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Journal of Dental Research Oct 1998Adverse tissue reactions of the gingiva and the periodontium close to dental cast alloys may be caused by the effects of released metal elements. Tissue reactions depend... (Comparative Study)
Comparative Study
Adverse tissue reactions of the gingiva and the periodontium close to dental cast alloys may be caused by the effects of released metal elements. Tissue reactions depend upon the amounts of elements available which are a function of corrosion rates. Since pH values of standard corrosion solutions are as low as 2.3, such extracts are a priori not biocompatible. In the present study, elements released from dental cast alloys into cell-culture media were determined, and the cytotoxicity of these medium extracts was compared with the effectiveness of metal salt solutions prepared according to the metal elements found in extracts. The elements Ag, Cu, Ni, and Zn were detected in extracts of dental alloys and copper (positive control) by inductively coupled plasma atomic emission spectrometry (ICP-AES). Medium extracts of dental alloys were non-toxic in mouse fibroblasts (L929 cells). However, the amounts of elements found in these extracts were weakly cytotoxic when tested as salt solutions prepared from chloride (Cu2+, Zn2+, Ni2+) or sulfate (Ag1+) salts. When the test specimens were heat-treated before extraction, extracts were clearly cytotoxic in a dose-related manner. Again, the amounts of elements that caused 50% cell death (TC50) were slightly lower in corresponding salt solutions than in extracts. In general, cytotoxicity of medium extracts consistently proved to be slightly less than that of the corresponding salt solutions, probably due to the limitations of the chemical analysis of extracts. This should be taken into account if salt solutions are used instead of the medium extract.
Topics: Animals; Cell Survival; Corrosion; Dental Alloys; Dose-Response Relationship, Drug; Inhibitory Concentration 50; L Cells; Mice; Salts; Solutions; Sterilization; Time Factors
PubMed: 9786633
DOI: 10.1177/00220345980770100401 -
Journal of Biomaterials Applications Jul 2003Proper hygienic care of removable partial dentures is important for maintaining a healthy oral mucosa. A daily home care routine is the responsibility of the patient to... (Comparative Study)
Comparative Study
Proper hygienic care of removable partial dentures is important for maintaining a healthy oral mucosa. A daily home care routine is the responsibility of the patient to maintain oral hygiene. A dentist must inform the patient about denture cleansers used for plaque control. Common denture cleansers may negatively affect the surface of alloys used to make partial dentures. The purpose of this study was to evaluate whether bleach and cleansing tablet have deleterious effects on the surface of a dental alloy used to fabricate removable partial dentures. Nineteen test specimens were prepared from CoCr dental alloy. The specimens were cast into 10 mm long x 10 mm wide x 1 mm thick. Fresh solutions made from a commercial bleach and a commercial cleansing tablet were used for each treating. Three groups (commercial denture cleansing tablet, bleach and tap water) were tested. Six specimens were immersed in 200 mL of tap water containing a single denture cleansing tablet. Two spoons of the commercial bleach was added to 200 mL of tap water. Seven specimens were treated. The control specimens were immersed in 200 mL of tap water. Six specimens were the control group. Each specimen was immersed for 30 min per day in the solution for a period of 30 days. The specimens were analyzed for reflectance with a spectrophotometer, for surface changes with a light microscope and weight which was measured with sensitive balance before and after treatment. The SPSS program was used for the statistical analysis. The Kruskal-Wallis Test and Wilcoxon Signed Ranks Test was used. No significant changes of reflectance was shown in the Kruskal-Wallis Test (p > 0.05). The Wilcoxon Signed Ranks Test was performed for comparison into groups. The difference between before and after treatment was statistically significant for the commercial denture cleansing tablet and the commercial bleach (p = 0.028) (p < 0.05). Reflectance was decreased after treatment. Within the limitations of this study, the commercial cleaning solutions had influenced the decrease of reflectance on the surface of the dental alloy. This solutions should not be limitlessly used on dentures with metal components, because they caused clinically significant reflectance changes on the surface of the alloy after 30 days.
