EFFECT OF THERMOCYCLING ON MECHANICAL AND SURFACE PROPERTIES OF THREE POSTERIOR RESTORATIVE MATERIALS

Background: To evaluate the mechanical and surface properties of two glass ionomer restorative systems (EQUIA Fil, Ionostar Molar) and a resin composite (Charisma Classic ) after thermocycling. Methods: Twenty disk-shaped samples were prepared from each material in teflon molds according to manufacturer’s instructions. After the samples were stored in distilled water at 37 0C for 24 h, microhardness and surface roughness measurements were performed from each group and repeated after 5000 and 10000 thermocycling. Scanning electron microscopy examinations were also performed. The data were analyzed by using Wilcoxon signed rank and Bonferroni corrected multiple comparison tests.Results: EQUIA did not exhibit significant differences in its micohardness values after thermocycling (p > 0.0056). In contrast, Ionostar Molar and Charisma Classic exhibited statistically significant decreases in baseline microhardness after 5000 and 10000 thermocycling processes (each p < 0.0056). However, there were no significant differences between 5000 and 10000 thermocycling groups for Charisma Classic (p = 0.007). Ionostar Molar exhibited no statistically significant differences between its surface roughness values before and after thermocycling groups (p > 0.0017). Similarly, there were no significant differences between baseline and 5000 thermocycling groups for EQUIA and Charisma Classic (p > 0.0017). However, a statistically significant increase was observed after 10000 thermocycles for both of these two materials (p < 0.001 and p = 0.002, respectively).Conclusion: The EQUIA and Ionostar Molar exhibited mechanical features similar to those of a resin composite, and thus, represent promising materials for permanent restorations. Keywords: Glass ionomer, scanning electron microscopy, surface properties Amaç: İki cam iyonomer restoratif sistem (EQUIA Fil, Ionostar Molar) ve bir kompozit rezinin (Charisma Classic ) mekanik ve yüzey özelliklerinin kıyaslanmasıGereç ve Yöntemler: Her materyalden 20 adet disk şeklinde örnek teflon kalıpta, üretici talimatları doğrultusunda hazırlandı. Örnekler distile suda 37 0C de 24 saat bekletildikten sonra 10 örnekte mikrosertlik, 10 örnekte yüzey pürüzlülük ölçümleri yapıldı ve ölçümler 5000 ve 10000 ısısal döngü sonrası tekrar edildi. Tarama elektron mikroskopisi değerlendirmesi için her materyalden üçer örnek daha hazırlandı. Veriler Wİlcoxon işaretli sıralar ve Bonferroni düzeltmeli çoklu karşılaştırma testi kullanılarak değerlendir