1.1 This part of ISO20795 classifies denture base polymers and copolymers and specifies their requirements. It also specifies the test methods to be used in determining compliance with these requirements. It further specifies requirements with respect to packaging and marking the products and to the instructions to be supplied for use of these materials. Furthermore, it applies to denture base polymers for which the manufacturer claims that the material has improved impact resistance. It also specifies the respective requirement and the test method to be used. 1.2 Although this part of ISO20795 does not require manufacturers to declare details of the composition, attention is drawn to the fact that some national or international authorities require such details to be provided. 1.3 This part of ISO20795 is applicable to denture base polymers such as those listed below: poly(acrylic acid esters); poly(substituted acrylic acid esters); poly(vinyl esters); polystyrene; rubber modified poly(methacrylic acid esters); polycarbonates; polysulfones; poly(dimethacrylic acid esters); polyacetals (polyoxymethylene); copolymers or mixtures of the polymers listed in a) to i).