摘要:

The microbiota associated with ligature‐induced marginal inflammation around osseointegrated dental implants, ankylosed teeth, and normal control teeth was investigated in 8 cynomolgus monkeys(Macaca fascicularis). Submucosa;/subgingival plaque was sampled with paper points on the day of ligature placement and after 7 weeks. The samples were evaluated by phase‐contrast microscopy and by cultivation on enriched non‐selective and various selective solid media. The submucosal/subgingival flora was changed 7 weeks after ligation. The total number of cultivable bacteria and the proportions of motile rods, anaerobic Gram‐negative rods, black‐pigmented rods, Porphyromonas gingivalis, and Prevotella intermedia increased significantly around implants, ankylosed teeth, and normal control teeth. Except for a significantly higher proportion of anaerobic Gram‐positive cocci around implants compared to ankylosed teeth and normal control teeth at the end of the study, no significant microbiological differences were observed between implants, ankylosed teeth, and normal control teeth neither at baseline nor at the end of the study. Consequently, the microbiota associated with marginal inflammation around implants, ankylosed teeth, and normal control teeth appears to he rather similar in cynomol

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070301.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Bacterial adhesion to intra‐oral, hard surfaces is firmly influenced by the surface roughness of these structures. Previous studies showed a remarkable higher subgingival bacterial load on rough surfaces when compared to smooth sites. More recently, the additional effect of a further smoothening of intra‐oral hard surfaces on clinical and microbiological parameters was examined in a short‐term experiment. The results indicated that a reduction in surface roughness belowRa=0.2 μm, the so‐called “thresholdRa”, had no further effect on the quantitative/qualitative microbiological adhesion or colonisation, neither supra‐ nor subgingivally. This study aims to examine the long‐term effects of smoothening immoral hard transgingival surfaces. In 6 patients expecting an overdenture in the lower jaw, supported by endosseus titanium implants, 2 different abutments (transmucosal part of the implant): a standard machined titanium (Ra=0.2 μm) and one highly polished and made of a ceramic material (Ra=0.06 μm) were randomly installed. After 3 months of intra‐oral exposure, supra‐ and subgingival plaque samples from both abutments were compared with each other by means of differential phase‐contrast microscopy (DPCM). Clinical periodontal parameters (probing depth, gingival recession, bleeding upon probing and Periotest‐value) were recorded around each abutment. After 12 months. the supra‐ and subgingival samples were additionally cultured in aerobic, CO,‐enriched and anaerobic conditions. The same clinical parameters as at the 3‐month interval were recorded after 12 months. At 3 months, spirochetes and motile organisms were only detected subgingivally around the titanium abutments. After 12 months, however, both abutment‐types harboured equal proportions of spirochetes and motile organisms, both supra‐ and sub‐gingivally. The microbial culturing (month 12) failed to detect large interabutment differences. The differences in number of colony forming units (aerobic and anaerobic) were within one division of a logarithmic scale. The aerobic culture data showed a higher proportion of Gram‐negative organisms in the subgingival flora of the rougher abutments. From the group of potentially “pathogenic” bacteria, onlyPrevotellu inter‐mediaandFusobacterium nucleatumwere detected after anaerobic culturing and again the inter‐abutment differences were negligible. Clinically, the smoothest abutment showed a slightly higher increase in probing depth between months 3 and 12, and more bleeding on probing. The present results confirm the findings of our previous short‐term study, indicating that a further reduction of the surface roughness, below a certain “thresholdRa”(0.2 μm), has no major imp

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070302.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 study the marginal peri‐implant tissues at intentionally non‐submerged (1‐stage implants) and initially submerged and subsequently exposed implants (2‐stage implants). 5 beagle dogs, about 1‐year‐old, were used. 3 months after the extraction of the mandibular premolars, fixtures of the Astra Tech Implants Dental System®, the Brånemark System® and the Bonefit®‐ITI System were installed. In each mandibular quadrant, 1 fixture of each implant system was installed in a randomised order. The installation procedure followed the recommendations given in the manuals for each system. Thus, following installation, the bone crest coincided with the fixture margin of the Astra Tech Implants Dental System® and the Brånemark System®, whereas the border between the plasma sprayed and the machined surface of the Bonefit®‐ITI implant system was positioned at the level of the bone crest. Following a healing period of 3 months, abutment connection was carried out in the 2‐stage systems (the Astra Tech Implants Dental System® and the Brånemark system®). A 6‐month period of plaque control was initiated. The animals were sacrificed and biopsies representing each implant region dissected. The tissue samples were prepared for light microscopy and exposed to histometric and morphometric measurements. The mucosal barrier which formed to the titanium surface following 1‐stage and 2‐stage implant installations comprised an epithelial and a connective tissue component, which for the 3 systems studied, had similar dimensions and composition. The amount of lamellar bone contained in the peri‐implant region close to the fixture part of the 3‐implant systems was almost identical. It is suggested that correctly performed implant installation may ensure proper conditions for both soft and hard tissue healing, and that the geometry of the titanium imp

