**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.


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).

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

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

The obtained shear bond strength data were analyzed by two way ANOVA with a level of

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

system Single bond SE bond

intensity(W) Control 1.4 W 2.25 W Control 1.4 W 2.25 W

Mean (MPa) 7.35 7.61 6.34 7.73 7.88 6.48

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).

Sample Group A Group B Group C Group D Group E Group F

SD 1.65 1.50 1.39 1.17 2.77 1.77

imposed force (Newtons) by the bonded area (mm2).

**2.5 SEM evaluation** 

1000X magnification.

**2.6 Statistical analysis** 

significance of P < 0.05 .

samples distribution.

Adhesive

Laser

**3.1 Shear Bond Strength (SBS) evaluation** 

**3. Results** 

Fig. 1. Shear bond strength between the experimental groups.
