title: Comparative in vitro evaluation of internal adaptation of resin-modified glass ionomer, flowable composite and bonding agent applied as a liner under composite restoration: A scanning electron microscope study.
abstract: BACKGROUND
  The use of resin-modified glass Ionomer cement in sandwich technique is widely practiced with the advent of various newer generation of composites the bond between resin-modified glass Ionomer and these resins should be validated. This study is done to evaluate the interfacial microgaps between different types of liners and dentin, liners and composite (Filtek p60 [FLp60]) using scanning electron microscope (SEM).
  
  
  METHODS
  Standardized Class V preparations were performed in buccal/lingual surfaces of 30 caries, crack and defect-free extracted human third molars. The prepared teeth were divided into three groups. Group I: Single bond (SB), Group II: SB + synergy flow, Group III: SB + vitrebond. They were restored with composite resin FLp60, according to the manufacturer instructions. The SB + vitrebond, cross-sectioned through the canter of the restoration. The specimens were fixed, dehydrated, polished, and processed for SEM. The internal adaptation of the materials to the axial wall was analyzed under SEM with ×1000 magnification.
  
  
  RESULTS
  The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, P < 0.05). flowable composite or resin-modified glass ionomer applied in conjunction with adhesive resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration.
  
  
  CONCLUSIONS
  Hybridization of dentin only provides superior sealing of the dentin-restoration interface than does flowable resin or resin-modified glass ionomer.
authors.affiliation: Reader, Department of Conservative Dentistry and Endodontics, Anil Neerukonda Institute of Dental Sciences, Sangivalasa, Visakhapatnam, Andra Pradesh.
authors.forename: M
authors.initials: M
authors.lastname: Soubhagya
authors.affiliation: Professor, Department of Conservative Dentistry & Endodontics, Bapuji Dental College, Davangere, Karnataka, India.
authors.forename: K Mallikarjun
authors.initials: KM
authors.lastname: Goud
authors.affiliation: Professor, Department of Conservative Dentistry & Endodontics, Bapuji Dental College, Davangere, Karnataka, India.
authors.forename: B S
authors.initials: BS
authors.lastname: Deepak
authors.affiliation: Professor, Department of Conservative Dentistry & Endodontics, Bapuji Dental College, Davangere, Karnataka, India.
authors.forename: Sophia
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Reader, Department of Conservative Dentistry & Endodontics, Bapuji Dental College, Davangere, Karnataka, India.
authors.forename: T N
authors.initials: TN
authors.lastname: Nandini
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry & Endodontics, Bapuji Dental College, Davangere, Karnataka, India.
authors.forename: J
authors.initials: J
authors.lastname: Arun
keywords: Composite resin; flowable resin; interfacial gaps; internal adaptation; liner; microleakage; resin-modified glass ionomer; scanning electron microscope