title: Study and characterization of the crest module design: A 3D finite element analysis.
abstract: BACKGROUND
  The importance of the crest module design in the cortical bone region triggered a need to understand its geometry and its influence on stress management and bone stimulation.
  
  
  OBJECTIVE
  The purpose of this study was to determine the effect of different crest module designs in the cortical bone region in terms of critical stress distribution and bone stimulation.
  
  
  METHODS
  Several 3-dimensional finite element analyses were conducted of a mandibular cross section with osseointegrated dental implants. For the numerical models, different crest module designs (cylindrical, divergent, convergent, and cup shaped) were analyzed. An average value of a maximum occlusal load of 250 N was applied to each dental implant design, 30 degrees from the top surface. The concentration and distribution patterns of principal and maximum shear stresses and strains were obtained and analyzed.
  
  
  RESULTS
  According to the comparative finite element analyses, the most pathologic stress and strain peaks around the implant collar in the cortical bone region were found in divergent crest modules with angles 14 degrees or larger. Nevertheless, the highest physiologic peaks of passive bone stimulation through compression, and the lowest tensile and shear stresses and strains in the cortical bone region were promoted by extended divergent crest module designs.
  
  
  CONCLUSIONS
  A slightly divergent and smooth crest module design extended to the cancellous bone increases the surface area available. This results in the dissipation of critical stresses expressed around the collar of the cortical bone region, not only promoting a higher bone-implant contact area and a physiologic bone stimulation but also boosting a healthy and strong bone-implant interface.
authors: Graduate student, CT2M Department, University of Minho, Guimarães, Portugal. Electronic address: mcfdc89@gmail.com.
authors: Cristiana
authors: C
authors: Costa
authors: Assistant Professor, Mechanical Engineering Department, University of Minho, Guimarães, Portugal.
authors: Nuno
authors: N
authors: Peixinho
authors: Assistant, Mechanical Engineering Department, University of Minho, Guimarães, Portugal.
authors: João Pedro
authors: JP
authors: Silva
authors: Assistant Professor, GRF-CFUM, Physics Department, University of Minho, Guimarães, Portugal, and SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, Coimbra, Portugal.
authors: Sandra
authors: S
authors: Carvalho
mesh_terms: D000497:Alloys; D019412:Anatomy, Cross-Sectional / Q000379:methods; D001696:Biomechanical Phenomena; D001732:Bite Force; D000069343:Bone-Implant Interface / Q000502:physiology; D000071556:Cancellous Bone / Q000502:physiology; D017076:Computer-Aided Design; D000071538:Cortical Bone / Q000502:physiology; D003722:Dental Alloys / Q000737:chemistry; D015921:Dental Implants; D017267:Dental Prosthesis Design; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008334:Mandible / Q000502:physiology*; D016348:Osseointegration / Q000502:physiology; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; C031462:titanium alloy (TiAl6V4); D014025:Titanium