title: Effect of Resin Bonded Luting Agents Influencing Marginal Discrepancy in All Ceramic Complete Veneer Crowns.
abstract: BACKGROUND
  Marginal discrepancy severely affects the long term success of All ceramic complete veneer crowns. The precise role of resin luting agents influencing this phenomenon needs to be explored further.
  
  
  OBJECTIVE
  To estimate and compare the marginal discrepancy in CAD/CAM processed All ceramic complete veneer crowns prior and following luting with resin bonded luting agents.
  
  
  METHODS
  Extracted human maxillary first premolars were randomly allocated into four groups of 27 samples each Viz., Group I-Resin Modified Glass Ionomer Cement (GIC) (RelyX), Group II-Bis-GMA based dual cure resin cement (Variolink II), Group III-PMMA based resin cement (Superbond), Group IV- Urethane Dimethacrylate resin cement (Calibra). Following tooth preparation, CAD/CAM All ceramic complete veneer crowns were fabricated and sectioned and marginal discrepancy was evaluated using a scanning electron microscope (TESCAN, Magnification power-1,00,000x) prior and after luting with the experimental resin cements.
  
  
  RESULTS
  The vertical and horizontal discrepancy before and after cementation with Group I [270.08±103.10μm, 165.3±53.00μm and 270.86±102.70μm, 166.62±54.96μm respectively]; Group II [254.21±79.20μm, 117.75±24.29μm and 234.81±79μm, 116.89±18.22μm respectively]; Group III [272.47±86.25μm, 142.08±50.83μm and 251.82±62.69μm, 136.07±44.95μm respectively]; Group IV were [260.28±64.81μm, 116.98±17.71μm and 233.08±69.44μm, 116.58±21.13μm respectively]. ANOVA inferred a statistically significant difference between the four test specimen with regards to vertical and horizontal marginal discrepancy after cementation (F=9.092, p<0.001), (F=10.97, p<0.001). Tukey HSD Post-hoc test observed significant differences in vertical and horizontal marginal discrepancies between the resin modified glass ionomer and resin cements (p<0.05).
  
  
  CONCLUSIONS
  Resin cements exhibited a greater reduction in the marginal discrepancy than the resin modified glass ionomer following luting in All ceramic complete veneer crowns. Hence resin cements are more preferable to GIC for luting All ceramic complete veneer crowns.
authors.affiliation: Professor and HOD, Department of Prosthodontics, Saveetha Dental College , Chennai, Tamil Nadu, India .
authors.forename: Dhanraj
authors.initials: D
authors.lastname: Ganapathy
authors.affiliation: Postgraduate Student, Department of Prosthodontics, Saveetha Dental College , Chennai, Tamil Nadu, India .
authors.forename: Anusha
authors.initials: A
authors.lastname: Sathyamoorthy
authors.affiliation: Postgraduate Student, Department of Prosthodontics, Saveetha Dental College , Chennai, Tamil Nadu, India .
authors.forename: Hemalatha
authors.initials: H
authors.lastname: Ranganathan
authors.affiliation: Intern, Department of Prosthodontics, Saveetha Dental College , Chennai, Tamil Nadu, India .
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Murthykumar
keywords: Bis-GMA resin; CAD/CAM crowns; Glass ionomer cement; Marginal adaptation; Urethane dimethacrylate resin