Bond strength evaluation of ceramic and stainless steel bracket bases subjected to cyclic tensile stress

Objectives. The current project evaluated the affects of fatigue (cyclic loading) on the bond strength of currently available ceramic bracket bases compared to a stainless steel foil mesh base. Fatigue testing is done to assess the influence of repetitive occlusal forces on dental materials.; Materials and methods. 160 permanent lower bovine incisors were obtained. Three ceramics (3M/Unitek ClarityRTM, RMO Signature IIIRTM, GAC MystiqueRTM) and one stainless steel bracket (3M/Unitek VictoryRTM) were used and divided into 2 groups (Static and Cyclic) each with four subgroups for the different bracket types. Mean tensile bond strengths were measured using a Instron 1125RTM Testing Machine and statistically compared for significant differences between all groups.; Results. The ClarityRTM, Mystique RTM, and VictoryRTM bracket bases showed a significant reduction in mean tensile bond strength due to cyclic loading. The Signature IIIRTM bracket base showed no significant difference. The MystiqueRTM bracket base had the highest bond strength in both static and cyclic testing near 11 MPa and 9 MPa respectively. The Clarity RTM bracket base had the lowest bond strength under cyclic loading around 2 MPa.; Conclusion. Bracket base designs have a significant impact on bracket performance under fatiguing conditions. Cyclic loading causes a significant reduction in mean tensile bond strength, thus fatigue testing is more reflective of realistic clinical performance.