After failure of root canal treatment, apical surgery with retrograde obturation may be a good alternative when conventional orthograde re-treatment cannot be accomplished. Successful surgery requires placing a root-end filling to prevent possible bacterial reinfection. The ideal root-end filling material should be biocompatible, bioactive, stable, insoluble, and have no mutagenicity; it should also be easy to handle and cost-effective. Mineral trioxide aggregate (MTA), which has been used for >2 decades, has demonstrated high rates of success as a root-end filling. However, only 1 small study has reported success rates for treatment using MTA after >5 years.

von Arx et al from the University of Bern, Switzerland, reported 1-, 5- and 10-year results for a large group of patients who had undergone apical surgery with MTA used as the root-end filling for re-treatment of failed root canal treatment. All 195 patients had been treated by the same surgeon at a specialty clinic of a university dental school between 2001 and 2007. The surgeon accessed the root via a full mucoperiosteal flap, then performed an osteotomy followed by a root-end resection. After removal of all the periapical pathologic tissue, the cavity was filled with MTA, the flap repositioned and the wound sutured.

All patients were invited to a follow-up appointment 1 year after surgery. Those respondents later received an invitation to a 5-year follow-up, and responders at 5 years received an invitation to a 10-year follow-up. Based on clinical and radiographic results, healing at the roots was categorized as 1 of the following:

  • complete healing
  • incomplete healing (scar tissue formation)
  • uncertain healing
  • unsatisfactory healing

Teeth in the final 3 categories were grouped together as not healed. Teeth showing clinical signs or symptoms were classified as not healed, regardless of radiographic findings.

The failure rate remained consistently <10% at both the 1- and 5-year follow-ups. However, the rate more than doubled at the 10-year follow-up (Table 2). Of the teeth judged as healed at the 1-year follow-up, 87% remained so at the 10-year follow-up. Possible confounders, including age, sex, type of MTA used (gray vs white), and type of surgery (first time vs repeat), demonstrated no effect on outcome. Mandibular molars and maxillary premolars had a lower rate of healed cases than did maxillary molars, which healed in >95% of cases.


The first of its size and length of follow-up, this clinical study of apical surgery with MTA used for re-treatment of failed root canal therapy, demonstrated excellent results after 1 and 5 years. While the rate of healed teeth declined at 10 years, teeth judged to be healed at 1 year showed greater success at 10 years than did those that had not healed at 1 year. Treatment was most successful in maxillary molars.

von Arx T, Jensen SS, Janner SFM, et al. A 10-year follow-up study of 119 teeth treated with apical surgery and root-end filling with mineral trioxide aggregate. J Endod 2019;doi:10.1016/j.joen.2018.12.015.