Endodontic retreatment of maxillary first molar: the importance of the fourth canal

Aim The targets of the endodontic therapy are damaged tissue and bacteria removal from the canals and dentinal tubules and the prevention of recontamination after the treatment. Introduction Correct endodontic treatment has to follow several parameters: proper diagnosis, isolation of operating field, full chemo-mechanical preparation of the complex endodontic system, three-dimensional obturation of the root canals, post endodontic restoration. Respecting all these parameters short and long term success can be achieved. Materials and methods In this article an orthograde retreatment of maxillary first molar has been described, which showed at pre-operative X-ray, an incongruous endodontic therapy, the failed finding of the fourth canal and the presence of periapical lesions. Discussion A high percentage of failures is due to missed root canals and therefore not cleansed, shaped and it is essential to use modern technologies to achieve safe and reproducible results. Conclusions The endodontic retreatment of this right maxillary first molar was performed with the proper protocols and sophisticated tools, with which we can achieve success in the short- and long-term treatments.