Objective: To test the null hypothesis that there are no statistically significant differences in the shear bond strength (SBS) and the pull out resistance of flowables and an orthodontic adhesive tested.
Methods: To test the SBS, LightBond, FlowTain, FiltekSupreme and TetricFlow were applied to the enamel surface of 15 teeth each. Each composite material was applied using matrices, cured for 40 seconds and subjected to SBS testing. To test pull out resistance, 15 samples were prepared for each composite where the wire was embedded in the composite material and cured for 40 seconds. Later the ends of the wire were drawn up and tensile stress was applied until failure of the resin. Findings were analyzed using ANOVA and Tukey HSD.
Results: The SBS values were 19.0±10.9, 14.7±9.3, 22.4±16.3 and 16.8±11.8 MPa and mean pull out values were 42.2±13.0, 24.0±6.9, 26.3±9.4 and 33.8±18.0 N for LightBond, FlowTain, FiltekSupreme, and TetricFlow respectively. No statistically significant differences were present among the groups in terms of SBS (P>.05). On the other hand, LightBond yielded significantly higher pull out values compared to the flowables FiltekSupreme and FlowTain (P<.01). However, there were no significant differences among the pull out values of flowables, and between Light Bond and TetricFlow (P>.05).
Conclusion: The hypothesis cannot be rejected. Flowable composites provide SBS and wire pull out values comparable to a standard orthodontic resin and therefore can be used as an alternative for direct bonding of lingual retainers.