两种漂白方法对牙本质与树脂粘结强度影响的实验研究

目的：比较牙本质经两种漂白方法漂白后,在不同时间粘结树脂其抗剪强度变化。方法：25颗恒前磨牙随机分为5组。A组为对照组：人工唾液内3周后制备牙本质粘结面,粘结树脂;B组：牙齿外漂白每天6h,共3周后制备牙本质粘结面,粘结树脂;C组：牙齿外漂白3周,人工唾液内储存2周后制备牙本质粘结面,粘结树脂;D组：牙齿内漂白3周后制备牙本质粘结面,粘结树脂;E组：牙齿内漂白3周,人工唾液内储存2周后制备牙本质粘结面,粘结树脂。电子万能实验机测试剪切粘结强度。结果：①抗剪强度测试结果：A组（18.61±3.56）MPa,B组（10.74±3.03）MPa,C组（17.21±3.15）MPa,D组（12.10±2.64）MPa,E组（16.78±2.84）MPa;②统计学分析：A-E组试件的剪切强度值单因素方差分析（one-wayANOVA）表明5组样本均数之间存在统计学差异（P〈0.05）。各组均数两两比较（Student-Newman-Keuls,SNK-q法）显示A与B组,A与D组,B与C组,D与E组的剪切强度值差别有统计学意义（P〈0.05）,而A与C组,A与E组,B与D组,C与E组的剪切强度值之间无统计学差异（P〉0.05）。结论：①两种漂白方法对牙本质与树脂粘结强度的影响无明显差别;②牙齿漂白后即刻粘结树脂,两种漂白方法均会降低牙本质与树脂的粘结强度;③牙齿漂白后延迟2周再粘结树脂,两种漂白方法均能够恢复牙本质与树脂的粘结强度接近未漂白组的水平。

Effect of two bleaching agent on the Shear bond strength of dentin to composite resin

Objective To compare the shear bond strength of dentin/composite resin in different time points after tooth bleaching with two dental whitening gel.Methods Twenty-five intact premolars were randomly divided into 5 groups（n=5）：group A（control）,specimens only immersed in artifical saliva for 3 weeks before adhesion;group B（external bleaching and bonded immediately）,specimens only bleaching with 6 hours per day for 3 weeks before adsion;group C（external bleaching and bonded two weeks later）,specimens bleached with 6 hours per day for 3 weeks and immersed in artificial saliva for further 2 weeks before adhesion;group D（internal bleaching and bonded immediately）：adhesion immediately after bleaching for 3 weeks;group E（internal bleaching and bonded two weeks later）：before adhesion the specimens immersed in artificial saliva for further 2 weeks after bleaching for 3 weeks.Specimens were submitted to shear bond strength test.Results Means of shear bond strength obtained from debonding test were as follow：group A（18.61±3.56）MPa,group B（10.74±3.03）MPa,group C（17.21±3.15）MPa,group D（12.10±2.64）MPa,group E（16.78±2.84）MPa.Analysis of variance（ANOVA） results indicated that there was significant difference of shear bond strength（P0.05）;Multiple comparison（SNK-q） results indicated that significant difference of shear bond strength values existed between group A and B,group A and D,group B and C,group B and E（P0.05）;no significant difference existed between group A and C,group A and E,group B and D,group C and E（P0.05）.Conclusion ①Internal tooth bleaching has the same effect on the shear bond strength of dentin to composite resin as external tooth bleaching has.②The use of internal tooth bleaching technique immediately before bonding significantly reduces bond strength,so does the external bleaching technique.③Immersion of bleached teeth（by external or internal bleaching technique） in artificial saliva for 2 weeks before bonding results in a return to control bond strength.