title: Effect of open-sandwich vs. adhesive restorative techniques on enamel and dentine demineralization: an in situ study.
abstract: OBJECTIVE
  To assess in situ the effect of different restorative techniques used with fluoride-releasing materials on enamel and dentine demineralization in the presence of a cariogenic challenge.
  
  
  METHODS
  Thirty human molars were prepared for 60 Class V cavities, with enamel and dentine margins. The teeth were divided into four groups (n=15): L1 - open sandwich technique with a conventional glass ionomer cement (GIC), L2 - open sandwich technique with a resin-modified GIC, A1 - total-etch bonding with a fluoride-containing adhesive, A2 - total-etch bonding with a nonfluoride-containing adhesive. All the cavities were restored with a nanofilled composite. Fifteen volunteers used appliances containing one specimen from each group. The cariogenic challenge was carried out with a 20% sucrose solution 8×/day for 7 days. The specimens were sectioned for microhardness test and EDS analysis at different depths below the enamel and dentine margins (25, 50 and 100μm) and distances from the tooth-restoration interfaces (25 and 75μm). The data were analyzed by ANOVA and Games-Howell test (α=5%).
  
  
  RESULTS
  Both GICs produced higher hardness in enamel at all depth-and-distance combinations, but only L1 produced higher hardness in dentine (p<0.05). L2 and A1 exhibited similar dentine hardness at 25μm distance for all depths (p>0.05). L1 demonstrated significantly higher amounts of calcium in dentine than the other groups, but had similar amounts in enamel to L2 and A1.
  
  
  CONCLUSIONS
  The open sandwich technique using conventional GIC proved more effective in reducing enamel and dentine demineralization at depths of up to 100μm under a cariogenic challenge.
  
  
  CONCLUSIONS
  Conventional GICs should be considered the materials of choice for lining of cavities not having all margins in enamel, particularly using the open sandwich technique.
authors.affiliation: Graduate Program in Dentistry, School of Health and Biosciences, Pontifícia Universidade Católica do Paraná, Curitiba, PR, Brazil.
authors.forename: Giovanna A
authors.initials: GA
authors.lastname: Kirsten
authors.forename: Rodrigo N
authors.initials: RN
authors.lastname: Rached
authors.forename: Rui F
authors.initials: RF
authors.lastname: Mazur
authors.forename: Sergio
authors.initials: S
authors.lastname: Vieira
authors.forename: Evelise M
authors.initials: EM
authors.lastname: Souza
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002118:Calcium / Q000032:analysis; D002326:Cariogenic Agents / Q000009:adverse effects; D002327:Cariostatic Agents / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003736:Dental Cavity Lining / Q000379:methods*; D003737:Dental Cavity Preparation / Q000145:classification; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000737:chemistry / Q000648:ultrastructure*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure*; D005459:Fluorides / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D006801:Humans; D053761:Nanocomposites / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis; D019279:Resin Cements / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013395:Sucrose / Q000009:adverse effects; D017001:Tooth Demineralization / Q000517:prevention & control*
chemical_list: D002326:Cariogenic Agents; D002327:Cariostatic Agents; D003188:Composite Resins; D003738:Dental Cements; D005899:Glass Ionomer Cements; C515713:Ketac Molar Easymix; C451600:OptiBond Solo Plus; D019279:Resin Cements; C533204:filtek Z350; C115612:single bond; C067790:Vitrabond; D010758:Phosphorus; D017438:Bisphenol A-Glycidyl Methacrylate; D013395:Sucrose; D005459:Fluorides; D002118:Calcium
keywords: Adhesive system; Cariogenic challenge; Energy dispersive spectroscopy; Glass ionomer cement; In situ study; Knoop microhardness