Both ethyl and methyl methacrylates can be used with an indirect technique. Usually, ethyl methacrylates demonstrate less polymerization shrinkage and thus better marginal integrity. Methyl methacrylates exhibit greater hardness and durability. Both materials are more dense when cured in a pressurized container. Bis-Acryl Composite Resins.
Most products are available in automix systems, which improve their ease of use.
However, automix systems limit the practitioner's ability to alter the viscosity of the material. The primary disadvantage associated with these systems is their high cost. Bis-acryl resins can be used for most types of provisional restorations. They make exceptional single partial veneer provisionals and are good materials for directly fabricated long span provisional fixed partial dentures. Dual cure systems exhibit a chemical cure preceding the final light cured set.