title: Evaluation of bond strength of silorane and methacrylate based restorative systems to dentin using different cavity models.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS) to dentin of two different restorative systems: silorane-based (P90), and methacrylate-based (P60), using two cavity models.
  
  
  METHODS
  Occlusal enamel of 40 human third molars was removed to expose flat dentin surface. Class I cavities with 4 mm mesial-distal width, 3 mm buccal-lingual width and 3 mm depth (C-factor=4.5) were prepared in 20 teeth, which were divided into two groups (n=10) restored with P60 and P90, bulk-filled after dentin treatment according to manufacturer's instructions. Flat buccal dentin surfaces were prepared in the 20 remaining teeth (C-factor=0.2) and restored with resin blocks measuring 4x3x3 mm using the two restorative systems (n=10). The teeth were sectioned into samples with area between 0.85 and 1.25 mm2 that were submitted to µTBS testing, using a universal testing machine (EMIC) at speed of 0.5 mm/min. Fractured specimens were analyzed under stereomicroscope and categorized according to fracture pattern. Data were analyzed using ANOVA and Tukey Kramer tests.
  
  
  RESULTS
  For flat surfaces, P60 obtained higher bond strength values compared with P90. However, for Class I cavities, P60 showed significant reduction in bond strength (p<0.05). No statistical difference between restorative systems was shown for Class I cavity model (p>0.05), or between Class I Cavity and Flat Surface group, considering P90 restorative system (p>0.05). Regarding fracture pattern, there was no statistical difference among groups (p=0.0713) and 56.3% of the fractures were adhesive.
  
  
  CONCLUSIONS
  It was concluded that methacrylate-based composite µTBS was influenced by cavity models, and the use of silorane-based composite led to similar bond strength values compared to the methacrylate-based composite in cavities with high C-factor.
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, CampinasSP, Brazil.
authors.forename: Stephano Zerlottini
authors.initials: SZ
authors.lastname: Isaac
authors.forename: Ana Claudia Pietrobom
authors.initials: AC
authors.lastname: Bergamin
authors.forename: Cecília Pedroso
authors.initials: CP
authors.lastname: Turssi
authors.forename: Flávia Lucisano Botelho do
authors.initials: FL
authors.lastname: Amaral
authors.forename: Roberta Tarkany
authors.initials: RT
authors.lastname: Basting
authors.forename: Fabiana Mantovani Gomes
authors.initials: FM
authors.lastname: França
mesh_terms: D000704:Analysis of Variance; D001840:Dental Bonding / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D003765:Models, Dental; D062047:Silorane Resins / Q000737:chemistry*; D013499:Surface Properties / Q000187:drug effects; D013718:Tensile Strength; D013997:Time Factors; D014082:Tooth Fractures
chemical_list: D008689:Methacrylates; D062047:Silorane Resins