Journal of Japanese Society of Oral Implantology
Online ISSN : 2187-9117
Print ISSN : 0914-6695
ISSN-L : 0914-6695
Volume 8 , Issue 2
Showing 1-14 articles out of 14 articles from the selected issue
  • Yasuyuki Horisaka, Hideo Kanitani, Rudi Wigianto, Reiko Kohno, Masanob ...
    1995 Volume 8 Issue 2 Pages 121-125
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Currently, osteointegrated implants are commonly used. In this study, the effects of osteoporosis on the bone around the implant was observed. Hydroxyapatite implants were inserted in the tibiae of female adult rats and then ovariectomized. One, 2 and 4 months after ovariectomy, the bone around the implants were observed histologically. In the experimental group, the bone to implant contact ratio was lower than that in the control group. At the substansia compacta, the implants were connected to the bone but at the substansia spongiosa, they were almost covered by connective tissues, and the surface of the implants were irregular in places. These findings suggested that the convalescence of the implants should be observed carefully during osteoporosis.
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  • ―Part 1. Development of a Temperature Indicator―
    Takeshi Yanase, Mitsuo Sasaki, Yutaka Yoshida, Yoshitsugu Ootsuka, Eis ...
    1995 Volume 8 Issue 2 Pages 126-131
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    A shape memory implant (SMI) temperature indicator with the functions stated below was developed as a peripheral instrument to promote the clinical success of SMI.
    1. Temperature within the range of 40-46℃ was measured to an accuracy of 0.2℃ on a real time basis and was displayed in an easy-to-read form to the operator.
    2. The temperature of the perfusion solution just before perfusion to the channel and just after applying heat energy to the SMI can be measured.
    3. Operation is simple and safe.
    This device permits anyone to simply and accurately monitor temperature, a task that previously required the experience and skill of the operator.
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  • Importance of Retainers
    Hiroyuki Yamamoto, Shogo Kanda, Michiko Miyata
    1995 Volume 8 Issue 2 Pages 132-136
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Clinical application of implants to young patients has been considered relatively as a contraindication. In Western countries, however, implants have been recently clinically applied to congenital dental defects in young patients, with an understanding that if the permanent dental arch is already completed, implant embedding will not cause any problem.
    We report herein our experience of a patient who was considered to have an indication of single POI two-piece implant construction. At 16 years of age,this male patient underwent embedding of a real implant in the right side of the mandible.
    After surgery, this patient did not visit the hospital for 2 years, although we repeatedly requested him to come to the hospital. During this period, he lost a retainer. Through this experience, we again realized the importance of retainers and the following conclusion was reached. In young patients, two types of retainer may be necessary, namely, a removable retainer which is used during off-load period and a retainer removable by an operating surgeon for observation until the end of developmental growth.
    In addition, in young patients, we routinely attach the final supplementation on the assumption that it does not connect to the natural teeth. However, it is desirable from the clinical point of view to observe the patient's clinical course until the end of developmental growth, using a retainer removable by an operating surgeon as in the present case.
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  • Part 1. Influence of Structures of Stud Attachment on Stress Distribution to Implants and Submucosal Bone
    Tetsuo Ichikawa, Rudi Wigianto, Hideo Kanitani, Masanobu Horiuchi, Nao ...
    1995 Volume 8 Issue 2 Pages 136-142
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    We made an acrylic resin mandibular edentulous model by placing two Apaceram® implants (RS 0490, Pentax, Tokyo) in bilateral canine regions. Four strain gauges were placed on the resin surface around the right implant. A load cell was embedded in the right molar alveolar ridge. The rubber base material was covered with the model surface representing the oral mucous. An acrylic mandibular complete denture was constructed on the model. As the attachment for the connection between the implant and the denture, a magnetic attachment (M), our original ball attachment (B), a magnetic attachment with a magnet surrounded by a stress-breaking material (D), and no attachment as a control (C) were used. Static load of 500 N was applied to three loading sites (“Center”,“ Right”and“Left”) of the experimental denture.Dynamic load was applied by dropping a 20 g metal rod on“Center”site from 30 mm in height. The stress transferred to the molar region and the strains around the implant were examined when either static or dynamic load was applied.
    The results were as follows:
    1.When static load was applied,
    1)The stress transferred to the molar region decreased in the order of C, D, B and M, and the strains around the implant increased in that order.
