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[Effects of three different surface treatments on bond strength between composite resin core and glass ionomer cement].

OBJECTIVE
To compare shear bond strength (SBS) between composite resin core (CRC) disposed with three different surface treatments and glass ionomer cement (GIC), so that to provide theoretical basis for luting of crowns to CRC.


METHODS
According to three different surface treatments, thirty blocks of CRC were randomly and equally divided into three groups: Roughening with diamond grit bur(RDB), RDB plus etching with Gluma Etch 35 Gel (RDBE), RDB plus coating with Adper Single Bond2 adhensive (RDBA). All CRC were cemented with GIC. All specimens were preserved in 37 degrees C water for 24 h, then SBS tests for eight specimens in each group were performed using a universal testing machine at a constant crosshead speed of 0.5 mm x min(-1). The surface topography of one CRC of each group was observed using field emission scanning electron microscope (FE-SEM) at 100 amplification. The interface between CRC and GIC was observed using FE-SEM at 500 amplification. Then the nature of failure was also recorded using FE-SEM at 25 amplification and the data were analyzed with a Kruskal-Wallis H test.


RESULTS
The surface topography of each group and the interface between CRC and GIC observed using FE-SEM were significantly different, but significant differences on the nature of failure between groups were not found (P > 0.10). SBS of each group was (4.28 +/- 0.18) MPa for RDB, (4.65 +/- 0.17) MPa for RDBE, (2.39 +/- 0.21) MPa for RDBA, respectively (P < 0.01).


CONCLUSION
The SBS between CRC and GIC is affected by the surface treatments of CRC.