Influence of light activation of simplified adhesives on the shear bond strength of resin cements to a leucite-reinforced ceramic

Effect of different surface treatments and multimode adhesive application on the Weibull characteristics, wettability, surface topography and adhesion to CAD/CAM lithium disilicate ceramic

This paper aims to evaluate the effect of different surface treatments on surface topography, wettability, and shear bond strength of resin cement to glass ceramic.

The Use of Bulk-Fill Flow in the Customization of Glass Fiber Post

Objectives  The aim of this study is to evaluate the influence of different composite resin in the customization of glass fiber posts (GFPs) on bond strength and failure mode.

Materials and Methods  Thirty bovine roots were selected. The wall roots were reduced so that each wall had a minimum dentin thickness of 1 mm. Thirty GFPs were divided into three groups ( n = 10), which received different types of customization. The first had the GFP relined by bulk-fill flowable composite resin (BF), the second group had the GFP customized by conventional regular composite resin (CR), and the third group was cemented with dual resin cements (DRC), without relining. The root were sectioned, resulting in two 1.0-mm thick slices from cervical root regions only and push-out bond strength test was performed (EMIC, Universal testing machine). To determine failure mode, a stereomicroscope was used at ×40 magnification, with a 2.5D analysis.

Statistical Analysis  Data were analyzed using two-way ANOVA ( α = 0.05) and Tukey’s test.

Results  BF (9.08 ± 1.9) and CR (9.17 ± 3.00) did not show a statistically significant difference ( p = 0.961), regarding the bond strength test values. However, there was a statistically significant difference between DRC (5.44 ± 1.89) and the others ( p < 0.05). BF (66.66%) and the CR group (47.61%) presented a predominantly failure mode type 6: mixed between resin cement and composite. While the highest failure index of the DRC group was type 2: adhesive between resin cement and dentin (47.61%).

Conclusion  BF can be an alternative for the customization of fiber posts, since it presented a similar behavior to the established technique with conventional composites.

Assessment of Bonding Effectiveness of Adhesive Materials to Tooth Structure using Bond Strength Test Methods: A Review of Literature

Background

The rapid developments in the field of adhesive dental materials have led to improvements in many aspects of clinical dentistry. Adhesive bond strength plays an important role in determining the clinical performance and longevity of dental restorations. Nevertheless, bond strength tests have never been well-standardized, although a number of important recommendations have been made.

Objective

The aim of this paper is to critically review the validity of different bond strength testing methods for assessment of bonding effectiveness of adhesive materials to tooth structure and discuss factors that may affect bond strength measurement.

Data Collection

Relevant literature published between 1983 and 2018 was collected and reviewed from the PubMed database and Google scholar resources.

Review Results

Results of the current bond testing methods should be used to compare materials tested under the same laboratory settings, but they shouldn't be used to make direct inferences on their clinical behaviour. Shear and micro-shear tests, result in non-uniform stress distribution, stress concentration at the substrate area, and predominantly tensile stresses rather than shear stresses. Micro-tensile bond tests provide many advantages over the shear tests, although these methods are technique sensitive and labour intensive.

Conclusion

Bond strength testing methods should be well-standardized, but there are many factors that cannot be fully controlled which leads to variation and misinterpretation of the data about the bonding abilities of adhesives.

Clinical Significance

New adhesive materials should be subjected to a combination of testing protocols to properly assess their bonding effectiveness.