title: Influence of Connection Types and Implant Number on the Biomechanical Behavior of Mandibular Full-Arch Rehabilitation.
abstract: OBJECTIVE
  To evaluate the influence of different implant numbers and connection types on the biomechanical behavior of mandibular full-arch implant-supported rehabilitation.
  
  
  METHODS
  Computed tomography-based finite element models comprising a totally edentulous mandible and 3.8 × 13-mmdiameter implants, abutments, abutment screws, bar retaining screw, and bar were constructed. Different implant numbers (three, four, and five implants) and loading conditions (symmetrical/balanced, unilateral, and posterior with diverse loading magnitudes) were simulated for both external hex and Morse-taper connections. The peak equivalent strain (EQV strain) in the bone and the peak of von Mises stress (EQV stress) in the abutment screw and bar retaining screw were evaluated.
  
  
  RESULTS
  Lower strain values were observed for a symmetrical loading distribution. Considering the same loading conditions, significantly higher bone strain levels were observed for external hex, compared with the Morse-taper connection. The number of implants had no significant influence on strain levels in bone, irrespective of the connection types. Compared with the external hex connection, the Morse-taper connection type presented significantly lower EQV stress values in abutment screws, but significantly higher stress in the bar retaining screw. Increasing the number of implants significantly reduced the EQV stress in the abutment screw and bar retaining screw.
  
  
  CONCLUSIONS
  The Morse-taper connection type significantly decreased the strain levels in peri-implant bone, while increasing the stress in bar retaining screws. A smaller number of implants in an inferior full-arch rehabilitation slightly increased the stress in the abutment and bar retaining screws. Balanced adjustments of the loading improve the biomechanics of a mandibular full-arch rehabilitation.
authors.forename: Ravel M
authors.initials: RM
authors.lastname: Sousa
authors.forename: Paulo Cézar
authors.initials: PC
authors.lastname: Simamoto-Junior
authors.forename: Alfredo Júlio
authors.initials: AJ
authors.lastname: Fernandes-Neto
authors.forename: Jos Vander
authors.initials: JV
authors.lastname: Sloten
authors.forename: Siegfried Vn
authors.initials: SV
authors.lastname: Jaecques
authors.forename: Roberto S
authors.initials: RS
authors.lastname: Pessoa
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported / Q000295:instrumentation / Q000379:methods*; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation* / Q000601:surgery; D008334:Mandible / Q000502:physiology / Q000601:surgery*; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed
chemical_list: D015921:Dental Implants