ABSTRACT
Objective:To explore the time interval of using electric toothbrush after the adhesion of zinc polycarboxylate cement (ZPC) and PanaviaTM F(PF) respectively.Methods:The facial surfaces of 60 premolars were exposed and embedded in self-curing resin with custom made cylinder-shaped molds.Then the facial surfaces were cut with a diamond saw and polished with waterproof polishing papers to create standardized dentin surfaces.30 co-cr ally test-pieces and 30 zirconia ceramic test-pieces (4.0 mm in diameter and 2.0 mm in height) were adhered on 30 dentin surfaces respectively with ZPC and PF.The samples of each kind were divided into 5 groups (n =6) and brushed with an electronic toothbrush for 30 seconds immedietly (group 1),12 h (group 2),24 h (group 3)and 48 h(group 4) after adhesion,respectively.The samples in group 5 without brush were the controls.Shear bond strength of the samples was measured and the fracture patterns were observed under steriomicroscope.Results:In the ZPC adhered samples the bond strength of group 1,2,3 was lower than that of group 4 and 5 (P ＜ 0.05),group 4 vs group 5,P ＞ 0.05.In the PF adhered simples the bond strenth of group 1 and 2 was lower than that of group 3,4 and 5 (P ＜ 0.05),group 3 or 4 vs group 5,P ＞ 0.05.The fracture patterns were mostly cement cohesive failure.Conclusion:The time intervals of using electric toothbrush after the adhesion of ZPC and PF are 48 h and 24 h respectively