title: Vertical Misfit of Single-Implant Abutments Made from Different Materials Under Cyclic Loading.
abstract: OBJECTIVE
  Little information is available in the literature regarding the accuracy of marginal fit of abutments made from different materials. The aim of this study was to compare the level of vertical misfit in abutments made from different materials before and after cyclic loading.
  
  
  METHODS
  Thirty external hexagon implants, 3.75-mm diameter and 13-mm length, were embedded in epoxy resin and divided into three groups according to abutment type (n = 10): (1) machined titanium (Ti) abutments; (2) premachined gold-alloy (Au) abutments; and (3) machined zirconia (Zr) abutments. The abutments were attached to their respective implants by titanium alloy screws at the manufacturer's recommended torque. A cyclic loading (0.5 × 10(6) cycles; 15 Hz) between 11 and 211 N was applied at an angle of 30 degrees to the long axis of the implants. Implant-abutment vertical misfits (μm) were measured at four predetermined points before and after loading with a stereomicroscope at 60× magnification. The group means were compared using a three-way repeated-measure analysis of variance (ANOVA) and Tukey test (α = .05).
  
  
  RESULTS
  The results from the ANOVA identified significant effects of the abutment type (P < .001). However, there were no significant effects of cyclic loading (P = .978) or measured surfaces (P = .955). When the abutment groups were compared regardless of cyclic loading and measured surfaces, the Au group showed the highest value of vertical misfit (14.93 ± 0.78), followed by the Ti group (8.53 ± 0.44) and the Zr group (5.64 ± 0.73), with statistically significant differences among them (P < .05).
  
  
  CONCLUSIONS
  The abutment groups showed statistically significant differences in vertical misfit. Zr abutments showed the highest accuracy in terms of marginal fit, and Au abutments showed the lowest. Cyclic loading did not significantly change the level of vertical misfit. All experimental groups presented acceptable values of marginal misfit.
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Butignon
authors.forename: Mariana
authors.initials: M
authors.lastname: de Almeida Basílio
authors.forename: Julia Sgavioli
authors.initials: JS
authors.lastname: Santo
authors.forename: João Neudenir
authors.initials: JN
authors.lastname: Arioli Filho
mesh_terms: D000704:Analysis of Variance; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D019250:Dental Implants, Single-Tooth; D003764:Dental Materials / Q000737:chemistry*; D017268:Dental Prosthesis Retention / Q000295:instrumentation / Q000592:standards; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods; D006046:Gold; D057893:Immediate Dental Implant Loading; D008422:Materials Testing; D008954:Models, Biological; D014025:Titanium; D019415:Torque; D015040:Zirconium
chemical_list: D003764:Dental Materials; D006046:Gold; D015040:Zirconium; D014025:Titanium