CLINICAL PROCEDURE OF IMMEDIATE DENTIN SEALING FOR INDIRECT BONDED RESTORATION

Immediate Dentin Sealing or pre-hybridization implies the application of resin adhesive to freshly cut dentin after teeth preparation, before impression. Immediate Dentin Sealing has been suggested as an alternative to the delayed dentin sealing (DDS), a technique in which resin adhesive is applied just before final bonding of indirect restorations. Immediate Dentin Sealing technique is universal i.e used in inlays, onlays, veneers, crowns and well documented clinically and experimentally. Various types of Dentin Bonding Agents are available on the market. Difference lies in the thickness of hybrid layer formed and the adhesive used.

The Effect of Different Condition of Pulpal Pressure on Microtensile Bond Strength of Several Dentin Bonding Agents on Deep and Superficial Dentin

The objective of this study was to examine the effect of different conditions of simulated hydrostatic pulpal pressure on the μTBS of HEMA-based and HEMA-free dentin bonding agents (DBAs). The influence of dentin location (deep and superficial) on μTBS was also evaluated. Flat coronal dentin surfaces of extracted human molars were prepared. Three groups of resin-bonded specimens were exposed to different pulpal pressures. Pulpal pressure was maintained for 20 min for each group. A flowable resin composite was used for coronal build-up. The bonded teeth were sectioned and, after 24 h of water storage, stressed to failure using the microtensile tester (μTBS). Failed samples were analyzed by SEM inspection. HEMA-based DBAs were much more sensitive to pulpal pressure conditions than non-HEMA-containing DBAs. Pulpal pressure had a greater influence in deep dentin. The HEMA-free DBA was insensitive to the presence or absence of pulpal pressure condition. SEM inspection confirmed a relationship between the presence of voids inside the HEMA-based DBAs layer and the lower μTBS results. HEMA-based DBAs are more sensitive to pulpal pressure conditions than HEMA-free DBAs. Interestingly, HEMA-free DBA showed a greater number of water droplets at resin–dentin interface in all tested conditions.

Resistência de união dos sistemas adesivos em dentina úmida e em dentina seca: revisão integrativa

A adesão à dentina é dificultada por se tratar de uma estrutura com alta composição hídrica, ao longo dos anos os protocolos clínicos, assim como os sistemas adesivos foram sendo alterados, visando melhorar a resistência de união e simplificar a técnica. Por meio de revisão integrativa, discorre-se aqui sobre a resistência de união dos sistemas adesivos em dentina úmida e em dentina seca visando sugerir melhorias dos protocolos clínicos. Selecionou-se os artigos através da biblioteca virtual em saúde (BVS), obtendo-os das bases MEDLINE, LILACS, Biblioteca Brasileira de Odontologia (BBO), além de buscas no Google® Scholar, usando os termos indexados: “Dentin”, “Dentina”, "Dentin-Bonding Agents" e “Adesivos dentinários”. Incluiu-se artigos publicados entre 2013 e 2020. Os estudos selecionados poderiam ser clínicos ou laboratoriais, em dentina úmida e em dentina seca, usando testes de resistência à tração, microtração ou cisalhamento nos estudos in vitro, com os sistemas adesivos convencionais, autocondicionantes e/ou universais. Foram excluídos artigos curtos, pôsteres ou revisões de literatura. Encontrou-se 969 artigos, sendo selecionados 8 deles, segundo os critérios de inclusão, todos os estudos abordavam o grau de umidade da dentina como um fator limitante na qualidade de adesão, assim como o conhecimento do operador a respeito da composição do sistema adesivo utilizado. Os sistemas adesivos universais foram eficazes tanto em dentina úmida quanto em dentina seca, já os sistemas adesivos convencionais foram eficientes apenas em dentina úmida.

Evaluating The Effect of pH of Dentin Bonding Agents on Dentin in Relation to the Push-Out Bond Strength of Composites in Class I Cavities in-vitro

INTRODUCTION: Today, the popularity of amalgam as restorative material has decreased due to poor esthetic characteristics and mercury contamination with composite resin materials becoming a choice among the both dentists and patients. AIM: The objective of this in-vitro study was to evaluate the effect of pH of dentin bonding agents (Adper Easy Bond and Xeno V) on dentin in relation to push out bond strength of composite restored with Filtek bulk fill posterior restorative composites.MATERIALS AND METHOD: Sixty caries free human molars with no cracks or previous restorations were used for investigation. Standard box-type Class-I Cavities of 3.5 mm x 3.5 mm and depth of 4 mm were prepared on the occlusal surface of the molars. Teeth were randomly divided into 2 groups namely Group A, Group B of 30 teeth each, according to the dentin adhesives applied i.e Adper Easy bond and Xeno V. Two bonding agents with different pH were selected for the study. One was Adper Easy Bond with Ultra mild pH of 2.7. Other was Xeno V Self etch with strong pH of <1.3. Push-out test was performed by placing specimens within a centralizing ring to ensure a centered application of the load, resting on another ring, with a central hole slightly larger than the restoration diameter. The test was performed with a universal Testing Machine to express bond strength in mega pascals (MPa), load value in Newton (N). After testing the push-out bond strength, the samples were analyzed under a stereomicroscope.RESULTS: Adper Easy bond with an ultra mild pH 2.7 is better as compared to Xeno V Self etch with strong pH of <1.3.The most common mode of failure observed with Adper was mixed fracture and cohesive dentin fracture, while in Xeno V, adhesive failure between resin and dentin and cohesive resin fracture was observed. The mean maximum force was significantly more among Adper compared to Xeno V.CONCLUSION: Comparison of dentin bonding agents in this in vitro study revealed that the push out bond strength of Adper Easy performed better than Xeno V.