title: Responses of immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures.
abstract: OBJECTIVE
  To report several types of response of immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscess to revascularization procedures.
  
  
  METHODS
  Twenty immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscesses from 20 patients were included. The teeth were isolated with rubber dam, and pulp chambers was accessed through the crowns. The canals were gently irrigated with 5.25% sodium hypochlorite with minimal mechanical debridement. Calcium hydroxide was used as an inter-appointment intracanal medicament and placed into the coronal half of the canal space. After resolution of clinical signs and symptoms, bleeding was induced into the canal space from the periapical tissues using K-files. The coronal canal space was sealed with a mixture of mineral trioxide aggregate (MTA) and saline solution. The access cavity was filled with composite resin. These immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscesses were followed up from 6 to 26 months.
  
  
  RESULTS
  Five types of responses of these immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures were observed: type 1, increased thickening of the canal walls and continued root maturation; type 2, no significant continuation of root development with the root apex becoming blunt and closed; type 3, continued root development with the apical foramen remaining open; type 4, severe calcification (obliteration) of the canal space; type 5, a hard tissue barrier formed in the canal between the coronal MTA plug and the root apex.
  
  
  CONCLUSIONS
  Based on this case series, the outcome of continued root development was not as predictable as increased thickening of the canal walls in human immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess after revascularization procedures. Continued root development of revascularized immature permanent necrotic teeth depends on whether the Hertwig's epithelial root sheath survives in case of apical periodontitis/abscess. Severe pulp canal calcification (obliteration) by hard tissue formation might be a complication of internal replacement resorption or union between the intracanal hard tissue and the apical bone (ankylosis) in revascularized immature permanent necrotic teeth.
authors.affiliation: Department of Endodontics, Chi Mei Medical Center, Yong Kang and Liouying, Tainan, Taiwan.
authors.forename: M Y-H
authors.initials: MY
authors.lastname: Chen
authors.forename: K-L
authors.initials: KL
authors.lastname: Chen
authors.forename: C-A
authors.initials: CA
authors.lastname: Chen
authors.forename: F
authors.initials: F
authors.lastname: Tayebaty
authors.forename: P A
authors.initials: PA
authors.lastname: Rosenberg
authors.forename: L M
authors.initials: LM
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D017607:Aluminum Compounds / Q000627:therapeutic use; D056624:Apexification / Q000379:methods*; D017610:Calcium Compounds / Q000627:therapeutic use; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002648:Child; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D003784:Dental Pulp Calcification / Q000473:pathology; D003790:Dental Pulp Necrosis / Q000628:therapy*; D003793:Dental Restoration, Permanent / Q000379:methods; D003809:Dentin, Secondary / Q000033:anatomy & histology; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology; D009805:Odontogenesis / Q000502:physiology; D010087:Oxides / Q000627:therapeutic use; D010482:Periapical Abscess / Q000628:therapy*; D010485:Periapical Periodontitis / Q000628:therapy*; D010486:Periapical Tissue / Q000098:blood supply; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000379:methods; D017640:Silicates / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D019227:Tooth Apex / Q000473:pathology; D014092:Tooth Root / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003188:Composite Resins; D003764:Dental Materials; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D017640:Silicates; C086631:mineral trioxide aggregate; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide