Primates as a teaching model for biopsy.

It is our intention to poll former participants in this elective to determine their experience in biopsy of oral tissues in practice. To date, student critiques of this elective course have been positive; participants have strongly suggested that we continue this method of instruction. The use of animals can be justified by the fact that experience gained in this course is applicable to the serious problem of early detection of oral cancer. Curricula that include biopsy procedures will produce dentists who will be comfortable using this important diagnostic method in their practices. Studies indicate that more general dentists are utilizing biopsy. It is important that this trend be encouraged, and the use of the nonhuman primate in a course such as that described above is a positive step in this direction.

Surface properties determine bioadhesive outcomes: methods and results.

This investigation developed experimental evidence for the influence of different surface energy states on tissue incorporation of biomedical materials. Implants of two smooth metals, each with three different surface energy states, were placed in the subdermal fascial plane of the backs of New Zealand White rabbits and were allowed healing times of 10 and 20 days. The implant surfaces were thoroughly characterized by physical-chemical criteria prior to surgical placement and again following removal from the tissue capsules generated by the host animals. Quantitative histopathologic analysis, using standard morphometric criteria, of the adjacent tissues revealed up to a threefold increase of fibroblastic-fibrocytic cells against the initially scrupulously cleaned, high-surface-energy materials. The cells were flattened and active, producing tenacious bonds through a thin pre-adsorbed protein-dominated "conditioning" film, that could be broken only by cohesive failure in the tissue itself. In contrast, the lower-surface-energy materials typical of standard dental implants were "walled off" by a cell-poor, nonadhesive capsule with a fibrous interface separated from a thicker "conditioning" film by a lipid-rich mucus zone. The advantages of proper surface treatment to favor the desired degree of biological adhesion are apparent.

Fibroblastic activities post implantation of cobalt chromium alloy and pure germanium in rabbits.

Different preimplantation surface finishes were applied to surgical vitallium discs and germanium prisms implanted for 20 days within the back muscles of adult rabbits. Histopathologic analysis of the numbers of nuclei of active fibroblasts immediately adjacent to the implants was carried out. The mean apparent volume fractions (MAVF) for the subdermal implant sites were found to depend on the surface cleanliness of the implant, the cleanest or highest-surface-energy surfaces giving the highest MAVF values for active fibroblasts.