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

By Maroulakos G, He J, Nagy WW

Date: 11/2019
Journal: JOE

Summary:  

Purpose: to discuss the potential of achieving a predictable bond between different post materials and dental substrates as well as the possible limitations that may lead to failure of the post–endodontic adhesive interface. 

Materials/Methods: 

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

Most highlighted Results: 

A total of 66 articles were identified that were related to the aim of this review. 

Bond to Fiber-reinforced Posts :

•Fiber-reinforced posts consist of fibers (glass, carbon, quartz, or polyethylene) embedded in a polymer–epoxy resin matrix. The purpose of the fibers is to increase the tensile and fatigue strength of the post and to enhance its volumetric stability 

•Many techniques suggest modification or treatment of the post surface to increase the adhesion of resin cements. Including: hydrofluoric acid, phosphoric acid, hydrogen peroxide, silane, airborne- particle abrasion .. Etc.

•All the techniques are highly material dependent, and there is no sound scientific basis for their predictable universal application on all fiber-reinforced posts. 

Bond to Metallic Posts:

•Metallic posts can be fabricated from high noble alloys or various types of base metal alloys (nickel-chromium alloys, stainless steel, and titanium)  •Techniques attempting to enhance the bond quality between metal surfaces and resin-based materials can be mainly divided into 2 categories:  1.surface modification techniques 

2.techniques involving the application of primers containing functional monomers. 

1- surface modification techniques:

•could be used for both noble and base metal alloys.

•Their main disadvantage is that they are more complicated procedures and require special equipment. Also, they cannot be easily applied chairside.

2- techniques involving the application of primers containing functional monomers:

•functional monomers have a chemical affinity to metals and can copolymerize with the structural monomers of resin-based materials.

•Air-particle abrasion with aluminum oxide (Al2O3) particles is necessary for the primers to be effective.

Bond to Radicular Dentin :

•Two mechanisms contribute to the resin-to-dentin bond strength: resin tag penetration and resin penetration into the dentin tubules

•Resin bonding to apical radicular dentin could be less strong compared with to cervical radicular and coronal dentin

•bonding Procedures related to endodontic treatment, post space preparation, and post cementation may further impact the quality of the post– endodontic adhesive interface (table 3)

Conclusion: 

Adhesive cementation of endodontic posts is a popular treatment option because of improved retention , the bond between the endodontic post and the pre- pared root canal could be easily jeopardized.

successful adhesion to radicular dentin may be hindered by factors related to the morphology of the dentinal tissue, the materials used during endodontic treatment, the technique for adhesive cementation of the endodontic post, and the geometric characteristics of the root canal space.

bonding between the adhesives and the post and between the adhesives and the dentin may be enhanced through various post surface treatments and careful selection of root canal irrigants and adhesives.

However, any conclusions should be drawn with caution because there are no clinical studies addressing the bonding potential of endodontic posts to radicular dentin.