Effect of geometry on deformation of anterior implant-supported zirconia frameworks: An in vitro study using digital image correlation.
OBJECTIVE
To evaluate the effect of geometry on the displacement and the strain distribution of anterior implant-supported zirconia frameworks under static load using the 3D digital image correlation method.


METHODS
Two groups (n=5) of 4-unit zirconia frameworks were produced by CAD/CAM for the implant-abutment assembly. Group 1 comprised five straight configuration frameworks and group 2 consisted of five curved configuration frameworks. Specimens were cemented and submitted to static load up to 200N. Displacements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V, W. Statistical analysis was made using the nonparametric Mann-Whitney test.


RESULTS
Up to 150N loads, the vertical displacements (V axis) were statistically higher for curved frameworks (-267.83±23.76μm), when compared to the straight frameworks (-120.73±36.17μm) (p=0.008), as well as anterior displacements in the W transformed axis (589.55±64.51μm vs 224.29±50.38μm for the curved and straight frameworks), respectively (p=0.008). The mean von Mises strains over the surface frameworks were statistically higher for the curved frameworks under any load.


CONCLUSIONS
Within the limitations of this in vitro study, it is possible to conclude that the geometric configuration influences the deformation of 4-unit anterior frameworks under static load. The higher strain distribution and micro-movements of the curved frameworks reflect less rigidity and increased risk of fractures associated to FPDs.
Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal.
Nuno
N
Calha
Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal. Electronic address: ana.messias@uc.pt.
Ana
A
Messias
Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal.
Fernando
F
Guerra
Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal.
Beatriz
B
Martinho
Centre for Mechanical Engineering, University of Coimbra, Portugal.
Maria Augusta
MA
Neto
Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal.
Pedro
P
Nicolau
D055598:Chemical Phenomena; D017076:Computer-Aided Design; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003764:Dental Materials; D019094:Dental Prosthesis, Implant-Supported; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D015040:Zirconium
D015921:Dental Implants; D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide
3D digital image correlation; All-ceramic restorations; Connector; Displacements; Fixed partial dentures; Flexural strength; Framework design; Implant; Micro-movements; Rigidity; Strain; Zirconia