title: Effect of crown-to-implant ratio on peri-implant stress: a finite element analysis.
abstract: The aim of this study was to evaluate stress distribution in the fixation screws and bone tissue around implants in single-implant supported prostheses with crowns of different heights (10, 12.5, 15 mm - crown-to-implant ratio 1:1, 1.25:1, 1.5:1, respectively). It was designed using three 3-D models. Each model was developed with a mandibular segment of bone block including an internal hexagon implant supporting a screw-retained, single metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm with crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. The applied forces were 200N (axial) and 100 N (oblique). The increase of crown height showed differences with the oblique load in some situations. By von Mises' criterion, a high stress area was concentrated at the implant/fixation screw and abutment/implant interfaces at crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. Using the maximum principal criteria, the buccal regions showed higher traction stress intensity, whereas the distal regions showed the largest compressive stress in all models. The increase of C/I ratio must be carefully evaluated by the dentist since the increase of this C/I ratio is proportional to the increase of average stress for both screw fixation (C/I 1:1 to 1:1.25 ratio=30.1% and C/I 1:1 to 1:1.5 ratio=46.3%) and bone tissue (C/I 1:1 to 1:1.25 ratio=30% and C/I 1:1 to 1:1.5 ratio=51.5%).
authors.affiliation: Department of Dental Materials and Prosthodontics, UNESP, Univ Estadual Paulista, 1193 José Bonifácio Street, Araçatuba, São Paulo 16015050, Brazil. Electronic address: fellippo@gmail.com.
authors.forename: Fellippo Ramos
authors.initials: FR
authors.lastname: Verri
authors.affiliation: Department of Dental Materials and Prosthodontics, UNESP, Univ Estadual Paulista, 1193 José Bonifácio Street, Araçatuba, São Paulo 16015050, Brazil.
authors.forename: Victor Eduardo de Souza
authors.initials: VE
authors.lastname: Batista
authors.affiliation: Department of Dental Materials and Prosthodontics, UNESP, Univ Estadual Paulista, 1193 José Bonifácio Street, Araçatuba, São Paulo 16015050, Brazil.
authors.forename: Joel Ferreira
authors.initials: JF
authors.lastname: Santiago
authors.affiliation: Department of Dental Materials and Prosthodontics, UNESP, Univ Estadual Paulista, 1193 José Bonifácio Street, Araçatuba, São Paulo 16015050, Brazil.
authors.forename: Daniel Augusto de Faria
authors.initials: DA
authors.lastname: Almeida
authors.affiliation: Department of Dental Materials and Prosthodontics, UNESP, Univ Estadual Paulista, 1193 José Bonifácio Street, Araçatuba, São Paulo 16015050, Brazil.
authors.forename: Eduardo Piza
authors.initials: EP
authors.lastname: Pellizzer
mesh_terms: D001863:Bone Screws; D015921:Dental Implants; D003776:Dental Porcelain / Q000737:chemistry*; D019094:Dental Prosthesis, Implant-Supported; D020342:Finite Element Analysis; D008954:Models, Biological; D013314:Stress, Mechanical
chemical_list: D015921:Dental Implants; D003776:Dental Porcelain
keywords: Biomechanics; Dental implants; Dental prosthesis; Finite element analysis; Implant-supported