The Influence Of Electric Toothbrush On The Bond Strength Of Two Common Luting Cements

Objectives We tend to explore when to use electric toothbrush after the adhesion of fixed prosthesis can minimize the negative effect on the bond strength of zinc polycarboxylate cement and PanaviaTM F, and to evaluate the long-term effect of electric toothbrush on the bond strength of zinc polycarboxylate cement and PanaviaTM F.Methods Expose the facial surfaces of the collected one hundred and eight human premolars, embedded in self-curing resin with custom made cylinder-shaped molds. Then cut the facial surfaces with a diamond saw to expose dentin and polish them with waterproof polishing papers to create standardized dentin surfaces. Make fifty-f our co-cr ally metal test-pieces and fifty-four zirconia ceramic test-pieces(4.0mm in diameter, 2.0mm in height). Paste thirty co-cr ally metal test-pieces and thirty zirco nia ceramic test-pieces on thirty dentin surfaces separately with zinc polycarboxylate cement and PanaviaTM F respectively. Divide every six samples into a group, then we had five groups of zinc polycarboxylate-bonded sample, called Group A(1,2,3,4,5) and five groups of PanaviaTM F-bonded sample, called Group B(1,2,3,4,5). Group A5 and Group B5 were control groups. Then clean Group A1 and Group B1 with an electronic toothbrush for 30 seconds the moment they were pasted by the cement. Li kewise, clean Group A2,B2(A3,B3;A4,B4) after 12hours(24hours and 48hours). Cond uct the shear bond strength experiment. Record the shear force values and fracture patterns respectively when the bonding interfaces were destroyed. Calculate every sh ear strength value. Then analyze the datas with SPSS 19.0 software for one-way: A NOVA. Paste the rest of the co-cr ally metal test-pieces and zirconia ceramic test-p ieces on dentin surfaces with zinc polycarboxylate cement and PanaviaTM F cement respectively. Divide every twelve samples into a group, then we had two groups of zinc polycarboxylate-bonded sample called Group C1,C2 and two groups of PanaviaT M F-bonded sample called Group D1,D2. Group C2 and Group D2 were control groups.Brush Group C1,D1 with electric toothbrush for 300 minutes. Conduct the shear bon d strength experiment. Record the shear force values and fracture patterns respective ly when the bonding interfaces were destroyed. Calculate every shear strength value.Then analyze the data with SPSS 19.0 software for t-test.Results 1 The shear bond strength of Group A1-5 was 2.600±0.731 MPa,4.176±0.491 MPa, 5.103±0.478 MPa, 5.865±0.843 MPa, 5.969±0.564 MPa respectively. The shear bond strength of Group A1,A2 and A3 all had statistically significant differences wit h the control group(P<0.05). By contrast, the shear bond strength of Group A4 did not(P>0.05). The shear bond strength of Group B1-5 was 8.564±2.446 MPa, 11.484±1.504 MPa, 15.153±1.768 MPa, 15.501±1.424 MPa, 15.647±1.248 MPa respectively. The shear bond strength of Group B1 and B2 both had statistically significant differences with the control group(P<0.05). By contrast, the shear bond strength of Group B3,B4 did not(P>0.05). The transverse sections of Group A and Group B were mostly ty peⅡ. The fracture patterns were mostly cement cohesive failure. 2 The shear bond strength of Group C1 and C2 were 5.159±1.023 MPa and 5.888±0.797 MPa respectivel y. There were statistically significant differences between the group C1 and the contr ol group(P<0.05). The shear bond strength of Group D1 was 15.617±1.385 MPa, Th e shear bond strength of Group D2 was 15.853±1.286 MPa. There was no statistically significant difference in shear bond strength between Group D1 and the control group(P>0.05). The transverse sections of samples of Group C were mostly typeⅠ. The transverse sections of samples of Group D were mostly typeⅢ.Conclusions 1 The time interval of using electric toothbrush after the adhesion of zinc polycarboxylate cement is 48 hours. The time interval of using electric toothbr ush after the adhesion of PanaviaTM F is 24 hours. 2 Long-term use of electric too thbrush can weaken the bond strength of zinc polycarboxylate cement. Long-term use of electric toothbrush has no negative effect on the bond strength of PanaviaTM F.