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Different Cleansing Methods Effect to Bond Strength of Contaminated Zirconia
Bond strength, Saliva contamination, Sodium hydroxide, Surface cleansing, Zirconia
Saliva contamination on a restoration is unavoidable during a try-in procedure. Many studies have shown
the negative effect of non-cleansing surface prior to cementation. The aim of this study is to investigate the efficiency
of cleansing methods on the shear bond strength of zirconia surfaces. Sixty-six zirconia specimens size 7.5x5.5x0.8
mm were randomly divided into six groups: non-saliva contamination (PC), saliva contamination without surface
cleansing (NC), saliva contamination then cleansing with Ivoclean (IC), 0.5 M NaOH solution (NaOH), sandblasting
(SB) and sandblasting followed by 0.5 M NaOH solution (SB+NaOH). One specimen in each group was separated for
SEM observation. The remaining zirconia specimens were bonded to a composite resin block with Panavia F2.0 and
were stored in 37๐C distilled water for 24 hours. All specimens were subjected to the SBS test. The data were
analyzed by One-way ANOVA and Tukey HSD. The bonded surfaces were observed under stereomicroscope to
identify the mode of failure. The results showed that the SBS of saliva contaminated zirconia without surface
cleansing (NC) was the significantly lowest (4.62±0.53 MPa) than that of the other groups (p<0.05), while SB (14.14±1.72
MPa) and SB+NaOH (15.41±1.65 MPa) were significantly higher than the others (p<0.05). However, SB and SB+NaOH
showed no statistically significant difference (p>0.05). Group PC, IC and NaOH showed no significant difference
(p>0.05). The mode of failure revealed a greater amount of mixed failure for the majority of SB and SB+NaOH but
other groups reveal adhesive failure between zirconia and resin cement for the majority. SEM showed surface
morphology changing in SB and SB+NaOH when compared to other group. The saliva contaminated zirconia should
be cleaned by Ivoclean, 0.5 M NaOH solution, sandblasting or sandblasting followed by 0.5 M NaOH solution prior
to cementation.