Date of Award
MSOB (Master of Science in Oral Biology)
Dr. Markus Blatz
Objectives: This study evaluated the influence of saliva contamination and the effect of several cleaning methods, on the resin bond durability to zirconia. Shear tests were performed to assess the shear bond strength of specimens after 24 h of storage or after thermocycling as an aging method.
Methods: One hundred KATANA Zirconia STML (n=20) specimens were sectioned and sintered in an induction furnace (CEREC SpeedFire, Dentsply Sirona, Germany). Specimen surfaces were ground finished with 800 grit silicon carbide abrasive with cooling water and cleaned with ultrasonication in alcohol. Specimens were air-particle abraded with 50 μm aluminum oxide at 2.8 bar pressure. All samples were equally divided into 5 groups (n = 20) according to the cleaning method. Groups were contaminated with saliva, and subjected to different cleaning protocols, namely: APC, Katana Cleaner (KC), Ivoclean(IC) and Zirclean(ZC). Cylindrical composite resin specimens (2.1 mm in diameter, 3 mm in height) were bonded to the zirconia samples with dual-cure multi-step composite resin cement Panavia V5 following manufacturers’ instructions. A load of 1000 g was applied to the composite cylinders during bonding in an alignment apparatus, then light cured for 80 s. Samples were stored in distilled water at 37° C for 48 h, then subjected to 10,000 thermal cycles. Shear bond strength was determined using a universal testing machine at a crosshead speed of 0.5 mm/min expressed in MPa. The fractured surfaces of specimens were inspected with a stereo microscope and classified as adhesive, cohesive, or mixed failures. Paired t-test and pairwise comparisons (Posthoc bonferroni test) with α=0.05 were applied for statistical analysis.
Results: Shear bond strength values [MPa] under normal conditions (NC) were for Control 22.2 (10.26 SD), APC 52.78 (2.76 SD), KC 33.45 (13.59 SD), IC 34.66 (9.97 SD), and ZC 32.77 (14.53 SD). Shear bond strength values [MPa] under thermocycling (TC) conditions were for Control 6.51 (2.44 SD), APC 18.97 (8.67 SD), KC 17.11 (9.60 SD), IC 16.26 (3.62 SD), and ZC 15.13 (2.90 SD). Intragroup analysis using paired t-test revealed statistically significant differences in shear bond strength in every group between normal condition (NC) and thermocycling conditions (TC) (p<0.05). Intergroup analysis using Bonferroni Post-hoc test revealed statistically significant difference in shear bond strength among the tested groups (p>0.5) when compared to the control group with group 2-APC having significantly higher shear bond strength when compared to the other test groups (p<0.05).
According to the results of this in vitro study, Zirconia ceramics’ cleaning protocol must be considered after exposure to saliva during intraoral try-in procedures. Application of zirconia cleaning agents to the contaminated zirconia surfaces is as effective as mechanical surface abrasion and offers a simple step-by-step cleaning method for restoring zirconia surfaces after contamination.
Musharbash, Leen, "The Effect Of Different Cleaning Agents On The Bond Strength Of Contaminated Zirconia" (2022). Dental Theses. 77.
Available for download on Wednesday, September 06, 2023