Biological evaluations of zinc hexyl vanillate cement using two in vivo test methods

The cellular and tissue responses to 3 dental cements were studied by 2 methodologies, the connective tissue implantation technique (CTI), recommended by the ADA, and the peritoneal cavity implantation technique (PCI), which has emerged as a method to quantitatively study the cellular response to implanted materials. A mixed inflammatory cell response consisting of neutrophils and macrophages occurred at most of the time periods for all the cements examined in the CTI study. Similar cell populations, including lymphocytes, were observed with the PCI study using differential staining techniques. The histopathological observations from both procedures were similar. Each cement elicited a chronic foreign body reaction containing few chronic cells and mature fibroblastic activity. The intensity of the observed tissue reactions for each cement, as determined by capsule thickness in the CTI study and the overall cell counts in the PCI study, did not differ significantly with increasing time. The cellular and connective tissue reactions to the zinc hexyl vanillate (ZHV) cement approximated those of zinc oxide-eugenol (ZOE) and zinc phosphate (ZP) cements for both methodologies utilized in this work. While similar histopathological results were obtained for the implantation of cements using both methodologies, the PCI technique offers a more thorough investigation of cellular and tissue responses to implanted materials. In addition to histopathological evaluations, the PCI techniques allows quantitative investigation of the specific cells responding to the implants, and provides a mechanism, using chemical analysis techniques, to quantify the concentration of specific degradative products within the retrieved cells and host tissue. Finally, the results from these 2 methodologies demonstrated the acceptable biological performance of ZHV cement compared with the clinically acceptable ZP and ZOE cement formulations.