title: An in vitro comparison of cast metal dowel retention using various luting agents and tensile loading.
abstract: BACKGROUND
  No clear consensus exists regarding the choice of luting agents for the retention of cast metal dowels used as a treatment alternative for endodontically treated teeth with excessive loss of coronal tooth structure.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to investigate the retention of the dowel/luting agent/tooth complex while applying different luting agents to cast metal dowels under vertical tensile loading.
  
  
  METHODS
  Sixty extracted, noncarious mandibular premolars with roots of approximately 15-mm length were selected. For each tooth, a tapered root canal preparation was completed to a maximum diameter of 1.60 mm and a length of 11 mm, a common clinical configuration to accommodate cast metal dowels. Sixty cast metal dowels were fabricated for the tooth specimens and cemented with 1 of 3 luting agents (n = 20): zinc-phosphate cement (ZPC) as a control, phosphate-methacrylate resin luting agent (PMRL, Panavia F), and phosphate-methacrylate resin luting agent with metal dowel surfaces modified with a silane coating technique (PMRLS, Panavia F + Siloc). Tensile bond strength (TBS) of the specimens was measured with a universal testing machine at a crosshead speed of 0.5 mm/min. Data (kg) were statistically analyzed using a 1-way analysis of variance and a Scheffe multiple range test (alpha=.05). The homogeneity of variances was analyzed using the Levene test.
  
  
  RESULTS
  The TBS values of ZPC (34.2 +/- 10.54 kg) were significantly higher than PMRL (22 +/- 9.57 kg) and PMRLS (21.7 +/- 7.64 kg). There was no significant difference between the PMRL and PMRLS groups.
  
  
  CONCLUSIONS
  Within the limitations of this study, the use of zinc-phosphate cement provided greater TBS for cast metal dowels than the resin luting agent with and without the silane coating technique. The TBS values with and without the silane coating technique were not statistically different.
authors.affiliation: School of Dental Medicine, Department of Prosthodontics, University of Pittsburg, Pittsburg, PA 15261, USA. ertugrul_z@hotmail.com
authors.forename: H Zeynep
authors.initials: HZ
authors.lastname: Ertugrul
authors.forename: Yahia H
authors.initials: YH
authors.lastname: Ismail
mesh_terms: D003738:Dental Cements / Q000737:chemistry*; D017268:Dental Prosthesis Retention; D006801:Humans; D008670:Metals / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013718:Tensile Strength; D019553:Tooth, Nonvital; D015036:Zinc Phosphate Cement / Q000737:chemistry*
chemical_list: D003738:Dental Cements; D008670:Metals; C438843:Panavia-Fluoro; D019279:Resin Cements; D012821:Silanes; C465121:Siloc; D015036:Zinc Phosphate Cement