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At least 415 records · Page 23Linked to original sources
PubMed2006

The effect of serial casting on gait in children with cerebral palsy: preliminary results from a crossover trial.

Serial casting aims to improve an equinus gait pattern in children with spastic cerebral palsy (SCP). We evaluated the effect of short-term stretch casting on gait in children with SCP, compared to the natural history. A crossover trial, consisting of a control phase and a casting phase, was conducted with children randomised into two groups. Both groups were assessed clinically, and using 3D gait analysis, at 0, 5 and 12 weeks. Subjects in one group had the 3 month casting phase first and in the other had the 3 month control period first. Casts were changed weekly and set at maximum available ankle dorsiflexion. The mean changes at 5 weeks and 12 weeks from baseline measurements in the casting phase were compared with the change within the same time interval in the control phase. Significant improvements in passive ankle dorsiflexion (knee flexed) were found at 5 and 12 weeks. Passive ankle dorsiflexion (knee extended), ankle dorsiflexion in single support, ankle dorsiflexion in swing and minimum hip flexion in stance improved significantly at 5 weeks but not at 12 weeks from baseline. Other kinematic parameters, the score on the Gillette Functional Assessment Questionnaire, and maximum reported walking distance were not changed by casting. Casting to improve range appears to improve passive and dynamic ankle dorsiflexion, but the changes are small, short lived and do not appear to affect function.

Biomechanical Phenomena↗
PubMed2005

Comparative study of the surface characteristics, microstructure, and magnetic retentive forces of laser-welded dowel-keepers and cast dowel-keepers for use with magnetic attachments.

STATEMENT OF PROBLEM: Information regarding the merits and problems associated with connecting a keeper to a dowel and coping using a laser welding technique has not been explored extensively in the dental literature. PURPOSE: This in vitro study compared the surface characteristics, microstructure, and magnetic retentive forces for a dowel and coping-keeper mechanism fabricated using a laser welding process and a cast-to casting technique. MATERIAL AND METHODS: Five cast-to and 6 laser-welded dowel and coping-keeper specimens were tested. Using 5 freestanding keepers as the control group, the surface characteristics and microstructures of the specimens were examined by means of stereomicroscopy, metallographic microscopy, and scanning electron microscopy (SEM). Energy-dispersive spectroscopic (EDS) microanalysis with SEM provided elemental concentration information for the test specimens. The vertical magnetic retentive forces (N) of the 3 groups were measured using a universal testing machine. The results were statistically compared using 1-way analysis of variance and the Newman-Keuls multiple range test (alpha =.05). RESULTS: The laser-welded dowel-keeper generally maintained its original surface smoothness as well as the original microstructure. Elements diffused readily through the fusion zone. The surface of the cast dowel-keeper became rough with the formation of an oxide layer, the microstructure changed, and there was only limited elemental diffusion in the fusion zone. The average vertical magnetic retentive force of the laser-welded group, the cast group, and the control group were 4.2 +/- 0.2 N, 3.8 +/- 0.3 N, and 5.6 +/- 0.3 N, respectively. Statistically significant differences in vertical magnetic retentive force were found between the control group and both the laser-welded and cast groups (P <.01). Compared with the cast dowel-keepers, the average vertical magnetic retentive force of the laser-welded dowel-keepers was significantly higher (P <.05). CONCLUSION: The laser welding technique had less influence on the surface characteristics, the microstructure, and the magnetic retentive forces of keepers relative to techniques that incorporate a keeper at the time of cast dowel and coping fabrication.

Dental Prosthesis Retention↗
PubMed1997

Quantitative study of bacterial colonization of dental casts.

