Quantitative Assessment of Root Development after Regenerative Endodontic Therapy: A Systematic Review and Meta-Analysis

The purposes of this review were to appraise the level of evidence of the existing regenerative endodontic therapy (RET) publications, perform a meta-analysis on the survival and healing rates of necrotic immature permanent teeth treated with RET, and run a meta-analysis on the quantitative assessment of the root development of those teeth. Electronic searches were performed in Web of Science, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Cochrane Library databases. Two authors independently screened the titles and abstracts for eligibility. The analyses were performed on the clinical outcomes (ie, survival, healing, and root development) of the procedure. Eleven articles were included in the qualitative and quantitative syntheses. Three studies were randomized controlled trials, 6 were prospective cohort studies, and 2 were retrospective cohort studies. The pooled survival and healing rates were 97.3% and 93.0%, respectively. The pooled rates of root lengthening, root thickening, and apical closure were 77.3%, 90.6%, and 79.1%, respectively. However, if 20% radiographic changes were used as a cutoff point, there were only 16.1% root lengthening and 39.8% root thickening. Within the limitations of the present study, it can be concluded that RET yielded high survival and healing rates with a good root development rate. However, clinical meaningful root development after RET was unpredictable.