title: Influence of Liquid Lubrication on the Screw-Joint Stability of Y-TZP Implant Abutment Systems.
abstract: OBJECTIVE
  To evaluate the effectiveness of abutment screws coated with liquid Vaseline on the screw-joint stability of yttria-stabilized tetragonal zirconia (Y-TZP) abutment systems.
  
  
  METHODS
  Forty Y-TZP prefabricated abutments, 20 Neodent and 20 Bionnovation, were tightened to 20 Ncm on their respective external hexagon implants, and divided into four groups (n = 10) according to the screws: coated with Vaseline or uncoated. The removal torque (RT) value of the abutment screw was measured before and after loading. A cyclic loading (0.5 × 106cycles; 15 Hz) between 11 and 211 N was applied. Means were compared using a repeated-measures ANOVA (α = 0.05).
  
  
  RESULTS
  There was no significant difference between coated and uncoated screws (p = 0.822). Significant differences were found between the abutment systems (p < 0.001). There was a significant effect of cyclic loading (p < 0.001).
  
  
  CONCLUSIONS
  Coated and uncoated screws presented similar effectiveness in maintaining preload.
  
  
  CONCLUSIONS
  The liquid lubricant used in this study does not influence the stability of Y-TZP single-implant restorations.
authors: Department of Dental Materials and Prosthodontics, UNESP-Univ Estadual Paulista, Araraquara School of Dentistry, Araraquara, São Paulo, Brazil.
authors: Mariana de Almeida
authors: MA
authors: Basílio
authors: Department of Dental Materials and Prosthodontics, UNESP-Univ Estadual Paulista, Araraquara School of Dentistry, Araraquara, São Paulo, Brazil.
authors: Filipe de Oliveira
authors: FO
authors: Abi-Rached
authors: Department of Prosthodontics, PI Brånemark Institute, Bauru, São Paulo, Brazil.
authors: Luis Eduardo
authors: LE
authors: Butignon
authors: Department of Dental Materials and Prosthodontics, UNESP-Univ Estadual Paulista, Araraquara School of Dentistry, Araraquara, São Paulo, Brazil.
authors: João Neudenir
authors: JN
authors: Arioli Filho
mesh_terms: D001863:Bone Screws; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D008153:Lubrication; D010577:Petrolatum; D015040:Zirconium
chemical_list: D010577:Petrolatum; D015040:Zirconium; C028541:zirconium oxide
keywords: Dental implants; cyclic loading; dental abutments; screw preload; single-tooth; zirconium