Shrinkage
Shrinkage is the specification most commonly discussed. Low shrinkage certainly improves the integrity of the filling margins. However, this value alone, actually says nothing about how the shrinkage affects the cavity walls. It is essential that the shrinkage stress force exerted, when curing the composite, is as low as possible, minimising stress to the cavity walls. As stated, low shrinkage stress is desirable, because a gap between the filling and the cavity wall can only arise if the force is so high, that the adhesive bond is damaged or stressed.