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A comparison of the relative costs of cast treatment and intramedullary nailing for tibial diaphyseal fractures in the UK.

A retrospective study was undertaken to compare the costs of treating tibial diaphyseal fractures non-operatively in a cast or operatively with locked intramedullary nailing. In total 39 patients with isolated closed or grade I open, two-part, displaced tibial diaphyseal fractures were studied. Of these, 18 were treated by manipulation under anaesthesia and cast immobilization, and 21 by closed, reamed, locked intramedullary nailing. A detailed analysis of the cost of treatment of each patient was performed and analysed in terms of the in-hospital costs and the overall costs, taking into account time off work. The mean hospital costs were 2226 pounds for plaster treatment and 3727 pounds for intramedullary nailing (significantly different, p < 0.05). The mean time off work was 9 weeks longer in the plaster group and when the cost of lost production through time off work was added to the hospital costs, the overall costs of plaster treatment and intramedullary nailing were 6810 Pounds and 6592 Pounds (difference not significant). This study suggests that the cost to the hospital of treating these fractures is less with plaster treatment but that the overall cost to the community is no different.

Adult↗

Implant position record and implant position cast: minimizing errors, procedures and patient visits in the fabrication of the milled-bar prosthesis.

This article describes a new rationale and method involved in the fabrication of a patient detachable prosthesis supported by a milled bar. This simple procedure improves prosthesis retention. The overdenture is processed directly over a milled bar, which provides an intimate relation between the bar and the acrylic resin denture base to create resistance against rotational and lateral forces acting on the prosthesis. Incorporating simple and predictable attachments, with low maintenance needs, controls resistance to dislodgment along the path of insertion of the prosthesis. The concepts used in the fabrication of the milled bar include an implant position record (IPR) and an implant position cast (IPC) to reduce the need for time-consuming procedures, such as sectioning the cast bar and soldering it to make it fit the abutments. This procedure also reduces the number of patient visits required of the completion of the prosthesis.

Dental Abutments↗

Marginal accuracy of complete crowns made from alternative casting alloys.

The marginal accuracy of complete cast crowns made from five alternative casting alloys was measured and compared with that of crowns made from the traditional type III high-gold alloy. The alternative alloys studied were low-gold-palladium, high palladium, silver-palladium, nickel-chrome-molybdenum, and copper-aluminum. The findings indicated that Ag-Pd alloy crowns exhibited the best marginal accuracy among the alternative alloys tested. However, their marginal discrepancy value was still slightly higher than that of crowns made of type III high-gold alloy. Conversely, Ni-Cr-Mo alloy crowns exhibited the poorest marginal accuracy.

Cementation↗

Failure of removable partial denture castings during service.

The fracture of removable partial denture castings does not occur in a random manner but rather at characteristic sites that are determined by the designs of the castings. These sites will be located where elastic stresses resulting either from handling or from normal function are likely to be concentrated. Regions of abrupt change in cross-sectional areas and internal voids also have been shown to cause stress concentration. In many instances the regions of stress concentration that are present may act as sites for crack initiation, with fatigue as the ultimate mode of failure.

Dental Alloys↗

A modified indirect cast post and core technique.

An indirect post and core technique in which the core is waxed and invested with the die has been described. The post and core are cast directly into the invested die, which has the advantage of an accurate casting of the post preparation obtained with less laboratory time and without the disadvantages of retrieving an intact wax pattern. This technique is particularly suited for long, narrow post preparations; short preparations where precise fit is necessary for retention; and multiple adjacent post preparations.

Calcium Sulfate↗

Preimpression preparation for positive recovery of master casts.

A technique has been described to ensure positive recovery of a cast by using wax to enlarge teeth that have diastemata and teeth that are periodontally involved with bone loss. On removal of the wax, a void is created in the impression. Stone poured into the void will strengthen the involved teeth so that the cast will not fracture on removal from the impression.

Dental Casting Technique↗

Custom-cast post fabrication with a thermoplastic material.

Problems associated with fabrication of custom-cast posts with a plastic rod and autopolymerizing resin include voids in the pattern, locking of the pattern into undercuts, and resin fracture during removal of the pattern. This article describes a system for fabricating custom-cast posts with a thermoplastic resin to address these problems. The system consists of a plastic support rod and a thermoplastic resin. A custom post pattern can be quickly and easily produced by trimming the plastic rod, heating the resin either over a direct flame or in a low-temperature glue gun and seating it into a lubricated prepared canal. The resin flows well and thereby reduces voids. The resin is elastic enough to be removed from small undercuts without locking into the canal or fracturing.

