摘要:

Soft tissues surrounding Brånemark titanium implants and single crystal sapphire implants were studied by conventional light‐ and transmission electron microscopy and by immunohistochemical markers for cytokeratin, protein S‐100, Factor VIII and KP1. Histological sections of biopsies obtained from clinically healthy peri‐implant mucosa were separated into a keratinized outer implant epithelium and an inner, non‐keratinized epithelium, both immunoreactive towards cytokeratin. The inner implant epithelium terminated in a junctional epithelium, apically only a few cell layers thiih. The cells adjacent to the implant showed a condensed cytoplasm, resembling hemidesmosomes. In the underlying connective tissue, rich in fibroblasts and factor VIII immunoreactive blood vessels, the bundles of collagen ran in different directions. S‐100 immunoreactive nerve structures were more frequently found beneath the outer than the inner implant epithelium. Inflammatory cell infiltrates, some KP1 positive, were observed in the apical parts of the inner implant epithelium. S‐100 positive Langerhans' cells were present mainly within the the outer implant epithelium. For the two implant systems, the techniques disclosed no qualitative structural differences in the adjacent

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070101.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

This study involved histometry of the healed tissues around submerged and nonsubmerged dental implants in beagle dogs. In a split‐mouth design, 19 submerged and 19 nonsubmerged commercially pure titanium implants, titanium plasma‐sprayed in the bone anchoring part and smooth in the transmucosal portion were placed in the mandibles of 6 dogs. Oral hygiene was performed 3 times weekly. After 3 months of healing, transmucosal abutments were inserted in the submerged implants. Six weeks after second stage surgery, the dogs were sacrificed and specimens obtained and processed for histology and histometry. Using a light microscope and a digitizing pad, the distance from implant top to mucosa border (DIM), the extent of epithelial downgrowth (ED), the attachment level (AL). the length of connective tissue contact (CTC) and the distance of the first coronal alveolar bone contact from the implant top (DIB) were measured at the mesial and distal aspects. Means+standard deviations for submerged and nonsubmerged implants were calculated, with the dog being the unit of measure. No statistically significant differences between submerged and nonsubmerged implants here found for DIM, CTC and DIB. However, significant differences were observed for ED and AL. This study in beagle dogs indicates that the apical extension of the peri‐implant epithelium is significantly greater and the attachment level significantly lower adjacent to submerged implants with second‐stage transmucosal abutments than in nonsubmerged, one‐stage

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070102.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Using 5 Labrador dogs, certain characteristics of the peri‐implant tissues were analyzed after using a 1‐step surgical procedure for installation of Brånemark® implants. Six titanium implants, 3 in each mandibular quadrant, were installed in the regions of the right and left first molars and the fourth and third premolars. In the right mandibular quadrant, a traditional 2‐step procedure was employed, whilst in the left quadrant, a 1‐step procedure was carried out. The animals were monitored during a 6‐month period. Biopsies of the healed peri‐implant mucosa showed signs of superficial inflammation. The histological analysis revealed that i) the connective tissue lateral to the junctional epithelium showed limited accumulations of inflammatory cells (PICT), and ii) that at implant sites that had been exposed to the oral cavity for 6 months (1‐step implants), an inflammatory cell infiltrate (abutment ICT) consistently was present in the tissues facing the abutment‐fixture junction (AFJ). This infiltrate was separated from the bone crest by a 0.8mm‐wide zone of normal connective tissue. Irrespective of the surgical procedure applied, the radiographic and histometric measurements disclosed that i) the crestal bone loss was about 2.4mm, ii) the height of the peri‐implant mucosa varied from 3.5mm to 3.9mm, iii) the bone crest was located 1.1–1.5 mm apical of AFJ as well as of the apical termination of the junctional epithelium (aJE), and iv) a junctional epithelium of 2.1–2.4mm faced the implant surface. In conclusion, this study demonstrates that, using a dog model, titanium dental implants ad modum Branemark installed according to a 1‐step or to a 2‐step surgical procedure will obtain similar soft tissue adaptation and proper bone anchorage (osseointegration). Further studies are, however, required to ascertain the long‐term clinical fea

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070103.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

