In vitro evaporative vs. convective water flux across human dentin before and after conditioning and placement of glass-ionomer cements.
OBJECTIVE
To assess the convective and evaporative fluid movement across glass-ionomer treated dentin.


METHODS
Crown segments made from extracted human teeth, were divided into two groups of 14 teeth each. Each segment was cemented onto a plexiglass slab penetrated by a stainless steel tube, permitting filling of the pulp chamber with water. This set-up was attached to a device that measured fluid movement through the dentin in the crown segment. The experimental design involved repeated measurements of convective and evaporative fluid movements in each of the following conditions: smear layer-covered dentin, conditioned dentin, dentin after placement of one of two glass-ionomers (Fuji IX or Ketac-Molar), with and without a protective coating. The same water fluxes were remeasured after storage of the samples for 24 hours in distilled water.


RESULTS
Statistical analysis of the results using ANOVA indicated a significant difference between the two measured water fluxes (P < 0.001). There was also a significant difference between the two materials (P < 0.001), with Ketac-Molar allowing higher permeability than Fuji IX. Conditioning the dentin surface with polyacrylic acid increased the convective water flux (P < 0.05) but did not change the evaporative water flux. Placement of the glass-ionomer material did not change the rate of spontaneous evaporation of water from the dentin, but the application of a coating agent reduced the evaporative water loss. These values were not significantly different when the specimens were stored for 24 hours.
Sidhu
Sharanbir K
SK
Department of Restorative Dentistry, School of Dental Sciences, University of Newcastle, Newcastle upon Tyne, UK.
Agee
Kelli A
KA
Waller
Jennifer L
JL
Pashley
David H
DH
D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D018481:Convection; D003804:Dentin / Q000378:metabolism*; D003806:Dentin Permeability / Q000502:physiology*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D019234:Dentinal Fluid / Q000378:metabolism*; D003890:Desiccation; D018495:Fluid Shifts / Q000502:physiology; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D012117:Resins, Synthetic / Q000737:chemistry; D016369:Smear Layer; D013997:Time Factors
D000180:Acrylic Resins; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D012117:Resins, Synthetic; C110713:fuji IX; C110712:ketac-molar; C006903:carbopol 940