IADR Abstract Archives
Thermal-cycle Resistance and Dimensional Stability of Self-adhesive Resin Cements
Methods: Flexural strength (FS) and hygroscopic expansion (HE) were compared among five self-adhesive resin cements: GAM-200, G-CEMTM Automix (GCA, GC), RelyXTM UnicemTM 2 Automix (U2A, 3M ESPE), Speed CEM (SPC, Ivoclar Vivadent) and Maxcem Elite (MCE, Kerr). For cement polymerization, light-curing mode was used. Test specimens for FS were prepared according to ISO4049. Specimens of FS were divided into two groups (n=5). One group was tested after 24hour storage in 37°C distilled water. The other group was subjected to 5,000 thermal-cycle(TC) between 5 and 55°C. For HE test, specimens were made in a stainless steel mold which creates a cylinder 4.0mm in diameter and 6.0mm in height (n=5). After 1hour storage at 37°C, the height was measured with micrometer as baseline. Subsequently, specimens were immersed in 37°C distilled water and height change was monitored up to 28days.
Results: In FS test, GAM-200 and GCA belong to the highest group, and GAM-200 did not significantly degrade after thermal-cycle although a sharp drop was seen in some cements. In terms of HE which may affect on cement degradation, GAM-200 and GCA showed the lowest values.
|
FS [MPa] |
HE [%] |
|
Cement |
24hour |
5,000TC |
28day |
GAM-200 |
135(12)A |
123(13)a |
0.29(0.01)α |
GCA |
133(2)A |
108(3)a |
0.26(0.02)α |
U2A |
105(6)B |
81(13)b |
0.61(0.03)γ |
SPC |
108(9)B |
65(8)bc |
0.48(0.02)β |
MCE |
94(13)B |
50(8)c |
0.92(0.01)δ |
Different letters in a same column and underline in a FS’s row indicate statistically-significant difference (p<0.01, one-way ANOVA).
Conclusions: GAM-200 showed high resistance to thermal-cycling and excellent dimensional stability on water sorption. These properties support the positive long-term performance of GAM-200 in an oral environment.