Abstracts (05)
Histological Investigation of the Healing Response Adjacent to Porous-surfaced Titanium Alloy Oral Implants in Dogs*
D.A. Deporter, A.H. Melcher, P.A. Watson, J.Winslow, T. Howley, P.
Hansel, C. Maniatopoulos, D. Abdulla, R.M. Pilliar and D.C. Smith
M.R.C. Programme in Dental Implantology, Faculty of Dentistry, University of Toronto
Proceedings of an International Congress, Brussels, May, 1985 (D. van
Steenberghe, ed.), Excerpta Medica, Amsterdam 1986;87-95
The osseointegration system developed by Branemark and his co-workers is by far the most successful oral implant system yet developed. The screw-threaded implant geometry used represents a design that can become mechanically interlocked with bone, assuming that bone newly formed during remodelling is in contact with the implant. Once this interlock occurs, stresses are transferred uniformly between the implant and bone along the length of the threaded portion.
A threaded implant is not the only form, however, which permits this uniform stress distribution. A similar situation can develop with porous-surfaced implant designs which achieve fixation by bone ingrowth. The establishment of implant fixation by bone ingrowth into porous-surfaced implants has been studied extensively by Pilliar and co-workers. Other investigators using different materials and porous-surfaced designs, have also demonstrated osseous fixation through ingrowth. The conditions necessary for bone ingrowth to occur are: initial implant stability, i.e., an initial healing period during which the implant is not in function or subject to any gross mobility; a sufficiently large pore size to permit bone ingrowth; and use of a biocompatible material. The recommended pore size is in the range of 100 to 400 µm as this encourages the ingrowth of bone rather than fibrous connective tissue. Titanium and its alloy, Ti6A14V have been used successfully for porous-surfaced implants.
We have developed a titanium alloy endosseous oral implant system which incorporates a porous-surfaced geometry with a tapered conical implant shape.
We are presently testing this implant system in dogs. The first experiment, which is partially reported here, was designed to determine a suitable healing period for porous-surfaced titanium alloy implants placed in the premolar areas of partially edentulous dog mandibles.
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