GC EUROPE Unifil Bond - Manual (Page 11)

GC UniFil Bond Technical manual version 1.10, November 2005,
11/23
Consequence of technique variables
Many factors contribute to unstable long term adhesive strengths due to technique
variables. These include application times, over dry/wet bonding conditions, air
drying conditions, film thickness of adhesive and variable dentine tubule orientation.
GC UniFil Bond shows minimal sensitivity to these variables which will contribute to
the overall success of this adhesive material.
• Relationship between self-etching primer application time and tensile bond
strength to tooth structure
The etching time is often quoted as having a potential influence on the bond strength
to tooth structure. In this experiment, the influence of different application times of
the self-etching primer on the tensile bond strength of GC UniFil Bond was measured.
For details on the tensile bond strength testing protocol, see above.
Within the limitations of this
test it can be concluded that:
1) Application time of 10 sec.
is not sufficient to etch
enamel properly.
2) Application time of 20 sec.
is sufficient to etch enamel
and dentine correctly.
3) Application time of 30 sec.
is not increasing the results
on either enamel or dentine.
• Relationship between drying of GC UniFil Bond self-etching primer and tensile
bond strength to tooth structure
To measure the influence of the air pressure whilst drying the self-etching primer,
tensile bond strength measurements were done under different air pressure
conditions. For details on the tensile bond strength testing protocol, see above.
Within the limitations of this
test it can be concluded
that:
1) When high pressure air
blow is applied, the bond
strength decreases
noticeably
. This weaker
adhesion is probably caused
by insufficient blending of
monomers from primer and
bonding agent due to
excessive dispersion of
Tensile bond st rengt h (Mpa) vs t reat ment t ime
0 5 10 15 20 25 30
10 sec.
20 sec.
30 sec.
Dent ine
Enamel
Tensile bond st rength (M pa) vs drying condit ions
0 5 10 15 20 25 30
High pressure air
blow
M edium pressure
air blow
Low pressure air
blow
Dent ine
Enamel