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At least 991 records · Page 55Linked to original sources
PubMed2006

[Effects of laser welding on bond of porcelain fused cast pure titanium].

OBJECTIVE: To investigate the influence of the laser welding on bond of porcelain fused to cast pure titanium. METHODS: Twenty cast titanium plates were divided into two groups: laser welded group and control group. The low-fusing porcelain was fused to the laser welded cast pure titanium plates at fusion zone. The bond strength of the porcelain to laser welded cast pure titanium was measured by the three-point bending test. The interface of titanium and porcelain was investigated by scanning electron microscopy (SEM) and energy depressive X-ray detector (EDX). The non-welded titanium plates were used as comparison. RESULTS: No significant difference of the bond strength was found between laser-welded samples [(46.85 +/- 0.76) MPa] and the controls [(41.71 +/- 0.55) MPa] (P > 0.05). The SEM displayed the interface presented similar irregularities with a predominance. The titanium diffused to low-fusing porcelain, while silicon and aluminum diffused to titanium basement. CONCLUSIONS: Laser welding does not affect low-fusing porcelain fused to pure titanium.

Dental Casting Technique↗
PubMed2006

[Characters of the surface of the cast-bonded keeper: an experimental study].

PURPOSE: This study is aimed to analyze the characters of the surface of the keeper after cast-bonded in varied temperatures. METHODS: Twelve keepers were divided into three groups: the gold alloy group, the Ni-Cr alloy group and the Ti group with four samples in each group. A sample that contained a Magdisc 500 keeper was fabricated with the cast-bonded technique. Then, the surface of the sample was observed under scanning electron microscope (SEM) and its elements were analyzed with the electron probe. RESULTS: The results showed that there was no oxide film on the surface of the keeper in the gold alloy group and the Ni-Cr alloy group, but there was an oxide film on the surface of the keeper in the Ti group. However, remains of the investment materials were found on the surface of the sample of three groups. CONCLUSIONS: The study suggested that the casting temperature affect the characters of the surface of the cast-bonded keeper. Gold alloy or Ni-Cr alloy is of better properties for clinical use.

Chromium Alloys↗
PubMed2007

Marginal and internal adaptation of commercially pure titanium and titanium-aluminum-vanadium alloy cast restorations.

AIM: The purpose of this in vitro study was to investigate the marginal accuracy and internal fit of complete cast crowns and three-unit fixed partial dentures (FPDs) cast with commercially pure titanium (CPTi) and Titanium-Aluminum-Vanadium alloy (Ti-6Al-4V). METHODS AND MATERIALS: CPTi and Ti-6Al-4V alloy were used to cast twelve single crowns and twelve three-unit FPDs. A traveling microscope was used to measure marginal gap and discrepancies in internal fit. Two and one-way analysis of variance (ANOVA) analyses were used to determine the effects of the marginal and internal fit discrepancies. RESULTS: The Ti-6Al-4V alloy demonstrated a significantly smaller marginal gap than CPTi (P<0.0001). The recorded marginal discrepancies for both metals were within a clinically accepted range (<100 microm). The single crown fit discrepancy was significantly smaller than the three-unit FPD for both the CPTi and the Ti-6Al-4V alloy (P<0.0001). For the internal fit discrepancy, the occlusal surface showed the greatest gaps. CONCLUSIONS: The Ti-6Al-4V alloy demonstrated a better fit than CPTi. Single crowns showed an improved fit when compared with the three-unit FPD. Mid-occlusal internal gap demonstrated greater values than the axial internal gap. CLINICAL IMPLICATIONS: This in vitro study suggested marginal fit of complete crowns and three-unit FPDs cast by CPTi or Ti-6Al-4V alloy were within the range of what is clinically acceptable for longevity of restorations.

Alloys↗
PubMedDate not supplied

New high-palladium casting alloys: 1. Overview and initial studies.

High-palladium alloys for metal ceramic restorations, based on the Pd-Cu-Ga and Pd-Ga systems, were introduced to the dental profession during the past decade. These alloys have become increasingly popular because they are much less expensive than the gold-based alloys, and recently marketed high-palladium alloy compositions have excellent mechanical properties. A summary of the important melting and casting considerations for these somewhat technique-sensitive alloys is presented together with an overview of important dental materials science aspects and the results of a dental laboratory survey. A maxillary central incisor coping was chosen as the clinically appropriate specimen shape, and the gas-oxygen torch melting technique was found to produce castings with clinically acceptable levels of marginal sharpness and little evidence of microporosity. The etched as-cast high-palladium alloys exhibited fine-scale multiphase microstructures, and a noteworthy finding was that relative proportions of the microstructural constituents frequently varied for thin versus thick sections of the cast specimens.

Crowns↗
PubMed1991

Metallurgical evaluation of a copper-based alloy for dental castings.

