title: Finite element analysis of stress distribution with splinted and nonsplinted maxillary anterior fixed prostheses supported by zirconia or titanium implants.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the effect of splinting titanium (Ti) or zirconia (Zr) implants supporting maxillary anterior fixed prostheses on the stress levels and patterns in the implants, prostheses, and the surrounding bone; and to compare the effects of Zr and Ti implant materials on the stress distribution in splinted and nonsplinted designs via finite element modeling.
  
  
  METHODS
  Zr and Ti dental implants and the anterior maxilla were modeled. In the nonsplinted design (D1), implants were placed into the maxillary left central incisor and canine regions, and a three-unit zirconia fixed prosthesis was modeled. In the splinted design (D2), a symmetric model of D1 was generated and the two prostheses were splinted together to create a six-unit prosthesis. Loading was applied horizontally and obliquely. Von Mises, tensile, and compressive stresses were evaluated in the implants, prostheses, and surrounding bone.
  
  
  RESULTS
  Under both loading conditions, the stresses on the D2 implants were lower than those in the D1 implants. Stresses were concentrated on the neck of the implant and decreased through the apex. All of the stress values in cortical bone in D1 were slightly higher than in D2 for both implant materials under both loading conditions.
  
  
  CONCLUSIONS
  When the implants were splinted together, stresses were reduced in the supporting bone and implants in both loading conditions, but increased stress was observed in the prostheses under oblique loading. Intense stress concentrations were found in the connector of the splinted prosthesis and the cervical region of the nonsplinted prosthesis. Zr and Ti implants showed very similar stress distributions in all materials. Under oblique loading, lower stresses occurred in implants and the prosthesis core material when Ti implants were used.
authors: Department of Prosthetic Dentistry, Gazi University Faculty of Dentistry, Ankara, Turkey.
authors: Bilge Turhan
authors: BT
authors: Bal
authors: Alper
authors: A
authors: Cağlar
authors: Cemal
authors: C
authors: Aydin
authors: Handan
authors: H
authors: Yilmaz
authors: Merve
authors: M
authors: Bankoğlu
authors: Atilim
authors: A
authors: Eser
mesh_terms: D019245:Compressive Strength; D015921:Dental Implants; D003764:Dental Materials; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D008437:Maxilla; D013165:Splints; D013314:Stress, Mechanical; D013718:Tensile Strength; D014025:Titanium; D015040:Zirconium
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide