Objective: The purpose of this study was to determine the shear bond strength (SBS) of composite to dentin comparing optimal (moist) over-dried and over-wet surface conditions using two “universal” adhesive systems.
Methods: Ten specimens each were used to determine composite (TPH
3 – Dentsply) to dentin (600 grit surface finish) shear bond strengths after 24 hours of water storage and 6000 thermocycles (5° C-55 °C). Optimal dentin surfaces were created by blotting excess moisture from dentin. Over-wet surfaces were created by applying 2.5 microliters of water to an isolated 4 mm diameter dentin surface. Over-dried surfaces were created by using a dry air stream for 10 seconds on the dentin surface. Scotchbond Universal (SBU) and Xeno Select (XS) were applied with both self-etch and etch and rinse techniques to dentin. One-way ANOVA and Tukey's post hoc test were used for data analysis.
Results:Self-etch
adhesive
|
condition-dentin
|
SBS MPa
|
SB U
|
moist
|
38.6 ± 6.5 A
|
XS
|
moist
|
36.8 ±3.6 A
|
XS
|
dried
|
34.6 ± 4.5 A,B
|
XS
|
over-wet
|
32.2 ± 4.3 A ,B
|
SB U
|
dried
|
29.7 ±3.6 B
|
SB U
|
over-wet
|
27.9 ±5.5 B
|
Etch and Rinse
adhesive
|
condition-dentin
|
SBS MPa
|
XS
|
moist
|
45.0 ± 4.5 A
|
SB U
|
moist
|
38.5 ± 5.6 B
|
XS
|
dried
|
37.9 ± 4.9 B
|
XS
|
over-wet
|
31.2 ± 8.8 B
|
SB U
|
dried
|
27.0 ± 3.3 C
|
SB U
|
over-wet
|
19.9 ±3.9 D
|
Groups connected by a similar letter were statistically similar (p>0.05). Both adhesive system and surface moisture conditions were significant factors (p<0.05). Conclusions: There were differences in the SBS to dentin based on the dentin surface condition. Lower SBS were generated to etched dentin in non-optimal conditions. Supported by Dentsply DeTrey.