Dental Casting Technique↗

In vitro corrosion behavior of cast iron-platinum magnetic alloys.

OBJECTIVE: The objective of this study was to investigate the corrosion resistance of cast Fe-Pt alloys of varying compositions for use as attachment keepers and to make a comparison with the corrosion resistance of magnetic stainless steel. METHODS: The corrosion behavior of cast Fe-Pt alloy keepers (Fe-40 at%Pt, Fe-38 at%Pt, Fe-37 at%Pt and Fe-36 at%Pt) was evaluated by means of an immersion test and an anodic polarization test. The solutions used were a 1.0% lactic acid aqueous solution (pH=2.3) (10 ml) and 0.9% NaCl solution (pH=7.3) (10 ml). As a control, the corrosion resistance of a magnetic stainless steel keeper (SUS 447J1: HICOREX) was also measured. RESULTS: Chromium and platinum ions were not detected in either the 1.0% lactic acid or 0.9% NaCl solutions. The only released ions detected were the Fe ions in the 1.0% lactic acid solution. The amounts of Fe ions released from the Fe-40 at%Pt and Fe-38 at%Pt alloys were significantly (p<0.05) lower than from the Fe-37at%Pt, Fe-36 at%Pt and SUS 447J1 alloys. In the anodic polarization test, the potentials at the beginning of passivation for the four Fe-Pt alloys were higher than for the SUS 447J1 alloy in both solutions. SIGNIFICANCE: The Fe-Pt alloys, especially the alloys with higher Pt percentages (Fe-40 and 38 at%Pt), indicated a high corrosion resistance compared to the magnetic stainless steel keeper. A reduction in the Pt percentage may decrease the corrosion resistance in the oral environment.

Chromium↗

Elemental release from dental casting alloys into biological media with and without protein.

OBJECTIVE: The objective of this study was to determine the role of proteins in affecting elemental release from a variety of clinically available dental casting alloys. An important role for proteins was suspected based on previous reports about the corrosion of stainless steel and the cytotoxicity of alloys after exposure to a saline-protein solution. METHODS: Clinically available alloys with compositions ranging from 0 to 94at.% noble elements were exposed for 1 week to either saline, saline with 3% bovine serum albumin (BSA), or complete cell-culture medium with 3% serum. Atomic absorption spectrophotometry was used to measure the release of elements from the alloys. Elemental release was normalized for the exposed surface area of the alloys. RESULTS: In general, more elemental release occurred into the saline-BSA solution compared to saline alone for all released elements (Ag, Cu, Pd, and Zn) except for Ni. Ni release from the NiCr alloy was lower in the presence of BSA. Each element responded somewhat differently with Pd being the least predictable in its behavior. Elemental release was less in the cell-culture medium than in the saline-BSA solution for most elements. For alloys which released multiple elements, all elements responded similarly but not identically to the presence of protein. A high elemental release during exposure to the saline-BSA solution correlated with a low alloy cytotoxicity post-exposure to the saline-BSA. SIGNIFICANCE: This study demonstrates the importance of defining exactly the composition of biological solutions used to assess in vitro corrosion and biocompatibility of dental casting alloys. Other molecules in addition to proteins appeared to be critical to the corrosion of these alloys in vitro.

Analysis of Variance↗

Complications of fractures repaired with casts and splints.

Complications of external coaptation of fractures include delayed and nonunion healing from lack of adequate fracture stability, pressure and rub sores, leg swelling, dermatitis, joint laxity or stiffness, cast or splint breakage, and refracture. Most of the complications are a result of improper application of the coaptation device or poor management of the patient. Early recognition and treatment of complications are needed to minimize their effect. The number of complications resulting from external coaptation can be minimized by proper application of the cast or splint.

Animals↗

Do arrhythmia patients improve survival by participating in randomized clinical trials? Observations from the Cardiac Arrhythmia Suppression Trial (CAST)and the Antiarrhythmics Versus Implantable Defibrillators Trial (AVID).

