Recently, oral implantation and teeth homotransplantation have drawn interest. We have tried many cases in teeth homotransplantation and expected this could be used in osteoankylosis.
Unfortunately, most of those teeth had fallen out. Therefore, in such cases, we had tried performing oral implants to recover them.
In this paper, two cases of oral implants which were implanted after failure in transplantation of teeth are reported.
The first case was a 42-year-old female. Seven teeth were homotransplanted, but they had to be extracted one year later.
The second case was a 65-year-old male. Seven teeth were also homotransplanted, but six of them had to be extracted from 4 to 7 months later. In both of these cases, oral implantation was performed after their teeth were extracted. Based on these two cases, the effectiveness of oral implantation after extraction of unfavorably homotransplanted teeth has been confirmed.

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This ultrastructural investigation deals with the mechanism of calcification which occurred after beta-phase tricalcium phosphate ceramics (Synthograft™) were subcutaneously administered to rats.
Experimental animals were 50 male Wistar rats.Granules of Synthograft™ were implanted in the subcutaneous tissue of rats. The rats were sacrificed 2, 4, 8, 16 and 24 weeks after implantation. Subsequently, nondecalcified ultrathin sections were prepared in accordance with the conventional method and were observed with a transmission electron microscope.
Two weeks after implantation, Synthograft™ was surrounded by degenerative and inflammatory cells. Occasionally, macrophages phagocytosed the test materials. From 4 weeks postoperatively, osmiophilic, amorphous electron density structures deposited on the surface of the test materials. Especially 8 weeks after implantation, these structures were also observed in the porous spaces which could be found between electron dense Synthograft™. Calcium and phosphorus were detected in these structures by energy dispersive X-ray microanalysis. However, these structures did not increase with the passage of time.
It is concluded that Synthograft™ may not initiate dystrophic calcification but does cause initial calcification.

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Replantation is the reinsertion of a tooth in its socket after its complete avulsion as a result of trauma or accidental extraction. Intentional replantation is intentional removal of a tooth and its reinsertion into the socket after endodontic manipulation and/or obturation of the canal or both. Intentional replantation is used as a last measure to preserve a tooth when there is no alternative treatment except extraction. When posterior teeth are involved, root preservation might not be feasible because of the proximity of the mandibular canal,mental foramen, or maxillary sinus or because of technical difficulties, such as a lack of accessibility or density of the bone structure.
Intentional replantation is rarely resorted to because the indications for this operation are few.
We present two cases of intentional replantation. Mandibular first molar (first case) and second molar (second case) were diagnosed as having chronic apical periodontitis and endodontic treatment was determined to be impractical. Although we believed that extraction was the preferred treatment, intentional replantations were performed as a last resort. The follow-up of both cases radiographically revealed periapical repair.

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Eight Apatite-coated sapphires and 2 Bioceram sapphire implants® were embedded in the mandible of a dog, and their mobilities were examined with Periotest®.
1. The average Periotest value (PTV) of 8 Apatite-coated sapphires was -4.4±0.8 (S.D.;n=8; range -3.0～5.6). By radiological examination, bone resorption was recognized only in the implant neck region.
2. The PTVs of 2 Bioceram sapphire implants® were＋23.2 and -1.4. Radiologically, the surface of the former was surrounded with a transparent layer and the latter showed the same figure as Apatite-coated sapphires.
3. Microscopic examination revealed that the hydroxyapatite-coated grooves of the screw were in contact with regenerative bone. The result indicates that Apatite-coated sapphire can prevent mobility. On the other hand, Bioceram sapphire implant® (PTV,＋23.2) was wrapped with fibrous connective tissue, and another one (-1.4) was in contact with bone only at the screw thread.

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A case treated with subantral augmentation without grafting materials, in which bone augmentation was postoperatively confirmed using x-ray examination, was reported.
Case: A 45-year-old man who complained of pain in 2 when drinking cold water, visited our institute on Jan.19, 1989. On Oct. 6, he complained about a swelling of the gingiva and had a feeling that foreign matter was present in 5. Present findings showed missing teeth of 6 and 7, and an extention bridge on 4 and 5. X-ray examination indicated that there was a fracture of a distal part of the root in 5 and the right sinus bottom line located near the apex of the roots. The atrophy of alveolar ridge in 6 and 7 was remarkable. Treatment: On May 27, 1990,5 was extracted. The right side of the maxillary sinus was opened, and after lifting up the sinus mucosa, screw vent dental implants of 10 mm in size were inserted at 6 and 8. The gingival flap was sutured. Panoramic radiograph soon after operation showed the amount of bone to be 5 mm at the menial part of the implant and 7 mm at the distal part. The radiograph on Nov.6 (23 weeks later),showed bone augmentation increased by 4 mm at the mesial part and 2 mm at the distal part of the implant.
Discussion and summary: The case suggests that the maxillary sinus is fundamentally an organ having osteogenetic activity. It is important when considering the mechanism of new bone formation in the maxillary antrum.

