Evaluation of reproducibility of the chemical solubility of dental ceramics using ISO 6872:2015

Abstract

Statement of problem. The current chemical solubility method in the International Standards Organization (ISO) 6872 (2015) specifies only the total surface area of specimens for testing (≥30 cm 2) but does not describe the morphology or geometry. This could impact the reproducibility of the test outcomes. Purpose. The purpose of this in vitro study was to investigate the factors influencing the reliability of the ISO 6872:2015 'Dentistry-Ceramic materials' test for chemical solubility. Material and methods. Chemical solubility analysis of a range of materials and specimen geometries was performed in accordance with ISO 6872:2015. Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), Vitablocs Mark II, IPS e.max Press, and IPS e.max ZirPress materials were formed into a range of cubic and spherical geometries to comply with the 30 cm 2 minimum surface area requirement. The surface microstructure of the specimens was analyzed by scanning electron microscope, inductively coupled plasma optical emission spectrometry (ICP-OES) was used to analyze the solutes, and surface hardness of the specimens was measured using a Vickers hardness tester before and after testing. An optimized solubility test was devised which eliminated specimen handling once the specimens had been ground and polished. This modified test was performed on Vitablocs Mark II and Y-TZP. Results. The results of the original chemical solubility method of ISO 6872:2015 showed significantly variable findings for each tested material, with a predictable relationship between

Effect of a Home Bleaching Agent on the Ion Elution of Different Esthetic Materials

“…Divalent Mg +2 , Ca +2 , Zn +2 , and Ba +2 , trivalent Al +3 and, immobile Zr ions increase chemical stability and decrease ion exchange 24,26 . Accordingly, feldspathic and lithium disilicate porcelain have been reported to be less stable than zirconium core structures 17 . Slightly soluble materials are considered to have low surface roughness.…”

“…24,26 Accordingly, feldspathic and lithium disilicate porcelain have been reported to be less stable than zirconium core structures. 17 Slightly soluble materials are considered to have low surface roughness. Karakaya and Cengiz-Yanardag reported that the materials containing zirconium showed least roughness, where they examined the roughness of materials exposed to different concentrations of bleaching agents.…”

“…The initial strength of ceramics is significantly reduced after function depending on the loading and liquid environment 15,16 . The broad pH and temperature ranges in the oral cavity might also have secondary effects on the durability of ceramic restorations 17 . Dissolution of dental ceramics is dependent on the chemical environment (acidic, neutral or alkaline), mechanical environment (loading) or their combination 18 .…”

“…15,16 The broad pH and temperature ranges in the oral cavity might also have secondary effects on the durability of ceramic restorations. 17 Dissolution of dental ceramics is dependent on the chemical environment (acidic, neutral or alkaline), mechanical environment (loading) or their combination. 18 Chemical resistance is an important property because ceramics can undergo degradation in the presence of solutions with different pH values.…”

“…19 Acids, such as hydrochloric acid and acetic acid, are used to test the chemical stability of dental materials; ISO 6872 stipulates that acetic acid should be used in chemical stability tests. 15,17 Acids are an excellent testing medium compared to saliva or distilled water because they cause faster material dissolution, thus allowing assessment of the long-term stability of dental ceramics. 14 In addition, the use of acids permits the simulation of low pH test conditions, similar to those found in the oral environment.…”