title: Role of TiF4 in Microleakage of Silorane and Methacrylate-based Composite Resins in Class V Cavities.
abstract: OBJECTIVE
  This study investigated the effect of TiF4 solution pretreat-ment on microleakage of silorane and nanofilled methacrylate-based composites in class V cavities.
  
  
  METHODS
  Forty-eight intact premolar teeth were randomly allocated to four groups of 12 teeth. Restorative techniques after standard class V tooth preparations were as follows: Group 1, Filtek P90 composite; group 2, Filtek Z350 XT; group 3, TiF4 solution pretreatment and Filtek P90 composite; group 4, TiF4 solution pretreatment and Filtek Z350 XT. After storing the specimens in distilled water at 37°C for 24 hours and followed by immersion of the specimens in a 0.5% basic-fuchsin solution for 24 hours, they were sectioned buccolingually to obtain four surfaces for each specimen for analysis of microleakage using a stereomicroscope. Data analysis was performed using Kruskal-Wallis test to compare the four groups and the Mann-Whitney test for paired comparisons with Statistical Package for the Social Sciences (SPSS) version 17 software.
  
  
  RESULTS
  At the enamel margins, microleakage score of the Filtek Z350 XT group was lower than those of the Filtek P90 with and without the application of the TiF4 (p = 0.009 and p = 0.031 respectively). At the dentin margins, groups 3 and 4 (TiF4+Filtek P90 and TiF4+Filtek z350 XT respectively) showed significantly lower microleakage than group 1 (Filtek P90). However, there was no significant difference between other groups (p > 0.05).
  
  
  CONCLUSIONS
  At the enamel margins, microleakage score of the silorane-based composite was more than that of the nanofilled composite. No significant differences were observed between the other groups. At the dentin margins, for the silorane-based composite restorations, TiF4 solution pretreatment resulted in significantly lower microleakage. However, the similar result was not observed for Filtek Z350 XT. Also, no significant difference was observed between microleakage scores of Filtek P90 and Filtek Z350 XT with or without TiF4 pretreatment.
  
  
  CONCLUSIONS
  In spite of better mechanical and physical properties of modern composites than earlier methacrylate-based composites, polymerization shrinkage has been remaining as one of the main shortcomings of them. Different methods, such as using new low shrinkage resin composites and different dentin pretreatments, have been suggested to overcome this problem. This study evaluated the effect of TiF4 as pretreatment on microleakage of class V tooth preparations restored with a nanocomposite and a silorane-based resin composite.
authors.affiliation: Department of Operative Dentistry, Biomaterials Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Koohpeima
authors.affiliation: Professor, Department of Operative Dentistry, Biomaterials Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran, Phone: 36263193 e-mail: sharaff@yahoo.com.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Sharafeddin
authors.affiliation: Department of Operative Dentistry, School of Dentistry Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Jowkar
authors.affiliation: Department of Operative Dentistry, School of Dentistry Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran.
authors.forename: Samaneh
authors.initials: S
authors.lastname: Ahmadzadeh
authors.affiliation: Department of Biology, Elite Club, Zarghan Branch, Islamic Azad University, Zarghan, Islamic Republic of Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Mokhtari
authors.affiliation: Tohid High School, Shahed Street, Shiraz, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Azarian
mesh_terms: D003188:Composite Resins; D003786:Dental Pulp Cavity; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008689:Methacrylates; D062047:Silorane Resins / Q000032:analysis*; D014025:Titanium / Q000494:pharmacology*
chemical_list: D003188:Composite Resins; D008689:Methacrylates; D062047:Silorane Resins; D014025:Titanium; D005459:Fluorides; C032240:titanium tetrafluoride
keywords: Laboratory research; Nanofilled composite silorane composite; TiF4.