Academic literature on the topic 'Dental implants Gold alloys Silver-palladium alloys'

Non-toxic allergy free alloying elements are mostly selected for preparing metallic biomaterials. Currently, functionalities such as low modulus, shape memory, super elasticity, etc. are required for the metallic biomaterials, especially for β type titanium alloys. The harmonization of metallic, ceramic, and polymer biomaterials is needed for advanced biomaterials in the future. Titanium and its alloys are attracting considerable attention with regard to applications not only in the biomedical field, but also for dental and healthcare products. In dentistry, titanium and its alloys are applied to dental products such as crowns, inlays, bridges, etc., as well as dental implants. For fabricating dental products, the dental precision casting process is important. A new dental precision casting process using calcia is currently being developed. Noble alloys such as gold base or silver base alloys are widely applied for the precision casting of dental products. Allergy-free elements, particularly Pd-free low- noble dental alloys are required.

The purpose of this systematic review was to investigate the clinical outcomes of frameworks made of different materials in patients with implant-supported full-arch prostheses. A literature search was conducted on MEDLINE, Scopus and Cochrane Library, until the 1st of March 2021, with the following search terms: framework or substructure combined with “dental implants”. The outcomes evaluated were: implant and prosthesis survival, bone resorption, biological and technical complications. The Cochrane Handbook for Systematic Reviews of Interventions was employed to assess the risk of bias in randomized clinical trials. The Newcastle–Ottawa quality assessment scale was used for non-randomized studies. In total, 924 records were evaluated for title and abstract, and 11 studies were included in the review: 4 clinical randomized trials and 7 cohort studies. The framework materials investigated were: gold alloy, titanium, silver-palladium alloy, zirconia and polymers including acrylic resin and carbon-fiber-reinforced composites. High implant and prosthetic cumulative survival rates were recorded by all included studies. Various materials and different fabrication techniques are now available as alternatives to traditional cast metal frameworks, for full-arch implant-supported rehabilitations. Further long-term studies are needed to validate the use of these materials and clarify their specific clinical indications and manufacturing protocols to optimize their clinical outcomes.

Long-term clinical observations show that widely used dentures made of metals and their alloys are not indifferent, cause a number of diseases of the oral mucosa, and have social and medical consequences in the form of intolerance to dental prosthesis materials[1,2]. Currently, ceramic materials, plastics, stainless steels, cobalt-chromium, silver-palladium alloys, gold-based alloys, platinum, etc. are used for orthopedic treatment. these alloys include the following metals: iron, chromium, Nickel, titanium, manganese, silicon, molybdenum, cobalt, palladium, zinc, silver, gold, etc. Signs of intolerance may occur when placing dentures and filling materials in the oral cavity. Intolerance to prosthetic materials can be caused by different reasons that have different mechanisms of pathology development. Solving problems with intolerance to dental materials in each patient requires analysis together with a dentist, an immunologist, and an immunological laboratory [1-4].

ABSTRACTObjectives: A nondestructive, rapid, and practical method of dental alloy sorting is desirable. In this study, the hypothesis to be tested is that dental alloys show significantly different and high thermoelectric power values, on the basis of which alloy sorting is possible.Methods: Six silver-colored commercial dental casting alloys are used in this study: two silver alloys, one gold-silver-palladium alloy, one cobalt-chromium alloy, one nickel-chromium alloy, and one titanium alloy. The thermoelectric power of their castings was determined against constantan using a simple apparatus developed in a previous study. Linear least square fitting was applied to the measured thermal-EMF-temperature curve to determine the thermoelectric power for the temperature ranges of 298.303 K (temperature difference Δt = 5 K), 298.308 K (Δt=10 K), 298.313 K (Δt=15 K), and 298.318 K (Δt=20 K). The results were analyzed using one-way ANOVA and by the Scheffefs test at a significance level of α=0.01.Results: When the temperature difference was 10 K or less, the difference in the thermoelectric powers of the alloys was not always statistically significant. However, when the temperature difference was 15 K or more, the thermoelectric powers of the six alloys differed significantly.Conclusions: The results indicated the feasibility of rapid sorting of specific dental alloys by the thermoelectric method, provided a sufficiently large temperature difference is achieved. (Eur J Dent 2010;4:66-70)

In recent years Titanium (Ti) has been the metal of choice for use as a dental implant material. Vitallium (Vi, and alloy composed of Co, Cr, Ni, and Fe) was considered in the past as an ideal implant material, but current studies show Ti is perhaps better tolerated by tissues in the oral cavity. The purpose of this study is to evaluate the surfaces of Ti and Vi endodontic endosseous implants (EEI) placed in a primate model for one year. In human clinical situations this type of dental implant is sometimes used to stabilize compromised teeth. Under intravenous general anestheisia four cynomolgus monkeys had root canal instrumentation in all central incisors. Placement of the EEI followed a pulpectomy and hand drilling to the proper depth and size for the solid rods to use the bore as a pathway to supporting bone. A total of eight Ti and eight Vi, tapered, size 50, EEI were cleanned, sterilized, and cut to length. Two EEI were inserted in the maxillary (Mx) incisors and two in the mandibular (Md) incisors of each animal. One year after placement animals were perfused via carotid cannulation with an aldehyde fixative. The jaws were retrieved, decalcified, EEI separated from tissue, and processed for scanning electron microscopy (SEM). These experimental EEI samples were critical point dried, mounted on stubs, coated with gold palladium, examined, and photographed with an Amray 1820D SEM. Non-operative control EEI samples were treated, processed the same as the experimentals and photographed with a JEOL JSM 35C SEM. Evaluation of the SEM photomicrographs suggest surfaces of EEI change during: 1) handling to implantation, 2) one year in vivo, and 3) processing. Nonoperative Ti control surfaces (Figs. 1 & 2) appear smooth with crater-like concavities of many sizes, subtle valleying, and crisscrossing machine mark (arrow) [Angle measurements of the crisscross marks compared to the long axis were significantly near 40° for both Ti experimental & control]; Vi control surfaces (Figs. 3 & 4) appear rougher with crevasse-like pits and a machine mark (arrow). Md Ti EEI (Fig. 5) has a prominent insertion gouge (⋆), smoother edged concavities than the control, and pre-operative machine marks like those in Fig. 1 (arrow). Mx Vi EEI surface (Fig. 6) has rounder edged pits and a right side smooth surface blemish (⋆). In conclusion these data suggest that Ti EEI surfaces change less than Vi counterparts. This gathering of information is being correlated with concurrent tissue studies indicating Ti may be better tolerated than Vi EEI which supports the premise that Ti is the material of choice for some dental implants in the tissues of the oral cavity.

AbstractThe amount of albumin adsorbed to three dental crown and bridge alloys (high- and low-gold content and silver-palladium), platinum, silver, and stainless steel was quantitated for the as-immersed conditions as well as with anodic and cathodic charge transfers in artifical saliva at a pH = 6.8. A methanolchloroform technique was utilized prior to protein assay which precipitated protein by phase separation. Amido black staining of protein on nitrocellulose filter paper was evaluated for optical density and compared to a standard curve of known quantities of protein. Cathodic charges decreased the quantity of adsorbed protein while anodic charges both increased and decreased adsorbed protein depending upon metal or alloy. Quantities adsorbed ranged from 0.5 to 8 μg/cm2. Interaction of positive oxidized species with the excess negative charges of the albumin molecules is thought to have increased protein adsorption. Formation of corrosion products with inorganic conponents is thought to have masked positive charges from protein thereby decreasing adsorption.