This study compared osteoblast proliferation, differentiation, and protein synthesis on new and used titanium (Ti) disks to test the hypothesis that cleaning and resterilization of previously used Ti disks does not alter cell response to a particular surface. Ti disks of varying roughness were prepared by one of five different treatment regimens. Standard tissue culture plastic was used as a control. Human osteoblast‐like cells (MG63) were cultured on the Ti disks and cell proliferation, cell differentiation, RNA synthesis and matrix production (collagen and noncollagen protein; proteoglycans) measured. After their first use, the disks were cleaned, re‐sterilized by autoclaving. and MG63 cells cultured on them as before. At confluence, the same parameters were measured and cell behaviour on new and used disks compared. When confluent cultures of cells on plastic were compared to those cultured on new Ti surfaces, cell number was reduced on the roughest surfaces and equivalent to plastic on the other surfaces. Cell number was further reduced when disks with the roughest surfaces were re‐used; no differences in cell number could be discerned after cleaning and re‐sterilization. Cell proliferation was inversely related to surface roughness and was less than seen on tissue culture plastic. Re‐use of the Ti disks resulted in no change in cell proliferation rate. Alkaline phosphatase specific activity in isolated cells was lowest on the rougher surfaces; no differences between new and used disks were observed. Similarly, enzyme activity in the cell layer was decreased in cultures grown on rougher surfaces, with no effect of prior disk use being noted. RNA synthesis was decreased with respect to plastic in cultures on smoother surfaces and increased on rougher surfaces; prior disk use did not alter RNA synthesis. Collagen production by the cells was decreased on smoother surfaces, but was comparable to tissue culture plastic when grown on rougher surfaces. Non‐collagen protein production was unaffected by culture surface and whether or not the disk had been previously used. Proteoglycan synthesis by cells was decreased on all surfaces studied and comparable on both new and used disks. The results of this study indicate that Ti implant surfaces are unaffected by cleaning and resterilization, although rougher surfaces may require more extensive cleaning than smoother ones. This suggests the possibility that implants, in the same patient, could be safely reused.In vivostudies in animals, however, need to be performed before clinical application can be

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070104.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

The aim of the present experiment was to test a novel model system, designed to obtain human specimens of regenerated and also newly generated jaw bone, for the study of the biological events under a variety of conditions. Following information and disclosure of possible risks associated with a minor oral surgical procedure, 9 systemically healthy subjects (5 men, 4 women, mean age 31.7 years) signed consent forms and volunteered to participate in this study. Hollow test cylinders with an outer diameter of 3.5mm, an inner diameter of 2.5mm, and 4mm in height were used. They were manufactured from commercially pure titanium and exhibited a highly polished inner surface and a titanium plasma sprayed outer rough surface. A mucoperiosteal flap was raised in the retromolar area of the mandible corresponding to standard retained third molar surgery. Following flap reflection a standardized hole was drilled through the cortical bone into the bone marrow using round burs. The congruent test cylinders were firmly placed into the prepared bony bed yielding primary stability. One‐and‐a‐half to 2mm of the test device were submerged below the level of the surrounding bone, while the remainder surpassed the level of the bone surface. The bone‐facing end of the cylinder was left open, while the coronal soft tissue facing end was closed by an ePTFE‐membrane. The flap was sutured to obtain primary wound closure. In order to prevent infection, penicillin was prescribed systemically and oral rinses of chlorhexidine were administered. After 2, 7, and 12 weeks one test device including the regenerated tissue was surgically harvested, while after 16, 24 and 36 weeks respectively, 2 devices were harvested and processed for soft or hard tissue histology or histochemistry. The two surgical procedures and the presence of the test cylinders during the time of healing were well tolerated by the volunteers. In all 9 subjects generated tissue could successfully be harvested. The tissue generated after 2 and 7 weeks presented with a cylindrical shape, whereas the specimens harvested at 12 weeks and thereafter resembled the form of an hourglass. Specimens of 12 weeks and less regeneration time were almost entirely comprised of soft tissue, while specimens with regeneration time of 4 months and more were composed of both soft and increasing amounts of mineralized tissue. It is concluded that the presented model system is suitable to study temporal dynamics and tissue physiology of bone re‐generation in humans with minimal risk for complications or adverse effects to the

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070105.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

The aim of the present study was to determine the tactile pressure thresholds perceived with dental implants during a three‐month healing phase following implant placement (osseointegration phase). The absolute threshold of tactile perception was measured in a group of patients 1 week, 1.2 and 3 months following implant placement (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland). Contralateral and neighbouring teeth were measured at the same time. For determination of the axial forces exerted on the implants and teeth, an electronic device with semi‐conductor strain gauges was used (Hämmerle et al. 1995). The results demonstrated mean thresholds of tactile perception for the implants of 160.2g (SD 61.7 g, range 77–283g) at 1 week, 133.4g (SD 5 1.9g, range 32–239g) at 1 month, 147.9g (SD 53.5g. range 70–257g) at 2 months, and 146.9g (SD 57.4g, range 77–248g) at 3 months. Statistical analysis using Student's paired t‐test revealed no significant differences between the values over time. The control teeth exhibited mean values for tactile perception of 13.1g (SD 9.6g, range 5–47g) at 1 week, 10.2g (SD 6.4g, range 4–29g) at 1 month, 14.8g (SD 15.9g, range 2–58g) at 2 months, and 15.4g (SD 12.2g, range 3–36g) at 3 months. Again, these values did not differ significantly from each other and indicated the absence of systemic alterations in perceived pressure threshold over the observation period. The mean perceived pressure threshold was more than 10 times higher for implants than for natural teeth (P<0.001) at all observation times. It is concluded that the absolute threshold of tactile perception with dental implants during the phase of osseointegration is not affected by bone and soft tissue healing taking place

