679 Validating FE Models For Dental Prostheses Using Digital Image Correlation

Friday, March 23, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
R. TIOSSI1, M.A.A. VASCO1, L. LIN2, H. CONRAD3, O.L. BEZZON4, A. FOK5, and R. RIBEIRO6, 1Department of Dental Materials and Prosthodontics, University of Sao Paulo, Ribeirao Preto, Brazil, 2Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, MN, 3Department of Restorative Sciences, University of Minnesota, Minneapolis, MN, 4Department of Dental Materials and Prosthodontics, University of Sao Paulo, Riberao Preto, Brazil, 5Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB), School of Dentistry, University of Minnesota, Minneapolis, MN, 6Dept. of Dental Materials and Prosthodontics, University of São Paulo, Ribeirão Preto, Brazil
Objectives: A validated numerical model for stress/strain predictions is essential to understand the biomechanical behavior of implant-supported dental prostheses. This study compared the predictions from finite element analysis (FEA) in assessing the bone strain induced by the implants with in vitro measurements given by the digital image correlation (DIC) method.

Methods: An epoxy resin model simulating the mandibular jaw bone was made for the experimental test with a combination of acrylic resin replicas of the first premolar and second molar and threaded implants replacing the second premolar and first molar. Splinted (G1 and G3) and non-splinted (G2 and G4) metal-ceramic screw-retained crowns were fabricated and loaded with (G1 and G2) or without (G3 and G4) the presence of a second molar that provided proximal contact. A single-camera, 2-dimensional DIC system was used to record deformation of the resin model surface at a frequency of 1.0 Hz until the load reached 250 N. Corresponding 3-dimensional FE models were constructed using computer-aided design (CAD) software for both splinted and non-splinted crowns.

Results: Surface strains were used for comparison between the two methods, while internal strains at the implant/resin block interface were calculated using FEA. Both methods found similar regions of compression and tension, and both found insignificant differences in surface strains between the splinted and non-splinted groups (P>0.05). However, FEA gave higher strain values (P<0.05), possibly due to an underestimated elastic modulus for the epoxy resin. The internal strains predicted by FEA at the implant-resin interface were at least 12 times higher than those on the surface of the models, but differences between the groups were again insignificant (P>0.05).

Conclusions: Within the limitations of this study design, it can be concluded that DIC is a useful tool for validating finite element models, and FEA is effective in qualifying the bone strain induced by implants.

This abstract is based on research that was funded entirely or partially by an outside source: Grant sponsor: FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo); Grant number: 2010/19221-9

Keywords: Digital image analysis, Finite analysis, Implants, Implants and Prosthodontics
See more of: Digital Dentistry
See more of: Prosthodontics Research