bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical problems in total hip replacements
Authors: Hirsch Carl 
Published: December 2004

AbstractTotal hip replacements are based on a long chain of efforts of partial exchange of joint compartments. Inplants of material of both biological and nonbiological origin have been applied over the past 50 years. Smith‐Pedersen, Judet, Moore, and Thompson are names to be remembered. It was primarily from the idea of firm fixation and low friction between the joint surfaces that today's constructions emerged. Immediate superior clinical results encouraged a strong trend towards hip‐arthroplasties. The orthopedic surgeon can now choose amongst several prosthetic designs, the most common being metal to metal or plastics with or without bone cement. But, after ten years a number of threatening problems have become evident, calling for critical analysis of total joint replacements. Biomechanical, chemical, and morphological disturbances, both in the early and late phases, show that the body has difficulties in tolerating the artificial joint. This survery presents some of the most obvious risks and failures in total hip replacements.
Total surface replacement of the hip joint
Authors: Walker P. S. , Mendes D. G. , Figarola F. , Bullough P. G. 
Published: December 2004

AbstractThe surface replacement hip prosthesis reported represents an attempt to improve upon some aspects of the present design of total hip. The prosthesis comprises a cap fitted over the femoral head and a liner fixed into the socket, both being cemented with methyl methacrylate. The chief advantage of this design is preservation of bone stock. The prostheses were inserted bilaterally into six dogs, and whilst ten joints failed, one case was strikingly successful at two years follow‐up. It was concluded that the design showed sufficient advantages over current total hips and that there was sufficient possibility of success in some application, to merit further study.
A look at the prosthesis‐cartilage interface: Design of a hip prosthesis containing pressure transducers
Authors: Carlson Charles E. , Mann Robert W. , Harris William H. 
Published: December 2004

AbstractThe human hip joint is capable of carrying loads exceeding several times body weight. The distribution of these loads over the load‐bearing cartilage surfaces in the hip is of considerable interest in terms of studying the behavior of cartilage under various loading conditions. A modified Moore prosthesis has been designed which is capable of measuring in vivo the spatial and temporal pressure variations generated by the loads carried by the hip. The pressures as measured by this device will not only give a good indication of the pressure distributions that occur in the normal hip but will yield quantitative data on the pressures generated between the cartilage surface in the acetabulum and the ball of the prosthesis.The instrumented prosthesis consists of three main elements: a network of pressure transducers distributed over the surface of the ball, a multichannel telemetry device located inside the ball to transmit the information from the transducers to external receiving and recording equipment, and an electromagnetic power induction system which provides an external source of power for the telemetry device inside the prosthesis.A prototype has been fabricated which demonstrates the satisfactory functioning of the complete pressure measuring system.
Evaluation of a total hip replacement
Authors: McGrouther D. A. 
Published: December 2004

AbstractThrough a survey of hip replacement arthroplasty the paper establishes the case for objective evaluation of these joints in the patient. It then outlines a simple, non‐invasive technique, based on Paul's (1967) locomotion studies, to assess pre‐ and postoperative functional capability. Preliminary results which establish viability of the procedure are presented.
Press fit implant arthroplasty of the hip and knee
Authors: Sbarbaro J. L. 
Published: December 2004

AbstractThe bone‐implant interface and the accompanying difficulties with fixation continue to be a major area of research activity. Biological fixation would appear to be the ideal method of fixation. Press‐fit metal implants may be part of a larger answer that may include sintering, coatings, or both.
The total Walldius knee endoprosthesis in combination with retropatellar facet replacement (Polyethylene). Indication, operative procedure, and clinical results in a two year follow‐up study
Authors: von Andrian‐Werburg Hanns F. , Jentschura Guenter 
Published: December 2004

AbstractTotal replacement of the knee joint often remains unsatisfactory because of severe femor‐patellar osteoarthritis.Twenty‐four Walldius knee prostheses were inserted in 21 cases. Since March 1971 we have used a combination of this type of hinge prosthesis with a high‐density polyethylene retropatellar facet prosthesis developed by our group in cooperation with the Badische Anilin‐ & Soda Fabrik AG (BASF).Fourteen knees of this combined type have been implanted and resulted in considerably less complaints than the original Walldius knee. The postoperative range of motion with an average of 66° does not differ in both groups.
The Sheffield knee prosthesis
Authors: Elson Reginald , Watts Norman 
Published: December 2004