    2)Loading site affected the stress and strains.The influence on the stress decreased in the order of C,D, B and M, and the influence on the strains increased in that order.
    2.The result of applying a dynamic load was almost corresponded to that of a static load. Influence of structure of stud attachments in dynamic load was lower than that of a static load.
    In case of implant-supported overdenture, the structure of stud attachments affected the stress and strains. The overall findings suggested that the occlusal stress had a tendency to concentrate in the implant.
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  • Two Dimensional Finite Element Analysis and a Clinical Case
    Kenji Nishimura, Naoyuki Shinohara, Kei Murakami, Tetsuo Wakuta, Takat ...
    1995 Volume 8 Issue 2 Pages 143-151
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    A removable partial denture (RPD) is supported by residual teeth and edentulous alveolar ridge. To preserve the health of remaining oral structures and to restore their functions, the RPD must be designed to distribute retentive forces among the residual teeth and edentulous alveolar ridge properly.
    However, previous designs do not seem to be able to yield the proper distribution of retentive forces,which leads to the irreversible changes of the retentive teeth and edentulous alveolar ridge. Especially, in the major edentulous cases like Eichner Class B-2 classified by Eichner method, the movement of the RPD is large in the edentulous areas, and the absorption of the edentulous alveolar ridge is aggravated.
    Therefore, we planned an overdenture with osseointegrated implant fixed in edentulous areas, which is supposed to decrease the movement of the denture and to limit the absorption of the edentulous alveolar ridge. A two-dimensional finite element technique was used to analyze the implant overdenture (IOD) which was set on the edentulous alveolar ridge side.
    The results obtained by the finite element analysis were as follows:
    1. The values of the movement of the RPD were about four times larger than those of the IOD.
    2. The von Mises stresses of the soft tissues in the edentulous areas of the RPD were about four times larger than those of the IOD.
    3. The maximum principal stresses of the alveolar bone in the edentulous areas of the RPD were about four times larger than those of the IOD.
    4. It is suggested that the clinical application of the overdenture with osseointegrated implant fixed in the edentulous areas is effective to decrease the movement of the overdenture and to limit the absorption of the edentulous alveolar ridge.
    Based on this analysis, the IOD was clinically applied. The present clinical case confirms that the movement of the IOD is smaller and the IOD is more stable than the RPD and that the absorption of the residual alveolar bone has not occurred.
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  • A Case Report of Application to High Dose Irradiated Mandible
    Kazumi Uehara, Satoshi Umino, Nobuyuki Mizuki, Hiroki Hayakawa
    1995 Volume 8 Issue 2 Pages 152-161
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Conventional implants are not suitable for the mandible which was reconstructed with apatite block, because it reduces blood circulation. It was previously confirmed in an experimental study that implant with iliac bone was effective even in the mandible under a poor condition. An irradiated mandible is also unfavorable for implantation due to the same reason. According to our experimental results, it was suggested that implant with iliac bone could be applicable for irradiated mandible. We modified the method of implant with iliac bone which we confirmed in a previous experimental study.
    A 63-year-old man with tongue carcinoma underwent the first clinical transplantation of implant with iliac bone. He had received 70 Gy of interstitial irradiation therapy, 90 Gy of external irradiation therapy, chemotherapy and partial glossectomy with radical neck dissection.
    Six apatite implants (4 mm in diameter, 9 mm in length) were inserted into the right iliac bone. After 6 months,4 implants were removed with a modified trephine bur and were immediately transplanted into the irradiated mandible. The time interval between irradiation therapy and transplantation was 32 months. Three months later, abutments were connected to each implant, and finally bone-anchored full bridge prosthesis was set. After the transplantation, there was no evidence of active symptom of inflammation after an elapse of 30 months.
    The results were as follows:
    1. The improvements of this method were designing of trephine bur and guide, bone thickness of the implant with iliac bone and the method of cutting between bottom layer of implants and ilium.It was easy to prepare the implant with iliac bone in consequence.
    2. Conventional implants were distinctly contraindicated in high dose irradiated mandible. However it was confirmed that this method of implant with iliac bone could be applied safely to these severe cases.
    3. It was suggested that indications of this method were not only the poor quality of bone, but also the small quantity of bone.
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  • ITI Bonefit® Implants
    Jyoji Tanaka, Shuhei Torii, Takeshi Kashiwabara, Shogo Shioji, Shukich ...
