title: Correlation between margin fit and microleakage in complete crowns cemented with three luting agents.
abstract: Microleakage can be related to margin misfit. Also, traditional microleakage techniques are time-consuming. This study evaluated the existence of correlation between in vitro margin fit and a new microleakage technique for complete crowns cemented with 3 different luting agents. Thirty human premolars were prepared for full-coverage crowns with a convergence angle of 6 degrees, chamfer margin of 1.2 mm circumferentially, and occlusal reduction of 1.5 mm. Ni-Cr cast crowns were cemented with either zinc phosphate (ZP) (S.S. White), resin-modified glass-ionomer (RMGI) (Rely X Luting Cement) or a resin-based luting agent (RC) (Enforce). Margin fit (seating discrepancy and margin gap) was evaluated according to criteria in the literature under microscope with 0.001 mm accuracy. After thermal cycling, crowns were longitudinally sectioned and microleakage scores at tooth-cement interface were obtained and recorded at x100 magnification. Margin fit parameters were compared with the one-way ANOVA test and microleakage scores with Kruskal-Wallis and Dunn's tests (alpha=0.05). Correlation between margin fit and microleakage was analyzed with the Spearman's test (alpha=0.05). Seating discrepancy and marginal gap values ranged from 81.82 microm to 137.22 microm (p=0.117), and from 75.42 microm to 78.49 microm (p=0.940), respectively. Marginal microleakage scores were ZP=3.02, RMGI=0.35 and RC=0.12 (p<0.001), with no differences between RMGI and RC scores. The correlation coefficient values ranged from -0.27 to 0.30 (p>0.05).
  
  
  CONCLUSIONS
  Margin fit parameters and microleakage showed no strong correlations; cast crowns cemented with RMGI and RC had lower microleakage scores than ZP cement.
authors.affiliation: Oral Rehabilitation Program, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Paulo Henrique Orlato
authors.initials: PH
authors.lastname: Rossetti
authors.forename: Accacio Lins
authors.initials: AL
authors.lastname: do Valle
authors.forename: Ricardo Marins
authors.initials: RM
authors.lastname: de Carvalho
authors.forename: Mario Fernando
authors.initials: MF
authors.lastname: De Goes
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Pegoraro
mesh_terms: D001641:Bicuspid / Q000473:pathology; D002484:Cementation / Q000379:methods*; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003722:Dental Alloys / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003763:Dental Leakage / Q000145:classification*; D017267:Dental Prosthesis Design; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; C103503:EnForce-Sure Cure; D005899:Glass Ionomer Cements; D019279:Resin Cements; C084550:Vitremer; D015036:Zinc Phosphate Cement