A simple 2-step silane treatment for improved bonding durability of resin cement to quartz fiber post

Push-out Bond Strength of Two Fiber Posts in Composite Resin Using Different Types of Silanization

OBJECTIVES

The aim of this study was to evaluate the effect of different surface treatments and thermocycling (TC) on the push-out bond strength of two brands of glass fiber posts (GFPs) to composite resin.

METHODS

White Post DC (WP) (FGM Dental Group International, Joinville, Santa Catarina, BR) and Exacto (EC) (Angelus, Clinical Research Dental, Londrina, PR, Brazil). GFPs were cleaned with 70% alcohol and divided into five groups, according to the surface treatment (n=15): control (C), without treatment; prehydrolyzed silane (S-pre) (Prosil, FGM Dental Group International); 37% phosphoric acid + prehydrolyzed silane AcS-pre); Scotchbond Universal Adhesive System (AdU), 3M Oral Care; two-bottle silane (S2B) (Dentsply Sirona Inc). The composite resin was inserted around the posts by using a split matrix. The samples were cut into 1-mm slices. Half of the samples were subjected to the push-out test immediately, and the other half underwent TC before the test. After failure analysis, the data were submitted to three-way analysis of variance (ANOVA) (α=0.05).

RESULTS

EC achieved higher bond strength than WP, regardless of TC (p<0.05). Regarding WP, surface treatments (p<0.001) and TC (p<0.001) influenced bonding strength. As for EC without TC, the highest bond strength (p<0.05) was found for C, then AcSpre, S-pre, AdU, and S2B. Application of TC resulted in a statistically higher bond strength values for the EC AcS-pre group (p<0.05), followed by S2B, S-pre, C, and AdU. The WP failures were predominantly cohesive, similar to the EC AdU and EC S2B groups. The other EC groups showed mostly mixed failures.

CONCLUSIONS

Surface treatment and TC affected the bond strength to composite resin, depending on which post was used. It is important for dentists to understand the effects of different types of silanization on their chosen post.

Novel hollow fiber sandwich composite post system: mechanical characteristics

BACKGROUND

There is currently no consensus on the optimal post system to provide effective long-term results. We used an engineering approach to investigate the mechanical properties of a sandwich hollow carbon fiber post in synergy with a new bonding technique.

METHODS

We studied two systems - a sandwich fiber hollow post (Techole®, Isasan, Como, Italy) composed of carbon fiber incorporated in a Dpp-MOR resin mix and a traditional non-hollow post (Tech 2000®, Isasan, Como, Italy). A bi-component composite (Clearfil Core®, Kuraray, New York, NY, USA) (2.2 gcm3, 12.3 GPa) and a dual cure composite with lower density and modulus of elasticity (Clearfil DC Core®, Kuraray, New York, NY, USA) (2.0 gcm3, 10.0 GPa) were also used into hollow posts. Results from three-point bending test (N.=81), compression test (N.=78) and cut test (N.=81) were achieved.

RESULTS

In the three-point bending test there were significant differences in flexibility/bending when sandwich fiber hollow posts were filled with composite of different modulus of elasticity. Hollow sandwich posts showed also significant (P=0.000) better resistance to compression and cutting than solid posts, independently of the type of composite. Moreover, hollow posts filled plus composite with a modulus of elasticity of 12.3 GPa showed significant (P=0.000) improved resistance parameters rather than hollow posts filled with a composite of 10.0 GPa.

CONCLUSIONS

The study confirms the favorable mechanical properties of the hollow sandwich fiber post system (Techole®) and the synergistic efficacy when used in combination with the composite Clearfil DC Core® (10.0 GPa) and, especially, Clearfil Core® (12.3 GPa).

The Post-endodontic Adhesive Interface: Theoretical Perspectives and Potential Flaws

INTRODUCTION

The aim of this review was to analyze the potential of successful bonds of endodontic posts to radicular dentin as well as the limitations of the post-endodontic adhesive interface.

METHODS

The MEDLINE/PubMed and Web of Science electronic databases were searched. The search was augmented by a manual search of the pertinent bibliographies.

RESULTS

The post-endodontic adhesive interface finds application in the endodontic cohesive units. Many techniques and materials exist to improve the bond between endodontic posts and resin-based materials as well as between resin-based materials and radicular dentin. Different techniques used for the adhesion of metallic and fiber-reinforced posts are discussed and critically analyzed.

CONCLUSIONS

Although adhesive cementation of endodontic posts is popular, a long-term predictable bond may be compromised because of procedures related to the endodontic treatment and/or the adhesive cementation procedures. Microleakage and degradation phenomena may further jeopardize the post-endodontic adhesive interface.

Influence of water immersion on the mechanical properties of fiber posts

PURPOSE

The purpose of this study was to evaluate the influence of water immersion on the mechanical properties of three kinds of glass fiber posts and the fracture resistance of structures using resin composites with glass fiber posts.

METHODS

Each post was divided into three groups; a control group and two water immersion groups (30 and 90 days). Flexural strength was determined by three-point bending test. Each structure was divided into two groups; a control group and a water immersion group for 30 days. The fracture strength of structures was determined by a static loading test.

RESULTS

In the flexural strength, two kinds of post in water immersion groups showed lower values than control groups. In the fracture strength, two kinds of structures in water immersion group showed lower values than control groups.

CONCLUSION

The prefabricated glass fiber posts and structures using resin composites with glass fiber posts were affected by water immersion.

Comparison of the effect of shear bond strength with silane and other three chemical presurface treatments of a glass fiber-reinforced post on adhesion with a resin-based luting agent: An in vitro study

Background:

Loss of retention has been cited to be the most common cause of the failure of postretained restoration with irreversible consequences when materials with different compositions are in intimate contact at the post/adhesive interface. With this background, a study was conducted to improve the adhesion at the resin phase of fiber posts using silane and other chemical pretreatments.

Materials and Methods:

Hundred glass fiber-reinforced posts were tested with 4 different protocols (n = 25) using silane as a control (Group A) and other three experimental groups, namely, Group B-20% potassium permanganate, Group C-4% hydrofluoric acid, and Group D-10% hydrogen peroxide were pretreated on the postsurface followed by silanization. These specimens were bonded with dual-polymerizing resin-based luting agent, which were then loaded at the crosshead speed of 1 mm/min to record the shear bond strength at the post/adhesive interface. The data were analyzed using one-way ANOVA test for multiple group comparisons and the post hoc Bonferroni test for pairwise comparisons (P < 0.05).

Results:

Group B showed more influence on the shear bond strength when compared to other protocols, respectively (P < 0.001).

Conclusion:

Alone silanization as a surface treatment did not improve the bond strength. Combination of chemical presurface treatments followed by silanization significantly enhanced the bond strength at the post/adhesive interface.