Biomedical Engineering Reference
In-Depth Information
compression using a knife-edge loading head at a cross-head speed of 1 mm/min. The
investigator, who was blinded to the group treatment, performed the load testing
procedure. The maximum load to failure was recorded for each sample and the Shear bond
strength (SBS) was expressed in megapascals (MPa), which was derived by dividing the
imposed force (Newtons) by the bonded area (mm
2
).
2.5 SEM evaluation
To evaluate the surface (treated with Etching, Laser, and Laser + Etching) before bonding
and the fractured surface between the composite resin and dentin side after measuring shear
bond strength, the representative dentin specimens were selected randomly and mounted
on aluminum stubs. The samples were then sputter-coated with gold palladium and
examined by scanning electron microscopy (SEM) (ISI SX-30 Cambridge, MA, USA) with
1000X magnification.
2.6 Statistical analysis
The obtained shear bond strength data were analyzed by two way ANOVA with a level of
significance of P < 0.05 .
3. Results
3.1 Shear Bond Strength (SBS) evaluation
The Mean SBS±SD (MPa) of each group followed by a Single bond was 7.35±1.65, 7.61±1.50
and 6.34±1.39, respectively, and the Mean SBS±SD (MPa) for each group followed by a SE
bond was 7.73±1.17, 7.88±2.77, and 6.48±1.77, respectively (Table 3), but there were no
significant differences between the groups. The maximum and minimum SBS was observed
in groups E and C, respectively. The maximum and minimum SBS in the Single Bond group
was observed in groups B and C, respectively. The maximum and minimum SBS in the SE
Bond group was observed in group E and F, respectively (Figure 1). Some samples
dislodged and de-bonded during preparation for the shear bond test due to the uneven
samples distribution.
Adhesive
system
Single bond
SE bond
Laser
intensity(W)
Control
1.4 W
2.25 W
Control
1.4 W
2.25 W
Sample
Group A
Group B
Group C
Group D
Group E
Group F
Mean (MPa)
7.35
7.61
6.34
7.73
7.88
6.48
SD
1.65
1.50
1.39
1.17
2.77
1.77
Table 3. Comparison of the mean shear bond strength of the control and laser irradiated
groups (Single bond and SE bond). Mean value (MPa) and standard deviation (SD) of the
Shear Bond Strength (SBS) Test for the specimens treated with the Er,Cr:YSGG laser are
shown but there were no significant differences between the groups (P>0.05).
