Implant placed in inadequate location causes many complications including esthetics, concentration of force on implants and prosthetic treatment. We asked 5 prosthodontics and 5 oral surgeons to form the channel for apatite 2-piece implant in plaster model of Kennedy class I case and examined the implant position.
As a result:
1.When the channel was formed without any instruction, there was no problem caused in buccolingual but there was in mesiodistal direction. The channel in 6 was formed slightly toward the distal and that in 7 was formed slightly toward the mesial,so that the positions might cause prosthetic problems..
2. The direction of the channel formed with or without instruction showed many variables in mesiodistal and buccolingual direction. There was the possibility that the variables in direction caused severe prosthetic treatment problem.
3. No significant difference was observed from the point of view of clinical experience of prosthetics and oral surgery. These data indicate that study must be made to find the technique of the channel formation to determine the exact direction and position of the channel when implant was inserted.

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One of the greatest advances in dentistry is the restoration of occlusal function with endosseous implants. Histopathological investigations have been executed in animals and many findings have beenreported. However, it is very difficul to clearly observe the healing condition of alveolar bone after implantation in the daily clinic practice of implantology.
In this study, the authors observed chronological change of mobility of implants with periotest and obtained the following findings;
1. The periotest values of mandibular implant declined after implantation and reached a negative (-)plateau in 3 months after postoperatively.
Accordingly, it can be thought that ITI implants completes osseointegration in 3 months after implantation.
2. The periotest values have never increased after insertion of superstructures keeping the same level as before.
3. All types of ITI implants tested have showed minus Periotest values.
4. The authors believe that periotest can be used to measure the mobilities of any kind of endosseous implants.

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The purpose of this research is to evaluate bone changes following implantation of Apatite 2-Piece Implant by radiographs. This paper mainly validates standards for radiographs and digital image processing. Exposure geometry and film processing conditions were standardized. The film holder for each subject was made by modifying a custom-made film holder(Hanshin Indicator). Copper steps(0.1,0.2,0.4,0.8mm)were attached to the X-ray film. A CCD camera was used for data sampling of radiographic images. Their sampling data were digitized and analyzed in digital image processor(Hamamatsu Photonics, DVS-3000)and a computer(HP-9000 series 300).
1. Coefficient of variation which indicates geometric reproducibility of radiograph was within 1%.
2. The linearity of the film density and the brightness was obtained for densities of from 0.2 to 1.5.(coorelation=-0.99)
3. Obvious bone changes were observed following implantation of the apatite implant.

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In our department, clinical application of dense particulate hydroxyapatite (HAP) to various types of jawbone defects has produced good results since July 1984. The present paper describes the clinical and radiographic evaluation of 5 cases of full all ridge augmentation with HAP. Primarily, they were evaluated by clinical and radiographic findings, and graded into three groups:
1. Cases in which no postoperative infection or wound dehiscence occurred and in which almost all of the HAP was retained and bonded to the peripheral bone.……(good)
2. Cases in which some loss of HAP occurred due to postoperative infection or dehiscence, but in which most of the HAP was retained.……(fair)
3. Cases in which postoperative infection or wound dehiscence occurred and in which almost all HAP was lost.……(poor)
Secondarily, they were evaluated chrologically with respect to Cephalo X-ray films and study models which were also obtained before surgery, immediately after surgery,3 months after, and 3 years after.
The material used was dense particulate hydroxyapatite,0.5～1.2mm in diameter, which had been sintered from amorphous hydroxyapatite by the wet cake method at 1,200℃.
Five cases of atrophied alveolar bone were treated with HAP employing the tunnel technique, and all results were satisfactory.

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There have been relatively few objective evaluations of endosteal implants. In 1986 we reported objective clinical and radiographic evaluations of endosteal implants(H. Abe et al:J. Tokyo. Wom.Med. Coll.56,547～561,1986).
In our department between January 1984 and November 1986,80 titanium(Ti)bladevent implants were inserted into maxilla and mandible. The present paper describes the clinical and radiographic evaluation of 41 cases which could be followed up formore than 3 years. The evaluation was performed by examining the gingival pocket at the implantneck, gingival health, tooth mobility and bone loss.After the evaluation, the cases were classified into 4 types:Class 1(good), Class 2(fair), Class 3(removal necessary), Class 4(removed).
It was found that 29 cases(70.7%)belonged to Class 1,10(24.4%)to Class 2, none to Class 3 and 2(4.9%) to Class 4. These results indicate that Ti-bladevent implants which were followed up for 3 years were associated with good periodontal health and were functional.

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Granular HAP is a well known material which can be planted into the defect and connect biochemically with the tissue without inflammation.
But sometimes we find the performance of the material poor in the end even when surgical operation was believed successful. To investigate the problem of granular HAP in clinical use we examined the literature on this matter.

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An experimental study using dog mandible was performed in order to reveal the histopathology of the exfoliation of HA-Al coating on a Sumicikon implant.
At the time of implantation, implant channel was prepared more tightly than usual, and then the implant was purposely strongly tapped with a mallet.The dog was sacrificed 28 days postoperatively.After that, semi-serial undecalcified histologic sections were made for light microscopic observations.
The results obtained were as follows:The implant was attached to the epithelium and fibrous tissue in the gingiva, and surrounded with regenerative bone and fibrous tissue at a rate of 50%, respectively, in the bone. The coated layer of the implant was partly exfoliated only at the apical region.
The exfoliated ceramic masses were also in contact with both regenerative bone and fibrous tissue.
A few foreign-body giant cells were observed around the small exfoliated mass, but inflammatory reaction was hardly seen in the sections.
From the results, the partial exfoliation of HA-Al coating on the Sumicikon implant seemed not to influence the stability and success of the implant.

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In recent years, the utilization of biomaterials has increased and expanded in the dental and oral surgery fields. In many cases, good results could be gained. On the other hand, in a few cases, satisfactory results could not be gained. The implantation of biomaterials, particularly in maxilla, is very difficult and must be done carefully.
With a few examinations, we report here a case which had received utilization of biomaterials in maxilla and followed by paresthesia of right upper lip, right perimaxillary inflammation and right maxillary sinusitis.

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A simultaneous operation of implantation and free autogenous gingival graft was improved. The process of this surgical method was as follows:1)Implantation. 2) Preparation of connective bed 2 to 3 mm apart from implant neck and suture of the apically positioned flap with periosteum down below.3) Section of the free graft from the donor site in the palate sutured in the position.
This method would secure attached gingiva around implant neck very easily and steadily. The features of this method were as follows:We could secure a surgical field large enough for a successful operation without running a risk of hurting the periosteum.The patients could get enough gingiva attached to the implant and wide vestibular.

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