Effects of acrylic restorations on the periodontium of monkeys.

Data dealing with successful or unsuccessful acrylic tooth implants have accumulated gradually during the past 20 years. Flohr' studied plastic material as a possible substitute for natural teeth by placing screw-type acrylic roots into surgically created alveolar sockets. He reported that normal connective tissue formed against the acrylic, and only minimal infiltration occurred. Hodosh, et al24 reported a high degree of success with acrylic implants in man, baboons, and dogs. Success was measured by the firmness and stability of the implants, by their ability to stand up under the stress of mastication, and by the absence of gross gingival and periodontal diseases. Brown, Neff, and Tylenda5 reported encouraging results in a preliminary study of acrylic tooth implants in monkeys. On the other hand, Waerhaug and Zander6 demonstrated that acrylic resin implants exerted little or no irritation on hard and soft tissues, but concluded that the life of the acrylic implant is limited and that it is probably of no practical value. Narang and Wells7 reported that efforts to achieve longterm maintenance of acrylic tooth implants have achieved only limited success. Failures were characterized by gingival inflammation, alveolar bone loss, and excessive mobility of the acrylic tooth implants. In spite of careful splinting, Iwaschenko8 found epithelial proliferation and subsequent exfoliation of the