Physical Properties of New High-strength Lithium-disilicate Press Ceramics
Objectives: The purpose of this study was to explore the relationship between bending strength and crystallographic structure of new high-strength lithium-disilicate (LDS) press ceramics. High-strength press ceramics are very useful materials in clinical restorative situation due to their aesthetics and biological compatibility. However, detailed mechanism for high-strength has not been analyzed sufficiently. Therefore we conducted a study to analyze the mechanism for high-strength and to understand the characteristics of high-strength press ceramics. Methods: Test materials were “MGCPSZAD05” (GCPS05, prototype high-strength LDS press ceramics, GC), “e.max Press” (EM, LDS press ceramics, Ivoclar Vivadent), “Vintage LD Press” (VP, LDS press ceramics, Shofu) and “initial PC” (IP, conventional feldspathic porcelain, GC). Specimens were prepared using dedicated investment material following manufacturer instructions. Biaxial bending test was conducted according to ISO 6872:2008 “Dentistry - Ceramic materials”. After biaxial bending test, we observed specimen’s surface with SEM and conducted XRD measurement to analyze crystal structure of each material. Results: BBS of “GCPS05” was significantly higher than “IP”, equal to “EM” and higher than “VP” (Means followed by same letter are not significantly different by Tukey’s test after one-way ANOVA, p<0.001). SEM observation demonstrated high levels of fine columnar crystals existing in LDS press ceramics. Crystal size was different for each product. XRD measurement revealed fine columnar crystal is LDS. GCPS05 and VP included only LDS. EM included not only LDS but also LMS (lithium-metasilicate). Conclusions: Even if the kind of crystal is same, BBS may be different. It is thought that BBS is influenced by volume of crystal. Regarding GCPS05, it is suggested that as a result of having reduced columnar crystal size LDS, crystal structure is highly dense, and may be one factor creating high BBS greater than 450MPa.
Division: AADR/CADR Annual Meeting
Meeting:2016 AADR/CADR Annual Meeting (Los Angeles, California) Location: Los Angeles, California
Year: 2016 Final Presentation ID:0612 Abstract Category|Abstract Category(s):Dental Materials 1: Ceramic-based Materials
Authors
Mashio, Go
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Mori, Daizaburo
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Fujimoto, Tatsuya
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Yoshinaga, Masatoshi
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Yokohara, Hayato
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Hoshino, Tomohiro
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Miyake, Takahiro
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Sato, Takuya
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)
Kumagai, Tomohiro
( GC Corporation
, Itabashi-ku
, Tokyo
, Japan
)