Effect Of Different Experimental Conditions On Adhesive Force Of Cements To The Implant-supported Fixed Bridge

Objective:To study the effect of different experimental conditions on adhesive force of different cements to the implant-supported fixed bridge.Methods:According to the different cements, we divided 32 3D printing production of Cobalt-Chromium alloy implant-supported fixed bridges into group A(self-etching bonding agent) and group B(resin modified glass ionomer cement). Both group had 4 subgroups:blank control(A1、B1),thermal cycling(A2,B2),fatigue loading(A3,B3),thermal cycling & fatigue loading(A4,B4). Abutments were fixed to the implant analogs, which were embed in self-curing resin block. Then the fixed bridges were bonding to the abutments. All the specimens were immersed in artificial saliva with 37℃ water bath for 24 hours after curing. Group A1 and B1 were done the tensile test after immersing; Group A2 and B2 were done the tensile test after 10000 times of thermal cycling; Group A3 and B3 were done the tensile test after 240000 times of fatigue loading; Group A4 and B4 were done the tensile test after 10000 times of thermal cycling and 240000 times of fatigue loading. The adhesive force(N) and the fracture mode for all subgroups were record. Then, the fixed bridges of group A and B were done the cross-over experiment after the fixed bridges and the abutments were cleansed. At last, all the experimental data and results are analyzed by SPSS 19.0 statistical software.Results:(1) Group of blank control: The adhesive force of group A1 were higher than group B1(P <0.05);(2) Group of thermal cycling: The adhesive force of group A2 were higher than group B2(P <0.05); The adhesive force of group A2 were lower than group A1(P <0.05); The adhesive force of group B2 were lower than group B1(P<0.05);(3) Group of fatigue loading: The adhesive force of group A3 were higher than group B3(P <0.05); The adhesive force of group A3 were lower than group A1(P<0.05);The adhesive force of group B3 were lower than group B1(P <0.05);(4) Group of thermal cycling & fatigue loading: The adhesive force of group A4 were higher than group B4(P <0.05); The adhesive force of group A4 were lower than group A1(P <0.05);The adhesive force of group B4 were lower than group B1(P <0.05);(5) The declining proportion of group A2 、A3、A4 to A1 was 35.95%、35.43%、41.84%, and group B2、B3、B4 to B1 was 29.80%、27.51%、37.97%,respectively;(6) The fracture mode observation shows that group A exhibited as“interface fracture” mode — fractured at the interface of cements and abutments,while group B exhibited as “mixed fracture” mode — not only fractured at the interface of cements and abutments, but also happened between the cements.Conclusions:Within the limits of this study:(1) Both of the adhesive force were significantly decreased after thermal cycling and(or) fatigue loading;(2) The descent range of the adhesive force of SAC were higher than Luting 2with different experimental conditions;(3) The adhesive force of self-etching bonding agent was higher than resin modified glass ionomer cement.