摘要:

The aim of this investigation was to evaluate whether augmentation of intramembraneous bone beyond the skeletal envelope can be predictably achieved by placing a completely occlusive barrier on the skull bone of rabbits, hereby creating a secluded space with bone tissue being the only adjoining tissue. The experiment was carried out in 3 New Zealand white rabbits. In each animal, a midline incision was made down to the bone surface of the skull and a skin‐periosteal flap was raised to expose the skull bone on both sides of the midline. Two prefabricated titanium domes with an inner diameter of 4.5 mm and an inner height of 3.0 mm were installed on each side. The domes were supplied with a horizontal, peripheral flange and a vertical edge, fitting tightly into a circular slit, prepared by a trephine into the skull bone. This arrangement ensured a stable anchorage of the dome and a reliable peripheral sealing of the space. The skin‐periosteal flaps were relocated to cover the domes and sutured. After a healing period of 3 months, the animals were killed and the experimental areas excised and prepared for histological transversal ground sections with each dome in situ. The results demonstrated complete bone fill of all domes, with no signs of ingrowth of other types of tissues, indicating that the use of a barrier with total occlusiveness, sufficient stiffness and stability and reliable peripheral sealing will result in predictable bone augmentation of spaces also beyond the skeletal envel

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060201.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The Periotest values of mandibular implants, registered before and after loading by overdentures, were compared. Thirty edentulous patients with 60 Bonefit ITI implants were selected with an average age of 69 years. The Periotest values were measured 1) after a healing period of 3 months and 2) after the overdentures had been worn for a period of 12 months. Periodontal parameters were recorded at both examinations. Furthermore, 17 biopsies of mandibular bone taken from the implant sites during implant surgery were analyzed to assess the bone density. The histomorphometric evaluation was done using a point count method. At the end of the healing period. all registered Periotest values were negative, ranging from −1 to −8 with an average of 4.08. One year later, all measurements showed negative values again, ranging from −2 to −8 with an average of 4.97. The difference was statistically significant. Seventeen biopsies of mandibular bone were evaluated to determine the density. The range of bone density was from 22.4% and 90.9%. There was no correlation found between bone density and Periotest values. However, a significant correlation could be observed between mandibular atrophy and bone

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060202.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The aim of this study was to determine the threshold of tactile perception of endosseous dental implants and to assess the relative difference of that threshold between implants and teeth. Twenty‐two subjects with implants of the ITI® Dental Implant System were included in the study. All implants served as abutments for single tooth crowns and had been in function for a minimum of 1 year. A strain gauge glued to the shaft of an amalgam plugger served as a force sensor. It transformed the elastic deformation exerted onto the shaft into an electronic signal for recording. By use of the amalgam plugger, a continuously increasing force was exercised on the implants or teeth until the first sensation of touch was indicated by the patient. Statistical analysis revealed threshold values for the implants ranging from 13.2 to 189.4g (1g=0.0lN)(mean 100.6; SD 47.7), while a range of 1.2 to 26.2g (mean 11.5; SD 11.5) was found for control teeth. Thus, the mean threshold values for implants were 8.75 times higher than for teeth. This difference was highly statistically significant. A general linear models procedure was applied to determine the influence of patient age, jaw, implant position and the threshold values of teeth on the measurements obtained for implants. Only gender and the threshold values for contralateral teeth had a significant influence. These 2 parameters together explained 27% of the variability in threshold measurements. It is concluded that a more than 8‐fold higher threshold value for tactile perception exists for implants compared with t

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060203.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

This study aims at evaluating an objective method for the description of bone structure in the human mandible. Human bone biopsies were harvested at mandibular implant sites prior to insertion of self‐tapping Mark II fixtures. Altogether 15 biopsies were taken from 12 patients. Three patients donated 2 biopsies each, one proximally and one distally taken. Ground sections of about 100μm thickness were prepared prior to microradiography. These sections were ground to a final thickness of about 10μm followed by histological staining. Histomorphometrical analyses were performed on the microradiographed plates and on the ground sections. On average there was a bone area of about 54% calculated on the microradiographed plates (the 100‐μm sections) versus a mean bone area of 62% light microscopically (the 10‐μm sections). Bone lengths were calculated on the 10‐μm sections in the central part (mid‐line) and on each side of the mid‐line, revealing a mean of 58% in the former case and a mean of 61% in the latter case. The amount of bone varied between individuals and in different locations of the same jaw. The postoperative healing period following fixture installation is standardized regardless of bone structure. It may in the future be appropriate to more individualize this healing period based on an objective bo