STATEMENT OF PROBLEM: Contamination of dental casts can occur if the record bases are improperly disinfected or inadvertently not disinfected during fabrication of a prosthesis. It is essential to develop an effective means of disinfecting dental casts from professional, medical, and legal points of view. PURPOSE: This study determined whether: (1) saliva contamination on the surface of the dental cast contributed to bacterial growth over time and (2) cleaning or disinfecting of dental casts can minimize bacterial growth. MATERIAL AND METHODS: Five dental casts were contaminated with saliva. Each cast was divided into six areas and swabbed at 15, 30, 60, 120, 180, and 240 minutes. Sheep blood agar plates were inoculated and incubated at 37 degrees C for 72 hours. Standardized dental stone cylinders were contaminated with 25 microliters of saliva and treated by rinsing in tap water, scrubbing with soap and tap water, soaking in 2% glutaraldehyde, or as controls with and without saliva contamination (n = 12). The treated dental stone cylinders were placed in individual test tubes containing 2.5 ml of sterile phosphate-buffered solution and a final dilution of 10(-4) was achieved. Sheep blood agar plates were inoculated and incubated at 37 degrees C for 24 hours. RESULTS: Contamination of dental casts did not decrease, even when allowed to sit 4 hours before handling. Results also demonstrated that rinsing saliva-treated stone cylinders for 20 seconds significantly diminished bacterial contamination. Scrubbing with soap and tap water or soaking in 2% glutaraldehyde significantly reduced the bacterial contamination of saliva-treated stone cylinders when compared with rinsing with tap water. CONCLUSION: Bacterial contamination of dental casts can occur and requires an effective method of disinfecting.

Agar↗
PubMed2002

Nutrient availability and maize growth in a soil amended with earthworm casts from a South African indigenous species.

The study was undertaken to assess the availability to maize of nutrients from earthworm casts (wormcasts) collected from a grazing paddock in the Eastern Cape province of South Africa. Maize (cv PAN 473) was grown in pots filled with ground wormcasts, non-casted surrounding soil and a mixture of the two media. Fertiliser application increased growth and uptake of nutrients by maize grown on both wormcast and non-casted soil. Maize grown on wormcasts had significantly (p < 0.05) higher plant height, stem diameter, dry weight and showed higher nutrient uptake and lower fertiliser response than that grown on corresponding non-casted surface soil. The uptakes of plant nutrients, growth and dry matter yields were in the order fertiliser>wormcasts>non-casted soil. Mixing worm casts with non-casted soil improved maize growth and nutrient uptake over non-casted soil. It is concluded that wormcasts could be used as a soil amendment for crop production, especially in small-scale production systems.

Animals↗
PubMed2001

Numerical simulation of the casting process of titanium tooth crowns and bridges.

The objectives of this paper were to simulate the casting process of titanium tooth crowns and bridges; to predict and control porosity defect. A casting simulation software, MAGMASOFT, was used. The geometry of the crowns with fine details of the occlusal surface were digitized by means of laser measuring technique, then converted and read in the simulation software. Both mold filling and solidification were simulated, the shrinkage porosity was predicted by a "feeding criterion", and the gas pore sensitivity was studied based on the mold filling and solidification simulations. Two types of dental prostheses (a single-crown casting and a three-unit-bridge) with various sprue designs were numerically "poured", and only one optimal design for each prosthesis was recommended for real casting trial. With the numerically optimized design, real titanium dental prostheses (five replicas for each) were made on a centrifugal casting machine. All the castings endured radiographic examination, and no porosity was detected in the cast prostheses. It indicates that the numerical simulation is an efficient tool for dental casting design and porosity control.

Journal Article↗
PubMed1984

Three-dimensional architecture of cerebral microvessels with a scanning electron microscope: a cerebrovascular casting method for fetal and adult rats.

Vascular casting for scanning electron microscopic studies on microvascular architecture is in common use for various visceral organs in the field of anatomy. However, only a few studies have been performed on the brain using the previously reported casting method, and no detailed descriptions deal with suitable methodology for producing brain vascular casts. Our casting method, introduced here, for the CNS from the fetal to the adult stage involves the following modifications: (1) Perfusion fixation of the brain is carried out before injecting the plastic resin for casting into the cerebral blood vessels; (2) digestion of nervous tissue is accomplished with a sodium hydroxide and sodium hypochlorite solution; and (3) vascular casts are dried by a freeze-drying method, while the nondigested brain slices opposite the casts can be investigated with light microscopy and transmission electron microscopy. This modified casting method enables one to represent the microvascular system of the rat brain three-dimensionally from embryonal day 17 onward. It is hoped that this method will prove to be a useful tool in morphological vascular research on the nervous system.