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070303.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

86 patients, in 2 Scandinavian centers, participated in a prospective study of mandibular edentulism, treated with overdentures supported by Bioceram sapphire implants. Implant success and prosthesis stability as well as parameters for peri‐implant health were evaluated. Masticatory function and complications were also documented. The study began in 1982 and clinical treatment of the last patients was completed in 1991. The patients have been followed for at least 3 years, and up to 12 years. 4 patients were lost to follow‐up. Of the initial 324 implants, 7 implants failed before prosthetic treatment. 3 patients lost 1 implant each within the 1st year, and 4 patients lost all 4 implants. 16 implants were lost between 36 and 42 months in function, due to lack of osseointegration and pain. The loss of implants could be attributable to an association, not statistically verified, between bone quality and anatomy, with heavy smoking as a risk factor. Based on the remaining implants, the cumulative implant success rates were 95.2%, 91.3%, 91.3%, 91.3% at 3, 5, 10 and 12 year follow‐up, respectively. The cumulative success rates for overdentures were 96.4%, 92.8%, 92.8% and 92.8% respectively, for the same follow‐up periods. Indices for the health of the peri‐implant mucosa disclosed no serious inflammatory reactions in the surrounding soft tissues. Patient satisfaction with this form of oral rehabilitation was high in all but 2 patients who experienced d

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070304.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 correlate the changes in the peri‐implant tissues occurring after functional loading of non‐submerged titanium implants and assessed by radiographic, clinical and mobility measurements. 11 patients with distal extension situations received 18 implants of the ITI® Dental Implant System. After a healing period of 3months, the suprastructures were fabricated and seated 5months post‐surgically. For the assessment of peri‐implant bone changes, standardized vertical bitewing radiographs with reproducible exposure geometry were evaluated using computer assisted densitometric image analyses (CADIA) and bone height measurements. Since the radiographic evaluations were performed at mesial and distal sites only, the clinical parameters from these implant aspects were included in the analysis. Clinical periodontal parameters modified for the use around implants were obtained, damping characteristics were expressed as Periotest® readings and standardized radiographs were obtained at 1, 3, 6, 12 and 24 months after loading. In addition, radiographs were also taken at the start of functional loading. The data obtained from this small sample of implants demonstrated a wide range of different tissue alterations when using radiographic. clinical and mobility assessments. The parameter of probing attachment level (PAL) in combination with radiographic parameters obtained at 1, 3 and 6 months after loading were good predictors for the peri‐implant tissue status at 2 years. This was shown by means of multiple stepwise regression analyses. Mobility measurements did not reveal valuable predictive information with the statistical models applied. Assessments of probing attachment levels using periodontal probes rendered information on peri‐implant tissue alterations, which were closely correlated to the radiographically measurable peri‐impla

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070305.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Previous studies have demonstrated in short‐term experiments that a sandblasted and acid‐etched (SLA) titanium implant had a greater bone‐to‐implant contact than a titanium plasma‐sprayed (TPS) implant in non‐oral bone. In the present study, an SLA implant was compared radiographically to a TPS implant under unloaded and loaded conditions in the canine mandible for up to 15 months. 69 implants were placed in 6 foxhounds. Standardized radiographs were taken at baseline, preload, 3, 6, 9, and 12 months of loading. Loaded implants were restored with gold crowns similar to the natural dentition. Radiographic assessment of the bone response to the implants was carried out by measuring the distance between the implant shoulder and the most coronal bone‐to‐implant contact (DIB) and by evaluation of bone density changes using computer‐assisted densitometric image analysis (CADIA). 5 different areas‐of‐interest (AOI) were defined coronally and apically along the implant. DIB measurements revealed that SLA implants had significantly less bone height loss (0.52mm) than TPS implants (0.69mm) at the preload evaluation (p=0.0142) as well as at 3 months of loading (0.73mm/1.06mm:p=0.0337). This difference was maintained between the implant types during the 1‐year follow‐up period. The same trend was also evident for CADIA measurements with SLA implants showing higher crestal bone density values when comparing preload to baseline data (p=0.0890) and 3 months to baseline data (p=0.0912). No measurable bone density changes were apparent in the apical areas of either implant. These results suggest that SLA implants are superior to TPS implants as measured radiographically in oral bone under unloa

