Seam structures observed along the junctional line of Hertwig's epithelial 'root' sheaths in rat incisors

Linear structures were occasionally found on the lingual surface of the cementum of infant rat incisors along the long axis of the incisors, which are teeth that grow continuously from a persistent odontogenic organ. The observations strongly suggest that these linear structures on the junctional line of Hertwig's epithelial 'root' sheaths correspond to the seams on the multirooted molar teeth of rats.