Animals↗
PubMed2006

Patient's age and extent of coronal and root destruction predict root canal treatment subsequent to after a full-cast crown.

DESIGN: A case-control study was carried out at the University of North Carolina School of Dentistry in the US. PARTICIPANT SELECTION: Dental charts from the university's dental clinical were audited for patients who had a single-cast crown between 1 January 1998 and 31 December 2002. Cases were defined as individuals who underwent root canal treatment at some time after the insertion of a single-cast crown up to 1 July 2004. The control group consisted of people who did not have root canal treatment after the insertion of a full-cast crown. DATA ANALYSIS: A list of 24 clinical factors was compared between groups (Table 1). Multiple logistic regression analysis was used to determine which preoperative nonprocedural factors were predictive of root canal treatment subsequent to a full-cast crown. RESULTS: A total of 6612 single-cast crowns (cast metal or porcelain fused to metal) were inserted during the 5-year period of interest. Of these, 5743 crowns, identified from 3357 patients' records (ie, the study subjects), were determined not to have undergone root-canal treatment prior to full-cast crown restorative treatment. Ninety-two subjects were initially determined to be eligible cases; ninety-two subjects were also therefore randomly selected from the remaining 3265 subjects to make up the control group. Twenty-six of the cases and 21 members of the control group were excluded because of incomplete records. The final case and control groups comprised 66 and 71 subjects respectively. Only subjects' age at the time of restorative treatment and their post-cementation tooth sensitivity was statistically significantly different between the two groups (P<0.05). Multiple logistic regression determined the statistically significant (P<0.05 ) predictors of case status: these were a patient's age and also the subgroup to which they were allocated according to the extent of pre-operative coronal and root destruction, on the basis of the restorative core size (more than three restored surfaces; Table 2). CONCLUSION: The age of a patient and the extent of coronal and root destruction can be used to predict the future need for root canal treatment on teeth for which a single-cast crown is planned.

Journal Article↗
PubMed2004

Differential effects of cast shadows on perception and action.

In two experiments we investigated the effects of cast shadows on different real-life tasks. In experiment 1, participants were required to make a speeded verbal identification of the target object (perceptual task), whereas in experiment 2 participants were required to reach for and grasp the target object (motor task). In both experiments real three-dimensional (3-D) objects were presented, one at a time, either with their own natural cast shadow (congruent condition) or with the cast shadow of a different object (incongruent condition). Shadows were cast either to the left or to the right of the object. We asked whether the features of the shadow (ie whether it is congruent or incongruent with the object, and whether it is cast to the left or to the right of the object) could influence perception and action differently. Results showed that cast shadows did not influence identification of real 3-D objects (experiment 1), but they affected movement kinematics, producing distractor-like interference, particularly on movement trajectory (experiment 2). These findings suggest a task-dependent influence of cast shadows on human performance. In the case of object-oriented actions, cast shadows may represent further affordances of the object, and as such compete for the control of the action.

Adult↗
PubMedDate not supplied

Mitochondrial DNA variation in ranked caste groups of Maharashtra (India) and its implication on genetic relationships and origins.

