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At least 1,261 records · Page 70Linked to original sources
PubMed1997

A comparison of intensive neurodevelopmental therapy plus casting and a regular occupational therapy program for children with cerebral palsy.

The purpose of this research was to evaluate the combined effect of intensive neurodevelopmental therapy (NDT) and casting in improving hand function, quality of upper-extremity movement and range of motion in children aged between 18 months and 4 years with cerebral palsy (CP). A randomized crossover design was used to evaluate the difference between intensive NDT plus casting and a less intensive regular occupational therapy (OT) program. Blinded assessments of hand function, quality of upper-extremity movement, and parents' perception of hand-function performance were carried out at baseline, 4 months (end of first intervention period), 6 months (after a 2-month 'washout' period), and 10 months (end of second intervention period). Analysis of the outcomes revealed no significant differences in hand function, quality of upper-extremity movement, or parents' perception of hand-function performance between the two treatment groups-intensive NDT plus casting or regular OT programs. There does not appear to be any beneficial effect of an increased amount of therapy for the children in this study.

Activities of Daily Living↗
PubMed1994

Restoring a failed prefabricated post and core with a sleeve casting: a clinical report.

A clinical case is described, and a technique is explained for making a custom sleeve cast post and core to salvage a fractured crown previously treated with an unretrievable prefabricated post. The restorative problem was to design and fabricate some sort of cast post and core that could be cemented to the remaining post. The amalgam and cement in the pulp chamber and coronal portion of the root canal were carefully removed so that a direct pattern could be made to form a tube which would surround the coronal part of the existing post like a sleeve. This sleeve casting was designed to provide attachment for a core to support a new restoration. This direct pattern technique results in a retained core that joins the already cemented post and provides a sound core for the retention of a new crown.

Crowns↗
PubMed2001

Retention of cast posts cemented with zinc phosphate cement using different cementing techniques.

PURPOSE: This study compares the effect of different cementation techniques on the retention of cast posts and cores. MATERIALS AND METHODS: Twenty-four extracted single rooted human teeth were used in this study. After routine preparation of the root canals, the canal space was enlarged with reamers. Direct post patterns were made with acrylic resin. Castings were fabricated using Ni-Cr-Mb alloy. Zinc phosphate cement was used as a luting agent using 4 different methods of cement introduction to the root canal space. This created 4 treatment groups consisting of 6 teeth in each group. In Group A, the cement was applied over the posts only. For the specimens in Group B, the cement was introduced into the root canals with a spiral filler and applied over the posts. In Group C, cement was injected into the root canals and then applied over the posts. Finally, for the specimens in Group D, cement was injected into the root canals and a spiral was used to spread it into the root canals, and cement was also applied over the posts. After cementation, teeth were stored in saline solution. The tensile retentive force of cast posts was evaluated using the Instron testing machine (Instron, Canton, MA). RESULTS: The retention obtained by the 4 techniques differed significantly (p <.05). The highest tensile force to post dislodgment was observed in Group D, and the least was in Group A. Analysis of variance test revealed a highly significant difference between groups (p <.0001). According to the Fisher exact test, there was a significant increase in retention from Group A to Group D (p <.05). CONCLUSIONS: Under the conditions of this study, the injection of cement into a root canal space followed by the use of a spiral resulted in the highest level of post retention. Retention was reduced when cement was placed using a Lentulo spiral alone (Kerr/Sybron Corp, Romulus, MI), a Jiffy tube (Teledyne Water Pik, Allegheny Teledyne Co, Fort Collins, CO) alone, or by application to the post only. J Prosthodont 2001;10:37-41.

Acrylic Resins↗
PubMedDate not supplied

Effect of sintering temperature on flexural properties of alumina fiber-reinforced, alumina-based ceramics prepared by tape casting technique.

