title: Longitudinal Cohort Study of Regenerative Endodontic Treatment for Immature Necrotic Permanent Teeth.
abstract: BACKGROUND
  The treatment of immature necrotic permanent teeth presents several clinical challenges in endodontics. Regenerative endodontic procedures (REPs) permit root development, increased canal wall thickness, and apical closure. This longitudinal cohort study aimed to evaluate the long-term clinical and radiographic outcomes of REPs of immature necrotic permanent teeth over a 30-month period.
  
  
  METHODS
  This study was performed at the Division of Dentistry of the Montreal Children's Hospital, Montreal, Quebec, Canada. Twenty-eight immature necrotic permanent teeth from 22 patients were included in this study. All teeth were treated with a standardized REP protocol. Patients had follow-up appointments at 1, 2, 3, 6, 12, 18, 24, and 30 months. At each appointment, signs and symptoms were evaluated. Radiographic evaluation was also performed by a calibrated endodontist in order to analyze different parameters.
  
  
  RESULTS
  Our results show a high survival rate (96.4%), clinical success (92.8%), and resolution of apical pathology (100%). Significant increases in the average root length (8.1%, P < .0001) and root thickness area (11.6%, P = .03) were observed after 30 months. In the study period, a significant decrease in the apical diameter was also noted, with 30.8% of the cases showing complete apical closure. Teeth with more immature stages of root development had a higher percentage of change in root thickness, length, and apical diameter; however, these results were not statistically significant.
  
  
  CONCLUSIONS
  Teeth treated with REPs presented resolution of symptoms. Although clinical meaningful change was not achieved in all cases, increased root thickness, root length, and apical closure were observed at 30 months.
authors.affiliation: Division of Dentistry, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada; Department of Pediatric Dentistry, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Edwin Ka Meng
authors.initials: EK
authors.lastname: Chan
authors.affiliation: Division of Dentistry, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Mia
authors.initials: M
authors.lastname: Desmeules
authors.affiliation: Division of Dentistry, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Margaret
authors.initials: M
authors.lastname: Cielecki
authors.affiliation: Division of Dentistry, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.
authors.forename: Basma
authors.initials: B
authors.lastname: Dabbagh
authors.affiliation: Division of Dentistry, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada. Electronic address: beatriz.ferrazdossantos@muhc.mcgill.ca.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Ferraz Dos Santos
mesh_terms: D002648:Child; D003790:Dental Pulp Necrosis / Q000000981:diagnostic imaging / Q000628:therapy*; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011861:Radiography, Dental; D012038:Regeneration; D012390:Root Canal Therapy; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000502:physiology*
keywords: Immature teeth; prospective cohort study; regenerative endodontics; revascularization