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Title Composite Resin with an Epoxy-Based Monomer System May be less Susceptible to Failure Than Traditional Methacrylate-Based Resins
Clinical Question In teeth restored with dental composite, does a composite with an epoxy-based monomer system, compared to a composite with traditional methacrylate chemistry, result in less restoration failure due to reduced resin degradation and subsequent formation of secondary caries?
Clinical Bottom Line Traditional methacrylate composite resins are susceptible to chemical and enzymatic degradation and secondary caries. Composite resins with an epoxy-based monomer system are less susceptible to this degradation and may last longer clinically.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 21469404Mirmohammadi/20115 materials, 6 groups of N=30 per materialLaboratory study
Key resultsTwo methacrylate-based and one silorane-based direct composite, and two indirect methacrylate-based composites, were subjected to chemical or enzymatic degradation. Flexural strength and rotary fatigue resistance were then measured. The enzymatic degradation of the methacrylate-based direct composites was found to be significant. It was not significant in the silorane or indirect composites. Esterase, an enzyme found in human saliva, degrades methacrylate-based resin monomers at ester bonds. This effect is not seen with indirect composites even though they are also methacrylate-based. This is likely because indirect composites are cured extraorally, often with heat and in vacuum, yielding a higher degree of conversion and crosslinking of the resin matrix. This provides superior mechanical properties and makes indirect composites more resistant to degradation than direct methacrylate-based resins. Silorane-based composite appears resistant to this degradation. It can be inferred that this quality is likely due to the absence of ester bonds in the resin, thus preventing esterase activity from degrading the composite.
Evidence Search composite resin AND degradation AND fatigue; composite resin AND degradation AND secondary caries
Comments on
The Evidence
Validity: Mirmohammadi indicated that flexural strength measurements alone do not represent clinical performance and suggested fracture toughness and fatigue studies are needed. The study is an in vitro study, a low level of evidence. However, an in vivo study assessing the biodegradation of resin would be time consuming. Perspective: There are many in vitro studies assessing the biodegradation mechanisms of composite, but few compare resins with different chemistries. This evidence suggests the production and clinical use of novel non-methacrylate based resin systems or even methacrylate-based indirect composites may decrease the public health burden of replacement dentistry.
Applicability Traditional methacrylate-based direct composites are the most commonly placed resin type and are the most susceptible to degradation in the oral environment. Novel resin chemistries may provide better mechanical properties and reduce the sensitivity of the restoration to degradation and subsequent secondary caries. Resin composites without ester functional groups may be less prone to degradation and therefore increase restoration longevity. This may reduce the number of restorations replaced per year due to failure. This evidence should be considered in further research to develop novel resin chemistries and when purchasing composite resin for use in clinical practice.
Specialty/Discipline (General Dentistry) (Pediatric Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Composite, resin, degradation, secondary caries, failure.
ID# 2794
Date of submission: 12/02/2014spacer
E-mail wshute@gmail.com
Author Wesley Shute, DDS
Co-author(s) e-mail
Faculty mentor/Co-author Kyumin Whang, PhD
Faculty mentor/Co-author e-mail whang@uthscsa.edu
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