title: The effect of different restorative and abutment materials on marginal and internal adaptation of three-unit cantilever implant-supported fixed partial dentures: an in vitro study.
abstract: OBJECTIVE
  Passive fit is generally assumed to be a significant prerequisite for long-term implant success. The aim of this study was to evaluate the precision fit of three-unit implant-supported fixed partial dentures with different restorative and abutment materials on two implant systems: the Straumann and Astra Tech.
  
  
  METHODS
  Two mandibular epoxy resin models (one for each implant system) were fabricated, and two implants were inserted at the first and second molar region. Poly(vinyl siloxane) impression material was used to make the dental impression. For each implant system, fifteen models were fabricated, and each group was divided into three subgroups (group 1: titanium abutment with metal framework, group 2: titanium abutment with zirconium framework, group 3: zirconium abutment with zirconium framework). The replica technique was used to examine the marginal and internal gap values. For each restoration, 20 measurements were performed, totaling 1200 measurements for all groups. Data were evaluated statistically using ANOVA and LSD post hoc test (p < 0.05).
  
  
  RESULTS
  The highest values at internal adaptation measurements were found at the occlusal surface for all groups. When the mean values of the marginal measurements were assessed, the lowest measurements were found in group 3 (51.416 μm), and the highest values were found in group 1 (79.394 μm). There were statistically significant differences between subgroups for marginal measurements (p < 0.05).
  
  
  CONCLUSIONS
  As included in our study, marginal measurement values were found to be 46 to 87 μm. The marginal discrepancy of the tested materials could be considered clinically acceptable.
authors.affiliation: Research Assistant, University of Marmara, Department of Prosthetic Dentistry, Istanbul, Turkey.
authors.forename: Erkut
authors.initials: E
authors.lastname: Kahramanoğlu
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Kulak-Özkan
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D003760:Dental Impression Materials / Q000737:chemistry; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003830:Denture, Partial, Fixed; D004853:Epoxy Resins / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D011145:Polyvinyls / Q000737:chemistry; D016628:Replica Techniques; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D003760:Dental Impression Materials; D003764:Dental Materials; D004853:Epoxy Resins; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; D015040:Zirconium; D014025:Titanium
keywords: Abutment; implant; implant-supported prosthesis; precision fit; restorative material