METHODS	Subsequently , the specimens were cut lengthwise into 2 halves and randomly divided into 4 groups ( n = 4 ) , according to the surface preparation modality of the sectioned surface : Group EA : ethylenediamine tetraacetic acid , Group PA3 : H 3 PO 4 , Group PA120 : H 3 PO 4 + NaOCl , and Group CA : HCl + NaOCl .\