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060204.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

Before implant surgery in the mandibular side segment, it is of utmost interest to locate the mandibular canal in radiographs to avoid interference with the neurovascular bundle during surgery. Six mandibular specimens were radiographically examined with 2 panoramic and 3 tomographic techniques. The distances between the superior border of the canal and the alveolar crest and between the mandibular base and the inferior border of the canal were measured. In addition, the height of the canal was measured. The measurements were performed by 3 or 4 observers and compared with measurements on contact radiographs of the same areas. Tomography gave more accurate values of the above distances than panoramic techniaues. The variation between observers in detecting the mandibular canal Aas large.

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060205.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

In 8 monkeys both the maxillary lateral incisors were extracted. In the 16 extraction sites an Al2O3‐ceramic dental implant (Frialit®) was immediately inserted. Eight implants were submerged under the oral mucosa and the other 8 were allowed to penetrate through the mucosa during the observation period. None of the implants was loaded during the observation periods. After experimental periods of 1, 2, 4 and 8 months, the interface region between the implant and bone was examined using scanning‐electron microscopy, X‐ray microanalysis, back scatter, microradiography and light microscopy. The results showed that osseointegration of Al2O3‐ceramic dental implant was obtained. The newly formed bone around the implant filled exactly the contours of the implant. Newly formed bone had a mineral content and a phosphorus‐to‐calcium ratio similar to that of the adjacent older mature jaw bone. There were no differences in the osseointegration rate between the submerged and the nonsubmerged implants. No leakage of aluminium from the implant could be detected

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060206.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The clinical question at issue, whether it is possible to combine implants and natural teeth via fixed bridges, is of current interest. The treatment of the subjects of this prospective study was performed between June 1984 and December 1986. This article presents the 5‐year results of the study. The consecutive patient material comprised 23 patients with Applegate Kennedy Class I residual dentition in the mandible and a complete maxillary denture. All 23 patients were provided with implants ad modum Bråemark in each mandibular quadrant. One side was randomized to rehabilitation with fixed bridge between the distal tooth of the residual dentition and an implant; the other side received a free‐standang bridge on2 implants. The fixture survival rate was 88%. No difference was found between the two sides. Bridge stability was 89% for the implant bridges and 91% for the combination bridges. The change in marginal bone level at the implants was small during the 5‐year follow up period (on average 0.1–0.3 mm) and with no difference between the two sides. In conclusion, it was not possible to demonstrate any higher risk of implant or prosthetic failure for tooth‐implant fixed bridges compared with implant‐suppo

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060207.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The aim of the present prospective clinical study was to analyze the feasibility of inserting Brånemark fixtures according to a one‐stage procedure including transmucosal healing and to subsequently evaluate the predictability of osseointegration as well as the potential of such implants for stabilizing complete overdentures in the edentulous mandible. Five patients (2 women, 3 men), completely edentulous in the mandible and with a mean age of 60 years, volunteered for this study. Two fixtures of various length Lpar;10–20 mm) and 3.75 mm in diameter were inserted in the lower canine regions. A standard surgical procedure including a mid‐crestal incision was used. After the placement of the fixtures, healing abutments, which are normally used during second‐stage surgery, were inserted instead of the usual cover screws. Three months after implant placement a clinical and radiographic examination was performed to confirm the presence or absence of osseointegration of the fixtures prior to exchanging the healing abutments with the spherical attachments. Finally, different clinical (Plaque Index, Bleeding Index, probing depth, Periotest® mobility) and radiographic (bone loss, peri‐implant radiolucency) parameters were recorded 9 months after loading of the fixtures by means of a complete mandibular overdenture, retained by two ball attachments in the canine regions. All fixtures were perfectly stable (mean Periotest values of −2) and presented favorable peri‐implant soft tissue conditions, and no patient was complaining about any particular symptom. As far as retention and stability of their implant supported overdenture was concerned, the participants without exception considered the therapeutic result as being perfectly adequate. The evaluation of the radiographic analysis showed a similar initial bone loss rate as reported in the literature for a submerged surgical procedure. Therefore, within the specific limits of this study. it may be concluded that Brånemark fixtures can be inserted using a single‐step surgical protocol predictably leading to successful osseointegration and subsequently provide similar peri‐implant results as reported for the traditional two stage technique. However, a longer period of observation as well as a more significant number of cases will be necessary to confirm these promis

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060208.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY