title: The selection criteria of temporary or permanent luting agents in implant-supported prostheses: in vitro study.
abstract: OBJECTIVE
  The use of temporary or permanent cements in fixed implant-supported prostheses is under discussion. The objective was to compare the retentiveness of one temporary and two permanent cements after cyclic compressive loading.
  
  
  METHODS
  The working model was five solid abutments screwed to five implant analogs. Thirty Cr-Ni alloy copings were randomized and cemented to the abutments with one temporary (resin urethane-based) or two permanent (resin-modified glass ionomer, resin-composite) cements. The retention strength was measured twice: once after the copings were cemented and again after a compressive cyclic loading of 100 N at 0.72 Hz (100,000 cycles).
  
  
  RESULTS
  Before loading, the retention strength of resin composite was 75% higher than the resin-modified glass ionomer and 2.5 times higher than resin urethanebased cement. After loading, the retentiveness of the three cements decreased in a non-uniform manner. The greatest percentage of retention loss was shown by the temporary cement and the lowest by the permanent resin composite. However, the two permanent cements consistently show high retention values.
  
  
  CONCLUSIONS
  The higher the initial retention of each cement, the lower the percentage of retention loss after compressive cyclic loading. After loading, the resin urethane-based cement was the most favourable cement for retrieving the crowns and resin composite was the most favourable cement to keep them in place.
authors.affiliation: Department of Prosthodontics and Occlusion, School of Dentistry, University of Oviedo, Oviedo, Spain.
authors.forename: Angel
authors.identifier: 0000-0003-2945-5992
authors.initials: A
authors.lastname: Alvarez-Arenal
authors.affiliation: Department of Prosthodontics and Occlusion, School of Dentistry, University of Oviedo, Oviedo, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gonzalez-Gonzalez
authors.affiliation: Department of Prosthodontics and Occlusion, School of Dentistry, University of Oviedo, Oviedo, Spain.
authors.forename: Hector
authors.identifier: 0000-0003-3711-7117
authors.initials: H
authors.lastname: deLlanos-Lanchares
authors.affiliation: Department of Oral Stomatology I, Faculty of Medicine and Dentistry, University of Basque Country, Bilbao, Spain.
authors.forename: Aritza
authors.initials: A
authors.lastname: Brizuela-Velasco
authors.affiliation: Department of Oral Stomatology I, Faculty of Medicine and Dentistry, University of Basque Country, Bilbao, Spain.
authors.forename: Joseba
authors.initials: J
authors.lastname: Ellacuria-Echebarria
keywords: Cements; Cyclic compressive load; Fixed prosthesis; Implants