A complete finite element model of a mandibular implant-retained overdenture with two implants: comparison between rigid and resilient attachment configurations.
OBJECTIVE
The aim of this study was to evaluate the influence of the retention mechanism on the behavior of a mandibular implant-retained overdenture (IRO) during the simulation of mastication. Therefore, a complete three-dimensional finite element model of a mandible with its IRO was developed.


METHODS
The geometry of the edentulous mandible and overdenture was generated from computed tomography. Two MKIII implants (Nobel Biocare) with ball abutments and Dalbo Plus (Cendres et Métaux) attachments were placed in the canine areas. Three foodstuff positions were analyzed for two retention mechanisms, "resilient" or "rigid". Special attention was given to the modeling of the mandibular environment and of the existing contact between the different components. A probable muscular action was determined following the minimal work principle.


RESULTS
The food-crushing force was provided by masseters with a two-third/one-third ratio between working and non-working sides. The "resilient" configuration provided a wider contact area between the mucosa of the denture bearing area and the prosthesis. An increase of the mastication force transiting through the mucosa was also noted and lower stresses were observed in the bone surrounding implants.


CONCLUSIONS
Resilient attachments allowed for an increase of the mastication load transiting through denture bearing surface. Furthermore, this study proposed an accurate model of the mandibular IRO, including its environment and faithful behavior reproduction.
Daas
M
M
Faculty of Dental Surgery, René Descartes University, Paris V, 92000 Montrouge, France.
Dubois
G
G
Bonnet
A S
AS
Lipinski
P
P
Rignon-Bret
C
C
D000497:Alloys; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D019094:Dental Prosthesis, Implant-Supported / Q000295:instrumentation*; D003828:Denture, Overlay; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D008409:Mastication / Q000502:physiology; D008422:Materials Testing; D008953:Models, Anatomic; D008954:Models, Biological; D003765:Models, Dental; D011474:Prosthesis Design; D014025:Titanium
D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium