Comparative study of the flexural strength and flexural modulus of local made orthodontic resins: A pilot study

Abstract

Objective: The aim of this in vitro study was to compare the flexural strength and flexural modulus of three formulae self-curing acrylic resin with commercial orthodontic resin. Materials and Methods: Three formulae of Thai local made resins and a commercial self-curing acrylic resin (Orthocryl) were tested. Thai resin powder was produced by varying amounts of initiator (Asobisisobutyronitrile; AIBN); formula 1, 2, and 3. To investigate the flexural properties, test specimens (3.3 mm × 10 mm × 64 mm) were fabricated, five specimens for each group. Flexural strength and flexural modulus were measured by three-point bending test according to ISO 20795-2: 2010. Statistical analysis was performed using the Kruskal-Wallis test followed by Dunn's multiple comparison test. Result: The Kruskal-Wallis test revealed significant (p < 0.05) differences in flexural strength and flexural modulus among some groups. Orthocryl had the highest flexural strength and formula 1 Thai local made resin had the highest flexural modulus according to Dunn's test (p< 0.05). Conclusion: From the results of this study, the amount of initiator in Polymethylmethacrylate (PMMA) beads synthesis had no effect on flexural strength, but it was consistent with flexural modulus of Thai local made resin. However, the molecular weight of each group of Thai local made resin powder needs to be investigated to find the optimal molecular weight distribution in a subsequent study. © (2013) Trans Tech Publications, Switzerland.