title: The Effect of Compressive Cyclic Loading on the Retention of Cast Single Crowns Cemented to Implant Abutments.
abstract: OBJECTIVE
  The aim of this study was to evaluate and compare the retention strength of three cements commonly used in implant-supported prostheses before and after compressive cyclic loading.
  
  
  METHODS
  The working model consisted of five solid abutments, 7 mm in height and with a 6-degree taper, screw retained to five implant analogs secured in a rectangular block of self-curing acrylic. On the abutments, 30 metal Cr-Ni alloy copings were cemented using three luting agents: glass ionomer, resin urethane-based, and compomer cement (n = 10). Two tensile tests were conducted with a universal testing machine, before and after 100,000 cycles of 100 N and 0.72 Hz compressive cyclic loading in a humid environment.
  
  
  RESULTS
  Before applying the compressive load, the retention strength of the resin urethane-based cement was slightly higher than that of the compomer cement and 75% greater than the glass-ionomer cement. After compressive loading, the resin urethane-based cement showed the highest percentage of loss of retention (64.45%, compared with 50% for glass-ionomer and compomer cement). However, the glass-ionomer cement showed the lowest mean retentive strength with 50.35 N as opposed to 75.12 N for the compomer cement and 71.25 N for the resin urethane-based.
  
  
  CONCLUSIONS
  Compressive cyclic loading significantly influences the retention strength of the luting agents tested. All three cements may favor the retrievability of the crowns.
authors.forename: Angel
authors.initials: A
authors.lastname: Alvarez-Arenal
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gonzalez-Gonzalez
authors.forename: Javier
authors.initials: J
authors.lastname: Pinés-Hueso
authors.forename: Hector
authors.initials: H
authors.lastname: deLlanos-Lanchares
authors.forename: Jaime
authors.initials: J
authors.lastname: del Rio Highsmith
mesh_terms: D002484:Cementation / Q000379:methods*; D002858:Chromium Alloys / Q000737:chemistry; D020770:Compomers / Q000737:chemistry; D019245:Compressive Strength; D003442:Crowns; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D019250:Dental Implants, Single-Tooth; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013718:Tensile Strength; D014520:Urethane / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D020770:Compomers; D005899:Glass Ionomer Cements; D019279:Resin Cements; D014520:Urethane