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.
Department of Restorative Dentistry, School of Dental Sciences, University of Newcastle, Newcastle upon Tyne, UK.
Sharanbir K
SK
Sidhu
Kelli A
KA
Agee
Jennifer L
JL
Waller
David H
DH
Pashley
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