Objectives: To evaluate the effect of simulated pulpal pressure (PP) on initial bond strength of one-stsep self-etch adhesives with different smear layer preparation. Methods: Flat coronal dentin surfaces were obtained from extracted molar teeth .Smear layers were created by grinding with either #180 or #600 grit paper. A HEMA-free one-step self-etch adhesive, Xeno V (XV; Denstply,Germany) and a HEMA-containing adhesive, Tokuyama Bond Force (TBF;Tokuyama Corporation,Japan) were applied to the dentin surfaces according to the manufacturer's instructions under a hydrostatic pressure of 0 or 15 cmH2O. Specimens bonded under 0 cmH20 pressure was served as a control group. After coronal build up with composite resin (CLEARFIL AP-X), the specimens were stored in water at 370C for 24 hour. Bond strength to dentin were determined using microtensile bond (µTBS) testing and all data were statistically analyzed using one-way ANOVA (materials and experimental conditions) and additional t-test. Results: The bond strength values (µTBS) results table are as follows.
MATERIALS
| EXPERIMENTAL CONDITION
| ||
SiC PAPERS (grit size)
| PULPAL PRESSURE
| ||
0 cm H20
| 15cm H20
| ||
TOKUYAMA BOND FORCE
| #180
| 33.4±9.7Ab
| 31.2±8.8 Ab |
#600
| 39.6+8.3Ab
| 33.3_6.8Ab
| |
XENO V
| #180
| 29.7±6.8Ab
| 21.6±8.9Bc
|
# 600
| 39.0±9.5Ac
| 34.2±10.5Ad
| |
Values are in MPa±S.D. n=8 (per group). Groups identified by the same capital and small superscript letter in each row and column are not significantly different (p>0.05).
Conclusions: .
The 15 cmH20 pulpal pressure (PP) had decreased the bond strength (BS) significantly of the HEMA-free material, XV in the thicker smear layer (#180-grit prepared).