title: Retentiveness of implant-supported metal copings using different luting agents.
abstract: BACKGROUND
  With regard to potential retrievability of cement-retained implant restorations, the retentive strength of the luting agents is critical. The aim of this study was to evaluate the retention values of implant-supported metal copings using different luting agents.
  
  
  METHODS
  Twenty ITI implant analogs and solid abutments of 5.5-mm height were embedded vertically in autopolymerizing acrylic resin blocks. Metal copings with a loop on the occlusal surface were fabricated using base metal alloy (Rexillium III). The copings were luted using eight cements with different retention mechanisms (Panavia F2.0, Fuji Plus, Fleck's, Poly F, Fuji I, Temp Bond, GC-free eugenol, and TempSpan) under static load of 5 kg (n=10). All specimens were incubated at 37°C for 24 hours, conditioned in artificial saliva for 7 days and thermocycled for 5000 cycles (5-55°C). The dislodging force was measured using a universal testing machine at a crosshead speed of 5 mm/min. Statistical analyses were performed using Kruskal-Wallis (α=0.05) and Mann-Whitney tests with Bonferroni correction (α=0.001).
  
  
  RESULTS
  Fuji Plus and TempSpan had the highest and the least mean retentive strength, respectively (320.97±161.47, 3.39±2.33). There was no significant difference between Fuji Plus, Fleck's, Ploy F, and Panavia F2.0. These cements were superior to provisional cements and Fuji I (P<0.001) which showed statistically same retentive strength.
  
  
  CONCLUSIONS
  Within the conditions of this study, the resin modified glass ionomer, zinc phosphate, zinc polycarboxylate, and Panavia F2.0 had statistically the same retentive quality and are recommended for definitive cementation of single implant-supported restorations. The provisional cements and glass ionomer may allow retrievability of these restorations.
authors.affiliation: Department of Prosthodontics and Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Biomaterials Research Group, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Nejatidanesh
authors.forename: Omid
authors.initials: O
authors.lastname: Savabi
authors.forename: Maziar
authors.initials: M
authors.lastname: Ebrahimi
authors.forename: Ghazal
authors.initials: G
authors.lastname: Savabi