Title: 0704 - Stability of Pressable Lithium Silicate Glass Ceramics Against Acidic Solution


Katsuhito Kato (Presenter)
GC corporation

Takuya Sato, GC corporation
Daizaburo Mori, GC corporation
Go Mashio, GC corporation
Tatsuya Fujimoto, GC corporation
Kenji Kojima, GC corporation
Shigenori Akiyama, GC corporation
Hayato Yokohara, GC corporation
Takahiro Miyake, GC corporation
Toshihiko Azuma, GC corporation
Kent Nagaoka, GC corporation
Tomohiro Kumagai, GC corporation


Objectives: Recently pressable lithium silicate glass ceramics have become very popular due to mechanical property and aesthetic requirements. However, it is known that, physiological condition especially acidic condition influences glass ceramic restorations in aesthetic stability. The aim of this study was to investigate the stability of lithium silicate based pressable glass ceramics against acidic condition.

Methods: Two test materials were used: Initial LiSi Press (MT-A2, GC Corporation), IPS e.max Press (MT-A2, Ivoclar Vivadent). Disc shape samples (13.2 ± 0.1 mm in diameter and 1.1 ± 0.1 mm in thickness) were prepared by press technique according to manufacturer instructions. All specimens were polished with 4000-grit silicon carbide paper followed by diamond paste Cerashine-polisher(GC Corporation). Each sample was immersed in 4 mL acetic acid aqueous solution adjusted to 4 vol% at 37 deg-C for 7 days. Change in glossiness of 10 surfaces by immersion in acidic solution was assessed using gloss meter VG2000 (Nippon Denshoku Industories). The data were statistically analyzed by t-test.

Results: There was no significant difference in glossiness between two test materials after polishing. After acid challenge, glossiness of Initial LiSi Press was significantly higher than that of IPS e.max Press (p < 0.01).

Conclusions: The surface of Initial LiSi Press had higher stability against to acidic condition than IPS e.max Press. It is thought that Initial LiSi Press has higher insoluble properties in glass and crystal composition than conventional glass ceramic materials.


  Before acidic challenge After acidic challenge
Initial LiSi Press 90.6 ± 1.8 83.0 ± 2.2
IPS e.max Press 90.0 ± 2.9 78.4 ± 1.4**

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None