TPS implants were applied as the retention of dentures to 6 patients and the mobility of the 20 TPS implants in situ was examined with PERIOTEST^®.The result was as follows.
1. The PERIOTEST^® value (PT value) after inserting was -2.90 on the average(stdev:1.93).
2. The average PT value of TPS implants with functional loading was -3.20(stdev:1.13).
3. TPS implants showed no changes from minus PT value to plus PT value with the passage of time.
On investigation it was considered that TPS implants were very useful as the retention of dentures.

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Gingival crevicular fluid volume in 37 patients applied various types of implants(Bioceram^®, Generation Ten and ITI implant)was measured by an electric measurement device,“Periotron^®economy”.
32 of 37 patients had clinically no problems. They were 10 patients applied Bioceram^®,10 patients applied Generation Ten and 12 patients applied ITI implant. The mean Periotron^® scores of Bioceram^®, Generation Ten and ITI implant were 7.7,11.6 and 8.2 respectively.
The mean Periotron^® score of 5 patients that had some clinical problems was 69.9. Its score remarkably increased as compared with that in a good condition.

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Bone regenetic ability of the periosteum plays an important role in oral surgery and orthopedics, especially in reconstruction after bone loss. Some researchers reported various levels of bone formation experimentally. This discrepancy may be due to a variety of experimental animals and operation techniques employed. For uniting such conditions, we employed SD rats. The purpose of this study is to evaluate the osteogenetic ability of SD rats' periosteum.
In SD rats(8 weeks old), the tibial periosteum was ablated and transplanted onto m. cutaneus trunci under intraperitoneal anesthesia. The transplanted site was examined histologically and radiologically.After 1 week an ectopic new bone formation was observed. It demonstrated a distinct osteogenesis both histologically and radiologically. It was conceived that this phenomenon was not contributed by induction of osteoprogenitor cells, but by bone lining cells derived from inner layer of the periosteum on the basis of scanning electron microgram and roentogenogram.
This results showed that SD rat is an adequate animal model for investigating periosteal bone generation and it can be applied easily to many samples.

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We examined the mobility of Bonefit^® and osseointegrated implant before setting a superstructure by Periotest^® (Siemens). For comparision, we examined the mobility of blade vent implant.
We used three kinds of Bonefit^®(one-part hollow cylinder, two-part hollow cylinder and two-part hollow screw type). The mean Periotest^® value of Bonefit^® was -0.5±2.8(n=16), that of osseointegrated implant was -0.9±3.0(n=11)and that of blade vent implant was＋17.7±7.0(n=10). In regard to the mobility, Periotest^® values of Bonefit^® and osseointegrated implant are efficiently smaller than that of blade vent implant.

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A clinicostatistical survey was made on subperiosteal implants in 27 cases with intravenous sedation during the past 1 year and 5 months period at the Clinical Implant Society of Japan.
Age distribution was;sixties 40.7%, seventies 18.5% and totaly cases over sixties 59%.
Subperiosteal implant division was;partial maxillary first stage 23.3%, full maxillary first stage 20.0%, full mandibular first stage 20.0% and partial mandibular first stage 13.3%. Maxillary cases were more encountered than mandibular cases for first stage.
Operation time was;1-2 hours 51.9%,2-3 hours 37.0% and over 3 hours 3.7%.
Pre-operative complication was;circulatory diseases 27.3%, hepatic diseases 27.7%.
Intravenous sedation was treated with;single administration of flunitrazepam 51.9% over 30 minutes followed by flunitrazepam with methohexital 25.9%.
Regional anesthesia performed with;2% lidocaine plus epinephrine 83.3% and 3% prilocaine plus felypressin 16.7%.
Interoperative complications, included very few cases of nausea, headache, increased blood pressure and oral pain.

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It is well-known that the prosthetic treatment for edentulous mandibulectomy patients is one of the most consistently frustrating area in the maxillofacial rehabilitation.
Practically speaking, if hemimandibulectomy patients are completely edentulous, it is frequently difficult to treat them with a conventional removable prosthesis, and then an application of oral implant is required.
This study reports a completely edentulous hemimandibulectomy patient complaining of unstable denture of the mandible which could be satisfactorily reconstructed with a fixed bridge on the osseointegrated implant(Brånemark implant).
Since a 69-year-old complete edentulous male had received hemimandibulectomy on the right side with out jaw reconstruction for radical cancer therapy, he hadn't been rehabilitated with a removable prosthesis satisfactorily, and two years after hemimandibulectomy Brånemark implant was applied to the prosthetized mandible. Five months after four fixtures were installed in the anterior and the left premolar portions of the residual mandible, an abutment operation and subsequent prosthetic treatment were carried out successfully.
We occasionally performed various prosthodontic and physiologic examinations to know the effectiveness of oral implant bridge, and then we ascertained that Brånemark implant is a very effective prosthetic measures in such patients as these received hemimandibulectomy.