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We examined the tissue reaction to IMZ implants with polyoxymethylene internal mobile element (POM-IME) and the other ones with titanium IME (Ti-IME). No histopathologic difference was observed between the implants with POM-IME and those with Ti-IME, except for the cervix. The gap between transmucosal implant extension (TIE) and implant body, and inflammatory reaction were observed around the cervix. These findings were very remarkable in the implant with POM-IME. In image analysis, no great difference of bone contact near the roots of implants was seen between the implants with POM-IME and those with Ti-IME.

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We treated an ITI hollow cylinder implant F-type (ITI・F) that had been removed from a patient due to breakage thereof and obtained the following conclusions.
1. The possibility of breakage must be stated as one of the risks of dental therapy when using ITI・F.
2. ITI・F osseointegrates with bone.
3. If radiolucency extends to the perforations, the tissue inside the cylinder might be degenerated; therefore, ITI・F could be a candidate for removal.
4. Patients treated with ITI・F require regular follow-up examinations at short intervals and detailed prognostic observations.

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A case of blade vent implant in the mandible with remaining teeth was observed clinically and radiographically for 20 years. Linkow-E 6 S and E 4 S type blade vents (Titanium) were implanted in the mandible of an edentulous 62-year-old man in March 1972. These system functioned for 20 years until they are removed in June 1993.
The sinking grade of the blade vent and resorption of alveolar bone were observed by panoramic radiography. The result revealed that the blade vent implanted adjacent to the remnant teeth gave no evidence of sinking, but on the opposite implanted side in the edentulous mandible, sinking of 3 mm and slight alveolar bone resorption were shown. The present case reveals that the endosseous implant does not always induce bone resorption, when excellent oral hygiene and maintenance are continued.

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Guided tissue regeneration (GTR) method is a new remarkable technique for getting new bone induction in bone defects around implants. We have experienced the case of a 16-year-old male patient who had treatment of titanium endosseous dental implant around upper left lateral incisor and also GTR method with a screw technique for obtaining sufficient bone volume for labial bone defects. GTR method would be successful and useful in this case.
We examined the Gore-Tex® membrane, which was removed one month after implantation because of infection, by using scanning electron microscopy, immunohistochemical observation of glycosaminoglycan, type I and III collagens, fibronectin and laminin staining and electron probe X-ray micro analysis.
It is concluded that Gore-Tex® membrane would be useful material to obtain osteogenesis for bone defects.

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The bone formation in the soft tissue with combined grafts of three categories of HAP granules and autogeneous bone marrow were examined histologically.
Two kinds of HAP granules were on the market (Apaceram^® and Bonetite^®) and another was newly developed (Kobeceram). Autogeneous bone marrow was obtained from New Zealand white rabbit tibia. Combined materials of each HAP granule and bone marrow were grafted into the abdominal subcutaneous regions of rabbits, and bone formation at four weeks after graft were observed histologically.
The results were as follows: In all groups, new bone formations, which were induced with osteoprogenitor factor in bone marrow, were observed, and histological examination of the 4-week specimens revealed excellent HAP-bone complex formations in the Apaceram^® and Kobeceram groups. Process of HAP-bone complex formation with combined graft of HAP granules and autogeneous bone marrow was similar to that which was observed when HAP granules were grafted into the rabbit tibia.

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The effects of HAP granules on soft tissue were studied histologically. HAP granules in the present study have irregular shape and many continuous pores ranging from 50 μm to 200 μm in diameter, which have a Ca/P molar ratio of 1:1.65. They are sintered at 1,200℃. These granules were grafted into the abdominal subcutaneous region of Wister-rats. Spacemens were removed at verious intervals and observed with light and electron microscopy.
The results were as follows: Macrophages were observed around HAP granules right after grafting, and they showed engulfing HAP particles during 0.4～1.2 μm at one week or two weeks after grafting.
After 4 weeks, mufti-nuclear giant cells engulfing HAP particles ranging from 2 to 6 μm were observed, however they did not have digesting and absorpting abilities.
Larger HAP particles, which were coated with overlap of multi-nuclear giant cells and connective tissue, were recognized. It seemed that multinuclear giant cells in contact with HAP granules, which were observed later, were formed with fusion of macrophages.
This suggested that macrophages and multinuclear cells in contact with HAP granules do not have the ability of osteoclast-like-cells.

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HA-coated Dental Implant (Kyoceya, Japan) were extracted from mandibular bone for fracture of the upper structure after 44 months, including a loading period of 40 months. And it was prepared using a cutting-grinding system and studied with transmission electron microscopy. The HA-coated Dental Implant showed an intimate bone contact at the ceramic surface under a loaded condition in human that appeared to achieve biointegration at the ultrastructural level. However, detachment of HA crystals from the coated surface is evident. Crystals are situated inside the newly formed bone surrounding the implant and the cytoplasm of phagocytic cells.

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