Lingual retainer materials: Comparative evaluation of wear resistance of flowable nanocomposites and universal composite: An in vitro study

Background: A bonded fixed retainer is used to stabilize the alignment of the teeth. Different composites have been introduced for this purpose. This study aimed to investigate the wear resistance of flowable nanocomposite in comparison with microhybrid composite in an in vitro situation. Materials and Methods: In this in vitro study, 46 disk-shaped specimens were divided into two groups: Filtek Ultimate flowable composite and Z250 microhybrid composite. The samples were prepared in 8 mm diameter and 3 mm thickness in an aluminum mold and light cured. They were polished with 600 grit sandpaper to achieve a smooth surface. Two-body wear test was accomplished by the pin-on-disk device (under 15 N, 20 rpm for 1 h). Analyzing the weight and thickness of specimens before and after the assay demonstrates the wear resistance. Data were analyzed using the t-test. P ≤ 0.05 was considered statistically significant. Results: The Filtek Ultimate flowable composite shows no significant difference compared to Z250 microhybrid composite in thickness (P = 0.701) and weight (P = 0.939) of specimens. Conclusion: Due to wear resistance of both materials, flowable composite can be recommended as an alternative material for bonded fixed retainers