AbstractA new variant of the hinge type knee prosthesis has been developed in Sheffield, England. To date, the results of the early clinical trial in five patients are satisfactory, but it is recognized that the operation is highly speculative and continuation of the trial is being conducted with extreme caution. The main features are as follows.
The hinge is not provided with a mechanical stop to extension, the posterior ligament providing this check.
The contours of the femoral condyles are preseved.
Debris is collected inside the device.
Replacement of worn plastic components can be conducted without dismantling the knee.
There is a built‐in resilience which is intended to protect the components and the bone‐implant interface.
Porous titanium alloy for fixation of knee prostheses
Authors: Nilles J. L. , Karagianes M. T. , Wheeler K. R. 
Published: December 2004

AbstractA porous titanium alloy called void metal composite (VMC) was investigated for use in knee prosthesis fixation. The interfacial ingrowth fixation of VMC intrameduallary, subchondral, and variable density implants in goat femora was evaluated biomechanically and histologically at six weeks and five months. Biomechanical tests were done under static shear and dynamic, cyclic (fatigue) loading conditions. Readily identifiable bone, strong fixation, and excellent biocompatibility were typical. Some subarticular implants appeared to induce normal hyaline cartilage overgrowth.
A simple shoulder replacement
Authors: Kenmore Peter I. , Maccartee Carl , Vitek Brantley 
Published: December 2004

AbstractAlthough degenerative arthritis of the shoulder is quite rare, it does occur. Pain relief was obtained in three such cases by the insertion of a polyethylene glenoid liner made for this purpose and used in conjunction with a standard metal prosthesis for humeral head replacement. Good pain relief and fair motion was obtained.
Elimination of unnecessary screw threads
Authors: Sutton Richard O. , Blackwell William M. , Luekens Claude A. 
Published: December 2004

AbstractAn investigation of metallic intramedullary fixation devices commonly used in orthopedic surgery revealed that the screw threaded portions of these devices were foci for corrosion and fatique fractures. After several design change proposals, a spherical head was developed which could be incorporated onto the intramedullary nails which would eliminate these problems. An extractor impactor was also developed to enable this new design concept to be utilized in surgery. The design and device are described and displayed.
A histopathological report on the nature of the epithelium and underlying connective tissue which surrounds oral implants
Authors: James Robert A. , Kelln Elmer E. 
Published: December 2004

AbstractThis report is concerned with the two tissue types (oral epithelium and fibrous connective tissue) which surround oral implants and the possible adhesion of cells of these tissues to the implant surface. A review of the literature reveals that there is disagreement as to which of these two tissue types encase the deeper portions of Vitallium implants. Using techniques developed for studying the dental epithelial attachment, the following observations are submitted.
A PAS‐possitive material is in abundance at the interface between the junctional epithelium and the implant post and present, but to a lesser degree, between the fibrous connective tissue and the implant surface.
An Oracine‐positive material is present at the interface of both tissue types and the implant surfaces.
Collagen fibers subjacent to the junctional epithelium are oriented at functional angles to the basement membrane.
A histological artifact has been frequently observed which is the result of the tearing of the end of the epithelium away from its basement membrane.
Bacterial plaque adhering to the exposed portion of the implant posts extends in an apical direction and terminates abruptly along a very distinct line.
From these observations it seems likely that an adhesion exists at the interface between the junctional epithelial cells and the penetrating implant surface.
Development and evaluation of porous ceramic and titanium alloy dental anchors implanted in miniature swine
Authors: Karagianes M. T. , Westerman R. E. , Rasmussen J. J. , Marshall R. P. 
Published: December 2004

