Histologic observation of a human immature permanent tooth with irreversible pulpitis after revascularization/regeneration procedure.
BACKGROUND
Histological studies of immature human permanent necrotic teeth with or without apical periodontitis after revascularization have not been reported. This case report describes the histological findings of tissue formed in the canal space of an immature permanent tooth #9 with irreversible pulpitis without apical periodontitis after revascularization.


METHODS
An immature human permanent tooth #9 was fractured 3.5 weeks after revascularization and could not be retained. The tooth was extracted and prepared for routine histological and immunohistochemical evaluation in order to examine the nature of tissue formed in the root canal following the revascularization procedure.


RESULTS
At 3.5 weeks after revascularization, more than one half of the canal was filled with loose connective tissue similar to the pulp tissue. A layer of flattened odontoblast-like cells lined along the predentin. Layers of epithelial-like cells, similar to the Hertwig's epithelial root sheath, surrounded the root apex. No hard tissue was formed in the canal.


CONCLUSIONS
Based on the histological findings in the present case, regeneration of pulp-like tissue is possible after revascularization. In this case, both the apical papilla and the Hertwig's epithelial root sheath survived in an immature permanent tooth despite irreversible pulpitis but without apical periodontitis.
Department of Endodontics, New York University College of Dentistry, New York, New York 10010, USA.
Emi
E
Shimizu
George
G
Jong
Nicola
N
Partridge
Paul A
PA
Rosenberg
Louis M
LM
Lin
D017607:Aluminum Compounds / Q000627:therapeutic use; D000954:Antigens, Surface / Q000032:analysis; D017610:Calcium Compounds / Q000627:therapeutic use; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002648:Child; D003094:Collagen / Q000648:ultrastructure; D003238:Connective Tissue / Q000473:pathology; D003782:Dental Pulp / Q000473:pathology; D003786:Dental Pulp Cavity / Q000473:pathology*; D003804:Dentin / Q000473:pathology; D004338:Drug Combinations; D004847:Epithelial Cells / Q000473:pathology; D006801:Humans; D007180:Incisor / Q000293:injuries; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology; D009804:Odontoblasts / Q000473:pathology; D010087:Oxides / Q000627:therapeutic use; D011671:Pulpitis / Q000628:therapy*; D012038:Regeneration / Q000502:physiology; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012390:Root Canal Therapy / Q000379:methods*; D017640:Silicates / Q000627:therapeutic use; D019227:Tooth Apex / Q000473:pathology; D019228:Tooth Crown / Q000293:injuries; D014082:Tooth Fractures / Q000628:therapy
D017607:Aluminum Compounds; D000954:Antigens, Surface; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C525591:STRO-1 antigen, human; D017640:Silicates; C086631:mineral trioxide aggregate; D003094:Collagen; D002126:Calcium Hydroxide