Topics: Dental Alloys; Dentures; Sodium Hypochlorite; Spectrophotometry; Surface Properties
PubMed: 12873071
DOI: 10.1177/0885328203018001001 -
Journal of Dental Research 1973
Topics: Chromium; Cobalt; Dental Alloys; Dental Stress Analysis; Humans; Microscopy, Electron; Nickel; Tantalum
PubMed: 4509486
DOI: 10.1177/00220345730520010701 -
Biomaterials May 1984Methods of electrochemical thermodynamics (electrode potential-pH equilibrium diagrams) and electrochemical kinetics (polarization curves) may help to understand and... (Review)
Review
Methods of electrochemical thermodynamics (electrode potential-pH equilibrium diagrams) and electrochemical kinetics (polarization curves) may help to understand and predict the corrosion behaviour of metals and alloys in the presence of body fluids. A short review of the literature is given concerning some applications of such methods, both in vitro and in vivo, relating to surgical implants (stainless steels, chromium-cobalt-molybdenum alloys, titanium and titanium alloys) and to dental alloys (silver-tin-copper amalgams, silver-base and gold-base casting alloys, nickel-base casting alloys). Attention is drawn to the necessity of more basic research on crevice- and fretting-corrosion of surgical implant materials and dental alloys, and to the toxicity of corrosion products. A perfect understanding of the exact significance of electrode-potentials is essential for the success of such a task.
Topics: Alloys; Biocompatible Materials; Body Fluids; Chromium Alloys; Corrosion; Dental Alloys; Dental Amalgam; Electrochemistry; Metals; Prostheses and Implants; Stainless Steel; Titanium; Vitallium
PubMed: 6375748
DOI: 10.1016/0142-9612(84)90046-2 -
Materials Science & Engineering. C,... Aug 2012In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used...
In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10-15% for female adults and 1-3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni-Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni-Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects.
Topics: Cell Line, Tumor; Chromium Alloys; Dental Alloys; Electrochemistry; Endothelial Cells; HeLa Cells; Humans; Materials Testing; Monocytes; Nickel; Saliva; Tumor Necrosis Factor-alpha
PubMed: 24364945
DOI: 10.1016/j.msec.2012.04.025 -
The Journal of Prosthetic Dentistry May 2021Selective laser melting (SLM) additive manufacturing (AM) technology is a current option to fabricate cobalt-chromium (Co-Cr) metal frameworks for dental prostheses....
STATEMENT OF PROBLEM
Selective laser melting (SLM) additive manufacturing (AM) technology is a current option to fabricate cobalt-chromium (Co-Cr) metal frameworks for dental prostheses. However, the Co-Cr alloy composition, surface roughness, and ceramic bond strength values that SLM metals can obtain are not well-defined.
PURPOSE
The purpose of this in vitro study was to compare the chemical composition, surface roughness, and ceramic shear bond strength of the milled and SLM Co-Cr dental alloys.
MATERIAL AND METHODS
A total of 50 disks of 5 mm in diameter and 1 mm in thickness were fabricated by using subtractive (control group) and AM with each of following SLM providers: SLM-1 (EOS), SLM-2 (3D systems), and SLM-3 (Concept Laser). The milled disks were airborne-particle abraded with 100-μm aluminum oxide particles. All the specimens were cleaned before surface roughness (Ra), weight (Wt%), and atomic (At%) percentages were analyzed. Three-dimensional profilometry was used to analyze the topographical properties of the surface parameters Ra (mean surface roughness). The chemical composition of Co-Cr alloy specimens was determined by using energy dispersive X-ray (EDAX) elemental analysis in a scanning electron microscope (SEM). Thereafter, the specimens were bonded to a ceramic (Dentine A3 and Enamel S-59; Creation CC) interface. Specimens were stored for 24 hours at 23 °C. The bond strength of the SLM-ceramic interface was measured by using the macroshear test (SBT) method (n=10). Adhesion tests were performed in a universal testing machine (1 mm/min). The Shapiro-Wilk test revealed that the chemical composition data were not normally distributed. Therefore, the atomic (At%) and weight percentages (Wt%) were analyzed by using the Kruskal-Wallis test, followed by pairwise Mann-Whitney U tests between the control and AM groups (AM-1 to AM-4). However, the Shapiro-Wilk test revealed that the surface roughness (Ra) and ceramic bond strength data were normally distributed. Therefore, data were analyzed by using 1-way ANOVA, followed by the post hoc Sidak test (α=.05).
RESULTS
Significant differences were obtained in Wt%, At%, and Ra values among the Co-Cr alloys evaluated (P<.05). Furthermore, the control group revealed significantly lower mean ±standard deviation Ra values (0.79 ±0.11 μm), followed by AM-3 (1.57 ±0.15 μm), AM-2 (1.80 ±0.43 μm), AM-1 (2.43 ±0.34 μm), and AM-4 (2.84 ±0.27 μm). However, no significant differences were obtained in the metal-ceramic shear bond strength among the different groups evaluated, ranging from mean ±standard deviation 75.77 ±11.92 MPa to 83.65 ±12.21 MPa.
