Flexural strength of fluorapatite-leucite and fuorapatite porcelains exposed to erosive agents in cyclic immersion

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate the fexural strength of two porcelain materials (IPS d.SIGN and IPS e.max Ceram) exposed to erosive agents. MATERIAL AND METHODS: One hundred and twenty bar-shaped specimens were made from each of fuorapatite-leucite porcelain (IPS d.SIGN) and fuorapatite porcelain (IPS e.max Ceram) and divided into 8 groups of 15 specimens each. Six groups were alternately immersed in the following storage agents for 30 min deionized water (control), citrate buffer solution, pineapple juice, green mango juice, cola soft drink and 4 percent acetic acid. Then, they were immersed for 5 min in deionized water at 37ºC. Seven cycles were completed, totalizing 245 min. A 7th group was continuously immersed in 4 percent acetic acid at 80ºC for 16 h. The final, 8th, group was stored dry at 37ºC for 245 min. Three-point bending tests were performed in a universal testing machine. The data were analyzed statistically by 2-way ANOVA, Tukey's HSD test and t-test at signifcance level of 0.05. RESULTS: The fexural strengths of all groups of each porcelain after exposure to erosive agents in cyclic immersion did not differ signifcantly (p>0.05). For both types of porcelain, dry storage at 37ºC yielded the highest fexural strength, though without signifcant difference from the other groups (p>0.05). The fexural strengths of all groups of fuorapatite porcelains were signifcantly higher (p<0.05) than those of the fuorapatite-leucite porcelains. CONCLUSIONS: This study demonstrated that the erosive agents evaluated did not affect the fexural strength of the tested dental porcelains.