Thirty-two teeth with artificial crowns cemented with four different cements were sectioned and the cementing interfaces were studied by means of a replica technique. Scanning electronic microscopic examination of the replicas demonstrated that slits occurred in all specimens either at the cement/tooth interface, the cement/alloy interface or both. Differences between the various cements in width and length of the slits could not be assessed by this method, but marked variations in the localization of the slits were noted. A composite resin cement showed slits only at the cement/tooth interface. A zinc phosphate and an EBA cement showed slits at both interfaces whereas a polycarboxylate cement was the only cement which exhibited good adaption to enamel and dentin, leaving gaps at the cement/alloy interface.
Adhesiveness Composite Resins