Effects of adhesive systems on dentin permeability:an in vitro study

Objective: To test the hypothesis that one-step self- etch or single-bottle total-etch adhesives are effective in reducing dentin permeability under in vitro conditions. Methods: crown preparations were made from human extracted teeth. After the roots were sectioned and the coronal pulp removed, the crown segments were connected to an automatic flow-recording device (Flodec-System, De Marco Engineering, Switzerland). Fluid conductance was measured before and after the bonding procedures with the adhesives Single Bond -3M ESPE (SB), One UP Bond F -Tokuyama Inc (OB) and Adhese- Ivoclar Vivadent (AD). For each specimen, fluid flow across the smear-layer and bonded dentin was expressed as a percentage of acid-etched dentin, which was assigned a value of 100% flow rate.Impressions were taken from the crown segments and epoxy resin replicas were produced for SEM examination. Results: bonding with SB, AD and OB resulted in a reduction of fluid conductance that was respectively 65%, 70% and 48% of those recorded for acid-etched dentin. One Way ANOVA showed that there were no differences among the adhesives in their ability to reduce dentin permeability. Dentinal fluid droplets were located over the surface of the adhesive layer. Conclusion: fluid conductance of bonded dentin was either similar to or greater than that of smear-layer-covered dentin. (Supported by: FAPESP – 03/04672-1- 03/00648-9, CAPES, CNPQ -300481/95-0 – 474226/03-4)