title: Tilted and short implants supporting fixed prosthesis in an atrophic maxilla: a 3D-FEA biomechanical evaluation.
abstract: OBJECTIVE
  This study compared the biomechanical behavior of tilted long implant and vertical short implants to support fixed prosthesis in an atrophic maxilla.
  
  
  METHODS
  The maxilla model was built based on a tomographic image of the patient. Implant models were based on micro-computer tomography imaging of implants. The different configurations considered were M4S, four vertical anterior implants; M4T, two mesial vertical implants and two distal tilted (45°) implants in the anterior region of the maxilla; and M6S, four vertical anterior implants and two vertical posterior implants. Numerical simulation was carried out under bilateral 150 N loads applied in the cantilever region in axial (L1) and oblique (45°) (L2) direction. Bone was analyzed using the maximum and minimum principal stress (σmax and σmin ), and von Mises stress (σvM ) assessments. Implants were analyzed using the σvM .
  
  
  RESULTS
  The higher σmax was observed at: M4T, followed by M6S/L1, M6S/L2, M4S/L2, and M4S/L1 and the higher σvM : M4T/L1, M4T/L2 and M4S/L2, M6S/L2, M4S/L1, and M6S/L1.
  
  
  CONCLUSIONS
  The presence of distal tilted (all-on-four) and distal short implants (all-on-six) resulted in higher stresses in both situations in the maxillary bone in comparison to the presence of vertical implants (all-on-four).
authors.affiliation: Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Erika O
authors.initials: EO
authors.lastname: Almeida
authors.forename: Eduardo P
authors.initials: EP
authors.lastname: Rocha
authors.forename: Amilcar C
authors.initials: AC
authors.lastname: Freitas Júnior
authors.forename: Rodolfo B
authors.initials: RB
authors.lastname: Anchieta
authors.forename: Ronald
authors.initials: R
authors.lastname: Poveda
authors.forename: Nikhil
authors.initials: N
authors.lastname: Gupta
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D001284:Atrophy; D001696:Biomechanical Phenomena; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D006801:Humans; D021621:Imaging, Three-Dimensional; D008437:Maxilla / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D055114:X-Ray Microtomography
chemical_list: D015921:Dental Implants
keywords: biomechanics; dental implants; finite element analysis; osseointegration