Effect of screw fixation on temporomandibular joint condylar prosthesis.

PURPOSE

The objective of the present study was to evaluate the effect of the number of screws on the stress and stability of the temporomandibular joint (TMJ) condylar prosthesis and on the strain distribution in the bone.

MATERIALS AND METHODS

Three-dimensional, finite element models of the mandible and a TMJ condylar prosthesis with fixations involving different numbers of screws in 8 configurations were established to investigate the effect of the number of fixed screws on the stress and stability of the implant and strain in cortical and cancellous bone.

RESULTS

The simulations showed that increasing the number of screws beyond 3 only slightly enhanced the implant stability and reduced the implant stress. The position of the inserted screws significantly affected the strain distributions in cortical and cancellous bone tissues.

CONCLUSIONS

The results of our study have shown that 3 staggered screws can provide optimal implant stability and bone stress and strain distributions in a TMJ condylar prosthesis.