Effect of a new liner/base on human dentin permeability.
OBJECTIVE
Resin-modified glass ionomers (RMGI) have demonstrated clinical success in their ability to minimize post-operative sensitivity of restorations. RMGIs have been recently introduced as paste-liquid systems for convenience of clinical usage. The objective of this study was to measure the ability of a new paste-liquid RMGI liner/base to reduce fluid flow through human dentin.


METHODS
Dentin permeability was measured on human crown sections on etched dentin, using etched dentin as a model for the exposed tubules typical of root sensitivity, and permitting measurement of the maximum permeability. In the one group, the etched dentin was coated with the RMGI, and pre- and post-treatment permeability was measured on the coated dentin. In the second group, a smear layer was created on the dentin with sandpaper, then the samples were coated with the RMGI; permeability was measured on the smeared and coated dentin. Samples from each group were sectioned and examined via scanning electron microscopy (SEM).


RESULTS
The new paste-liquid RMGI liner/base significantly reduced fluid flow through dentin, and exhibited excellent seal on dentin with either a smear layer or open tubules. SEM images show evidence that the RMGI infiltrated the smear layer with resin during placement, penetrated dentin tubules, and formed resin tags in acid-etched dentin.


CONCLUSIONS
Based on these results, combined with previous research on adhesion and microleakage, it is concluded that the new RMGI liner/base should minimize post-operative sensitivity in restorations.
Rusin
Richard P
RP
3M ESPE Dental Products, Saint Paul, MN, USA. rprusin@mmm.com
Agee
Kelli
K
Suchko
Michael
M
Pashley
David H
DH
D000704:Analysis of Variance; D003736:Dental Cavity Lining; D003793:Dental Restoration, Permanent; D057133:Dentin Desensitizing Agents / Q000494:pharmacology / Q000627:therapeutic use; D003806:Dentin Permeability / Q000187:drug effects*; D003807:Dentin Sensitivity / Q000517:prevention & control*; D019234:Dentinal Fluid / Q000502:physiology; D005899:Glass Ionomer Cements / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016369:Smear Layer
D057133:Dentin Desensitizing Agents; D005899:Glass Ionomer Cements; C541368:Vitrebond Plus