FEM stress analysis in different diameter onplant osseointegration interfaces

Objective: To investigate the stress distribution in the onplant-bone osseointegration interface, and compared this kind of subperiosteum implant with other endosseous implants. Thus to provide instructions to clinical application. Methods: Three-dimension finite element method was used to analyze the stress distribution in the Onplant-bone osseointegration interface. Three finite element model with the diameter of 5mm, 7.7mm and 10mm were fabricated by the Pro/E and analyzed by the Ansys. All the data came from the model and cepholometric of a successfully treated real patient with onplant as absolute anchorage for maxillary protraction. One hundred percent osseointegration rate was supposed. The osseointegration was treated by a node to node connection of the onplant and the palatal bone surface. A forward and downward 30 degree to the occlusal plane force of 800g was loaded. Results: The stress distrbution of each model was 0.154MPA 0.124MPA and 0.103MPA, respectively. The stress distribution was almost equal in the interface and there was almost no torque force in the interface. Conclusions: Enlargement of the diameter of onplant can be useful to decrease stress distribution in the interface. This may contribute to the early loading of onplant. The almost 0 torque force may be a result of the individual data. Things may be different according to different individuals. There may be biomechanical reason for the success and failure of a treatment. So future investigation should be taken in other patients. *This research is supported by the Foundation of Hubei Hygiene Office: JX1A13 Protract the maxilla to correct the crossbite using Onplant as absolut anchorage.