Poly(methyl methacrylate) as used in polymer replica tooth implants was fabricated into 6 X 6 mm cylindrical specimens and cured in either an air oven, pressure pot, autoclave, or microwave oven. Polymer porosity was achieved by means of either 1) intrinsic foaming agents, or 2) compacting different sizes of large beads with a minimum of monomer, with dense PMMA used as a control. Specimens were then implanted in the long bones of baboons. Histology of thin-sectioned and ground specimens from the sacrificed animals revealed complete tissue ingrowth into implanted material made of medium and large PMMA beads, very superficial ingrowth into material containing foaming agents and anorganic bone chips, and no ingrowth into dense PMMA implants. None of the implants were rejected or caused chronic inflammation. The effect on histologic response of the different curing methods could not be distinguished.

The purpose of this study was to assess the addition of a ceramic coating upon a Vitallium implant to increase the implant's biologic acceptability in the oral environment. The mandibular premolar teeth in 9 adult beagle dogs were removed bilaterally and these areas allowed to heal for 6 weeks. Ceramic coating with either Al2O3 or ZrO2 was carried out by flame spray deposition upon Vitallium anchor implants (9 of each), and the implants placed into the 18 healed premolar areas. Clinical and radiographic evaluation was conducted by 2 independent investigators over a 32 week period. Implants which exhibited mobility greater than II on a scale of 0 to III, at intervals of one-half, were judged unsatisfactory. After 19 weeks, all 9 Al2O3 coated implants and 5 ZrO2 coated implants were rated unsatisfactory. After 32 weeks, 4 ZrO2 coated implants were in situ with 0 or I mobility. Radiographically the width of the peri-implant space increased in direct proportion to both time and mobility. Histologic sections demonstrated encapsulating dense fibrous connective tissue which was oriented parallel to both ZrO2 and Al2O3 implants. Results suggest the zirconia used is a superior ceramic coating to the alumina. Neither seemed to increase biologic acceptability over uncoated Vitallium implants.