AbstractA study sponsored by the National Institute of Dental Research has as its major goal the development of easily fabricated and implantable dental anchors for replacement of missing or extracted teeth. Tissue ingrowth fixes the anchors in the mandibular or maxillary bone where they can serve as a base for future attachment of prefabricated dental caps, bridges, or other dental prostheses. More immediate objectives are to determine the suitability of specific porous titanium and ceramic materials for anchor applications, to develop satisfactory designs and fabrication procedures for producing these devices, and to define material/bone interface bonding characteristics through in vivo studies. The value of the Hanford Miniature Swine as a human analog for dental research is being assessed concurrently.
The foreign body reaction: A chronic inflammatory response
Authors: Coleman D. L. , King R. N. , Andrade J. D. 
Published: December 2004

AbstractA brief discussion is presented of some of the problems and artifacts inherent in the testing of soft tissue reactions to artificial implants. The process of inflammation and wound healing is presented. The various factors affecting the foreign body reaction (chemical, mechanical, geometrical, and others) are discussed. The cellular components of the foreign body reaction are described and the sequential cellular changes that may occur as a result of implanting an artificial device are examined. The foreign body reaction should be considered as a chronic inflammatory response.
Surface topography of a new polymer material for tooth implants
Authors: Hodosh Milton , Shklar Gerald , Povar Morris 
Published: December 2004

AbstractA new polymer material has been developed for tooth implants. This material appears to be more successful than previous materials used, in that self support of tooth‐replica implants have been demonstrated in baboons. The surface topography of the new material has been studied with a scanning electron microscope and a lace‐like pattern was demonstrated, which had certain similarities to the surface of cementum of natural teeth.
A wear resistant material for total joint replacement—tissue biocompatibility of an ultra‐high molecular weight (UHMW) polyethylene—graphite composite
Authors: Tetik Robert D. , Galante Jorge O. , Rostoker William 
Published: December 2004

AbstractA new prosthetic material, ultra‐high molecular weight (UHMW) polyethylene graphite, was developed for use in total joint replacement and found to exhibit 1/7–1/30 lower wear rate than UHMW polyethylene bearing against Vitallium alloy.A preliminary study was undertaken to test the biocompatibility of the new material. Specimens of 316L stainless steel, high‐purity graphite, UHMW polyethylene, and the composite material were implanted in rabbits and cynomologous monkeys. The materials were evaluated in both solid and particulate forms after implantation in bone, joint cavities, and paravertebral muscles. The tissue reactions to the materials were noted at time intervals from 6 weeks to 1 year.All materials showed good tissue acceptance in solid form. The UHMW polyethylene and the composite material were noted to be more reactive than either the high‐purity graphite alone or the stainless steel when in particulate form.The eventual use of the polyethylene graphite composite in total hip arthroplasties is suggested by virtue of its identical biocompatibility with UHMW polyethylene. In addition, its superior wear resistance, and hence low volume of wear debris particles presented to the surrounding tissues would offer an advantage in terms of longevity of the implant both mechanically and biologically.
Haversian osteons: Size, distribution, internal structure, and orientation
Authors: Black Jonathan , Mattson Richard , Korostoff Edward 
Published: December 2004

AbstractMeasurements of Haversian osteons in human tibial cortical bone specimens from seven donors demonstrate that, for this study:

Haversian osteonal area, as a proportion of cross‐sectional area of cortical bone, increases with the age of the donor, whether or not the area of the central Haversian canal is taken into account.
Haversian canal area, as a proportion of cross‐sectional area of cortical bone, either remains the same or increases with the age of the donor.
The number of osteons present per unit cross‐sectional area has no observable age dependence.
The percent inorganic content or cortical bone increases with the age of the donor.
Optical studies on thin sections of cortical bone, utilizing crossed polarizing filters, suggest that the classification of osteons as light, dark and intermediate, as proposed by others (Anat. Rec., 161, 377 (1968)) is incorrect in that only one general type of Haversian osteon structure was detected in this study.
Antithrombin activity of a polyelectrolyte synthesized from cis‐1,4‐polyisoprene
Authors: Beugeling T. , van der Does L. , Bantjes A. , Sederel W. L. 
Published: December 2004

