Shear bond strength of different materials used for pit and fissure sealing

Introduction. Pit and fissure sealing is a effective procedure in preventing caries, as proven in numerous clinical trials. Materials used for this technique are usually resin-based fissure sealants, but some studies suggested using flowable composites as well. The latest generations of these materials include self-adhesive flowable composites and bulk fill composites. Retention of these materials is one of the main factors that contribute to caries prevention. Therefore, shear bond strength tests that determine the material’s ability to bond with the enamel may help determine their clinical effectiveness. Aim. The aim of the study was to assess the shear bond strength to the enamel of the following materials: Helioseal F (Ivoclar Vivadent), Vertise Flow (Kerr), and SDR (Dentsply Sirona) with XP Bond (Dentsply Sirona). Material and methods. 15 permanent third molars extracted for orthodontic reasons with prepared flat enamel surfaces were randomly divided into three groups. Tested materials ? Helioseal F, Vertise Flow and SDR with XP Bond were polymerised on these surfaces, using a mould. Samples were immersed in distilled water, kept at 37°C for 24 h, and then installed in an Instron testing machine. The machine stopped at sample fracture and the load was recorded. Shear bond strengths were calculated. Statistical analysis was performed. Also, samples were assessed using an optical microscope to assess sample failure type. Results. 35 samples, including 11 Helioseal F, 12 Vertise Flow, and 12 SDR were analysed. SDR with XP bond had the highest shear bond strength ? 23.70 (± 6.35) MPa; Vertise Flow ? 20.10 (± 3.95) MPa, and Helioseal F the lowest ? 15.93 (± 3.17) MPa. There was a statistically significant difference between flowable composites (SDR and Vertise Flow) and resin-based fissure sealant (Helioseal F). There were 18 cohesive sample fractures within the enamel, 14 adhesive fractures and 4 mixed. Conclusions. The shear bond strength of SDR with XP Bond and Vertise Flow is statistically significantly higher than that of Helioseal F. However, it is also crucial to clinically assess the effectiveness of these materials.