GC EUROPE G-aenial Bond - Manual (Page 19)

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24 h 20 000TC 24 h 20 000 TC
Etch (-) Etch (+)
Shear bond strength (MPa)
G-ænial Bond Technical Manual
Shear Bond Strength to Dentine after Thermocycling
Tests performed by GC R&D, Japan
etched and unetched samples were stored in water and a shear bond strength (SBS) test was
conducted at 24 hours after 20 000 cycles of thermocycling (etch +group only).
Test set-up: Bovine dentine specimens were polished with 320-grit Sic paper. For the etch(+) group, etching was conducted
for 10 seconds with a 37% phosphoric acid etching gel (link master etchant, Gc). no etching agent was apply to the etch (-)
surfaces. G-ænial Bond was then applied to the surfaces of the etch (+) and etch (-) groups according to the manufacturer’s
instructions. Clearfil AP-X (Kuraray) was placed on the surface using an Ultradent mould (D=2.38mm) and light-cured. The
specimens were then stored in 37°C water for 24 hours. The specimens were subjected to thermocycling (5°C-55°C, 20000
cycles) after water storage. Shear bond strength (SBS) was measured at a cross-head speed of 1 mm/min. the statistical analysis
was conducted using the tukey test (P<0.05).
Figure 14: influence of etching on shear bond strength to dentine. Source: Gc corporation, Japan, 2009
etch (-): Self-etching; etch (+): etch-and-rinse; tc: thermocycling
No significant differences in shear bond strengths were found under the four test conditions
(self-etching at 24 hours; self-etching after thermocycling; etch-and-rinse at 24 hours; or etch-and-
rinse after thermocycling).
From the above sets of tests results, it can be concluded that the bonding values of G-ænial Bond
to dentine were not influenced by etching (neither positively nor negatively). therefore, there
is no added value in etching dentine and, additionally, inadvertent etching of dentine would not
affect bond strength. However, tests performed at the KUL showed that although etching of
dentine does not affect bond strength, it could result in the procedure becoming more technique
sensitive. therefore, the recommendation from Gc is to not etch the dentin in order to avoid any
risk of nano-leakage or post-operative sensitivity.
influence of etching on shear bond strength to dentine