ผลของวิธีการกำจัดการปนเปื้อนของน้ำลายต่อความแข็งแรงยึดเฉือนระดับจุลภาคของเรซินซีเมนต์กับเซอร์โคเนียมไดออกไซด์เซรามิกชนิดพัฒนาขึ้นใหม่

Abstract

Purpose: To investigate the effect of different saliva decontamination methods on microshear bond 4strength (µSBS) between Developed zirconium dioxide ceramic (DZ) and resin cement, in conjunction with thermocycling. Methods: Seventy-two cylindrical plates of Cercon® xt zirconia and DZ were embedded in metal rings and sandblasted with aluminum oxide particles. The specimens were randomly divided into 6 groups according to saliva decontamination methods: group 1 (NC): no contamination (positive control), group 2 (IC): Ivoclean, group 3 (EN): 70% ethanol, group 4 (SH): 1% sodium hypochlorite, group 5 (SB): sandblasted with aluminum oxide particles and group 6 (W): no decontamination (negative control). Two samples from each group were randomly selected, first one for surface morphology examination by a scanning electron microscope (SEM) and second one for surface elements analysis by an X-ray photoelectron spectroscopy (XPS). Specimens were applied with CLEARFILTM CERAMIC PRIMER PLUS and cemented on surface with PANAVIATM V5 by injecting into polyethylene tubes (4 resin cement rods per sample). After being stored in distilled water at 37°C for 24 hours, the specimens in each group were divided into 2 subgroups (n=20); subgroup 1 was defined as a short-term test and subgroup 2 was thermocycled (5 and 55°C, 5,000 cycles), to stimulate a long-term test. The specimens were subjected to a microshear bond strength (µSBS) test at a cross-head speed of 1 mm/min. Data were analyzed using Three-way ANOVA, followed by the Dunnett’s T3 multiple comparison test (p<0.05). Modes of failure were categorized by using the SEM. Results: XPS analysis showed similar element distributions between group NC, IC, SH and SB. There were no statistically significant differences (p>0.05) in µSBS between Cercon® xt and NDZ in all saliva decontamination methods. Bond strength of NC, IC, SH and SB group were significantly higher than EN and W group before thermocycling. After thermocycling, µSBS of all groups significantly decreased. The most decreased µSBS were showed in EN group and W group compare to other groups. Before thermocycling, failure mode analysis showed predominantly mixed failure in every group. Adhesive failure was observed in EN and W group and cohesive failure was observed in others. After thermocycling; NC, IC, SH and SB group showed only mixed failure while EN and W group showed only adhesive failure. Conclusion: There was no significant differences in µSBS between Cercon® xt zirconia and NDZ. The use of Ivoclean, Sodium hypochlorite and sandblast as saliva decontamination method for zirconia are effective in regaining µSBS between zirconia and resin cement. Thermocycling significantly reduced µSBS in all groups.