title: In vitro marginal fit of three all-ceramic crown systems before and after cementation.
abstract: BACKGROUND
  Full-coverage all-ceramic restorations are widely used. The impact of various classifications of luting agent on marginal discrepancies is not well understood.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the cervical fit of all ceramic crowns (IPS e.maxPress, Cergogold, and In Ceram) on bovine teeth with two luting agents before and after cementation.
  
  
  METHODS
  Ninety bovine incisors were embedded in resin. The coronal portions of the teeth were prepared to receive full-coverage crowns. Thirty crowns of 7.0 ± 0.5 mm height, 8.0 mm cervical diameter, and 4.2 mm incisal diameter were fabricated for each ceramic system. The crowns were seated on the teeth, and the marginal discrepancy was measured using a measuring microscope. Then, 15 crowns of each ceramic system were luted on the teeth with resin cement (Variolink II) or resin-modified glass ionomer cement (Rely X luting), and the marginal discrepancy was measured. The results were submitted to analysis of variance, t test and Tukey's test (p<0.05).
  
  
  RESULTS
  The three ceramic systems showed cervical fits after cementation statistically inferior to cervical fits before cementation for the two cements. The IPS e.maxPress showed values for cervical fit statistically superior to Cergogold before cementation. No statistically significant difference was found between IPS e.maxPress and In Ceram and In Ceram and Cergogold. After cementation, no statistically significant difference was found for the three ceramics systems when luted with resin or resin-modified glass ionomer luting agents.
  
  
  CONCLUSIONS
  Within the limitations of this study, it can be concluded that both cements studied increase the marginal discrepancy between the crown and the preparation for the three ceramic systems evaluated.
authors.affiliation: University of Uberaba, Dental Materials and Restorative Dentistry, Minas Gerais, Brazil. gilberto.borges@uniube.br
authors.forename: G A
authors.initials: GA
authors.lastname: Borges
authors.forename: J S
authors.initials: JS
authors.lastname: Faria
authors.forename: P
authors.initials: P
authors.lastname: Agarwal
authors.forename: A M
authors.initials: AM
authors.lastname: Spohr
authors.forename: L
authors.initials: L
authors.lastname: Correr-Sobrinho
authors.forename: B A S
authors.initials: BA
authors.lastname: Miranzi
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002484:Cementation / Q000379:methods*; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry; D008422:Materials Testing; D017680:Potassium Compounds / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D019231:Tooth Preparation, Prosthodontic / Q000379:methods
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D005899:Glass Ionomer Cements; C508050:IPS e.max Press; C483026:In-Ceram Alumina; D017680:Potassium Compounds; D019279:Resin Cements; C084550:Vitremer; C493120:lithia disilicate; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; C103502:Variolink