PURPOSE: The purpose of this study was to investigate the effect of sintering temperature on flexural properties of an alumina fiber-reinforced, alumina-based ceramic (alumina-fiber/alumina composite) prepared by a tape casting technique. MATERIALS AND METHODS: The alumina-based ceramic used a matrix consisting of 60 wt% Al(2)O(3) powder and 40 wt% SiO(2)-B(2)O(3) glass powder with the following composition in terms of wt%: 33 SiO(2), 32 B(2)O(3), 20 CaO, and 15 MgO. Prepreg sheets of alumina-fiber/alumina composite in which uniaxial aligned alumina fibers were infiltrated with the alumina-based matrix were fabricated continuously using a tape casting technique employing a doctor blade system. Four sintering temperatures were investigated: 900 degrees C, 1000 degrees C, 1100 degrees C, and 1200 degrees C, all for 4 hours under atmospheric pressure in a furnace. The surface of the alumina-fiber/alumina composite after sintering was observed with a field-emission scanning electron microscope (FE-SEM). A three-point bending test was carried out to measure the flexural strength and modulus of alumina-fiber/alumina composite specimens. In addition, sintered alumina fiber was characterized by X-ray diffraction (XRD). RESULTS: FE-SEM observation showed that alumina-fiber/alumina composite was confirmed to be densely sintered for all sintering temperatures. Three-point bending measurement revealed that alumina-fiber/alumina composite produced at sintering temperatures of 1100 degrees C and 1200 degrees C exhibit flexural strengths lower than those of alumina-fiber/alumina composite produced at sintering temperatures of 900 degrees C and 1000 degrees C; alumina-fiber/alumina composite produced at sintering temperatures of 1100 degrees C and 1200 degrees C exhibit flexural moduli lower than that of alumina-fiber/alumina composite produced at a sintering temperature of 1000 degrees C. Additional XRD pattern of alumina fiber indicated that with increasing sintering temperature, the crystallographic structure of gamma-alumina transformed to mullite. CONCLUSIONS: There were significant differences in the flexural properties between the alumina-fiber/alumina composite sintered at the four temperatures. This indicates that the choice of optimum sintering temperature is an important factor for successful dental applications of alumina-fiber/alumina composite developed by the tape casting system.

Aluminum Oxide↗
PubMed1997

Corrosion casts of the suprachoroidal space and uveoscleral drainage routes in the human eye.

Human cadaver eyes were studied by corrosion casting technique. Batson's mixture No. 17 (methyl methacrylate) was injected through a sclerotomy into the suprachoroidal space. Following polymerisation of the injected mixture the surrounding tissue was dissolved with 10% natrium hydroxide. Macroscopic and scanning electron microscopic findings in casts of the suprachoroidal space are presented. Due to transscleral drainage of resin from the suprachoroidal space, different types of branches deriving from the outer (scleral) surface of the casts were found. Some of these branches corresponded to the perivascular spaces of both ciliary vessels and vortex veins. In addition, we found branches probably representing channels deriving directly from the suprachoroidal space, communicating with the intrascleral venous plexus. Such channel systems have previously not been described, and their possible relation to the uveoscleral drainage of aqueous humour is discussed.

Aged↗
PubMed1990

Effect of casting atmosphere on the quality of Ti-crowns.

Ti has a strong affinity to elements like O, N, and C. During melting a non-reacting crucible and vacuum and/or Ar-gas protection therefore have to be used. If the impurity content becomes too high, the material turns hard and brittle. In the present work vacuum/Ar-pressure casting of crowns has been carried out at different air pressure levels. Recording of hardness on cross-sections of the castings and the degree of mold filling show that an air pressure level less than 1 torr in the melting chamber and less than 10 torr in the mold chamber is sufficient to obtain sound castings of a small size like a crown.

Argon↗
PubMed2005

Cast titanium overlay denture for a geriatric patient with a reduced vertical dimension.

An older patient reporting to the dental surgery for his/her dental treatment is becoming a common occurrence. Improved oral hygiene has meant that teeth are retained for a longer time, along with the potential problems of attrition, decreased vertical dimension, temporomandibular joint discomfort/strain, and poor aesthetics. The case in question is that of a 65-year-old male patient who had severe attrition in the lower arch, temporomandibular joint pain and reduced vertical dimension. The maxillary arch had previously been restored with a fixed partial prosthesis. For restoration of the lower teeth, a removable cast titanium overlay denture was fabricated incorporating an increased vertical dimension. Porcelain facings were placed to restore the aesthetics of the anterior teeth. The titanium was cast in a semi-automatic electric arc, pressure type casting machine. A titanium overlay denture with porcelain facing on the anterior teeth may provide a means of restoring a patient's concerns regarding aesthetics and function.

Aged↗
PubMed1975

The effects of remelting on the mechanical properties of a nickel base partial denture casting alloy.

