The rabbit as an animal model in dental implant research : with special reference to bone augmenting materials

Abstract: Dental implants that are integrated into the jaw bones are widely used to replace lost teeth in human beings. Tooth-loss is often related to loss of the surrounding alveolar bone. This can make implant placement difficult and a bone substituting material may be required. The standard method is to use a bone graft harvested from the patient which requires additional surgery than that needed for implant placement. Limitations in the amount of bone that can be harvested also pose a problem. In order to decrease the need for bone grafts, materials that can serve as substitutes and stimulate bone growth have been, and are being, developed. In this pilot study the research protocol for an in vivo experiment with a new calcium phosphate bone augmenting ceramic material, was evaluated. Two titanium screw type dental implants were placed in each tibial diaphysis of three, 12 month old, female New Zealand White rabbits. The implants where either surrounded by the experimental material, Straumann®BoneCeramic (positive control) or blood (negative control). For one week before as well as post-surgery the rabbits’ body weights were recorded daily. Each rabbit’s general condition, state of surgical wounds and the grade of limping was evaluated every day for as long as needed. Two weeks post-surgery an injection of a bone marker (calcein green) was planned. Three month post-surgery the rabbits were to be euthanized and the amount of newly formed bone evaluated with light microscopy. The osseointegration of the implants was to be measured histomorphometrically as the bone to implant contact in percent. However, the calcein green was never given and the bone formation and osseointegration never evaluated. All rabbits had to be euthanized within 24 days post-surgery because of fractures appearing in one or both tibia/e. Apart from the pilot study, the master thesis includes a literature review of dental implants, bone augmenting materials and how the rabbit can be used as an animal model in dental implant research.