Rare adverse root development after regenerative endodontic procedures: two case reports and contributing factors analysis.

Regenerative endodontic procedures (REPs) promote continued root development in immature teeth with pulp necrosis. However, endodontic infection or physical trauma during tooth development may lead to abnormal root formation. This report describes two cases of immature teeth with periapical disease secondary to dens evaginatus, both treated with REPs and followed up for 4 years. Uncommon root developments, including root curvature and segmental root formation, were observed. A review of the relevant literature was conducted to identify the potential contributing factors. Clinicians should be aware that even clinically successful REPs may result in unusual root morphology, especially in cases with pre-existing inflammation or concurrent orthodontic treatments.