It is debatable whether patients benefit directly from participation in a randomized clinical trial. We attempt to address this question for participants in the Cardiac Arrhythmia Suppression Trial (CAST) and the Antiarrhythmics Versus Implantable Defibrillators (AVID) studies. Survival rates were compared between eligible patients who enrolled in the trials and eligible patients who did not enroll, adjusting for baseline covariates. In CAST, despite that the active therapy was found to confer an almost threefold increased risk of death, survival was similar between the 3163 enrolled and the 1363 nonenrolled eligible patients. However, when patients were under study management, their risk of death was approximately 20% lower than when they left study management. In AVID, overall survival was similar between the 1016 enrolled and the 1246 nonenrolled eligible patients. However, mortality was substantially higher among patients not enrolled because the referring physician mandated the type of therapy. Overall these observational analyses suggest a net improvement in survival for the participants in these two trials.

Arrhythmias, Cardiac↗

The measurement of the rotational deformities with computed tomography in femoral shaft fractures of the children treated with early spica cast.

Twenty-eight children with femoral shaft fractures, treated with early spica cast, were evaluated with computed tomography (CT), for their femoral shaft rotational deformities. The femoral torsion angles were measured on both sides. If the torsion angle of the fractured side was more than the other side, it was considered as an internal rotational deformity and if it was less, it was considered as an external rotational deformity. Internal rotational deformities were detected in nine cases and external rotational deformities were detected in 17 cases. Rotational deformity was not observed in two cases. Four cases, with a rotational deformity more than 10 degrees, were corrected with a gypsotomy through the level of the fracture. We concluded that a rotational deformity, which is an important complication in conservative treatment of the femoral shaft fractures in children, can be determined exactly with CT and corrections on the spica cast can be made with a gypsotomy.

Casts, Surgical↗

Deep venous thrombosis and pulmonary embolism following cast immobilization of the lower extremity.

It is generally accepted that venous thrombosis in the lower extremity predisposes to pulmonary embolism. A case of pulmonary embolism after cast immobilization of the lower extremity, as well as a review of thromboembolic disease is presented. A high level of vigilance and close follow-up of even simple cast treatment is necessary to avoid this complication.

Achilles Tendon↗

Lactation, birth spacing and maternal work-loads among two castes in rural Nepal.

The nursing behaviour of rural Nepali women, from two castes inhabiting the same village, is quantified on the basis of 2202 hr of continuous and direct day-time observation over 1 year. Feed duration, interval, total time and daily frequency are examined in relation to women's work, particularly the type of subsistence activity and seasonality. 'Opportunity' feeds are governed both by infant demands and maternal activity. Caste differences in birth intervals are also discussed.

Adolescent↗

Retinal vascular architecture is maintained in retinal degeneration: corrosion cast and electron microscope study.

PURPOSE: To demonstrate the changes of the retinal vascular architecture in the diffusely degenerated thin retina. METHODS: Three-week-old weanling Wistar Kyoto rats were divided randomly into two groups. One group (n = 20) was fed a vitamin E-deficient solid diet and the other group (n = 20) was fed a solid rat chow diet. Rats were maintained on their respective diets for 14 months and then killed for scanning electron microscopy of vascular corrosion casts, light and electron microscopy and biochemical determinations. RESULTS: The serum level of vitamin E in the E-deficient rats was 1.0 +/- 0.49 microg/ml, while that in the rats fed a normal diet was 13.7 +/- 1.0 microg/ml (Student's t-test, p = 0.0001). In vitamin E-deficient rats, light microscopy showed degenerated retinas only half as thick as normal. Corrosion casts and scanning electron microscopy revealed that the retinal capillaries of the entire retina were decreased in number and scattered with localised narrowing, calibre irregularity and frequent loop formation. In the posterior pole of the retina, some capillaries clustered into small tortuous knots. However, the two-layered architecture of the capillary network in the retina was maintained. The differences in calibre of retinal capillaries between the vitamin E-deficient and normal rats were statistically significant (p < 0.0001). No remarkable abnormal changes were observed in the large retinal vessels other than arterial calibre differences (p < 0.022). No arteriovenous shunts, crossing defects or microaneurysms were seen. Transmission electron microscopy revealed complete disappearance of the photoreceptor outer and inner segments and nuclei. The retinal pigment epithelium contained lipofuscin granules and retinal capillaries with narrow lumens. The capillary endothelial cells were thickened and had scarce cytoplasmic components with vacuoles and irregularly thickened basement membranes. The capillary pericytes had vacuoles. No abnormalities were seen in the control normal rats. CONCLUSION: These findings indicate that the decrease in retinal capillaries in vitamin E-deficient rats is secondary to retinal degeneration. It was assumed that the morphological changes in the capillary network reflected structural damage to the retinal vascular cells caused by free radicals and lipid peroxides generated by oxidation. However, even in such severe degeneration the retinal vascular architecture, including the main artery and vein and two-layer capillary networks, was maintained. This is may be because of the basic anatomical arrangement of the blood vessels.

