title: Influence of application site of provisional cement on the marginal adaptation of provisional crowns.
abstract: BACKGROUND
  Marginal discrepancies may lead to cement washout and marginal leakage, damaging periodontal and pulp tissues or causing premature loss of the restoration.
  
  
  OBJECTIVE
  This study evaluated the influence of application site of provisional cement on the marginal adaptation of provisional crowns.
  
  
  METHODS
  Four different application sites of provisional cement (Temp Bond NE, Kerr Corporation) were used for cementation of provisional crowns on phantom teeth prepared for full crown restorations, performing 4 experimental groups (n=10): cement applied to all internal surfaces of the crown (CAO); cement applied to all internal surfaces of the crown, except for the occlusal surface (CA); cement applied to the cervical crown margin (CM); and cement applied to the cervical tooth margin (TM). A comparison microscope (Mitutoyo America Corporation) was used to measure the distances between the internal tangents of two circular marks, one made on the provisional crown and one made apical to the tooth preparation margin, in areas corresponding to buccal, lingual, mesial and distal surfaces. Marginal adaptation was determined before and after cementation, with 0.0001-mm accuracy. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level.
  
  
  RESULTS
  Mean values of marginal opening obtained for each group were: CAO: 145 microm; CA: 67 microm; CM: 46 microm; TM: 34 microm. CA, CM and TM presented significantly lower marginal openings than CAO (p<0.05).
  
  
  CONCLUSIONS
  complete filling of the crown with provisional cement, including the occlusal surface, provided greater marginal discrepancies when compared to the other methods evaluated.
authors.affiliation: Department of Prosthodontics and Dental Materials, Dental School, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Mayra
authors.initials: M
authors.lastname: Cardoso
authors.forename: Marcelo Ferreira
authors.initials: MF
authors.lastname: Torres
authors.forename: Mariana Ribeiro de Moraes
authors.initials: MR
authors.lastname: Rego
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: Santiago
mesh_terms: D002484:Cementation / Q000379:methods*; D003442:Crowns; D003738:Dental Cements; D018772:Dental Marginal Adaptation; D003794:Dental Restoration, Temporary / Q000379:methods*; D019231:Tooth Preparation, Prosthodontic; D015034:Zinc Oxide
chemical_list: D003738:Dental Cements; C474196:Tempbond NE; D015034:Zinc Oxide