    1995 Volume 8 Issue 2 Pages 162-168
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Magnetic attachments have been reported to have many advantages when used as denture retainers.One such advantage is the elimination of excessive stress on the abutment teeth at the time of insertion and removal of dentures. In this study, we clinically used magnetic attachments for ITI Bonefit® implants. The following methods were devised and clinically applied as techniques for connecting the keeper to the implant body.
    Method 1. An impression is taken of the implant body in the oral cavity. The root cap is then prepared by casting and attached with a cementing agent.
    Method 2. The root cap is cast using a ground extended healing cap and connected with a screw.
    Method 3. The extended healing cap is ground,and the root cap is then prepared with composite resin and connected with a screw.
    Magnetic attachments are non-directional during insertion and removal of dentures. Therefore,these may be used when implants cannot be placed in an ideal position or direction owing to conditions such as residual bone. Magnetic attachments are also very useful clinically for dental implants because they avoid excessive stress on the implant body.
    With regard to the methods for connecting the keeper, method 1 is good in terms of its ease of preparation. However, the method using an extended healing cap is considered to be best with respect to compatibility with the implant body,prevention of effects on MRI, one of the problems of magnetic attachments, and the possibility to modify the superstructure. When the direction of implant placement is good, method 3, in which the casting does not place strain on the extended healing cap, is preferred. When the direction of implant placement in poor, method 2 is suitable.
    Better outcomes of implant therapy can be achieved by selecting one of these three methods depending on the placement status of the implant body.
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  • Takashi Tejima
    1995 Volume 8 Issue 2 Pages 169-175
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Subperiosteal implants are indicated for patients for whom endosteal implants cannot be used in the maxillary molar region. This paper describes the clinical evaluation of subperiosteal implants in that region.
    Subjects and methods
    At our clinic, 25 patients underwent subperiosteal implant operation in the maxillary molar region. Eighteen who responded to regular recalls were enrolled in this study. Subperiosteal implants were evaluated basically by the method of Abe et al.(1990). Evaluation was based on pocket formation around the head, inflammation of surrounding tissue at subperiosteal implants, implant mobility, resorption of alveolar bone around subperiosteal implants and frame exposure. These were comprehensively assessed, and the results were categorized into four grades(Grade 1-4). The feeling of satisfaction with the treatment was also evaluated.
    Results
    In comprehensive assessment,12 cases were categorized as Grade 1, three as Grade 2, two as Grade 3 and one as Grade 4. On examining the feeling of satisfaction, one patient expressed dissatisfaction but did not desire to have the implants removed.
    Conclusion
    The total ratio of Grades 1 and 2, clinically judged as “excellent” and “good” respectively, amounted to 83.3%. Of the 18 patients including the case of implant-removal,16(88.9%) were found generally satisfied with the treatment. This result almost agreed with the result of comprehensive assessment.
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  • Takeshi Okamoto, Kentaro Kaikawa, Yasuhiro Yamanaka, Osami Koide, Hiro ...
    1995 Volume 8 Issue 2 Pages 176-180
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Several surgical procedures, which have been employed when installing the implant body in recent years, are free gingival graft, vestibular extension or frenectomy to acquire adequate keratinized attached gingiva, autogenous or artifical bone graft to expand the width or supplement the bony defect in the surgical area, or GTR procedure to improve the peri-implant environment more aggressively.
    In order to prevent the onset of peri-implantitis, the thickness of the alveolar mucosa around the implant body neck was observed and the middle layer connective tissue of the submucosa, in cases with thick alveolar mucosa, was removed to reduce the size of the pouch around the implant body neck,and good prognosis was obtained.
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  • ―Agar Diffusion Method―
    Seiho Fukuyo, Toshikuni Masukawa, Hiroyasu Nakazato, Sumiko Matsuura, ...
    1995 Volume 8 Issue 2 Pages 181-185
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    The Ti-Ni shape memory alloy has favorable biocompatibility. The shape memory alloy exhibit unique deformation behavior such as the shape memory effect.
    The authors developed the Shape Memory Implant with excellent effects in clinical use.
    However, some reports are presented on the uncertainty of bio-effect ively of Nickel. Therefore,this in-vitro test using cell culture to determine general cytotoxic effects of the Ti-Ni shape memory alloy.
    The agar diffusion method was used for cytotoxic screening of this alloy. This in vitro test uses cell culture to determine the cytotoxic effect of sample on discolaration and disintegration.
