title: Effect of the Coronal Wall Thickness of Dental Implants on the Screw Joint Stability in the Internal Implant-Abutment Connection.
abstract: OBJECTIVE
  To evaluate the effect of implant coronal wall thickness on load-bearing capacity and screw joint stability.
  
  
  METHODS
  Experimental implants were customized after investigation of the thinnest coronal wall thickness of commercially available implant systems with a regular platform diameter. Implants with four coronal wall thicknesses (0.2, 0.3, 0.4, and 0.5 mm) were fabricated. Three sets of tests were performed. The first set was a failure test to evaluate load-bearing capacity and elastic limit. The second and third sets were cyclic and static loading tests. After abutment screw tightening of each implant, vertical cyclic loading of 250 N or static loading from 250 to 800 N was applied. Coronal diameter expansion, axial displacement, and removal torque values of the implants were compared. Repeated measures analysis of variance (ANOVA) was used for statistical analysis (α = .05).
  
  
  RESULTS
  Implants with 0.2-mm coronal wall thickness demonstrated significantly low load-bearing capacity and elastic limit (both P < .05). These implants also showed significantly large coronal diameter expansion and axial displacement after screw tightening (both P < .05). Greater vertical load and thinner coronal wall thickness significantly increased coronal diameter expansion of the implant, axial displacement of the abutment, and removal torque loss of the abutment screw (all P < .05).
  
  
  CONCLUSIONS
  Implant coronal wall thickness of 0.2 mm produces significantly inferior load-bearing capacity and screw joint stability.
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Lee
authors.forename: Yoon-Hyuk
authors.initials: YH
authors.lastname: Huh
authors.forename: Chan-Jin
authors.initials: CJ
authors.lastname: Park
authors.forename: Lee-Ra
authors.initials: LR
authors.lastname: Cho
mesh_terms: D000704:Analysis of Variance; D001863:Bone Screws; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque; D016474:Weight-Bearing
chemical_list: D015921:Dental Implants