Frequency and associated factors of segmental root developmental arrest in endodontically treated immature permanent teeth with apical periodontitis: a retrospective cohort study

Segmental root developmental arrest (SRDA) is an uncommon developmental pattern in immature permanent teeth with apical periodontitis, in which a separated apical segment continues to develop independently of the main root. This retrospective study evaluated the frequency, clinical features, and factors associated with SRDA after regenerative endodontic procedures (REPs) or apexification.

A total of 103 immature permanent teeth with apical periodontitis treated with REPs or apexification were retrospectively reviewed. Clinical records and radiographs were assessed for SRDA. Data collected included age, sex, tooth type, etiology, Nolla root developmental stage, treatment modality, timing of SRDA detection, and apical inflammation. Associations between candidate factors and SRDA were analyzed using the chi-square test or Fisher exact test, with Bonferroni correction for pairwise comparisons.

SRDA was identified in 12 of 103 teeth (11.65%). Ten cases occurred in premolars and 2 in incisors; 10 were detected postoperatively and 2 preoperatively. Five affected teeth had undergone apexification and 7 had received REPs. SRDA occurred mainly in teeth at Nolla stage 7 or 8. Univariate analysis showed a significant association between root developmental stage and SRDA occurrence (P = 0.030), with stage 7 teeth significantly more susceptible than stage 9 teeth after Bonferroni correction. Age, sex, tooth type, etiology, and treatment modality were not significantly associated with SRDA.

SRDA is an uncommon but clinically relevant outcome in immature permanent teeth with apical periodontitis. It may occur before or after treatment and appears to be associated primarily with earlier root developmental stages rather than treatment modality. Long-term radiographic follow-up is warranted.