Evaluation of Polypropylene Fiber Reinforced Glass Ionomer Cement: A Comparative In-Vitro Study

Aim: To compare the surface roughness, microtensile bond strength (mu TBS), and flexural strength of polypropylene (PP) fibers reinforced glass ionomer cements (GICs). Materials and Methods: A comparative in vitro study was designed to test the PP fiber reinforced GIC, which was formed when 0.5-1 mm length PP fibers were added into the powder of conventional GIC. Four groups were prepared (Group 1: control, Group 2: 1 wt% PP fiber, Group 3: 3 wt% PP fiber, and Group 4: 5 wt% PP fiber) to evaluate flexural strength, surface roughness values, and mu TBS. A total of 10 samples with 25 x 2.5 x 5 mm dimensions were prepared for each group to test flexural strength. Disk-shaped specimens (n = 10) of 2 mm thickness and 10 mm diameter were used to test surface roughness. A total of 24 human primary molar teeth were used to evaluate mu TBS, and 12 sticks were obtained for each group. The fractured surface analyses of samples from mu TBS was performed using scanning electron microscope. The data obtained from the experiments were recorded and analyzed with one-way analyses of variance technique, and the normality was tested using the Shapiro-Wilk technique. A significance level of .05 was used. Results: In flexural strength tests, Group 3 (3 wt% PP fiber) showed significantly increased values (p < .05) when compared with other groups. Group 4 (5 wt% PP) showed significantly highest values in surface roughness tests (p < .05). No significant differences were seen between the groups (p > .05) according to mu TBS results. More PP fibers were seen in fractured surfaces, when PP ratio increases. Conclusion: It was observed that increased PP fiber percentage showed increased surface roughness, and 3 wt% PP fiber gave optimal values for fracture toughness. Incorporation of PP fiber to GIC does not affect the bonding to primary tooth dentine.