[Testing dental implants with an in vivo finite element model].
The finite element method (FEM) makes it possible to simulate biomechanical situations on a computer. In the present study the so-called voxel method [9, 14, 17, 18, 19] was used for the construction of the mandible model. For this, the relationship between the biological tissue (e.g. bone) and the corresponding attenuation coefficient of CT data (Hounsfield units = HU) were utilized. The CT data were obtained from an edentulous patient provided with a prosthesis borne on two titanium implants. In a parallel study, the bite forces of the same individual were measured. These were recorded digitally in three dimensions (cranio-caudal, anterior-posterior and left-right) The forces determined by a special program were then transferred to the FEM model implants. We were able to show that a bar joining the implants had a far greater effect on maximum equivalent stress than was expected from the measuring data alone. The highest stress at maximum occlusive force was lowered by 704% on using the connecting bar. On chewing, a stress reduction of 59.9% was observed. The reduction in stress achieved by the bar could, we believe, prolong the life of the implant.
Günter
T
T
Klinik für Orthopädie, Philipps-Universität, Marburg.
Merz
B
B
Mericske-Stern
R
R
Schmitt
J
J
Leppek
R
R
Lengsfeld
M
M
D001696:Biomechanical Phenomena; D001732:Bite Force; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008334:Mandible; D008875:Middle Aged