The Effect of Compositional Variation on Fluorcanasite Glass-Ceramics
Objective: Fluorcanasite is a multiple chain-silicate glass-ceramic with high strength and fracture toughness, and is a potential material for all-ceramic restorations. The purpose of the study was to investigate the properties of various experimental fluorcanasite glass ceramics with reduced fluorine content. Methods: Two variations of a fluorcanasite glass with the formulation 80SiO2-10Na2O-5K2O-15CaO-yCaF2-1ZrO2 were investigated (y=13or14). The melting schedule was one hour static followed by one hour stirred at 13500C and the glass was annealed at 4600C. DTA and XRD identified crystallisation temperatures and composition respectively. Two different heat treatments were used for the two glasses: 2hrs nucleation followed by 2hr crystallisation; and 2hrs nucleation followed by 4hr crystallisation. SEM was used to examine the microstructure of the cerammed glass. Biaxial flexural strength (BFS) and chemical solubility (n=10) of the four glass ceramics was investigated using ISO methods. Results: XRD and SEM analysis confirmed fluorcanasite formation and correct microstructure. The solubility varied with the fluorine content, from 722.4 ± 177 µg/cm2 for the 13mol% (2hr+2hr), 1297 ± 370 µg/cm2 for the 14mol% (2hr+4hr), 1307± 290 µg/cm2 for the 13mol% (2hr+4hr) and 2565 ± 177 µg/cm2 for the 14mol% (2hr+4hr). The mean BFS was 70±16MPa for 14mol% (2hrs+2hrs), 171±29MPa for 14mol% (2hrs+4hrs), 230±30MPa for 13mol% (2hrs+4hrs), and 250±26MPa for 13mol% (2hrs+2hrs). The chemical solubility and BFS improved when the calcium fluoride content was reduced from 14 to 13mol% (2hrs+2hrs). Increasing the crystallisation time resulted in an increase in BFS and chemical solubility for the 14mol% glass but a decrease for the 13mol% glass. The 13mol% (2hrs+2hrs) glass achieved the best results. Conclusion: The fluorcanasite formulation with reduce fluorine content has an acceptable chemical solubility and adequate BFS for use as a core material for resin-bonded ceramic restorations.
Division: British and Scandinavian Divisions Meeting
Meeting:2007 British and Scandinavian Divisions Meeting (Durham, England) Location: Durham, England
Year: 2007 Final Presentation ID:137 Abstract Category|Abstract Category(s):Dental Materials
Authors
Pollington, Sarah
( University of Sheffield, Sheffield, N/A, United Kingdom
)
Van Noort, Richard
( University of Sheffield, Sheffield, N/A, United Kingdom
)