AbstractA polyelectrolyte synthesized from cis‐1,4‐polyisoprene, containing aminosulfonate and carboxylate groups was shown to have an anticoagulant activity of about 1/30 compared with heparin. Because the substance prevents the coagulation of plasma in the presence of thrombin it is assumed that it acts as an antithrombin.
Couple corrosion among alloys for skeletal prostheses
Authors: Rostoker W. , Pretzel C. W. , Galante J. O. 
Published: December 2004

AbstractUsing a metallographic technique to identify and count corrosion pits, the tendency for passive film breakdown has been studied under conditions that simulate a crevice and a combination of two different materials. Potential corrosion couples were formed among: 316L stainless steel, cast CoCrMo alloy, wrought CoCrWNi alloy, Ti–6% Al–4% V alloy, a CoNiCrMo (multiphase) alloy and graphite. Only 316L stainless steel seems significantly prone to pitting corrosion in a crevice condition. Dissimilar metals in the crevice configuration did not seem to accelerate the corrosion of stainless steel.
Long‐term phase changes in dental amalgam after setting
Authors: Vrijhoef M. M. A. , Driessens F. C. M. 
Published: December 2004

AbstractThe integrated peak intensities of certain reflections of the γ, γ1 and γ2 phase of six dental amalgams at a mercury content of 45 wt% were selected and their dependence on the annealing time (1 < t < 140 days) at 37°C was determined. Also the overall changes in phase composition were studied qualitatively by means of the peak heights of all phases found in the X‐ray patterns of these amalgams at different annealing times.The γ2 phase content did not seem to depend on the annealing time. It was established also that the γ and γ1 phase contents of these dental amalgams decrease with increasing annealing time at 37°C whereas the quantity of another phase, probably the ternary β phase increases with increasing annealing time.
Investigation of the phase composition of six dental amalgams by X‐ray diffraction
Authors: Vrijhoef M. M. A. , Driessens F. C. M. 
Published: December 2004

AbstractThe integrated intensities of certain reflections of the γ, γ1, and γ2 phase have been determined as a function of the mercury content of 6 amalgams after annealing for 20 hr at 37°C. This dependency could be described satisfactorily by means of the regression model:

. Here Ii is the integrated peak intensity for phase i at a mercury fraction of W by weight, whereas I and αi are constants of the material, whereby i = 0, 1, 2 stands for the γ, γ1, and γ2 phase respectively. Considerable differences between the αi and I parameters of the different amalgams were detected.
Grafting of polymeric side chains to soft tissues
Authors: Brauer G. M. , Termini D. J. 
Published: December 2004

AbstractThis paper describes a novel approach for obtaining covalent bonding to tissues by chemical grafting of polymeric side chains to the collagenous backbone. Soft tissues such as calfskin or ratskin can be modified by acrylic, methacrylic, or vinyl monomers containing a variety of functional groups using ceric ions, persulfate–bisulfite or comonomers forming donor–acceptor complexes as initiators. Reactions take place within 20 min to 3 hr under experimental condition which, with suitable changes, might be tolerated clinically. The resulting products are insoluble in solvents for the respective homopolymers. It is likely that the polymeric side chain is attached chemically to the collagenous backbone. With ratskin, the grafting takes place mainly at the surface, resulting in a change in wettability and water sorption of the substrate. Modified hydrophilic, hydrophobic or even oil repellent surfaces can be prepared by judicious choice of monomer used. Thus, hydrophobic, oleophobic subdermal ratskin surfaces are obtained on reaction with flourinated monomers. Treated ratskins appear more resistant to fungal attack than the original substrate. It is conceivable that the polymeric side chains can serve as adhesive liners since the modified surface may improve the ability of the substrate to adhere to restorative materials.
Evaluation of the physical properties of crown dental porcelain and the effect of newly developed anti‐balling additive
Authors: Mabile C. P. 
Published: December 2004

AbstractA colloidal silica‐based substitute for the water added to dental porcelain has been developed which restricts rounding on firing and gives greater and indefinitely prolonged unfired biscuit strength. In conjunction with product evaluation, it has been found that both the modulus of rupture and the diametrical tensile strength of dental porcelains can be measured with a high degree of precision.
Degree of polymerization of acrylic bone cement
Authors: Bayne S. C. , Lautenschlager E. P. , Compere C. L. , Wildes R. 
Published: December 2004