BACKGROUND: Polymorphism in mitochondrial DNA have been proven to be useful in studying genetic relationships and origins. The origins of caste populations have remained an enigma and genetic relationships among ranked caste groups are not uniform across geographical regions in India. AIM: This study was undertaken to investigate the nature and extent of mtDNA variation and relationships among caste groups of the western Indian State of Maharashtra and examine the implication of the results on their origins. SUBJECTS AND METHODS: One population was selected from each of the three caste ranks and blood samples were obtained with informed consent from unrelated individuals. The ranked caste populations were: upper (Brahmin; n=31), middle (Maratha; n=41), and lower (Nava Baudh; n=40). Ten relevant restriction site polymorphisms (RSPs) and one Insertion/Deletion (InDel) polymorphism were studied. The Hypervariable Segment 1 (HVS1) was sequenced in a subset of sampled individuals. RESULTS: Four RSP loci were found to be monomorphic in all populations. The InDel locus was monomorphic in two (Brahmin and Maratha) populations. One haplotype, constructed on the basis of the RSPs, was found to be predominant in all populations. Haplotype diversity was of similar magnitudes among Maratha and Nava Baudh (68% and 64%, respectively), and was much higher than among the Brahmin (49%). The frequency of haplogroup M was found to be high in all three groups, but, contrary to expectations, was highest in the upper caste Brahmin. About 10% of Brahmins, however, possessed the haplogroup C. Extensive variation was found in the HVS1 region. The nucleotide diversities and mean number of mismatches were found to be of similar magnitudes in all three groups. CONCLUSIONS: The upper caste group, Brahmin, is genetically distinct from the middle and lower caste groups. However, in view of the highest frequency of haplogroup M among the Brahmin, it appears that there may have been recruitment from other populations into this group.

DNA, Mitochondrial↗
PubMed1998

The effects of custom tray material on the accuracy of master casts.

PURPOSE: The accuracy of master cast reproduction by a polyvinylsiloxane impression material using two visible-light-curing resin and an autopolymerizing polymethyl methacrylate resin custom tray materials was investigated. MATERIALS AND METHODS: Custom trays were fabricated from a master cast that had three index points marked on both the inner and outer vestibules. Impressions were made of the master cast using Extrude and then poured in Die Keen Green stone. The distances between the reproduced index points were measured to +/- 0.01 mm with a traveling microscope and the algebraic norms calculated for each tray material. RESULTS: No differences (p > .05) were found in the dimensions of the inner index points, while the separations of the outer index points indicated that there were differences in the accuracy of reproduction (p < .01) by the three tray materials. The index points reproduced on the casts, compared with the master cast, were closer together for the Triad Blue trays than for the TruTray and Ontray impression trays. CONCLUSIONS: All three tray materials produced acceptable casts, but the greatest accuracy was achieved with TruTray, followed by Ontray. Triad Blue produced casts that were slightly smaller than the master. In practice, the small measured differences in cast dimensions may not have clinical significance.

Analysis of Variance↗
PubMed1997

Bronchial casts in children: a proposed classification based on nine cases and a review of the literature.

Bronchial casts are characterized by the formation of obstructive airway plugs that may be large enough to fill the branching pattern of an entire lung. The condition is rare but can occur at any age. Casts may be secondary to underlying diseases such as asthma and cystic fibrosis, but there are often no predisposing factors. There is no accepted classification system for bronchial casts; but only a confusion of descriptive terms such as mucoid impaction, fibrinous bronchitis, and pseudomembranous bronchitis. Based on a review of nine well-documented cases and the available literature, we have separated bronchial casts into two well-defined groups: Type 1 (inflammatory), consisting of casts composed mainly of fibrin with a dense eosinophilic inflammatory infiltrate; and Type 2 (acellular), consisting of casts composed mainly of mucin with little or no cellular infiltrate and occurring only in children with congenital cyanotic heart disease. Acute mortality was high in both groups. Survivors of Type 1 casts seem to be well controlled with inhaled steroids. Optimal therapy for patients with Type 2 casts is not clear; the prognosis probably depends on underlying cardiac status. We hope that this simple classification will provide a framework for further study of this obscure condition.

Adolescent↗
PubMed1996

The cognitive assessment screening test (CAST) for dementia.

