title: Marginal quality and wear of extended posterior resin composite restorations: Eight-year results in vivo.
abstract: OBJECTIVE
  To evaluate wear and marginal quality of resin composite restorations over eight years of clinical service in vivo.
  
  
  METHODS
  30 patients received 68 resin composite restorations (36 Grandio, 32 Tetric Ceram) in the course of a prospective clinical trial. 3-D evaluation of 36 selected teeth involving 144 epoxy replicas was carried out using a special 3-D scanning device with an accuracy of U1=2.5+L/350 μm; U3=3+L/300 μm. In vivo replicas were sputter-coated with gold and examined under a SEM at 200× magnification. Marginal integrity between resin composite and enamel was expressed as a percentage of the entire judgeable margin length.
  
  
  RESULTS
  During the clinical 8-year observation period, wear significantly increased in the restored areas as well as in OCAs. RBCs under investigation showed no significant differences regarding wear (p>0.05). Localization of the restorations (premolar vs. molar or upper vs. lower) did not show a significant influence on wear rates (p>0.05). Clinically, by SEM, and by 3-D scanning distinct changes of worn contours on enamel and RBC were visible. Quantitative margin analysis revealed a change of perfect margins (58% at baseline vs. 14% at 8 years), positive step formations (15% at baseline vs. 10% at 8 years), and negative step formations (20% at baseline vs. 71% at 8 years) over time (p<0.001). Regarding the portion of gap-free margins (baseline vs. 2 years) and total margin length (baseline to 8 years), Grandio showed lower values (Mann-Whitney U-test; p<0.05). The portion of negative step formations was lower for Tetric Ceram at baseline (Mann-Whitney-U test; p<0.05).
  
  
  CONCLUSIONS
  After eight years of clinical service, neither wear nor marginal quality was a critical factor for estimation and survival of extended posterior resin composite restorations.
authors.affiliation: Department of Pediatric Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Giessen, Schlangenzahl 14, D-35392 Giessen, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Krämer
authors.affiliation: Department of Pediatric Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Giessen, Schlangenzahl 14, D-35392 Giessen, Germany.
authors.forename: Pierre
authors.initials: P
authors.lastname: Küssner
authors.affiliation: Department of Pediatric Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Giessen, Schlangenzahl 14, D-35392 Giessen, Germany.
authors.forename: Ila
authors.initials: I
authors.lastname: Motmaen
authors.affiliation: Department of Prosthetic Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Giessen, Schlangenzahl 14, D-35392 Giessen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Köhl
authors.affiliation: Department of Prosthetic Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Giessen, Schlangenzahl 14, D-35392 Giessen, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Wöstmann
authors.affiliation: Department of Operative Dentistry and Endodontics, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Marburg, Georg-Voigt-Str. 3, D-35039 Marburg, Germany. Electronic address: frankbg@med.uni-marburg.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Frankenberger
mesh_terms: D000328:Adult; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent; D005260:Female; D006801:Humans; D008297:Male; D055595:Mechanical Phenomena; D008875:Middle Aged; D012117:Resins, Synthetic; D013997:Time Factors; D055815:Young Adult
chemical_list: D012117:Resins, Synthetic
keywords: Clinical trial; Etch and rinse; Extended lesions; Marginal integrity; Nano fillers; Resin composites; Wear