Animals↗

The microvascular architecture of the rat vagina revealed by image analysis of vascular corrosion casts.

BACKGROUND: Female sexual dysfunction is a common but poorly understood human condition. One of the aspects hindering progress in this area is the lack of appropriate animal models that can be used to study the complex factors involved in this sexual health problem. Recently, attention has focused on the probable role of vascular dynamics of the genital organs and their potential for impact on female sexuality. The objective of this study was to provide a better description of the vascular anatomy of the female rat vagina and external genital organs in an attempt to better develop this as an animal model to study female sexual dysfunction. METHODS: Young female (nonestrous) virgin rats were anesthetized, the abdominal aorta was cannulated, and the distal vasculature was flushed and fixed in vivo for histological studies or for subsequent infusion with Mercox resin for vascular corrosion casting. Vascular corrosion casts of the external genitalia (vagina and vulva) were studied using a scanning electron microscope (SEM). Fixed tissue specimens were also embedded and sectioned for histochemical and immunohistochemical analysis. RESULTS: Scanning electron microscopy imaging allowed a description of the vascular and microvascular system of the nonestrous female rat genitalia. Major feeding vessels were located laterally in the muscular and serosal layers of the vagina with a complex system of interanastomosing collaterals between these large lateral trunks. The sub-epithelial region of the vaginal wall contains a dense and rich network of capillaries that perfuse the epithelium. These data were corroborated by two- dimensional histochemistry and immunostaining for endothelial and smooth muscle cells on paraffin-embedded thin sections of the female vagina and vulva. CONCLUSION: This study provides the first detailed three-dimensional en bloc view of the macro- and microvascular anatomy of the female rat vagina and vulva. The findings suggest an active interaction between the microvasculature and the epithelial cells of the vaginal wall. This study will provide the basic anatomic groundwork for future experiments on perturbations of the vascular system of the rat female genitalia in response to hormonal stimuli and various disease states.

Animals↗

Evidence of angiogenesis and microvascular regression in autosomal-dominant polycystic kidney disease kidneys: a corrosion cast study.

Autosomal-dominant polycystic kidney disease (ADPKD) accounts for about 10% of all cases of chronic renal failure requiring dialysis. The disease is characterized by proliferation of renal epithelial cells and formation of cysts that expand over years and replace the normal parenchyma of the kidney. As the cysts grow, the volume of the kidney can increase by more than 10-fold, implying that remodeling and expansion of the vasculature must occur to provide oxygenation and nutrition to the cyst cells. Our previous studies support the notion that there is angiogenesis in ADPKD. We report here results from resin casting of ADPKD kidneys vasculature. In this study, the corrosion-casting method was used in conjunction with scanning electron microscopy to study the vascular architecture and the evidence for angiogenesis in ADPKD kidneys. We found a well-defined vascular network around the cysts forming a 'vascular capsule' somewhat similar to that described in avascular leiomyomata. We also found that the normal vascular architecture is lost and replaced by an assortment of capillaries of larger size than those in the normal kidney, mixed with flattened and spiral arterioles, damaged glomeruli, and atresic venules, indicative of regression of the microvasculature. In the same areas, there was capillary sprouting, considered the hallmark of angiogenesis. The present study documents regression changes of the vasculature and confirms the existence of angiogenesis in ADPKD kidneys, and suggests the use of inhibitors of angiogenesis as a possible avenue for the treatment of the disease.

Adult↗

Plastic casts and confocal laser scanning microscopy applied to the observation of enamel tubules in the red Kangaroo (Macropus rufus).

Scanning electron microscopy for plastic casts and confocal laser scanning microscopy for Villanueva bone-stained ground sections were used together to observe enamel tubules in red kangaroo molars. Although the tubular structures such as terminals, bends, expansions, splits, divergences and rejoinings in this species were within the variations of marsupial species, their morphological characteristics were demonstrated with extremely clear and persuasive images. Thus, the combined observations of plastic casts by scanning electron microscopy and Villanueva bone-stain sections by confocal laser scanning microscopy were found to be of value for the investigation of enamel tubules and tubular structures in other hard tissues.

Acrylic Resins↗