CONCLUSIONS
Co-Cr dental alloys demonstrated a significant difference in their chemical compositions. Subtractive and additive manufacturing procedures demonstrated a significant influence on the surface roughness of the Co-Cr alloy specimens. However, the metal-ceramic shear bond strength of Co-Cr alloys was found to be independent of the manufacturing process.
Topics: Ceramics; Chromium; Chromium Alloys; Cobalt; Dental Alloys; Dental Bonding; Dental Porcelain; Materials Testing; Metal Ceramic Alloys; Shear Strength; Surface Properties
PubMed: 32466963
DOI: 10.1016/j.prosdent.2020.03.012 -
The Journal of Prosthetic Dentistry Apr 1985
Comparative Study
Topics: Chromium Alloys; Cyanates; Cyanoacrylates; Dental Alloys; Dental Soldering; Radiography; Surface Properties; Tensile Strength
PubMed: 2860244
DOI: 10.1016/0022-3913(85)90624-9 -
Journal of Dental Research Jan 1997For many years, the amalgamation of silver with mercury to produce a condensable mixture which could be used to restore carious defects in teeth followed a tortuous path...
For many years, the amalgamation of silver with mercury to produce a condensable mixture which could be used to restore carious defects in teeth followed a tortuous path of negative results. However, at the turn of the century, amalgam alloys having acceptable characteristics for successful clinical use emerged. From that point on, silver amalgam was widely accepted as the material of choice for low-cost, easily placed, and durable restorations. About 60 years later, a major discovery occurred that resulted in a most significant improvement in the clinical performance of this material. The key to this improvement was an increase in the Cu content of the amalgam alloy which previously had been considered to be inappropriate. This paper describes the history of this discovery, which produced what has come to be known as high-copper dental amalgam alloys.
Topics: Canada; Copper; Dental Alloys; Dental Amalgam; History, 19th Century; History, 20th Century; United States
PubMed: 9042075
DOI: 10.1177/00220345970760010301 -
Australian Dental Journal Aug 1980A two component system of pure gold and an alloy of silver, copper, palladium and zinc has been shown to have similar mechanical properties to those of Type C casting...
A two component system of pure gold and an alloy of silver, copper, palladium and zinc has been shown to have similar mechanical properties to those of Type C casting golds. The system may offer some cost advantages in dental gold alloy restorations.
Topics: Chemical Phenomena; Chemistry, Physical; Copper; Dental Alloys; Dental Casting Technique; Gold Alloys; Palladium; Silver; Zinc
PubMed: 7004418
DOI: 10.1111/j.1834-7819.1980.tb03866.x -
Fukuoka Shika Daigaku Gakkai Zasshi 1989This study was made to compare the physical and chemical properties of amalgam with those of gallium alloy in which the invented liquid alloy containing the three... (Comparative Study)
Comparative Study
This study was made to compare the physical and chemical properties of amalgam with those of gallium alloy in which the invented liquid alloy containing the three fundamental components of Ga-Sn-In or Ga-Sn-In-Ag were used instead of mercury. Experiment 1. The physical and chemical properties were investigated after the liquid gallium alloy and high copper amalgam powder were mixed. The following results were obtained; 1) The invented gallium alloy group showed expansion in dimensional changes immediately after mixing. This alloy group showed the same compressive and diametral tensile strength as those in amalgam after 7 days. 2) This alloy group showed slightly more corrosion weight loss in 0.05% HCl and 1% lactic acid solutions than that in amalgam, but this alloy group showed the same corrosion weight loss in 1% NaCl solution and artificial saliva as in amalgam. Also this alloy group showed more discoloration (delta E, NBS) in 0.1% Na2S solution than that in amalgam, but this showed the same degree of discoloration in artificial saliva. Experiment 2. The physical and chemical properties were investigated after the same liquid gallium alloy and Ag-Pd-Sn-Cu-Zn alloy powder were mixed. The following results were obtained; 1) The invented gallium alloy group showed expansion in dimensional changes immediately after mixing. This showed superior quality in compressive and diametral tensile strength as compared with those of amalgam. 2) The invented gallium alloy showed slightly more corrosion weight loss in 0.05% HCl and 1% lactic acid solutions than that in amalgam, but this alloy group showed the same corrosion weight loss in 1% NaCl solution and artificial saliva as in amalgam. Also this alloy group showed more discoloration (delta E, NBS) in 0.1% solution than that in amalgam, but it was the same in artificial saliva.
Topics: Dental Alloys; Dental Amalgam; Dental Restoration, Permanent; Gallium; Indium; Materials Testing; Silver; Tin
PubMed: 2488904
DOI: No ID Found