (MTA) creates high alkalinity after mixing with water, using MTA as a protective barrier over the canal filling may not only prevent leakage of bleaching agents and microorganisms, but may prevent cervical resorption. The aim of this study was to evaluate sealing ability of white mineral trioxide aggregate (WMTA) as a coronal barrier before nonvital bleaching. Study design: Root canals of one hundred thirty human maxillary incisors were instrumented and filled with gutta-percha without sealer. Gutta-percha was removed up to 3 mm below the cementoenamel junction (CEJ). The teeth were randomly divided into six experimental groups of 20 teeth each and two control groups of 5. In three experimental groups, WMTA was packed into the canal to the level of CEJ. In the remaining experimental groups, glass-ionomer (GI) was used as a coronal barrier. After a 24-hour incubation period, one of the following three bleaching agents was placed in the access cavity of each of the WMTA or GI groups. These three bleaching agents were 30% hydrogen peroxide, sodium perborate mixed with 30% hydrogen peroxide, and sodium perborate mixed with distilled water. The bleaching agents were replaced every 3 days for three times. In the positive controls, no Comparison of glass-ionomer and white mineral trioxide aggregate used as a coronal barrier e1018 coronal barrier was used. In the negative controls, all the tooth surfaces were covered by two layers of nail varnish. Microleakage was evaluated using protein leakage test. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney tests.Results: The experimental groups showed minimum leakage which was not significantly more than tha in the negative controls. There was no statistically significant difference in leakage between the experimental groups (p<0.05).Conclusions: This study indicated that different bleaching agents have no effect on sealing ability of WMTA.

Aesthetic management of a discoloured non-vital immature maxillary central incisor

“…With time, as the material sets, the concentration of calcium ions increases resulting in a mineralized dentin-MTA interstitial layer 6 which could have occluded the passage of hydrogen peroxide to the periodontium. An in-vitro study by Vosoughhosseini et al 7 showed white MTA had superior sealing property when used as a barrier material compared to GIC.…”

Effect of Carbamide Peroxide on the Push-out Bond Strength of Different Composition Glass-Ionomer Cement to Root Canal Dentin when used as Cervical Barrier

“…The material evaluated by the push-out test and failure mode analysis can assess the dental bleaching materials effects on the cervical barrier with accuracy, in comparison to infiltration methods. 4,29,35,36 The cervical barrier using glass-ionomer cements may have different results depending on the bleaching agent chemical composition and/or application time at the cervical barrier of endodontically-treated teeth. However, future studies using the described methodology are needed to evaluate the best material for use as a cervical barrier in endodontically-treated teeth bleaching.…”

Infiltration of Rhodamin B into three materials used as cervical barrier

“…The pH on the root surface is reduced after the use of endogenous bleaching agents. This acid medium appears to contribute to osteoclastic activity that will result in root resorption 21 . The lack of bond between the cement and enamel is a predisposing factor for the occurrence of external cervical resorption after endogenous bleaching, since it favors penetration of bleaching agents during the treatment 1,3,5,9 .…”