The purpose of this study was to assess the usefulness, the sensitivity, and the specificity of the Cognitive Assessment. Screening Test (CAST), a paper-and-pencil self-administered cognitive test designed to screen elderly people for possible dementia, for use in general physicians' offices, requiring little expertise or staff time. CAST consists of three parts: part A (relatively easy), part B (more demanding), and part C (self-report of concerns). CAST was administered in two studies to: (1) 19 patients known to be mildly to moderately demented versus 24 age-matched normal controls (to establish cutoff standards); and (2) a "real world" sample of 26 elderly patients not known to be demented, attending a general medicine clinic. The sensitivity and specificity of CAST were compared with the Mini-Mental State Examination (MMSE) and the Blessed Dementia Scale cognitive portion (BDS-cog). In study 1, controls were given a detailed neuropsychological battery; in study 2, all patients were given the neuropsychological battery, which served as the "gold standard" to identify individuals with cognitive impairment. In study 1, the cutoff scores for dementia using CAST (Parts A and B) were established. CAST discriminated demented patients from controls with a sensitivity of 95% and a specificity of 88%; the MMSE had a sensitivity of 74% and a specificity of 100%; and the BDS-cog had a sensitivity of 100% and a specificity of 96%. In study 2, CAST discriminated cognitive impairment with a sensitivity of 88% and a specificity of 100%, the MMSE had a sensitivity of 38% and a specificity of 100%; and the BDS-cog had a sensitivity of 50% and a specificity of 94%. Part C was not used to discriminate demented from normal elderly individuals, but to screen for those concerned about their cognitive functioning. CAST is highly useful as a dementia screening test, with sensitivity and specificity equal to or better than the MMSE and BDS-cog, yet requiring minimal examiner time and little training or experience to administer.

Aged↗
PubMedDate not supplied

Variability of neutral-position casting of the foot.

Neutral-position casting of the foot is used for the manufacture of functional foot orthoses, and an accurate cast is widely assumed to be a prerequisite for a good orthotic device. The primary aim of this study was to determine the variability of casting between inexperienced and experienced clinicians and the variability of one experienced clinician taking multiple casts. Ten inexperienced and ten experienced clinicians took a cast of the right foot of a single subject, and a single experienced clinician took ten casts of the same foot. The frontal plane forefoot-to-rearfoot relationship of each cast was determined, and no difference was found in the mean and variances among the three groups. The range of the forefoot-to-rearfoot relationship across all groups was from 10.0 degrees everted to 6.5 degrees inverted, indicating that there is a wide range in neutral-position casting of the foot. As outcome studies have reported the successful outcomes of functional foot orthoses, this wide variability may not necessarily be a problem.

Foot↗
PubMed1999

Evaluation of the implant master cast by means of the Periotest method.

Accurate master casts are essential for the construction of implant-supported prostheses with a precision of fit. The stability of the abutment replicas in the master cast is critical in the accurate reproduction of the patient's oral presentation. The Periotest method is an objective method of quantifying mobility in a tooth and implant. Eighteen gypsum implant master casts containing two brass abutment replicas per cast were evaluated. The abutment replicas were measured three times each for a total of 108 measurements. The mean periotest values and standard deviations were calculated for the master casts and the abutment replicas. The abutment replicas displayed mean periotest values that ranged from +1.3 to -8.0. The study shows that there are significant differences between stable and unstable implant master casts (P = 0.0001, ANOVA-Fisher's protected least significant difference) and abutment replicas (P = 0.0001, Contrast test). The Periotest method will quantify differences in gypsum stone implant master casts as well as the prosthesis supporting brass abutment replicas that are an integral part of the master cast.

Analysis of Variance↗
PubMed2002

[Experimental study of the effect on marginal seating of the castings by different investing methods].

OBJECTIVE: The purpose of this study was to observe the effect on marginal seating of the castings with and without ring investments. METHODS: Standarded as-cast specimens and round capsules simulated post tooth crowns were made. 12 wax pattern were prepared on the as-cast specimens. The 12 specimens were divided into two groups with 6 wax pattern in each group. Two different investing methods with the same investing material were tested. The marginal seating of the castings was measured under travelling microscope. RESULTS: The marginal seating of the casting without ring investment had significant difference compared with the castings with ring investment (P<0.05). CONCLUSION: Casting without ring can improve the marginal seating of the castings.

