title: Validation of finite element models for strain analysis of implant-supported prostheses using digital image correlation.
abstract: OBJECTIVE
  A validated numerical model for stress/strain predictions is essential in understanding the biomechanical behavior of implant-supported dental prostheses. The digital image correlation (DIC) method for full-field strain measurement was compared with finite element analysis (FEA) in assessing bone strain induced by implants.
  
  
  METHODS
  An epoxy resin model simulating the lower arch was made for the experimental test with acrylic resin replicas of the first premolar and second molar and threaded implants replacing the second premolar and first molar. Splinted (G1/G3) and non-splinted (G2/G4) metal-ceramic screw-retained crowns were fabricated and loaded with (G1/G2) or without (G3/G4) the second molar that provided proximal contact. A single-camera, two-dimensional DIC system was used to record deformation of the resin model surface under a load of 250N. Three-dimensional finite element (FE) models were constructed for the physical models using computer-aided design (CAD) software. Surface strains were used for comparison between the two methods, while internal strains at the implant/resin block interface were calculated using FEA.
  
  
  RESULTS
  Both methods found similar strain distributions over the simulant bone block surface, which indicated possible benefits of having splinted crowns and proximal contact in reducing bone strains. Internal strains predicted by FEA at the implant-resin interface were 8 times higher than those on the surface of the model, and they confirmed the results deduced from the surface strains. FEA gave higher strain values than experiments, probably due to incorrect material properties being used.
  
  
  CONCLUSIONS
  DIC is a useful tool for validating FE models used for the biomechanical analysis of dental prosthesis.
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Tiossi
authors.forename: Marco A A
authors.initials: MA
authors.lastname: Vasco
authors.forename: Lianshan
authors.initials: L
authors.lastname: Lin
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Conrad
authors.forename: Osvaldo L
authors.initials: OL
authors.lastname: Bezzon
authors.forename: Ricardo F
authors.initials: RF
authors.lastname: Ribeiro
authors.forename: Alex S L
authors.initials: AS
authors.lastname: Fok
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D019245:Compressive Strength; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000379:methods*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D009716:Numerical Analysis, Computer-Assisted; D018709:Statistics, Nonparametric
chemical_list: D015921:Dental Implants