Three series of tensile test pieces were produced using a nickel base partial denture casting alloy. For the first series induction heating was employed, for the second a resistance crucible, and for the third, an oxy-acetylene torch. In each series the same metal was cast sequentially a number of times and all test pieces so produced were subjected to mechanical testing. The mechanical properties were found to vary according to both the number of times the alloy was cast and the method of heating used to render the alloy molten.

Acetylene↗
PubMed1977

The influence of the refractory investment on the development of porosity in cast structures.

Four series of standard tensile specimens were produced by casting into moulds composed of silica bonded, gypsum bonded, and phosphate bonded refractories. Two nickel base alloys were employed, one a standard dental casting alloy and the other a specially formulated ductile material. Subsequently, all specimens were subjected to mechanical testing, and radiographic and metallographic evaluation, in conjunction with porosity determinations, in order to ascertain how the nature of the refractory investment influences the structural quality of the castings produced.

Dental Alloys↗
PubMed1981

The effect of alginate impressions on the surface of cast gypsum. II. The role of sodium sulphate in incompatibility.

Of the materials tested only two alginates, Palginex (D), and Echo (C), show good surface reproduction when Vel-Mix (1), Ainsworth Greenstone (4), and Investo Greenstone (5) are cast against them. The above two alginates were shown to have a potassium and sulphate rich exudate. The reasonable surface produced by CA-37 (A) can be attributed to a proportional decrease in the ratio of potassium to sulphate present in the exudate, compared with Echo (C) and Palginex (D). S.S. White (B), Kromopan (E), and Tissutex (G) produce poor cast surfaces when high strength gypsum products are set against them. The exudates from these alginates were found to consist almost entirely of sodium sulphate. This study suggests that one way to improve the surface compatibility of alginates with gypsum products would be to modify the chemistry of the impression material so that a reactor other than calcium sulphate is used, to eliminate the appearance of sulphate ions in the exudate. Moreover, sources of sodium ions should also be eliminated. Therefore soluble alginates other than sodium alginate should be preferred, and a retarder other than one or other of the forms of sodium phosphate should be used. These changes would ensure that sulphate, particularly sodium sulphate, would not be produced as a by-product of the setting reaction. This in turn would eliminate the effects of incompatibility at present encountered to a greater or lesser extent with most combinations of alginate impression materials and gypsum cast materials.

Alginates↗
PubMed1996

Comparison and assessment of casting materials for use in small animals.

This paper describes an investigation to evaluate the properties and uses of the different casting materials available for small animals. After a consideration of the properties that make an 'ideal cast', clinically relevant tests were performed on tubular casts of the various products. No single product demonstrated consistent superiority by all the criteria. All the products tested can be useful in a variety of situations, and suggestions for their uses are set out.

Animals↗
PubMedDate not supplied

Retinal and choroidal vasculature in rats with spontaneous diabetes type 2 treated with the angiotensin-converting enzyme inhibitor cilazapril: corrosion cast and electron-microscopic study.

The long-term effects of the angiotensin-converting enzyme (ACE) inhibitor cilazapril on retinal and choroidal circulation in rats with spontaneous diabetes type 2 were assessed by corrosion casts, scanning electron microscopy (SEM) and transmission electron microscopy. One group of 20 male Otsuka Long-Evans Tokushima Fatty (OLETF) rats was treated with 10 mg/kg/day of cilazapril from 4 to 64 weeks of age, and 20 other OLETF rats received no treatment. A third group, 20 male Long-Evans Tokushima Otsuka (LETO) rats, served as age-matched controls. At regular intervals, the rats were weighed, and their blood glucose was measured. Before the experiment, their systolic blood pressure and total cholesterol level were determined. At 64 weeks of age, the OLETF rats weighed significantly less than the cilazapril-treated OLETF and the LETO rats (p < 0.0001). At the same age, 100% of the untreated OLETF rats had bilateral cataracts, while the lens was clear and no fundus abnormality was detected in the cilazapril-treated OLETF rats and the LETO rats. Cilazapril lowered systolic blood pressure to a nearly normal level, significantly prevented the increase in blood sugar and inhibited the increase in serum cholesterol in the OLETF rats throughout the treatment. In the 64-week-old OLETF rats without treatment, corrosion cast and SEM revealed diabetic retinal and choroidal vascular changes: tortuosity of the vessels, variations in caliber, narrowing of arteries, arterio-arteriolar anastomoses and hairpin loop formation in precapillary arterioles, sparse collecting venules in the choroid and marked capillary changes such as caliber irregularity, narrowing, tortuosity, loop formation and decreased capillaries, outpouching and microaneurysms. In the cilazapril-treated OLETF rats, these changes were markedly decreased to the level seen in the LETO rats, in which the retinal and choroidal blood vessels had a definite and fairly constant pattern and the capillaries were more regularly and densely arranged and had a remarkably uniform caliber. Our results show that the long-term administration of cilazapril before or from the initial onset significantly prevented the increase in blood sugar and inhibited the increases in serum cholesterol in OLETF rats throughout the treatment, lowered systolic arterial pressure to a nearly normal level and prevented diabetic ocular complications. The effects of cilazapril on the diabetic retinal and choroidal vasculature are described for the first time. SEM of corrosion casts is a valuable and easy technique for showing precisely and three-dimensionally the effects of some drugs on the vasculature.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Retinal vascular changes during aging in Wistar Kyoto rats. Application of corrosion cast and scanning electron microscopy.

