摘要:

The experiment was performed to evaluate the effects of long‐standing plaque on the gingiva and peri‐implant mucosa. 5 beagle dogs were used in the study. The mandibular right premolars were extracted. 3 months later, 3 titanium fixtures were installed and after another 3 months, abutment connection was performed. Plaque control, in the implant as well as the contralateral tooth regions, was maintained during a 4‐month period prior to the start of the main experiment. On Day 0, the teeth and implant sections were examined with respect to plaque and gingivitis. The plaque control program was terminated. The animals were subsequently fed a diet which allowed gross plaque accumulation. After 90 days of undisturbed plaque formation, the dogs were re‐examined and biopsies harvested from implants and contralateral teeth. On day 90, all teeth and implants had accumulated large amounts of plaque. The soft tissue at implants and teeth bled on gentle probing. The histological examination of the gingiva and the peri‐implant mucosa revealed:(i) both tissues contained an inflammatory cell infiltrate; ICT, (ii) the apical extension of ICT was more pronounced in the peri‐implant mucosa than in the gingiva and (iii) the composition of the 2 lesions had many feature

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030301.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

It has been documented that the long‐term clinical outcome of the Brånemark® system is very favourable. However, failures do occur before and after loading. This study examined the differences in marginal bone loss between standard and self‐tapping fixtures and attempted to explain excessive marginal bone loss or loss of osseointegration during the first 3 years of loading. Marginal bone loss (scored on long cone radiographs) and fixture failure rate were compared for different fixture designs. For standard fixtures, in comparison with self‐tapping fixtures, the failure rate was clearly higher before as well as after loading. However, for successful fixtures no difference in marginal bone loss was observed. For the conical fixtures an increased marginal bone loss around the smooth part was observed. The effect of fixture overload, marginal bone height and loss of osseointegration was examined in 69 patients with 1 and 15 patients with 2 fixed full prostheses, and in 9 patients with an overdenture in the upper jaw. Excessive marginal bone loss (more than 1 mm) after the first year of loading and/or fixture loss correlated well with the presence of overload due to a lack of anterior contact. the presence of parafunctional activity and osseointegrated full fixed prostheses in bo

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030302.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2‐month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re‐establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was<1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on te

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030303.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

The cleaning effectiveness of different treatment methods for titanium abutments was evaluated using scanning electron microscopy (SEM). In the mandible of 4 beagle dogs, 25 titanium abutments were installed (modum Brånemark). After 16 weeks of plaque accumulation, mineralized deposits had formed on 23 abutments. Each of these abutments was subjected to one of the following treatment methods: scaling with (1) metal, (2) plastic, or (3) ultrasonic instruments;(4) air‐polishing, (5) weekly rubber cup polishing or (6) daily brushing with a conventional toothbrush. Fourteen abutments were removed immediately after treatment. On 9 abutments, the scaling procedures and air‐polishing were repeated after another 16 weeks of plaque accumulation. The abutments were prepared for SEM, and each of them was viewed and photographed at 3 different magnifications. The photomicrographs were evaluated by 3 examiners who, guided by reference pictures, gave each abutment a “cleanliness” score, ranking from 0 to 5. Regular rubber cup polishing and regular brushing resulted in the highest surface cleanliness, while the air‐polishing procedure showed the lowest cleanliness score. None of the 3 scaling methods created a cleanliness score better than 3. The 3 scaling methods were considered equal in their cleaning effectiveness. No differences could be observed between surfaces treated 1 x or 2 x Taken the present findings and those of other studies concerning the effects of scaling on the surface roughness and biocompatibility into consideration, it was concluded that plastic scalers may be the instruments of choice for debridement of titanium implan

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030304.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

In order to improve the prosthetic versatility of the ITI‐Bonefit implant system, a clinical technique was tested whereby a custom made post and core buildup was cemented into implants. Specially designed threaded and serrated posts were machined in precious metal. After the posts were seated into the threaded channel of the implants, cores were built using autopolymerizing resin. Those were then cast and cemented into the implants. For the remainder of the procedure, the buildups were treated like natural abutments using conventional prosthodontic techniques. Mechanical tests were performed to assess the clinical viability of these buildups. The ultimate tensile strength of annealed posts lies in the 700–800 N range. By comparison, the pull‐out resistance of posts cemented into natural roots ranged between 108 and 177 N, and the maximum pull‐out resistance of manufactured abutments is about 1040 N. When the resistance against lateral forces was tested, the cemented build‐ups ranged between 981 and 1128 N. whereas natural teeth fractured between 206 and 903 N depending on the diameter of the root. Manufactured abutments failed at stress levels of about 1020 N. Considering these favorable results, we conclude that the technique described above can be applied clinically for further investigation. Additionally, we suggest some modifications in implant design that would enhance the versatility of t

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030305.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

The aim of these animal experiments was to characterize and evaluate the healing‐in of root analogue titanium implants fitting with high precision to the alveolar wall. Four beagle dogs were used in the study. The roots of the 3rd and 4th mandibular premolars in both quadrants of 3 dogs and in 1 quadrant of 1 dog (dog 4) were extracted after hemisection. Each root was machine‐copied to 1 titanium analogue. In dog 4, however, 2 titanium analogues were fabricated from each of the 4 extracted roots. This enabled insertion of analogues also into the contralateral sockets obtained by extraction of the corresponding roots immediately before implant installation, which was undertaken 2 weeks after the first extractions. Thus, in all, 32 analogues were implanted in their respective (or contralateral) sockets following ridge incision and elevation of mucoperiosteal flaps. The analogues were carefully covered by the repositioned flaps. In dog 4, 2 analogues from the immediate sockets and 2 from the 2‐week sockets were surgically exposed and supplied with titanium crowns after a healing period of 2 months. The healing after implantation was evaluated by clinical, radiographic and histological measures after 2, 12 or 36 months. Two analogues (6%) were lost due to early (during the 1st week) exposure to the oral cavity. Another 2 analogues (6%) were, although not exposed, encapsulated by soft tissue and were easily removed with a surgical forceps. Twenty‐eight analogues (88%) were healed‐in by contact between bone and implant (osseointegration). The mean percentages of bone tissue in contact with the implant of such analogues were 30.5% after 2 months, 64.8% after 12 months and 68.1% after 36 months, as evaluated by histomorphometric analysis. The 4 analogues supplied with titanium crowns carried those with maintained bone anchorage throughout an experimental period of 36 months. The character of the interface between the analogue and the surrounding bone tissue was the same regardless of whether the implantation was performed immediately 1 or 2 weeks after extraction of

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030306.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY

摘要:

The aim of this study was to test whether healing of extensive transosseous defects in the calvaria can successfully be achieved using guided bone regeneration. The results demonstrated complete osseous bridging of the skull defect in the test specimen. In the control specimen, fibrous connective tissue occupied the area of the skull defect.

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1992.030307.x

出版商:Munksgaard International Publishers    

年代:1992

数据来源: WILEY