Effect of Light-Curing on Mutans Streptococci Colonization of Silorane-Based Composites

Methods: 96 disks of Filtek Silorane® and 96 disks of a standard methacrylate-based composite (Filtek Z250®) were divided into 6 groups and light-cured respectively for 10, 40, or 80 seconds using two different curing-power levels: 400 mW/cm2 and 800 mW/cm2. A wild strain of MS was isolated and biochemically identified. Then a 48-hours multilayer monospecific biofilm, adherent to the surfaces of the composite disks, was obtained on the wells of a 96-well plate. A colorimetric technique (MTT assay) was used to evaluate the viable biomass adherent to the surfaces of the specimens. ANOVA and Scheffè's test were used to statistically analyse the data.

Results: MS colonization was significantly lower on silorane surfaces than on the standard composite surfaces. Curing time influence on in vitro MS colonization was demonstrated only for the standard resin composite that showed a reduction of this parameter as curing time increased. This phenomenon is probably due to the presence of unpolymerized methacrylate monomers on the material's surface.

Conclusions: these results are in agreement with those of Buergers et al. (2008). Furthermore no curing-time or curing-power level influence on silorane surfaces colonization was highlighted. This phenomenon may be related to the increased hydrophobicity of the material.