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070106.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

In a combinedin vitroandin vivostudy strain gauges were used to register the deformation in two terminal implant abutment cylinders, when connecting three different prosthetic appliances. The prosthetic constructions were placed on the abutments and fastened bothin vitroandin vivoby using different torque sequences. Furthermore, in the in vitro situation the three medial abutments were replaced by abutments which were 100 μm shorter.The results show that even if the prosthetic constructions were judged to have a good clinical fit, relatively large External Preloads were registered bothin vitroandin vivo. No significant differences in axial force or in bending moment were found between the torque sequencesin vivo. There were, however, significant differences in axial force as well as in bending moment in thein vitroexperiment. When the shorter medial abutments were used in vitro, a change in the axial force of approximately 200N was registered. The results confirm that the methodological approach used in this study is valid when evaluating preloads

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070107.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

The aim of the present study was to evaluate surface alterations on titanium implant necks subsequent to different prophylaxis procedures. Fifty ITI implants were utilized. Forty implants were treated with 10 different prophylaxis procedures (ultrasonic scaler, plastic tip ultrasonic scaler, stainless steel curette, titanium curette, teflon curette, air powered system, abrasive rubber cups, polishing rubber cup and brush), and 10 implants were left as untreated controls. Surface alterations were studied on an area of 1mm×0.9mm and quantified using optical microscopic, SEM and laser prophylometer analysis. The use of the laser prophylometer provided an objective criterion for evaluation, expressing implant neck surface alterations in numeric values in terms of two roughness indexes, Ra and Rz. The results showed that, in comparison with the controls (Ra=0.50; Rz=3.98) the procedures investigated could be divided into 3 main groups:1) Methods which altered the implant neck surface producing increased roughness (Ra=0.68–2.08; Rz=4.68–11.92);2) Methods which left the implant neck surface unaltered (Ra=0.44–0.57: Rz=0.42–3.46);3) Methods resulting in a smoothening of the implant neck surface (Ra=0.36; Rz=2.15).Group 1 included procedures that should be avoided. However, it appeared safe to apply the procedures of groups 2 and 3. To confirm these results, it will be necessary to evaluate the plaque‐ and calculus‐removing efficacy from titanium neck implant sur

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070108.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Osseointegrated dental implants have now become an accepted form of treatment for patients with a fully or partially missing dentition. The purpose of this study was to evaluate the performance of 3i threaded and cylindrical implants. During a 5‐year period, a total of 1969 3i endosseous implants were placed at 6 centers in the United States and 2 elsewhere in the edentulous and partially edentulous jaws of 653 consecutive patients ranging in age from 18 to 82 years. Of the total number of implants placed, 1341 were commercially pure titanium threaded implants and 628 were titanium plasma‐sprayed implants with a cylindrical configuration. A total of 28 patients with 110 implants were lost to follow‐up. Implants in these patients were considered neither a success nor a failure. Success was predicated on the osseointegration of each and every implant followed in this analysis rather than the persistence of prosthetic function. Confirmed bone anchorage was considered essential for success. A total of 625 patients with 1871 implants remain in the study with a follow‐up period ranging from 6 to 60 months. A total of 93 implants (5.0% of the total implants followed) were considered as failures. A mean implant survival rate was 95.0% for both the threaded and the cylindrical implant was calculated. The success rate of threaded implants was 97.0% in the mandible and 93.8% in the maxilla. The success rate for the 3.3mm cylindrical implants was 96.0% in the mandible and 95.5% in the maxilla, and the success rate of 4.0mm diameter cylindrical implants was 95% in the mandible and 92.0% in the maxilla. Causes of failure consisted of loss of osseointegration 2.3%crestal bone loss requiring periodontal therapy after the first year of function 1.7% and mechanical problems associated with the prosthesis 0.9%. This retrospective analysis of the 3i endosseous implant system is comparable to previous reports on other implant systems in terms of implant survival and prosthesis stability. It is demonstrated that 3i implants are predictable and can provide lasting osseointegration leading to improvement of oral function if the recommended surgical and restorative protocol is f

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070109.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY