Fifty years ago the Dutch Journal of Dentistry published methods and opinions concerning root canal treatment. Qualitative bacterial culture, inclusion of aggressive disinfectants, as well as antibiotics and widening of the apical constriction were carried out. Nowadays, because of several reasons, these are not clinical practise anymore. Controversy over the clinical consequences of bacterial presence in tubules and in the peri-apical area prevailed in the past and seem to be prevalent once again.