title: Effect of dentin desensitizing procedures on methyl methacrylate diffusion through dentin.
abstract: BACKGROUND
  Acrylic and bisacryl resins are widely used both during the temporization phase as well as for provisional restorations and the effect of external agents on dentin sensitivity can be reduced by the obliteration of the tubules.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate diffusion of methyl methacrylate monomer through dentin by high performance liquid chromatography (HPLC) after three different desensitizing procedures during the fabrication of two different provisional crown materials.
  
  
  METHODS
  Forty extracted restoration and caries free human premolar teeth were used in this study. Thermoplastic vacuum formed material was used as a matrix to fabricate provisional restorations for each tooth before crown preparation. Teeth were prepared for a metal supported ceramic crown with 1 mm shoulder margins and then crown parts were separated from cementoenamel junction with a carborundum disk perpendicular to the long axis of the teeth. To the cementoenamel junction of each tooth a polypropylene chamber was attached that contains 1.5 cm 3 of deionized distilled water. Prepared teeth were divided into four groups ( n = 10) including control, desensitizing agent (DA) application, neodymium-doped yttrium aluminum garnet (Nd: YAG) laser irradiation (LI), and LI after DA application groups. After application of DA (except control) each group were divided into two subgroups for fabrication of provisional restorations ( n = 5). Two autopolymerizing provisional materials (Imident (Imicryl) and Systemp C and B (Ivoclar, vivadent)) were used to fabricate provisional restorations using the strips. Water elutes were analyzed by HPLC at 10 min and 24 h.
  
  
  RESULTS
  The monomer diffusion values varied statistically according to desensitizing procedures, provisional resin systems, and the time periods. Monomer diffusion through dentin surfaces desensitized with Nd: YAG LI after DA application was the lowest.
  
  
  CONCLUSIONS
  Nd: YAG LI in association with DA application is an effective combination to eliminate monomer diffusion through dentin to pulpal chamber.
authors.affiliation: Departments of Prosthodontics, Faculty of Dentistry, University of Gaziantep, Gaziantep, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Bulbul
authors.forename: S H
authors.initials: SH
authors.lastname: Altintas
authors.forename: O
authors.initials: O
authors.lastname: Tak
authors.forename: A
authors.initials: A
authors.lastname: Secilmis
authors.forename: A
authors.initials: A
authors.lastname: Yasar
authors.forename: A
authors.initials: A
authors.lastname: Usumez
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid / Q000737:chemistry; D003804:Dentin / Q000737:chemistry* / Q000187:drug effects* / Q000648:ultrastructure; D003807:Dentin Sensitivity; D004058:Diffusion; D006801:Humans; D053844:Lasers, Solid-State; D020366:Methylmethacrylate / Q000737:chemistry* / Q000494:pharmacology*; D003765:Models, Dental; D014088:Tooth Permeability / Q000187:drug effects*
chemical_list: D020366:Methylmethacrylate