Retinal vasculature changes during aging in normal Wistar Kyoto rats maintained to longevity without known diseases were studied by corrosion casts and scanning electron microscopy (SEM). Six-month-old rat retina showed regular running and arrangement of retinal blood vessels. In 18-month-old rats, a definite morphological change was moderate tortuosity of the vessels, especially at the posterior pole of the retina. In 24-month-old rats, the retinal arteries and veins were very tortuous and narrow, and their calibers were irregular. In some animals occlusion of the veins and localized constriction of the arteries and veins were evident in the vascular casts. Neither arteriovenous crossing defects nor microaneurysms were seen. Retinal capillaries showed marked changes: localized narrowing, constriction, bead-like features, caliber irregularity and occlusion. The corrosion cast method with SEM can demonstrate the details of the capillary networks in the rat retina. The findings demonstrated appear to be related to aging.

Aging↗
PubMed1977

Compratative distortion in three-unit fixed prostheses joined by laser welding, conventioanl soldering, or casting in one piece.

This study evaluated three different joint-forming procedures: laser welding, soldering, and one-piece casting. Fifteen three-unit bridges were fabricated. The findings showed post-jointing distrotion to be significantly less for laser-welded and one-piece castings than for soldering; and significantly greater reliability (least error variance) in joining with the laser than either one-piece casting or soldering.

Dental Abutments↗
PubMed1978

Pressure distribution in centrifugal dental casting.

Equations are developed for liquid metal pressure in centrifugal dental casting, given the instantaneous rotational velocity, density, and certain dimensions of the casting machine and casting pattern. A "reference parabola" is introduced making the fluid pressure concept more understandable. A specially designed specimen demonstrates experimentally the reference parabola at freezing.

Dental Casting Technique↗
PubMed1985

A technique for characterizing casting behavior of dental alloys.

A technique for characterizing casting behavior of dental alloys has been developed and tested. The method employs easily reproducible specimen patterns and uses equipment and procedures generally available in dental prosthetic laboratories. A castability value is arrived at by counting complete segments of a cast alloy grid. Test results indicate that the castability evaluation procedure described can be a valuable aid in the laboratory for both selecting and using dental materials for producing cast restorations. The test method would also appear useful for the evaluation of products and techniques during research and development. An absolute minimum for the castability value determined relative to clinical and laboratory efficacy has yet to be established.

Chemical Phenomena↗
PubMedDate not supplied

A modified cast brace: its use in nonoperative and postoperative management of serious knee ligament injuries.

It has been well-proven that prolonged immobilization is detrimental to synovial joints. For the past 5 years, in an effort to minimize these undesirable sequelae, we have treated 94 patients with major knee trauma by early protected motion. Acute ligament injuries not requiring surgery were placed in the cast brace immediately, while operated cases were started about the 10th postoperative day. Our method of cast bracing stresses proper alignment of the joints, security of limb position, prevention of swelling complications, and economy of physician time. A special feature is a modified single axis joint that restricts the arc of motion to safe limits, generally 30 to 90 degrees. Functionally, our results compare quite favorably with our previous traditionally treated experience. Rehabilitation times were markedly shortened, patient acceptance was high, and complications were rare. Early motion was extremely well-tolerated with only one cast removed because of discomfort. Postoperative effusion rapidly disappeared with commencement of motion. Rapid return of motion did not correlate with a poor result, and the stability of operated knees did not loosen with time. Although lack of controls precludes definitive comparisons, we conclude that early protected motion is safe and provides significant benefits.

Braces↗