Clinical Evidence for Regenerative Endodontic Procedures: Immediate versus Delayed Induction?

Clinicians face many challenges when treating immature permanent teeth in young patients. Immediate blood clot induction can be a successful option as described by some case reports. No experimental studies or clinical trials have addressed this question. We have designed a clinical trial in which we hypothesized that there is no difference in success between immediate or delayed induction protocols. After confirmation of pulpal necrosis, patients were randomized. In the delayed group, 15 teeth were treated following the American Association of Endodontists guidelines, and calcium hydroxide was used as the intracanal medication. In the immediate group, 13 teeth had a blood clot inducted at the first appointment. The teeth were evaluated after 1, 3, and 12 months. Three independent evaluators assessed the periapical healing. The Pearson chi-square test or the Fisher exact test was used to compare the success rates between the 2 groups. Currently, of the 25 recruited patients (28 teeth), 19 have completed their 12-month follow-up. The group with delayed induction had a 71% success rate, and the group with immediate induction had a 33% success rate. In most cases (79%), trauma was the etiology. All successful cases started at stage 9 of root development (Nolla), and the majority showed healing type 2. Determination of the stage of root formation and etiology are possible critical factors for any therapeutic decision. In summary, it is early to conclude or suggest any of the protocols. Clearly, much more data are needed before sample size requirements can be met.