848 Flexural Strength and Modulus of Bioactive Glass-containing, Anti-microbial Dental Composites

Friday, March 23, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
J.C. MITCHELL1, J. FERRACANE2, F. GWINNER3, M. WANG4, S. SALEHI4, and J. KRUZIC5, 1Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, 2Dept. of Restorative Dentistry, Oregon Health & Science University, Portland, OR, 3Oregon Health & Science University, Portland, OR, 4Division of Biomaterials & Biomechanics, Oregon Health & Science University, Portland, OR, 5Oregon State University, Corvallus, OR

The principal reason for replacement of dental composites is recurrent decay of the tooth due to bacterial colonization at the interface or below the restoration.

Objectives: In this project, we prepared novel dental polymer composite restorative materials containing sol-gel bioactive glasses (BAGs) as fillers.  These BAGs may render the restoration more resistant to bacterial colonization via the demonstrated anti-bacterial effect of the BAG and the release of fluoride.

Methods: Two types of BAG were synthesized in our lab: 65 wt% silica - 31 wt% calcia - 4 wt% phosphate; and 61 wt% silica - 31 wt% calcia - 4 wt% phosphate - 4 wt% flouride.  These were incorporated in three proportions (5, 10 and 15 wt%) along with silane-treated strontium glass into a 50:50 bisGMA/TEGDMA visible light-cured resin. Test bars for flexure testing (strength and E) in 3-point bending (25mm x 2mm x 2mm) were prepared.  Composite containing the glass only (no BAG) served as a control. Test bars were aged for 24 hours in water, and for two months in a bacterial culture system of brain-heart infusion (BHI) media containing Streptococcus mutans (strain 25175), a known acid-producing microbe. Bars were also immersed in BHI without bacteria as a control. Samples were incubated at 37ēC, 5%CO2 and agitated daily; media was changed every other day. Bacterial growth and colonization of the bars was confirmed throughout the test period.

Results: Samples with BAG had comparable strength and flexural modulus to the control samples - no significant differences were seen after any of the treatments (ANOVA/Tukey's; α=0.05). 

Conclusion: The inclusion of anti-bacterial BAG as a filler component did not diminish the initial strength or the stability over 2 months of these new composite materials, which may ultimately increase longevity and service life of dental composite restorations.


This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR R01 DE021372

Keywords: Bacterial, Bioactive glass, Biomaterials, Composites and Dental materials