In-vitro Evaluation of Shear Bond Strength of Self Adhering Flowable Composite to bovine dentin

Objectives:.;The objectives of this study are: (1) to compare the shear bond strength of Vertise Flow and Fusio Liquid Dentin to conventional flowable composite bonded with two step etch and rinse adhesive. (2) to determine the effect of aging with thermocycling on the shear bond strength of conventional flowable composite bonded with a two step etch and rinse adhesive, Vertise Flow and Fusio Liquid Dentin. (3) to assess the effect of surface pre-treatment with chlorehexidine in shear bond strength of conventional flowable composite bonded with two step etch and rinse adhesive, Vertise Flow and Fusio Liquid Dentin.;Material and Methods:.;One hundred and twenty bovine mandibular incisors were collected. The dentin specimens were randomly divided into six groups (n20) according to adhesive used (OptiBond Solo Plus, Vertise Flow and Fusio Liquid Dentin) and application of Consepsis (with or without). After bonding, all samples were placed in distilled water at 37 C for 24 hours. After water storage each group was further subdivided into two group (A and B) 10 samples each. Group A samples had the shear bond immediately after water storage, whereas Group B samples were subjected to Thermocycling 10000 cycles. Shear forces was applied to the adhesive interface in a universal testing machine with cross-head speed 1 mm/min until fracture occurred. The mean peak force was measure in MPa.;Results:.;There was a significant difference in mean shear bond strength by adhesive type (p < 0.005), and a significant difference in mean shear bond strength by aging (p = 0.002). However, there was no significant difference in mean SBS by surface pretreatment (p = 0.419). There was a significant interaction between aging and adhesive type (p = .019).;Conclusions:.;The mean shear bond strength of two commercial self adhesive flowable composite (Vertise Flow and Fusio Liquid Dentin) were significantly lower than that found when using an etch-andrinse adhesive system (OptiBond Solo Plus) followed by application of a conventional flowable resin composite material. Thermocycling resulted in significantly lower mean shear bond strength of Fusio Liquid Dentin, whereas Vertise Flow show marginally significantly lower mean shear bond strength after thermocycling. Thermocycling did not affect the shear bond strength of OptiBond Solo Plus. 2% chlorhexidine surface pretreatment did not affect the mean shear bond strength of OptiBond Solo Plus, Vertise Flow or Fusio Liquid Dentin. Representative samples of Vertise Flow and Fusio Liquid Dentin groups failed adhesively. However, representative samples of OptiBond Solo Plus groups had mixed fracture.