title: An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations.
abstract: BACKGROUND
  There are a number of studies citing the primary reason for replacing auto cure glass ionomer cements was due to recurrent caries. The purpose of this study was to use an in vitro model to measure caries at the dentine restoration interface of bonded composite resin and auto cure glass ionomer cement restorations and to measure the amount of surface degradation occurring in the restorative materials.
  
  
  METHODS
  Specimens of auto cure glass ionomer cements (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and bonded composite resin restorations (Ice, SDI) were placed separately at the dentino-enamel junction of 10 recently extracted human third molar teeth, disinfected and placed into the overflow from a continuous culture of S. mutans for two weeks. Restorations were sectioned and prepared for scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Restoration tooth interfaces were photographed and the distance from the surface of the teeth to the surface of the restorations measured. EPMA of percentage weights of calcium, phosphorous and fluoride were made outwards from the restoration surface 130pm at a depth of 10 microm below the surface of the dentine.
  
  
  RESULTS
  There were significant differences between the surface heights of composite resin, auto cure glass ionomer cements compared to teeth surfaces. Percentage weights of calcium and phosphorus levels were similar to non-demineralized dentine in the auto cure glass ionomer cement samples but there were significant reductions in mineral content of dentine adjacent to bonded composite resin restorations. Fluoride levels were mixed.
  
  
  CONCLUSIONS
  This study shows that placing a bonded composite resin restoration into dentine affords little protection to the surrounding tooth from caries attack although insignificant degradation of the restorative surface occurs. Placing a glass ionomer cement restoration into dentine protects the surrounding tooth from caries but degradation of the restoration surface occurs.
authors.affiliation: School of Dentistry, Faculty of Health Sciences, The University of Adelaide, South Australia. geoffbds@dentalk.com.au
authors.forename: G M
authors.initials: GM
authors.lastname: Knight
authors.forename: J M
authors.initials: JM
authors.lastname: McIntyre
authors.forename: G G
authors.initials: GG
authors.lastname: Craig
authors.lastname: Mulyani
authors.forename: P S
authors.initials: PS
authors.lastname: Zilm
authors.forename: N J
authors.initials: NJ
authors.lastname: Gully
mesh_terms: D002327:Cariostatic Agents / Q000627:therapeutic use; D003188:Composite Resins / Q000009:adverse effects; D003731:Dental Caries / Q000209:etiology*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000009:adverse effects* / Q000379:methods; D003804:Dentin / Q000737:chemistry / Q000473:pathology*; D004577:Electron Probe Microanalysis; D005459:Fluorides / Q000627:therapeutic use; D005899:Glass Ionomer Cements / Q000737:chemistry / Q000627:therapeutic use*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D012008:Recurrence
chemical_list: D002327:Cariostatic Agents; D003188:Composite Resins; D005899:Glass Ionomer Cements; D005459:Fluorides