There were no significant differences statistically both in shear bond strengths( t=1.542, P >0.05) and in ARI scores ( Hc=0.000, P >0.05) between the two kinds of bracket bases.

• 两种底板托槽之间的抗剪切强度比较 ；差异无显著性(t=1.；5 4 2；P >0