title: Bone-implant interface with simulated insertion stress around an immediately loaded dental implant in the anterior maxilla: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  The purpose of the present study was to investigate the stress distribution around the bone-implant interface and the effect of the length of an immediately loaded implant in the anterior maxilla using a finite element model with simulated loading stresses.
  
  
  METHODS
  Four-mm-diameter external-hex implants with different lengths (8.5, 10.0, 11.5, 13.0, and 15.0 mm) were used in this study. The anterior maxilla was assumed to be D3 bone quality. All of the material was assumed to be homogenous, isotropic, and linearly elastic. Average bone deformation during implant placement was calculated through the simulation process, and using this, insertion stress was created. The bone-implant interface was constructed using a contact element to simulate a nonosseointegrated condition. Then, 176 N of static force was applied at the middle of the palatoincisal line angle of the abutment at a 120-degree angle to the long axis of the abutment. The von Mises stresses were measured at intervals of 0.25 mm along the bone-implant interface.
  
  
  RESULTS
  Prior to loading, the stresses were evenly distributed around the implant and highly concentrated in the cortical area. When the load was applied, von Mises stresses were concentrated in the cortical bone of the implant neck area. More favorable stress distribution was seen with increasing implant length. However, when the implant length reached 15.0 mm, the stresses increased.
  
  
  CONCLUSIONS
  In the maxilla, when immediate loading is applied after implant placement, 11.5- and 13.0-mm-long single implants showed more favorable stress patterns than the others analyzed. If implants longer than 15.0 mm are used in immediate loading, sufficient bone volume in the recipient site should be considered an important factor.
authors.affiliation: Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Korea.
authors.forename: Joon-Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: In-Ho
authors.initials: IH
authors.lastname: Cho
authors.forename: Yung-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Seong-Joo
authors.initials: SJ
authors.lastname: Heo
authors.forename: Ho-Beom
authors.initials: HB
authors.lastname: Kwon
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Lim
mesh_terms: D001732:Bite Force; D015519:Bone Density / Q000502:physiology; D003198:Computer Simulation; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D057893:Immediate Dental Implant Loading; D008422:Materials Testing; D008437:Maxilla / Q000033:anatomy & histology* / Q000601:surgery; D008954:Models, Biological; D013314:Stress, Mechanical; D013499:Surface Properties