The present study was designed to evaluate the metallurgical properties of an experimental, low-cost copper-zinc-aluminum-nickel alloy for dental castings. Some specimens were subjected to heat treatment after induction casting. The extent of corrosion was determined by measuring weight loss of specimens stored in a sodium sulfite solution. In the as-cast specimens, tests demonstrated the presence of three phases: the first consisted of copper-zinc-aluminum, the second was similar but lower in copper and aluminum, and the third consisted of an intermetallic compound of manganese-nickel-phosphorus. After heat treatment, the first phase remained relatively constant, the second was converted to Cu3Al, and the third increased in volume. The weight loss from the as-cast specimens was eight times that of the heat-treated specimens. It was concluded that the heat treatment substantially changed the microstructure and improved the corrosion resistance of the experimental alloy.

Copper↗
PubMed1990

Effect of serial casting for the prevention of equinus in patients with acute head injury.

Ten adults with traumatic head injury received serial casts within 14 days of injury for the prevention or correction of equinus. Eighteen limbs (16 bilateral) with spasticity were involved. An average of five casts for a total duration of four to 64 days were used for each limb. Comparisons of passive dorsiflexion measures before and after casting showed a mean gain of 21 degrees (paired t-test, P less than .05). Of the 18 limbs, 13 reached a passive dorsiflexion of 0 degrees or more (ie, no equinus) which could be maintained without force for at least one hour. The procedures appeared safe and the results of the trial were clinically judged to be favorable. There is a need to further assess the efficacy of serial casting through randomized controlled trials and long-term followups.

Adult↗
PubMedDate not supplied

[Cervical adaptation of complete cast crowns of various metal alloys, with and without die spacers].

A metallic replica from a dental preparation for crown was used to make 8 class-IV stone dies. The wax patterns for the casting of the crowns were obtained in two conditions: a) from the stone die with no spacer; and b) from the stone die with an acrylic spacer. Thus, 64 metallic crowns were casted, using 4 different alloys: DURACAST (Cu-Al), NICROCAST (Ni-Cr) and DURABOND (Ni-Cr), and gold. The casted crowns were fitted in the metallic replica and measured as to the cervical discrepance of fitting. The results showed that the use of die spacers decreases the clinical discrepancies of fitting of the casted crowns (in a statistically significant level), no matter the metallic alloy employed.

Acrylic Resins↗
PubMedDate not supplied

Serial casting: a method for treating burn contractures.

The purpose of this study was to assess the effectiveness of serial casting of burn contractures that were resistant to traditional methods of treatment such as paraffin therapy, massage, exercise, and splinting. Serial casting was used to increase the range of motion in 35 joints in 15 patients with burns. A mean increase of 54% was achieved. Casting provided immediate results with minimal complications and was accepted well by patients. Casts were easy to apply and effective even with noncompliant patients. They also delayed or eliminated the need for surgical correction.

Adult↗
PubMed1989

[Homogeneity and corrosion resistance of cast dental precious metal alloys compared with uncast alloys].

60 cast crowns were manufactured in 6 different dental laboratories using 3 different alloys. The relative areas of cavities at the crown margins and the palatal crown surfaces were measured. Subsequently the crowns and uncast alloy plates were stored in artificial saliva and 1nHCl. After 30 days the dissolved amounts of Cu or, respectively, Ag were measured. All crowns exhibited cavities and porosities. The area of cavities at the crown margins was twice as high as that at the palatal surfaces. The copper ion concentrations measured for cast crowns of the PdCuGaIn-type Pd base alloy were increased by a factor of 20 (maximum) when compared to the uncast alloy. The solubility of the cast PdAgSnIn alloys was characterized by an only slight increase in the amount of dissolved silver. The results suggest that, in view of the inadequacies of dental casting, the use of alloys that may release toxic metal ions should be abandoned.

Copper↗
PubMed1988

[The cast walking shoe combined with modern synthetic support bandages].

Rehabilitation with regard to mobility and function of immobilized lower extremities can be speeded up if the patient can move more frequently and freely with a loadbearing cast. This paper reports on the use of a new external cast system together with a cast shoe. Based on documented cases of empirical experience it is demonstrated that in many cases patients can return to work despite having to wear a cast.

Adult↗
PubMed1987

Total contact casting and chronic diabetic neuropathic foot ulcerations: healing rates by wound location.

This study investigated healing rates of chronic diabetic neuropathic foot ulcerations located on the plantar surface of the forefoot (n = 30) versus those located on other parts of the foot (n = 25). Each type of ulceration was treated with total contact casting. Ulcerations in the first group were located on the metatarsal heads and toes, while ulcerations in the second group were located on the dorsum of the foot, heel, plantar arch, ankle, medial aspect of foot, and toe or transmetatarsal amputation sites. Successfully healed diabetic neuropathic foot ulcerations treated with total contact casting were rated according to patient age, ethnic origin, sex, patient weight, ulcer size, ulcer location, duration of ulcer prior to casting, and ulcer grade. Analysis of variance and posthoc analyses demonstrated that (1) total contact casting was a highly effective method of treatment regardless of ulcer location (forefoot ulcer healing time mean = 30.6 days; nonforefoot ulcer healing time mean = 42.1 days) and (2) forefoot ulcerations healed significantly faster than ulcerations located on other parts of the foot. Complex correlational relationships were explored in this study, and multiple regression equations were developed for each location grouping.

