title: Tissue engineering strategies for immature teeth with apical periodontitis.
abstract: BACKGROUND
  Regenerative endodontic treatment on immature teeth with apical periodontitis is promising but still not well-established. The purpose of this study was to explore novel strategies to engineer a vital support structure within a root canal space by a combination of induced blood clot, exposure of dentin matrix, and a cross-linked collagen scaffold.
  
  
  METHODS
  Apical periodontitis was induced in 6 dogs with immature teeth (n = 64). After disinfection, the following groups were randomly assigned: blood clot (BC) alone, BC with a cross-linked collagen scaffold (CCS), BC with exposure of dentin matrix by ethylenediaminetetraacetic acid (EDTA), and BC with CCS and EDTA. Positive (infected only) and negative controls (untreated) were also included. The dogs were followed up for 3.5 months and killed. Periradicular healing and root wall thickening were radiographically analyzed and statistically evaluated. The jaws were then fixed, demineralized, and subjected to histologic analyses. Newly formed mineralized tissues were histomorphometrically analyzed, quantified, and statistically evaluated.
  
  
  RESULTS
  Radiographically there was significant difference in periradicular healing and root wall thickening (P < .05). Histomorphometric analysis showed significantly more mineralized tissue formation in the groups containing the scaffold (P < .05). Exposure of the dentin matrix by EDTA appeared to increase the adherence of the newly formed mineralized tissue to the root walls.
  
  
  CONCLUSIONS
  The use of cross-linked collagen scaffold and exposure of dentin matrix combined with blood clot might provide an efficient approach to generate a vital support structure for the treatment of immature teeth with apical periodontitis.
authors.affiliation: Department of Endodontics, University of North Carolina School of Dentistry, Chapel Hill, North Carolina 27599, USA. noz.yamauchi@gmail.com
authors.forename: Nozomu
authors.initials: N
authors.lastname: Yamauchi
authors.forename: Shizuko
authors.initials: S
authors.lastname: Yamauchi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nagaoka
authors.forename: Derek
authors.initials: D
authors.lastname: Duggan
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhong
authors.forename: Sun Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Fabricio B
authors.initials: FB
authors.lastname: Teixeira
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Yamauchi
mesh_terms: D000818:Animals; D056624:Apexification / Q000379:methods*; D001777:Blood Coagulation / Q000502:physiology; D002113:Calcification, Physiologic / Q000502:physiology; D025021:Cementogenesis / Q000502:physiology; D002614:Chelating Agents / Q000627:therapeutic use; D024042:Collagen Type I; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000473:pathology; D003790:Dental Pulp Necrosis / Q000628:therapy; D003804:Dentin / Q000187:drug effects / Q000473:pathology; D004195:Disease Models, Animal; D004285:Dogs; D004492:Edetic Acid / Q000627:therapeutic use; D048091:Guided Tissue Regeneration / Q000379:methods; D010485:Periapical Periodontitis / Q000628:therapy*; D011897:Random Allocation; D018915:Root Canal Preparation / Q000379:methods; D013997:Time Factors; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D019227:Tooth Apex / Q000187:drug effects / Q000473:pathology*; D014945:Wound Healing / Q000502:physiology
chemical_list: D002614:Chelating Agents; D024042:Collagen Type I; D004492:Edetic Acid