Production of amelogenin by enamel epithelium of Hertwig's root sheath.
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.
Hamamoto
Y
Y
First Department of Oral and Maxillofacial Surgery, Niigata University School of Dentistry, Japan.
Nakajima
T
T
Ozawa
H
H
Uchida
T
T
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
D053523:Amelogenin; C507201:Amelx protein, rat; D003746:Dental Enamel Proteins