Different interventions and outcomes in four teeth with regenerative endodontic procedures in the same patient: A case report with 7‑year follow‑up.

The present study reported on the case of a 10-year-old male patient with four second premolar teeth undergoing regenerative endodontic procedures (REPs) for periapical periodontitis due to abnormal central cusp fracture, and the follow-up over 7 years. Annual follow-up clinical and radiographic examinations were performed to assess the effectiveness of treatment. After the initial RPEs, the apical inflammation of teeth #15 and #45 disappeared and their roots continued to develop. However, teeth #25 and #35 exhibited different signs of inflammation and were treated with calcium hydroxide apexification and the second REPs, respectively. Subsequently, the narrowing of the apical foramen and healing of periapical inflammation were observed. The root of tooth #35 continued to develop but still exhibited apical inflammation. In the present case, apexification with calcium hydroxide and the second REPs were used as alternative interventions for teeth that failed after REPs. However, interventional treatment after a failure was not able to predict outcomes, necessitating a further study with a large number of cases for observational description.