摘要:

Critical events in the adaptation of osseous tissues to implant materials involve initial calcification of the newly synthesized bone. Previous studies indicated that bone‐bonding but not nonbonding glass ceramics increase the matrix vesicle number, thereby compensating for delayed maturation of the extracellular organelles. The present study assessed whether this was also true for metal implants commonly used in orthopaedics and oral medicine. Bone‐bonding titanium (Ti) or nonbonding stainless steel (SS) implants were placed in the right tibias of Sabra rats following ablation of the marrow. At 3, 6, 14, and 21 days postinjury, newly formed endosteal bone in the treated and contralateral limbs was removed and matrix vesicle‐enriched membranes isolated. Alkaline phosphatase and phospholipase A2specific activities and phosphatidylserine (PS) content were determined and compared with those of a nonsurgical control group. Results show that matrix vesicle alkaline phosphatase and phospholipase A2activity and PS content was increased in the Ti‐implanted limbs at 6 (peak). 14, and 21 days, although at levels less than observed in normal ealing. Alkaline phosphatase activity remained elevated throughout the healing period. In contrast, these parameters were markedly inhibited in the SS‐implanted limbs with respect to Ti or to normal healing. Both implants altered the systemic response associated with marrow ablation. but in an implant‐specific manner. The results support the hypothesis that cells adjacent to bone‐bonding materials can compensate for negative effects on primary mineralization during osteogenesis, whereas cells adjacent to nonbonding materials either do not compensate or are further depressed. The data support the use of the rat marrow ablation model as a tool for rapid, initial assessment of biomate

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060101.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

This investigation had 2 aims: 1) to determine the levels of acute‐phase proteins and immunoglobulin G (IgG) against Porphyromonas gingivalis in peri‐implant crevicular fluid (PICF) and their association with the clinical condition of the peri‐implant mucosa; and 2) to compare the inflammatory and immunological responses at implants and teeth as reflected by the gingival crevicular fluid (GCF) and PICF levels of acute‐phase proteins and immunoglobulins. Thirty‐one partially edentulous subjects were recruited for this study. PICF was sampled from 1 healthy and 1 inflamed site from each patient; GCF was sampled from an additional 21 healthy and 27 inflamed tooth sites of the same patients. GCF and PICF were collected with paper strips (for 30 s) and analysed using enzyme‐linked immunosorbent assays for α2‐macroglobulin, α1‐antitrypsin, transferrin, lactoferrin and IgG againstP. gingivalis. This investigation demonstrated that the absolute amounts of the acute‐phase proteins and IgG againstP. gingivalisare higher in GCF and PICF from inflamed than healthy sites. No significant differences were observed between PICF and GCF components at either healthy or inflamed sites, suggesting that inflammatory and immune events are similar in the peri‐implant mucosa and gingiva in humans and that PICF and GCF production is governed

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060102.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

Screw‐shaped implants with 3 different surface topographies, evidenced visually as well as numerically with an optical profilometer. were inserted in rabbit bone. After a healing period of 12 weeks, a statistically significant higher removal torque was needed to unscrew screws blasted with25 μm TiO2particles and screws blasted with 75 μm particles of A1203 compared with screws with a turned surface. The histomorphometric evaluation demonstrated a higher percentage of bone‐to‐metal contact for implants blasted with 25 μm particles of TiO2compared with the as‐machined implants. A greater surface area of bone in threads was found for the turned screws compared with screws blasted with 25 μm TiO2particles. In the short‐term follow‐up, there was a better fixation of implants with an average surface roughness of 0.9–1.3 μm and with a homogeneous surface structure than of implants with an average surface roughness of 0.4 μm and with a clear direction of

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060103.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The Periotest® device was used to evaluate the damping characteristics of different bone‐to‐implant interfaces of Brånemark implants. Implant and abutment lengths were found to have a significant influence on Periotest value (PTV). There was no statistical difference between PTVs of implants located in the anterior and posterior areas of the same jaw at abutment connection. No differences were found between PTVs of standard and self‐tapping implants. PTVs at abutment connection were highly influenced by the bone quality. The contact with two corticals, one at each extremity of the implant, was of a greater influence in the maxillary than in the mandibular jaw, indicating a firmer anchorage between the bicortical implants and the surrounding bone. A proaressive decrease of PTVs over time was observed, significant up to 5 years of

