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Title Bioactive Glass Increases Resistance of Dental Composite Restorations to Streptococcus Mutans
Clinical Question Does the addition of bioactive glass (BAG) to dental restorative composites, as opposed to traditional composites, provide antibacterial properties and increase the longevity of direct composite restorations?
Clinical Bottom Line Dental composite restorations that contain BAG reduce biofilm penetration of S.mutans into marginal gaps of simulated tooth restorations and demonstrate adequate and stable mechanical properties. Three laboratory studies show that this material would be a strategic additive to composite resins used in dentistry.
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) 24050766Khvostenko/2013Unspecified number of samples. Groups of 0, 5, 10 and 15 wt% (0BAG, 5BAG, 10BAG, 15BAG) bioactive glass Laboratory study
Key resultsFlexural strength, fracture toughness, and fatigue crack growth resistance were unaffected by increasing BAG content up to 15%. Flexural strength of the BAG composites was unaffected by 2 months exposure to aqueous media and a bacterial challenge, but some decreases in fracture toughness and fatigue resistance did occur. Overall, the BAG composites demonstrated adequate and stable mechanical properties relative to successful commercial composites.
#2) 26621028Khvostenko/2016Recently extracted human molars Laboratory study
Key resultsRecently extracted human molars were machined and then restored to produce simulated tooth restoration samples in two groups (0BAG [0wt%] and 15BAG [15wt%]) with six samples each. Simulated tooth-composite restoration fillings were created to have a gap at the interface between tooth structure and composite. The average depth of bacterial penetration into the marginal gap for the 15BAG was significantly smaller (61%) compared to 0BAG groups in which 100% penetration occurred.
#3) 25564110Salehi/2015Dental composites containing different concentrations (0, 5, 10, 15%) of bioactive glass Laboratory study
Key resultsDental composites containing different concentrations (0%, 5%, 10%, 15%) of bioactive glass were evaluated for cytotoxicity using Alamar Blue assay. The results show that the composites, whether or not they had bioactive glass at any concentration, had equivalent potency in terms of reducing the viability of cells in culture. Soaking the composites for 7 days before introducing them to the cells showed that the “toxic” components had been extracted and the materials were no longer cytotoxic. This demonstrates that the cytotoxicity of composites with and without BAG must be predominantly attributed to the release of residual monomers, not the presence of BAG. Dental composites themselves do not provide a chronic source of unreacted monomers; relatively short-term exposure to fluids will lead to extraction of unreacted monomers.
Evidence Search "Composite Resins"[Mesh] AND bioactive glass
Comments on
The Evidence
All of these studies were laboratory studies. Bioactive glass is known to possess antimicrobial and remineralizing properties. Secondary caries at the margins of dental restorations is the most common reason that dental restorations need replacement. To increase the resistance of restorations to secondary caries the restorative material can either negatively influence the surrounding microorganisms or promote remineralization of tooth structure. The second study (Khvostenko/2016) shows that composite resins with BAG have an antimicrobial effect and reduce the depth of bacterial penetration in open marginal gaps. Moreover, based on the first laboratory study (Khvostenko/2013), composites that contain BAG exhibit mechanical properties comparable to commercially successful composites. The third study (Salehi/2015) concludes that the incorporation of BAG into composites is not cytotoxic to human cells when all of the unreacted monomer is extracted from the material. All unreacted monomers of composites, regardless of composition, are cytotoxic, but fluids wash the monomers away in a short term. However, since clinical trials have not yet been established to date for the use of BAG containing composites, this needs to occur prior to widespread incorporation of bioactive glass into dental restorative composite material.
Applicability The external validity for the first study is medium; this laboratory study manufactured a novel dental composite resin containing bioactive glass and tested the material in three different categories while having a commercially successful composite as a control. The mechanical properties of the novel BAG composite were directly comparable to the control composite. The values that they obtained for the composite with BAG were also comparable to published values of two other commercial composites. The external validity of the second study is also medium because this laboratory study used extracted human molars to test the effectiveness of composites impregnated with BAG. The oral environment was simulated with a constant fluid flow and this is a modest substitute for the actual complex oral environment. The external validity of the third test is also medium because this study also took place in the laboratory. The different composite materials were either directly exposed to cell cultures or they had the unreacted monomer extracted before exposure. Results showed that the composites with regardless of containing bioactive glass or not was not cytotoxic after the unreacted monomer was gone. Based on this evidence, dental composite restorations that contain BAG have great potential in the field of dentistry and clinical trials should be established to test this material in vivo.
Specialty/Discipline (Restorative Dentistry)
Keywords Dental composite, Bioactive glass
ID# 3251
Date of submission: 06/13/2017spacer
E-mail amontalvo48@midwestern.edu
Author Andrew Montalvo
Co-author(s) e-mail
Faculty mentor/Co-author Dr. John Mitchell
Faculty mentor/Co-author e-mail jmitch@midwestern.edu
Basic Science Rationale
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