English Abstract↗
PubMed2004

[Study on elastic limit and relevant enclasp force of non-precious metal casting clasp].

OBJECTIVE: To investigate the elastic limit and relevant enclasp force of the non-precious metal casting clasp. METHODS: Casting clasp samples of five cobalt-chromium alloys and one 18 - 8 nickel-chromium alloy were made from prefabricated clasp wax by invesing, casting, sandblasting, and ultrasonic cleaning. The process of casting clasp samples deflected by loading and returned by unloading was tested and electric signals were collected by an omnipotent material machine. The analog electric signal was converted to digital signal by an analog to digital converter and stored in a computer. The elastic limit and the relevant enclasp force were analyzed using a relative software. RESULTS: The elastic limit and the relevant enclasp force of the casting clasp made from the 18 - 8 nickel-chromium alloy were smallest and those of the clasps made from the cobalt-chromium alloys in various brands were different. The range of the elastic limit of the cobalt-chromium alloy casting clasp with the length of 5.0 mm in undercut was 0.28 mm-0.33 mm and the relevant enclasp force was 14.42 g-19.28 g. CONCLUSIONS: In clinic, we should select the suitable undercut deepness wherein the cobalt-chromium alloy casting clasps, according to different brands of the casting alloy, undercut length, undercut slope, and the clasp thickness.

Chromium Alloys↗
PubMedDate not supplied

High-level microwave disinfection of dental gypsum casts.

PURPOSE: To test whether microwave oven irradiation can disinfect gypsum casts in compliance with current disinfection requirements, and to determine whether this procedure would be as effective as a validated method of chemical disinfection of impressions. MATERIALS AND METHODS: In 2 in vitro experiments, samples of 5 irreversible hydrocolloid impressions of a disinfected acrylic resin model were contaminated with suspensions of recommended test organisms Staphylococcus aureus and Pseudomonas aeruginosa, respectively. In 1 in vivo experiment, 10 impressions were made of 10 subjects. All impressions were poured and the resulting casts cut in 2 halves. One half of each cast was exposed to 5 minutes of irradiation in a microwave oven at 2,450 MHz and 900 W. The other halves were left untreated as controls. In a second in vivo experiment, 10 impressions were disinfected by immersion in a 0.07% solution of NaOCl at pH of about 10 for 3 minutes, and then poured. All casts were incubated aerobically in Bacto tryptic soy broth at 37 degrees C for 6 hours and assessed for bacterial growth by counting colony-forming units per milliliter (cfu/mL) of the culture. The results were analyzed using the Wilcoxon signed-rank test. RESULTS: Untreated gypsum casts showed cfu/mL counts with a median log value of 6, while microwave-irradiated ones had median cfu/mL counts of 0. Casts poured from chemically disinfected impressions demonstrated cfu/mL counts with a median log value of 4. CONCLUSION: Under the described conditions, microwave-irradiated gypsum casts satisfy current disinfection requirements, but gypsum casts poured from chemically disinfected impressions do not.

Alginates↗
PubMed2006

[Obstructive jaundice due to biliary cast syndrome followed by orthotopic liver transplantation].

Biliary complication occurs in 6-34% of all liver transplant patients. Although bile leaks and strictures are relatively common, other biliary complications such as T-tube leak, choledocholithiasis, and biliary cast syndrome can also be observed. The biliary cast syndrome describes the presence of casts causing obstruction with its resultant sequelae of biliary infection, hepatocyte damage secondary to bile stasis and ductal damage, all contributing to cholangiopathy. Because the exact timing of cast formation after orthotopic liver transplantation is not consistent, it is difficult to define the true incidence of biliary cast syndrome without long-term follow-up data. Proposed etiological mechanisms include acute cellular rejection, prolongation of cold ischemic time, infection, biliary drainage tubes, and biliary obstruction. The diagnosis of biliary cast syndrome is usually confirmed by endoscopic retrograde cholangiopancreatography. There have been few published articles about biliary casts in Korea. Herein, we report a case of biliary cast syndrome followed by orthotopic liver transplantation.

Adult↗