“…On the one hand, it seems that only a minority of radiographic failures translate into clinical failures and the need to retreat (24), whereas it is advocated that retreatment is required and suitable to mend radiographic imperfections or allow resolution of periapical lesions (25)(26)(27). Prediction of disease progression or exacerbation in teeth with such findings is difficult (10,11), and many outcomes used for assessing the ''success'' of initial and retreatments are defined by professionals, not patients who might prioritize other parameters (28)(29)(30). Dentists often understand retreating teeth with insufficient root fillings or periapical lesions as their Mean (standard deviation) costs were calculated in Euro, whereas mean (standard deviation) retention time in years was used as effectiveness measure.…”