An evaluation of the compressive strength and shear bond strength of resin-modified glass-ionomer cement containing purified powder of .

Background: In this study, the effect of adding purified powder of on the mechanical properties and bonding ability of resin-modified glass ionomer (RMGI) cement is investigated.

Materials And Methods: In this study Purified powder of with particles smaller than 50 μ, in weight percentages of 0.5%, 0.75%, 1%, and 1.25%, was added to RMGI powder (GC Fuji II LC, GC USA). Fifty samples in five groups of control and percentages that considered, from the powder of GI combined with liquid, according to the manufacturer instructions and prepared samples with 4 mm × 6 mm dimensions and placing in distilled water in an incubator with temperature 37°C for 24 h. Fifty sound extracted upper premolars were collected and divided into five groups. The dentinal cross-sections on the occlusal surfaces of teeth were prepared and assessed under a stereomicroscope with ×16. Then, samples with 2 × 4 dimensions from RMGI was prepared on dentin surface and keeping in moisture environment in an incubator with temperature 37°C for 24 h. Compressive strength and shear bond strength test done with a universal testing machine at the rate of 0.5 mm/min. For the assessment of mode of failure, stereomicroscope with a digital camera and ×20 was used, and photographs from bonding surface were taken. After collecting data, the ANOVA test was used for comparing shear bond strength between groups and Kruskal-Wallis test was used for comparing compressive strength. The Chi-square test was used for comparing the mode of failure between groups. The significance level for all tests was considered 5%.

Results: According to the statistical analysis, compressive strength ( = 0.486) and shear bond strength ( = 0.076) were not significantly different between the five groups. The distribution of mode of failure was not significantly different between groups ( = 0.663).

Conclusion: The addition of purified powder of to RMGI powder does not affect compressive strength and shear bond strength of RMGI cement.