[Three dimensional finite element analysis on the mandibular complete overdenture supported by nature roots or implants].

OBJECTIVE

To investigate the stress distribution around the bone tissue of overdenture supported by teeth roots or implants in the process of mastication which may assist to improve the design of the dentures.

METHODS

By means of CT scan, CAD and a three distribution finite element methods to study the stress distribution of the supporting tissue of overdenture supported by roots or implants when various attachment retentive apparatus and various bite forces were applied.

RESULTS

No matter overdenture supported by roots or implants the stress distribution on bone tissue are difference between the bar and stud attachments, However these difference were minor compared with the difference caused by the direction of force. The stress value of cortical bone around the roots or implants with twenty degree oblique force is 2.2-3 times higher than that with vertical force. Overdenture supported by implants produced 2.5-4 times higher stress in the cortical bone around than that of overdenture supported by roots when various superstructures or various loads were applied.

CONCLUSION

It must consider to reduce the stress peaks and provent bone resorption by increasing the number of implants and using the force-breaking design of implant super-strcture when the overdenture were supported with implants only.