[Critical considerations on the development of composite filling materials]

Following the report given at the FDI congress in Chicago in 1975, the question is raised about the present state of acrylic filling materials, i.e. whether further developments are necessary or even possible. The importance of clinical testing is emphasized and the problems involved in chemical binding to the dental hard substances discussed. The influence of the thermal coefficient of expansion on the marginal seal is discussed in connection with marginal discoloration, and acid cauterization as well as remineralization are critically evaluated. The significance of wear and tear for maintaining the contours is emphasized, especially in connection with occlusal fillings of lateral teeth, as well as the problem of shaping a contact point and tensile strength after repair of an old filling. Improvements in UV light polymerisation are described. The different opinions on the importance of histological findings regarding pulp tolerance are critically discussed and finally the significance of water uptake and radiological opacity is delt with. In conclusion, the indication for acrylic filling materials at the present time is defined.