title: The influence of experimental silane primers on dentin bond strength and morphology: a laboratory and finite element analysis study.
abstract: BACKGROUND
  The inconsistency of dentin bonding affects retention and microleakage.
  
  
  OBJECTIVE
  The purpose of this laboratory and finite element analysis study was to investigate the effects on the formation of a hybrid layer of an experimental silane coupling agent containing primer solutions composed of different percentages of hydroxyethyl methacrylate.
  
  
  METHODS
  A total of 125 sound human premolars were restored in vitro. Simple class I cavities were formed on each tooth, followed by the application of different compositions of experimental silane primers (0%, 5%, 25%, and 50% of hydroxyethyl methacrylate), bonding agents, and dental composite resins. Bond strength tests and scanning electron microscopy analyses were performed. The laboratory experimental results were validated with finite element analysis to determine the pattern of stress distribution. Simulations were conducted by placing the restorative composite resin in a premolar tooth by imitating simple class I cavities. The laboratory and finite element analysis data were significantly different from each other, as determined by 1-way ANOVA. A post hoc analysis was conducted on the bond strength data to further clarify the effects of silane primers.
  
  
  RESULTS
  The strongest bond of hybrid layer (16.96 MPa) was found in the primer with 25% hydroxyethyl methacrylate, suggesting a barely visible hybrid layer barrier. The control specimens without the application of the primer and the primer specimens with no hydroxyethyl methacrylate exhibited the lowest strength values (8.30 MPa and 11.78 MPa) with intermittent and low visibility of the hybrid layer. These results were supported by finite element analysis that suggested an evenly distributed stress on the model with 25% hydroxyethyl methacrylate.
  
  
  CONCLUSIONS
  Different compositions of experimental silane primers affected the formation of the hybrid layer and its resulting bond strength.
authors.affiliation: Assistant Professor, Dental Materials Science Department, Faculty of Dentistry, International Islamic University Malaysia, Kuantan Campus, Pahang, Malaysia. Electronic address: drammar71@gmail.com.
authors.forename: Ammar A
authors.initials: AA
authors.lastname: Mustafa
authors.affiliation: Associate Professor, Dental Materials Science Department, Faculty of Dentistry, University of Hong Kong, Hong Kong SAR, China.
authors.forename: Jukka P
authors.initials: JP
authors.lastname: Matinlinna
authors.affiliation: Doctor, Clinical Sciences Department, Faculty of Biosciences & Medical Engineering, University of Technology, Malaysia, Johor Bahru, Malaysia.
authors.forename: Syafiqah
authors.initials: S
authors.lastname: Saidin
authors.affiliation: Professor, Medical Devices Technology Group (MEDITEG), Faculty of Biosciences & Medical Engineering, University of Technology, Malaysia, Johor Bahru, Malaysia.
authors.forename: M R Abdul
authors.initials: MR
authors.lastname: Kadir
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000293:Adolescent; D003188:Composite Resins / Q000737:chemistry; D003198:Computer Simulation; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D020342:Finite Element Analysis; D006801:Humans; D017953:Isocyanates / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D055815:Young Adult
chemical_list: C514436:3-isocyanatopropyl trimethoxysilane; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D017953:Isocyanates; D008689:Methacrylates; C451600:OptiBond Solo Plus; D010756:Phosphoric Acids; D019279:Resin Cements; D012821:Silanes; C451741:point 4 composite resin; C005044:hydroxyethyl methacrylate; C030242:phosphoric acid; C515211:1,2-bis(triethoxysilyl)ethane