title: Production of amelogenin by enamel epithelium of Hertwig's root sheath.
abstract: OBJECTIVE
  To study the multiple potentials of differentiating odontogenic epithelial cells.
  
  
  METHODS
  Bilateral first and second maxillary molars of 30 immature rats were perforated into the pulp chambers with a round bur. The pulps were observed histologically and immunohistochemically for amelogenin 3, 7, and 14 days after the perforation.
  
  
  RESULTS
  On day 7, the enamel epithelium of Hertwig's root sheath migrated and formed oval-shaped epithelial islands that resembled epithelial rests of Malassez. On day 14, the islands consisted of epithelial cells with large nuclei and cytoplasm partially surrounded by a subsequently formed osteodentin and cementum. Immunoreactivity for amelogenin was observed in the large epithelial cells and in the area between the cells as well as the calcified tissues. Some of the enamel epithelium resembling columnar ameloblasts of the enamel organ were also positive for amelogenin.
  
  
  CONCLUSIONS
  The enamel epithelium of Hertwig's root sheath appeared to differentiate into ameloblasts and produce amelogenin.
authors.affiliation: First Department of Oral and Maxillofacial Surgery, Niigata University School of Dentistry, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hamamoto
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: H
authors.initials: H
authors.lastname: Ozawa
authors.forename: T
authors.initials: T
authors.lastname: Uchida
mesh_terms: D000565:Ameloblasts / Q000166:cytology / Q000378:metabolism*; D053523:Amelogenin; D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D003746:Dental Enamel Proteins / Q000096:biosynthesis*; D003789:Dental Pulp Exposure / Q000150:complications / Q000473:pathology; D004658:Enamel Organ / Q000166:cytology*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D008963:Molar / Q000166:cytology; D009804:Odontoblasts; D009807:Odontogenic Cysts / Q000209:etiology*; D010513:Periodontal Ligament / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D014092:Tooth Root / Q000166:cytology* / Q000254:growth & development
chemical_list: D053523:Amelogenin; C507201:Amelx protein, rat; D003746:Dental Enamel Proteins