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070306.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Cells with procollagen α1(I) transcripts were demonstrated at the interface of natural coral mineral implanted in the femur of rats after 7, 14, 21 and 28 days by in situ hybridization with digoxigenin‐labelled RNA probes. Procollagen α1(I) transcripts were detectable in osteoblasts between 7 and 28 days after implantation. As early as 7 days after implantation, procollagen α1(I) RNA expression was also demonstrated in fibroblasts; the transcript steady state levels decreased until the 28th day, when they subsided completely. The development of bone was significant during the 4 weeks of implantation. Inhibition of bone development by the coralline material could not be reco

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070307.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

Bone anchored implants are now being used in dentistry for supporting intraoral and craniofacial prostheses. Although high success rates have been reported, a small number of implants may fail during the early healing phase or later in function. Currently available clinical methods to determine implant stability and osseointegration are relatively crude and may entail percussing a fixture with a blunt instrument. Radiographs are of value, but a standardised technique is necessary to ensure repeatability. This investigation was designed to study the application of a non‐invasive test method using resonance frequency analysis to make quantitative measurements of the stability of the implant tissue interface in‐vitro and in‐vivo. The resonance frequency of a small transducer was measured when attached to implants embedded at different heights in an aluminium block. A strong correlation (r=0.94,p<0.01) was observed between the observed frequency and the height of implant fixture exposed. The change in stiffness observed in the bone surrounding an implant during healing was modelled by embedding implants in self‐curing polymethylmethacrylate and measuring the resonance frequency at periods during polymerisation. A significant increase in resonance frequency was observed related to the increase in stiffness. Resonance frequency measurements were also made on implants in‐vivo and the results correlated well with the in‐vit

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070308.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 compare the peri‐implant mucosal conditions 1 year after immediate transmucosal implant placement without or in combination with guided tissue regeneration with the situation after regular placement of transmucosal 1‐stage procedure implants in partially edentulous patients. The test group consisted of 15 patients who required the immediate replacement of 20 teeth with oral implants in combination with guided tissue regeneration. The control group 1 consisted of 6 patients who received 8 immediate implants, without concomitant bone regeneration procedure due to the small size of the extracted roots in comparison to the diameter of the implants. The 20 patients of the control group 2 were randomly chosen from over 150 partially edentulous patients who received implants of the ITI® Dental Implant System according to the standard procedure. Similar favorable clinical parameters were found around the implants of all the 3 groups with low plaque and mucosal indices, similar amounts of recession, pocket probing depths and clinical attachment levels. The immediate implants demonstrated lower frequencies of sites bleeding on probing. The study has established that immediate oral implants are a feasible treatment modality with high predictabi

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070309.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY

摘要:

The efficacy in restoring a buccal dehiscence after tooth extraction has been studied in12 consecutive cases using guided bone regeneration with (6 patients) or without (6 patients) a biomaterial (DFDBA or Bio Oss®) beneath an e‐PTFE membrane. A correlation between the clinical impression of density at drilling time and the histological signs of bone formation has been evaluated too. The membrane was removed after 6 or 9 months and a biopsy was performed. Clinically, GBR was highly predictable for regeneration of the alveolar bone after tooth extraction with buccal dehiscence. The histology fully confirmed the clinical and radiographical results, showing bone formation in all cases with individual variations in the amount of bone formed. 6‐month biopsies from the membrane sites had lamellar bone with large medullary spaces, while a good bone density was observed at 9 months. The membrane/biomaterial sites demonstrated mineralization and large amounts of allograft at 6 months. Thus, bone regeneration seems to take more time when grafting material is

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1996.070310.x

出版商:Munksgaard International Publishers    

年代:1996

数据来源: WILEY