The Effect Of Luting Agents On Stress Distribution Of The Cement-retained Implant Denture

Purpose: The objective of this study was to test the effects of (1) cement type, (2) cement thickness, (3) loading magnitude, (4) loading direction on stress distribution of the single implant denture.Material and Methods: Four three-dimensional computer models of single cement-retention implant denture were generated in the right lower first molar area, respectively. Zinc phosphate and glass ionomer were used in the thickness of 25 and 100 # m . Models were loaded axially (10N and 150N) on the occlusion, and loaded buccollingually (10N and 150N) on the buccal edge of the occlusion. The area and level of stress concentrationon the abutment, implant and within luting agents were tested.Results: The stress on the implant denture chiefly concentrated in the neck and the apical of the implant under the axial load, and the stress in the neck of the implant was bigger thanthat in the apical of it. But under the buccollingual load, the stress on the implant denturechiefly concentrated in the cervical cortical bone of the implant. And the stress under the buccollingual load was much higher than that under the axial load. The stress on the implant denture increased in proportion to the magnitude of the load. The difference of the stress on the implant denture was not significant in the models of the two luting agents. But under the same load, the stress in the same thickness ZP was much higher than that in the GI. The difference of the stress on the implant denture was not significant in the models of the twokinds of thickness luting agents. But under the same load, the stress in the 25 nm luting agentwas much higher than in the 100#m in the same luting agent.IIConclusions:1. The type of the luting agents had very little effect on the stress level and stress distribution of the implant. But GI had the more favorable mechanical properties for resisting to microfracture than ZP did, so GI was more adapted to cement-retained implant denture.2. The thickness of the luting agents had very small effect on the stress level and stress distribution of the implant. But the thick luting agent had the more favorable mechanical properties for resisting to microfracture than the thin luting agent.3. The directpn of the load had very significant effect on the stress level and stress distribution of the implant. And the stress under the buccollingual load was significantly higher than that under the axial load, so the oblique load on the implant denture should be avoided as far as possible.4. The magnitude of the load had very significant effect on the stress level and the stress distribution of the implant. And corresponding with the load increasing, the stress level on the implant increased. So the occlusion on the implant denture should be decreased.