Abstract:
Purpose: to evaluate the effect of repeated heat pressing and thermocycling on micro-shear bond strength of PEEK to resin cement.
Methods: A total of 30 PEEK specimens 10 mm x 10 mm x 2 mm were prepared and divided to three groups (n=10). Group I was pressed using new PEEK, Group II ; 50% new PEEK and 50% reprocessed PEEK, and Group III ; 100% reprocessed PEEK. Bonding surfaces were sandblasted and thin layer of bonding agent was applied and polymerized. Plastic tygon tubes with an inner diameter of 1 mm and a height of 1.5 mm were fixed on the sample and filled with dual polymerized self etch self adhesive resin cement and cured. Half the specimens in each group (n=5) underwent 5000 thermocycles (5‐55°C) before shear bond strength (µSBS) test. Two-way Analysis of Variance (ANOVA) studied the effect of PEEK condition, thermocycling and their interaction on mean micro-shear bond strength µSBS. Bonferroni's post-hoc test was used for pair-wise comparisons when ANOVA test is significant.
Results: The PEEK condition (regardless of thermocycling) had a statistically significant effect on mean µSBS (P-value = 0.001, Effect size = 0.455). Thermocycling (regardless of PEEK condition) also had a statistically significant effect on mean µSBS (P-value = 0.002, Effect size = 0.331). The interaction between two variables had no statistically significant effect on mean µSBS (P-value = 0.442, Effect size = 0.066).
Conclusion: Both repeated heat pressing and thermocycling had a negative effect on micro-shear bond strength of resin cement to PEEK