Effect of simulated pulpal pressure on dentin permeability and adhesion of self-etch adhesives.
OBJECTIVE
Dentin bonds made with one-bottle etch-and-rinse and self-etch adhesives are affected by the formation of interfacial blisters, porosities and deterioration. The first objective of this study was to evaluate the fluid flow through resin-dentin interfaces created by self-etching adhesives applied to deep dentin using a replica technique and by directly measuring dentin permeability (P). The second objective was to examine the effect of intrapulpal pressure on the microtensile bond strength of these adhesives.


METHODS
A fluid-transport model was used to measure the fluid permeability (%P) through different adhesives. Impressions of bonded dentin were taken with a polyvinylsiloxane impression material to monitor fluid transudation from the surface of the adhesive. Positive replicas were fabricated for SEM examination. Two groups of resin-bonded specimens (pulpal pressure versus no pulpal pressure) were created for microtensile bond strength evaluation. Adhesive application was performed under 0 cm H(2)O. Pulpal pressure group was submitted to 20 cm H(2)O of pulpal pressure during build-up procedures.


RESULTS
Clearfil Protect Bond exhibited the lowest permeability and fewest numbers of fluid droplets over the surface of the bonded dentin. G-Bond and Clearfil-S3 Bond were more permeable than Clearfil Protect Bond. One Up Bond F was the most permeable adhesive. A highly significant correlation was observed between the relative permeability of these adhesives (%P) and the number of fluid droplets on the adhesive surfaces. The application of pulpal pressure significantly reduced bond strength.


CONCLUSIONS
Resin-dentin bonds created by contemporary self-etch adhesives are susceptible to fluid permeation induced by pulpal pressure. HEMA-based adhesives showed the largest reductions in bond strengths after pulpal pressure application.
Sauro
Salvatore
S
Department of Oral Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy. salvatore.sauro@studio.unibo.it
Pashley
David H
DH
Montanari
Marco
M
Chersoni
Stefano
S
Carvalho
Ricardo M
RM
Toledano
Manuel
M
Osorio
Raquel
R
Tay
Franklin R
FR
Prati
Carlo
C
D000134:Acid Etching, Dental / Q000379:methods; D000328:Adult; D000704:Analysis of Variance; D001840:Dental Bonding; D003782:Dental Pulp / Q000502:physiology*; D003799:Dental Stress Analysis; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents; D006801:Humans; D006874:Hydrostatic Pressure; D008855:Microscopy, Electron, Scanning; D008963:Molar; D012044:Regression Analysis; D016628:Replica Techniques; D019279:Resin Cements; D013718:Tensile Strength; D017155:Wettability
D017220:Dentin-Bonding Agents; D019279:Resin Cements