[3D finite element analysis of stress distributions in supporting tissues of clasp-type partial dentures of...

To provide a theoretical basis for clinical application of the clasp-type partial denture of transferring occlusion force, the stress distributions in its supporting tissue were analyzed.

The 3D finite element model was made, and the features of stress distributions in the supporting tissues of the clasp-type partial dentures which had different rest recess angles were discussed.

The medial stress component was significantly larger than the distal one in the supporting tissue around main abutment root. When the rest recess angles were equal or greater to 60 degrees, the stress values were greatly reduced in the supporting tissue around the roots of the three abutments. When the rest recess angle reached 75 degrees, the stress values in the supporting tissue around the main abutment root wore decreased by 30% than the angle 0 degree and by 52% than the angle 45 degrees, the stress values in the supporting tissue around the root of second abutment (adjacent to the main abutment) were wholly increased by 44% than the angle 0 degree and reduced by 23% than the angle 45 degrees, the stress values in supporting tissue around the root of third abutment (outside of the second abutment) were wholly increased by 53% than the angle 0 degree and decreased by 31% than the angle 45 degrees, the stress values in the medial root of the main abutment were reduced by 73%.

The clasp-type partial denture can resolve part of the occlusion force into two components the medial and distal components, and the occlusion force is distributed to several abutments, at the same time the conversed force components can be canceled by each other. So the whole stress values are greatly reduced and the stress around abutment root is greatly decreased. As a result the damage to the abutment will be eliminated. A design with centralized multi abutments and multi fixed bodies are used in this denture, which are more fixed and stable and have no obvious sinkage in the plate base. Therefore, the mastication function can be satisfactorily recovered, and the reasonable rest recess angle for the clasp-type partial denture of transferring occlusion force is about 75 degrees.