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060104.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

In vivo bite forces, implant axial forces and bending moments were measured on 5 patients with fixed posterior prostheses supported by a natural tooth and a single Brinemark implant. The results demonstrate that the vertical loads applied to the prostheses are shared between the tooth and the implant. The maximum bending moment transferred to the implant (10–15N.cm) was well below the acceptable load limits for the mechanical components (50–60N.cm), even at bite forces exceeding 100 N. The main reason for this load sharing seems to be the inherent bending flexibility of the implant screw joint, which matches the axial flexibility of the periodontal ligament of the to

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060105.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

This study is based on data from routine follow‐up registration following functional loading of a consecutive number of osseointegrated prostheses at the Dental School, University of Oslo. Fifty‐six patients with 240 Brånemark implants were examined 24 months after the implants were loaded, and a protocol form for collecting information about the status of the treatment was completed. The examinations included registration of oral hygiene, pathological alterations in soft and hard tissues, type of material used in contacting occlusal surfaces, occlusal design and technical and mechanical failures. All superstructures, except CeraOne single‐tooth prostheses. were unscrewed for inspection of implant and screw joint mobility. Eighty‐three per cent of the implants were found in the upper and lower frontal segments of the jaws. The survival rate for individual implants in this study was 94%. which is well within the generally accepted level for osseointegrated implant systems. Plaque and soft tissue complications were low and could not be associated with the early losses of implants. Group function was the preferred design of the occlusal contact pattern (53.4%), followed by 37% for canine guidance and about 9% for balanced articulation. Fourteen abutment screws and 7 gold screws loosened during the period between permanent loading and the first follow‐up registration. A majority of the failures occurred in osseointegrated bridges occluding with complete dentures in the opposite jaw. The failing screw joints were found in 25% of the patients, which means that one fourth of the patients needed extra mending appointments. The failures are assumed to be iatrogenic, and measures to avoid them are

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060106.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

The aim of this investigation was to test the hypothesis that jaw bone, subjected to mechanical intervention, will heal with increased density compared with conditions before the traumatic insult. The natural edentulous area between the incisor and the first molar on both sides of the maxillary jaw of 8 adult New Zealand white rabbits constituted the experimental model. On the test side, holes were drilled through the cortical plate and into the cancellous bone. No drilling was performed on the contralateral control side. One transversal ground section from each specimen, taken in the centre of and representing both the test and control site, was prepared to ensure that the same sagittal level of the jaw was represented. Morphometric measurements were performed and comprised assessments of the total cross‐sectional area of 1) the edentulous part of the jaw, 2) the cortical bone plates and 3) the bone trabeculae and marrow spaces of the cancellous bone. The mechanical intervention resulted in a substantial alteration of the bone tissue morphology, the most conspicuous change being a markedly increased number of bone trabeculae per cancellous bone unit. Thus, the area occupied by bone trabeculae was about twice as large in the test sites compared with the control sites (+103%), whereas the area occupied by bone marrow cavities and cortical bone was significantly smaller. The clinical implications of the findings for potential treatment of fragile bone tissues and bone sites intended for implant insertion are discusse

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060107.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY

摘要:

Complete wound closure over an immediate implant is considered to be a desirable goal. This case report describes for the first time the use of a connective tissue autograft placed under the existing flap margins of an extraction socket to successfully achieve closure over an immediate implant covered with an occlusive membrane. The rationale of the method is described. Healing was uneventful and epithelization of the graft surface from surrounding tissues was achieved. This technique created an increased width of keratinized tissue and avoided the need to disrupt the normal anatomical relationships of the surrounding buccal tissues, in contrast to current techniques. The advantages of the technique, together with factors that may influence healing and predictability, are discussed.

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1995.060108.x

出版商:Munksgaard International Publishers    

年代:1995

数据来源: WILEY