title: Assessment of the Shear Bond Strength between Nanofilled Composite Bonded to Glass-ionomer Cement Using Self-etch Adhesive with Different pHs and Total-Etch Adhesive.
abstract: BACKGROUND
  In the sandwich technique, the undesirable bond between the composite resin and glass-ionomer cement (GIc) is one of the most important factors which lead to the failure of restoration. Total-etch and self-etch adhesives may improve the bond strength based on their pH.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the shear bond strength between the nanofilled composite resin and GIc using different adhesives.
  
  
  METHODS
  In this experimental study, 40 specimens (6×6mm) in 4 groups (n=10) were prepared in acrylic mold. Each specimen contained conventional GI ChemFil Superior with a height of 3mm, bonded to Z350 composite resin with a height measured 3mm. In order to bond the composite to the GI, the following adhesives were used, respectively: A: mild Clearfil SE Bond self-etch (pH=2), B: intermediate OptiBond self-etch (pH=1.4), C: strong Adper Prompt L-Pop (pH=1), and D: Adper Single Bond 2 total-etch (pH=7.2). The shear bond strength was measured by using universal testing machine with a crosshead speed of 1mm/min. One-way ANOVA and Tukey's test were used to analyze the data (p< 0.05).
  
  
  RESULTS
  The shear bond strength in group A was significantly higher than group B (p= 0.002), C (p< 0.001), and D (p< 0.001). Moreover, the shear bond strength of groups A and B (self-etch) was significantly different from group D (total-etch) (p< 0.001); and C (self-etch) with D (p= 0.024).
  
  
  CONCLUSIONS
  The results of this study showed that applying the mild self-etch adhesive between the composite and the GIc results in stronger shear bond strength compared to intermediate and strong self-etch adhesives. Moreover, the self-etch adhesive increased the shear bond strength between composite resin and GIc more significantly than total-etch adhesive.
authors.affiliation: Dept. of Operative Dentistry, Biomaterials Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Sharafeddin
authors.affiliation: Undergraduate Student, School of Dentistry, International Branch of Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Choobineh
keywords: Conventional Glass-ionomer Cement; Nanofilled Composite; Self-etch Adhesive; Shear Bond Strength; Total-etch Adhesive