AbstractSelf‐curing poweder‐liquid admixed acrylic systems are used for internal fixation of total hip and total knee prostheses. Gel permeation chromatography revealed that the polymer chain length distributions of set cements were basically unaffected by their curing pressures. However, a decrease of approximately 11% in porosity coupled with a measured increase in mechanical strengths could be induced through the use of high curing pressures well beyond those attainable by the surgeon in the current arthroplasties. The conclusion of the investigation was that, to improve such cements, attention should be focused on elimination of porosity rather than attempting to produce higher degrees of polymerization.
The surface area of aggregates applied to dental materials
Authors: Loebenstein William V. 
Published: December 2004

AbstractThere is a continuing need for the complete characterization of the physica and chemical properties of dental materials. Among these properties is surface area. The problem is further complicated by the fact that most dental materials are, themselves, mixtures of two or more identifiable components. If the vapor adsorptive properties of these components are different in the mixture from that which would be expected of them collectively, then interaction is present. Interaction must not be confused with the lack of additivity which results from the limitations of the BET theory applied to mixtures. Equations are derived herein to estimate the extent of this latter source of variability and to correct for it giving a “true” surface area for the aggregate. Conversely, the adsorptive properties of either component can be calculated from the properties of the mixture and the remaining component together with the percentage composition. An immediate application can be made in determining the water‐vapor adsorptive properties of human dentinal collagen without necessitating its removal from dentin. Any attempt to extract it chemically may produce denaturation or chain rupture thus precluding the possibility of direct determination. In the case of nitrogen adsorption, however, interaction definitely is indicated.
Antimicrobial polymers
Authors: Ackart W. B. , Camp R. L. , Wheelwright W. L. , Byck J. S. 
Published: December 2004

AbstractA number of carboxyl‐containing ethylene copolymers have been prepared which exhibit long term antibacterial and antifungal properties. These materials, containing antimicrobial agents bound to the copolymer backbone as carboxylate salts, have been tested for their applicability to hospital products as a means of providing “self‐sanitizing” articles. Tests have shown that these materials, although not bactericidal, do inhibit microbial growth. Investigations of the compatibility of these polymers with commodity polymers have been made and water emulsions of the polymers have been tested for applicability as components of product protectant coatings.
Investigation of possible oncogenic action of zinc polycarboxylate cement by implantation in mice and hamsters
Authors: Main J. H. P. , Mock D. , Beagrie G. S. , Smith D. C. 
Published: December 2004

AbstractPowdered, sterilized zinc polycarboxylate was implanted subcutaneously in 56 young hamsters and 54 mice, using equal numbers of each sex, with 24 sham operated hamsters and 26 mice as controls. The hamsters were sacrificed after 15 months and the mice after 12. Implant material was recovered from one of 42 surviving mice and from 16 of 43 surviving hamsters. Benign adenomas of the gut, thyroid, sebaceous glands and ovary were found in 3 experimental mice and in one control. Benign adrenal adenomas were found in 3 experimental hamsters and in one control. One control hamster developed a rhabdomyosarcoma in a limb. One experimental hamster developed a leiomyosarcoma in close relation to an implant.
A vitreous carbon‐polymethacrylate composite for dental implants
Authors: Hodosh Milton , Shklar Gerald , Povar Morris 
Published: December 2004

AbstractA study has been carried out on the structure and surface texture of a new dental implant material composed of vitreous carbon balloons (3 wt % or 6 wt %) and poly(methyl methacrylate). Tooth replica implants using this material had been successfully placed in baboons, and histologic study revealed normal alveolar bone and a peri‐implant membrane with the connective tissue fibers oriented in a horizontal direction. Square wafers (10 mm × 10 mm × 1 mm) were studied, with the surface sandblasted in one‐half of the specimens. Light microscopy revealed that in the 3% carbon specimens, the vitreous carbon microballoons were evenly spaced and often appeared to be fragmented within their spaces. S.E.M. studies revealed a finely porous surface with numerous large craters. Microballons were often seen within the craters in the nonsandblasted specimens.