    As a result, there are no detected cytotoxic effects on test samples of Ti-Ni alloy and negative collated sample of pure Titanium.
    The cytotoxic effect on pure Nickel was quite modest.
    In addition, the positive collated sample of Asbestos strongly indicated cytotoxic effects.
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  • Kiyoshi Tagawa, Tomoko Kurotani, Taketo Shimizu, Tsuyoshi Kato, Hirota ...
    1995 Volume 8 Issue 2 Pages 186-191
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    In clinical levels, the prosthetic restoration of edentulous mandibles with severe alveolar ridge atrophy cause numerous problems.
    This report concerns a successful case in which the root form Shape Memory Implant was used Perio Root Implant(P.R.I.).
    In this case, five pieces of PT type of P.R.I. were implanted between left and right mental foramens.
    These implants were combined to the fixed removable bridge by samarium-cobalt magnets.
    The patient has been healthy for 3 years and 6 months since the operation. The PT type of P.R.I.bulges and expands at one-third of the apical area by the shape memory function after implantation.This is an osteo-integrated type implant which is expected to obtain good primary fixation and continue supporting occlusal forces.
    There are four kinds of P.R.I., P-type, PS-type,PI-type, and PT-type. They are used according to the condition of the clinical case.
    In conclusion, the type of P.R.I. is useful for prosthetic restoration of Anodontia.
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  • Part 1. Osseointegration of Implanted 262 Fixtures
    Shigeru Fujino
    1995 Volume 8 Issue 2 Pages 192-200
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Thirty years have passed since the Osseointegrated Implant System was developed, and it has been used mainly for rehabilitation of stomatographic function. In Japan, the clinical application of the system has been gradually popularized.
    Thus this report was made to describe the use of this system in a prospective study of 65 patients,between 25 and 85 years of age, from 1989 to 1994,and total of 262 fixtures were implanted.
    During the observation period, from fixtures insertion to abutment connection, non acquired Osseointegration 14 fixtures were checked, and 4 of these fixtures were removed due to loss of their osseointegration after superstructures were fitted. The implant survival rate was 94.4%at abutment connection operation, and after superstructures were fitted, the implant survival rate was 97.5%. For 5 years, the cumulative survival rate of implants was 92.1%.
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  • Part 2. Clinical Problems in Superstructures
    Shigeru Fujino
    1995 Volume 8 Issue 2 Pages 201-208
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    From 1989 to 1994, using the Osseointegrated Implant System, a total of 262 fixtures were implanted in 65 patients.
    For 5 years, the cumulative survival rate of implants was 92.1%.
    4 cases of overdentures and 66 cases of bridge type for a total of 70 superstructures were fitted to the implants in the maxilla and mandible.
    During the observation period, clinical structural problems, that is, broken artificial teeth 8, fractured gold screw 2 and fractured abutment screw 1 in the superstructures occurred in 11 cases. Other clinically functional problems occurred in 3 cases,that is, trouble of pronunciation 1, aesthetic problem 1, and difficult situation of implants cleaning 1. In this report I studied the problems of the design and manufacture, the point of contact during pronunciation, aesthetics, and condition of implant maintenance.
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  • ――Placing 13 mm Metal Guide Pin in Jaw Bones Actually――
    Yasufumi Kawaue, Shigehiro Yamauti, Kazuo Inoki, Manami Kawamoto, Yasu ...
    1995 Volume 8 Issue 2 Pages 209-218
    Published: September 30, 1995
    Released: February 15, 2018
    JOURNALS FREE ACCESS
    Currently, three-dimensional image of jaw bones are required in implant operation. Previously, we recognized this concept and performed Multilayer Cross-sectional Tomography of jaw bones with a 13-mm metal guide pin placed in jaw bones. The relationship of fixtures with anatomical structures(maxillary sinus, mandibular canal, lingual cortex etc.)can be obtained by this tomography.
    In this article, the advantage of our method, typical clinical cases and comparison with different methods of other institutions are presented. CT scanning is used frequently in diagnosis of jaw bones, but Multilayer Cross-sectional Tomography is considered to be more useful than CT scanning. Exact CT scanning can show jaw bones more precisely and offer more detail information. However, in CT scanning, guide pin made from metal fragments cannot be used.
    In implant surgery, obtaining the relationship of jaw bones and anatomical structure with fixtures is more useful than obtaining the detailed shape of jaw bones.
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