Differences in the tensile strength of direct nanohybrid composite veneers between the V and VIII generation dentin bonding agent after extracoronal bleaching

Abstract

Introduction: Tooth discolouration is the most common esthetic problems in dentistry. Direct composite veneer is an adjunctive therapy for severe teeth discolouration by attaching to the tooth surface using an acid etching and dental bonding agent. In several cases of severe discolouration, it is required to have certain preliminary treatments such as bleaching prior to the placement of the composite veneer. However, bleaching agents are able to lead the enamels morphology and microstructure alteration by inhibiting the polymerisation bonding thus affecting the veneer adhesion. This study was aimed to determine the tensile bond strength of direct composite veneers between the V and VII generation dentin bonding agent after extracoronal bleaching. Methods: This study was an experimental laboratory of as much as 32 human permanent maxillary central incisors were divided into 4 groups. Group 1 was treated with extracoronal bleaching and bonded with the V generation bonding nanohybrid composite. Group 2 was treated with extracoronal bleaching and bonded with the VIII generation bonding nanohybrid composite. Group 3 was only bonded with the V generation bonding nanohybrid composite. Group 4 was only bonded with the VIII generation bonding nanohybrid composite. All samples were immersed in artificial saliva then incubated at the room temperature for 24 hours. Results: The tensile strength value was determined using the Universal Testing Machine. The ANOVA test results showed significant differences in all four groups (p < 0.05). Conclusion: The VIII generation bonding agent had a higher tensile strength than the V generation.

Evaluation of the Sealing Ability of Direct versus Direct-Indirect Veneer Techniques: An In Vitro Study

“…Microfill has been proved to be the only composite material that can withstand the test of time in terms of color stability and polishability [14]. On the other hand, nanohybrid composite is a popular direct veneer material because it incorporates nano-and microsized filler particles that provide good mechanical strength as well as finishing and polishing results and a relatively smooth surface and a high gloss that are similar to porcelain restorations [15] As a result, we used two types of composite resin in this study: microfilled and nanohybrid composite restorations and two veneer application techniques: direct veneer and direct-indirect veneer to assess the gingival marginal sealing ability of composite laminate veneers using the dye penetration method. To our knowledge, no research has been done to compare the marginal sealing performance and microleakage of direct veneer versus direct-indirect veneer techniques.…”