Polymerization Stress and the Influence of TOSU Addends on Methacrylate Composites

The aesthetic appeal of composite-resin restoratives promotes their use, however their functional life is significantly shorter when compared to their metal counterparts.¹ One possible reason is the effect of polymerization stress on marginal integrity. Shrinkage of the composite, and its associated stress, has been found to cause gap formation and stress interactions between the restorative and the adhesive. These gaps offer an ideal niche for bacteria, and, when compounded by the mechanical strain of chewing, can lead to premature failure of the restorative.^2,3 Additionally, it is well known that incomplete conversion of the double bonds occurs during methacrylate polymerizations.^4–7 A high degree of conversion is needed to prevent the presence of potentially hazardous monomers.⁸