IADR Abstract Archives
Chemical Durability of Pressable Lithium Silicate Glass Ceramics
Objectives: Pressable lithium silicate glass ceramics are known as useful materials clinically from the viewpoint of aesthetics and biological compatibility. However, chemical durability of these materials have not been analyzed sufficiently. The purpose of this study was to explore the chemical durability of pressable lithium silicate glass ceramics.
Methods: Three materials were selected for analysis: 1) MGCPSZAD05 (GCPS05, prototype pressable lithium silicate glass ceramics, GC Corp.); 2) IPS e.max Press (EM, lithium-disilicate pressable ceramics, Ivoclar Vivadent); 3) Vintage LD Press (VP, lithium-disilicate pressable ceramics, SHOFU). Specimens were prepared using dedicated investment material following the manufacturer’s instructions. Chemical solubility test was conducted according to ISO 6872 “Dentistry - Ceramic materials”. After chemical solubility test, we observed surface of specimens with SEM and laser microscope, and conducted XRD measurement to analyze crystal structure of each material.
Results: Chemical solubility of “GCPS05” was significantly lower than “EM” and “VP”. SEM and laser microscope observation showed specimen surface of “GCPS05” was less degraded by acidic environment. XRD measurement revealed that “GCPS05” and “VP” included lithium disilicate, but “EM” included not only lithium disilicate but also lithium metasilicate. After chemical solubility test, the crystal structure of each pressable ceramics did not change.
Conclusions: This study confirmed significant improvement of newly developed lithium silicate glass ceramic “GCPS05” related to chemical durability in comparison with existing products tested. Based on this study utilizing chemical solubility as a determination of chemical durability and stability, “GCPS05” was found to be considered a stabile material.
Methods: Three materials were selected for analysis: 1) MGCPSZAD05 (GCPS05, prototype pressable lithium silicate glass ceramics, GC Corp.); 2) IPS e.max Press (EM, lithium-disilicate pressable ceramics, Ivoclar Vivadent); 3) Vintage LD Press (VP, lithium-disilicate pressable ceramics, SHOFU). Specimens were prepared using dedicated investment material following the manufacturer’s instructions. Chemical solubility test was conducted according to ISO 6872 “Dentistry - Ceramic materials”. After chemical solubility test, we observed surface of specimens with SEM and laser microscope, and conducted XRD measurement to analyze crystal structure of each material.
Results: Chemical solubility of “GCPS05” was significantly lower than “EM” and “VP”. SEM and laser microscope observation showed specimen surface of “GCPS05” was less degraded by acidic environment. XRD measurement revealed that “GCPS05” and “VP” included lithium disilicate, but “EM” included not only lithium disilicate but also lithium metasilicate. After chemical solubility test, the crystal structure of each pressable ceramics did not change.
Conclusions: This study confirmed significant improvement of newly developed lithium silicate glass ceramic “GCPS05” related to chemical durability in comparison with existing products tested. Based on this study utilizing chemical solubility as a determination of chemical durability and stability, “GCPS05” was found to be considered a stabile material.