PubMed · 278779
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J Fechtner. 1978. Tissue changes during tooth movement.. https://pubmed.ncbi.nlm.nih.gov/278779/
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The purpose of this study was to evaluate four commercial apatite products. Subperiosteal alveolar ridge augmentation was performed on the maxilla of rats by implantation of granules of two dense products and of two porous products, and the tissue response was compared with the material characteristics obtained by chemical analysis and infrared spectrometry. None of the apatites caused osteoinduction or osteoconduction; fibrous encapsulation with multinuclear giant cells was observed around all four types. One of the apatites was fluorapatite and not hydroxylapatite, as claimed by the manufacturer. The tissue response to this implant material was dominated by multinuclear giant cells.
The purpose of this investigation was to evaluate the effect of radiation on hydroxylapatite (HA) implanted subperiosteally for alveolar ridge augmentation in dogs. All bicuspids and molars were extracted from 16 dogs. After 6 weeks, nonporous HA granules were implanted subperiosteally on the alveolar ridge. Following 4 months of healing, 12 dogs (experimental group) underwent therapeutic radiation therapy (Co60, 4,000 rad [40 Gy]) to the head and neck region. Four dogs were not irradiated and served as controls. Four animals (three experimental and one control) were killed at 5,6,7, and 8 months after HA augmentation. Light microscopic evaluation showed that approximately 25% of HA granules were encased by bone while the others were surrounded by fibrous connective tissue. Dissolution of the HA was observed. Microparticles of HA were phagocytized as part of a granulomatous inflammatory reaction. This reaction decreased significantly as time elapsed after implantation. Osteoclastic activity was seen at the junction of HA and periosteum and as part of bone remodeling. Dissolution of the HA granules and the granulomatous inflammatory reaction were not significantly increased by therapeutic radiation. The radiation did not cause development of dehiscence or osteonecrosis.
The aim of these animal experiments was to characterize and evaluate the healing-in of root analogue titanium implants fitting with high precision to the alveolar wall. Four beagle dogs were used in the study. The roots of the 3rd and 4th mandibular premolars in both quadrants of 3 dogs and in 1 quadrant of 1 dog (dog 4) were extracted after hemisection. Each root was machine-copied to 1 titanium analogue. In dog 4, however, 2 titanium analogues were fabricated from each of the 4 extracted roots. This enabled insertion of analogues also into the contralateral sockets obtained by extraction of the corresponding roots immediately before implant installation, which was undertaken 2 weeks after the first extractions. Thus, in all, 32 analogues were implanted in their respective (or contralateral) sockets following ridge incision and elevation of mucoperiosteal flaps. The analogues were carefully covered by the repositioned flaps. In dog 4, 2 analogues from the immediate sockets and 2 from the 2-week sockets were surgically exposed and supplied with titanium crowns after a healing period of 2 months. The healing after implantation was evaluated by clinical, radiographic and histological measures after 2, 12 or 36 months. Two analogues (6%) were lost due to early (during the 1st week) exposure to the oral cavity. Another 2 analogues (6%) were, although not exposed, encapsulated by soft tissue and were easily removed with a surgical forceps. Twenty-eight analogues (88%) were healed-in by contact between bone and implant (osseointegration).(ABSTRACT TRUNCATED AT 250 WORDS)