title: Effect of gingival fluid on marginal adaptation of Class II resin-based composite restorations.
abstract: OBJECTIVE
  To evaluate in vitro the marginal quality of Class II composite restorations at the gingival enamel margins as affected by contamination of the cavities with gingival fluid (GF) during different steps of resin bonding procedures.
  
  
  METHODS
  70 Class II cavities were prepared in extracted human molars and restored with composite using a multi-component bonding system (OptiBond FL/Herculite XRV; OPTI) or a single-bottle adhesive (Syntac Sprint/Tetric Ceram; SYN). The cavities were contaminated with human GF: C1 after acid etching, C2 after application of the primer (OPTI) or light-curing of the primer-adhesive (SYN), and C3 after light-curing of the resin adhesive (OPTI). Uncontaminated cavities were used as the control (C0). The restored teeth were subjected to thermocycling (TC) and replicated for SEM analysis of marginal gap formation. Microleakage at the gingival margins was determined by dye penetration with basic fuchsin.
  
  
  METHODS
  non-parametric tests (Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction).
  
  
  RESULTS
  In both bonding systems, contamination with GF after acid etching (C1) did not impair the marginal quality; the mean percentages of continuous margin/mean depths of dye penetration were: OPTI: C0: 88.5%/0.10 mm, C1: 95.6%/0.04 mm; SYN: C0: 90.9%/0.08 mm, C1: 97.0%/0.05 mm. Marginal adaptation was adversely affected when GF contamination was performed after
authors.affiliation: Department of Conservative Dentistry, Periodontology and Pedodontics, University of Ulm, Germany. axel.spahr@medizin.uni-ulm.de
authors.forename: A
authors.initials: A
authors.lastname: Spahr
authors.forename: F
authors.initials: F
authors.lastname: Schön
authors.forename: B
authors.initials: B
authors.lastname: Haller
mesh_terms: D000134:Acid Etching, Dental; D000328:Adult; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification / Q000473:pathology; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000145:classification*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005883:Gingival Crevicular Fluid; D006801:Humans; D008027:Light; D008297:Male; D008855:Microscopy, Electron, Scanning; D008963:Molar; D019279:Resin Cements / Q000737:chemistry; D012394:Rosaniline Dyes; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; C092987:Optibond; D019279:Resin Cements; D012394:Rosaniline Dyes; C078484:Syntac dentine adhesive; C121818:Tetric ceram; C065770:Herculite XR; C025485:basic fuchsin