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It is important, in the prosthetic therapy, to prevent the alveolar ridge from the bone resorption after tooth extraction and denture insertion.
For the purpose of preservation, the authors have studied the procedure of root-submergence in which only the root of a tooth is retained intentionally in the alveolar socket below the mucoperiosteum.
However it should not be applied to the fractured roots, the decayed roots, and the roots with an extended periapical infection. These cases should be regarded as a contraindication of the root-submergence procedure, to which the authors apply a hydroxyapatite ceramics implant(HAC)inserted into the fresh alveolar socket just after tooth extraction.
There are two types of cone and particle in the HAC. It has been reported in a study comparing the effect of the two forms, that the cone type is more effective than the particle type to prevent bone resorption. The authors utilize the cone type HAC under the criteria determined preliminarily, that is, in addition to the above mentioned contraindication of the root-submergence procedure, the presence of abutment in the region adjacent to the HAC to be submerged.
The following results were obtained.
1. The presence of HAC is useful to prevent the bone resorption around the abutment adjacent to the submerged HAC and, on the other hand, the abutment works to support the occlusal force and serves to reduce the imposition of the ridge retaining the HAC.
2. It is possible to apply the HAC to the cases as well in which there is no abutment around the region to submerge the HAC and the HAC stands isolated.
3.We can expect a successful result if the HAC is fixed steadily in the socket and immobile during initial stage inserted into the socket.
4.We should be afraid of having an unsuccessful prognosis in those who have some general diseases and/or the following alveolar conditions: 1) having a curved tooth root 2) having a shallowed socket 3) having little expansion of the wall

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The purpose of this study was to obtain a basic information on the activation of melt-spray materials using a natural electrode potential measuring method.
Body fluid is a sort of electrolytic solution with pH always kept at 7.4. However, its pH level is adapt to change in a range from 5 to 7.8 due to several causes.
Therefore, activation and adhesion of porous surface were investigated by monitoring changes of sprayed porous films using sample solutions of different pHs.
The experimental results revealed that aluminum with high corrosivity was most compatible with living tissues, whereas a high corrosion resistant nickel porous was incompatible with the living tissues. Implants coated with melt-sprayed film porous containing a high proportion of nickel were discharged from the body within one month.
It was also found that a certain composition of nickel alloys can improve the affinity of implant significantly.

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Intra-Mobile Zylinder(IMZ)implant, a kind of osseointegrated implant, is equipped with Intramobile Element(IME)between the superstructure and the implant. It was reported that IME gave a shock-absorption effect, being similar to that of periodontal tissues. Though IMZ implant is made of pure titanium, IME is consisted of synthesized organic materials, which may be deteriorated or permanently deformed during long-term usage. To confirm this possibility, we observed by SEM the surface configuration of IME which had been used clinically for 1 or 2 years and collected from 3 edentulous patients, and we also analysed extrinsically deposited materials on the surface of IME by means of EDAX. As a result, the following findings were obtained:
1)There were no signs of complete fracture or breakage into the deep part of IME among the IME we collected.2)On the outer-surface of IME, deposited materials containing Ca and P were found,which might be derived from tarter oris or calculus.3)The internal thread of IME was destroyed, while the outer thread of IME was intact.4)It was indicated that a tight fastening between the internal thread of IME and the prosthesis-fastening Screw was loosen because the surface of the internal thread was scratched to be worn off by the relative motion of prosthesis-fastening Screw. 5)Therefore, it is clear that IMZ implant allowed the prosthesis to mobile not only by the physical property of IME but also by loosening of the fastening Screw. These findings suggest that A)IME should be checked periodically and changed at least once a year for maintaining the unique function of IME and B)The present design of IME should be improve to tightly close an avenue from outer environment.

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We made an experimental study on the mandibular reconstruction with porous hydroxyapatite ceramics(HAP)for the purpose of clinical use. Block type of porous apatite was implanted into an artificial defect of dog mandible and the bone formation was examined histologically.
The following results were obtained:New bone formation was observed around the apatite and in the pores one month after the implantation. Bone formation was, however, stopped when a granulation tissue developed between the apatite and mandibular bone in the early stage. Bone formation around the apatite attached to the periosteum was not observed.Although in the area of alveolar bone active new bone formation was observed, it was poor in the area of cortical bone.

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