title: Dentin permeability: effects of smear layer removal.
abstract: The results of this study permit the following conclusions: 1. The use of dilute (6%) citric acid for very short time intervals permits sequential removal of the smear layer on human dentin. 2. Acid-etching for as little as 5 seconds removes much of the smear layer and exposes the orifices of dentinal tubules. 3. Dentin permeability increased rapidly during acid-etching with 6% citric acid, reaching a maximum value after only 15 seconds of etching. 4. The production of a smear layer on dentin during restorative procedures establishes a protective diffusion barrier. Removal of the smear layer by acid-etching increases the permeability of dentin which, under some conditions, must be regarded as a liability.
mesh_terms: D000134:Acid Etching, Dental; D002951:Citrates / Q000494:pharmacology*; D019343:Citric Acid; D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure*; D003806:Dentin Permeability / Q000187:drug effects*; D003781:Denture Retention; D006801:Humans; D008855:Microscopy, Electron, Scanning; D014088:Tooth Permeability / Q000187:drug effects*
chemical_list: D002951:Citrates; D019343:Citric Acid