Casts, Surgical↗
PubMed1986

Coxofemoral luxation in two foals wearing hindlimb casts.

Two foals wearing hindlimb casts developed coxofemoral luxations 6 days and 9 days after the casts were applied. One foal had a cast on one hindlimb up to the proximal portion of the tibia and the other foal had tube casts on all 4 limbs. Although the incidents that resulted in the luxations were not observed, they probably occurred during awkward attempts to stand or from being pushed by the mare, with the affected limb being caught under the body in a forward extended and adducted position.

Animals↗
PubMed1980

Evaluation of a technique alloy for use in teaching intracoronal cast gold procedures.

The instability of the gold market has not diminished the position of the intracoronal cast gold restoration as the treatment of choice in certain clinical situations. While cast gold inlay and onlay techniques will probably remain part of the dental school curriculum, the cost factor in teaching these procedures at the preclinical level can be minimized by using a less expensive technique alloy. One such alloy was evaluated for suitability as a gold substitute in teaching the fabrication of the intracoronal cast gold restoration. The remarkable similarity of the handling characteristics of this metal to type I and type II casting gold alloys is discussed.

Costs and Cost Analysis↗
PubMed1984

Intracast muscle stimulation prevents bone and cartilage deterioration in cast-immobilized rabbits.

Tibial articular cartilage and the knee meniscus from cast-immobilized rabbits whose quadriceps were electrically stimulated for 17 days were compared with those from cast-immobilized rabbits without muscle stimulation. Cartilage from non-stimulated rabbits showed evidence of deep fibrillation and loss of Safranin O metachromasia. Scanning electron microscopy (SEM) showed large areas of cavitation and cartilage erosion. Cartilage from cast-immobilized muscle-stimulated rabbits demonstrated no fibrillation, pitting, or surface erosion at either the light microscopic or SEM levels. Electrical muscle stimulation prevented bone loss by significantly increasing bone turnover rate. These observations suggest that electrical muscle stimulation can prevent bone and cartilage deterioration in short-term cast-immobilized limbs.

Animals↗
PubMed1984

Treatment of femoral fractures with the cast brace.

The authors report a retrospective review of 82 patients with femoral fractures treated nonoperatively by skeletal traction and cast bracing at the University of Alberta Hospital between 1975 and 1979. Fractures were classified as stable or unstable and the position of the fracture was assessed at the time of application of the cast brace and at the time of removal, using angulation, shortening and healing time as criteria for classification of results. Satisfactory results were seen in 88% of patients. At the time of cast brace removal, average knee flexion was 97 degrees, thigh atrophy was 2.5 cm and shortening was 1.4 cm. The unsatisfactory results are analysed and a protocol for successful use of the cast brace is suggested.

Adolescent↗
PubMedDate not supplied

Polyurethane foam in postoperative casts.

One-half inch thick polyurethane foam is recommended for use in postoperative casts to avoid complications seen with postoperative swelling. The polyurethane is placed over the operative area, over the dorsum of the foot, and the anterior surface of the leg. The use of polyurethane foam in the postoperative cast not only avoids the necessity of having to split the cast in many instances but the foam also constitutes a compression dressing. If splitting of the postoperative cast should become necessary, the foam protects the skin.

Casts, Surgical↗
PubMed1982

Multidirectional in vivo strain analysis of the equine radius and tibia during dynamic loading with and without a cast.

Rosette strain gauges were applied to the equine radius and tibia. Three sites were examined on each bone on separate occasions (proximal metaphysis, middiaphysis, and distal metaphysis). At each site, 4 rosette gauges were applied around the bone (ie, cranial, caudal, medial, and lateral). Strain recordings were made while walking the horse with and without a full-limb plaster cast. The principal axis of tensile strain was on the craniolateral aspect of the radius. Distally, on the radius, the largest strains were torsional. The cast changed the principal axis of tensile strain on the radius from the craniolateral surface to the caudal surface. The principal tensile strain of the tibia was just to the lateral side of cranial in the proximal and diaphyseal regions. Distally, the principal axis of tensile strain was craniolateral; however, the largest strains measured here were torsional. The cast changed the principal axis of tensile strain on the distal metaphysis of the tibia, but it did not reduce the magnitude of the strains measured. Casts may not aid stabilization of radial or tibial fractures repaired with internal fixation and may in fact place additional stress on the fracture site.

Animals↗
PubMed1982

[The upper arm plaster cast].

In order to treat the scaphoid bone fracture, the most frequent of all carpal fractures, a long immobilization is necessary. This can only be guaranteed by an upper arm plaster cast eliminating pronation and supination of the forearm. We use a modified plaster cast of Verdan, namely a hinge-type plaster cast applied to the upper arm, allowing flexion and extension but blocking pronation and supination. The indications are: - conservative treatment of scaphoid bone fractures - postoperative retention of scaphoid bone fractures operated upon - insecure osteosynthesis of the forearm shaft - postoperative elbow luxation We apply the Baycast bandage and hinge splints without stop made of V2A steel. Until now, four patients have been treated successfully with the hinge-type plaster cast.

Arm Injuries↗