has part has part has_part characteristic of abnormal dental epithelium morphology abnormal cervical loop morphology 2018-01-03T12:00:30Z MP:0030521 MPheno.ontology any structural anomaly of the most cervical part of an enamel organ where the inner enamel epithelium and the outer enamel epithelium merge in a loop, thus delineating the end of the anatomic crown and the site where root formation begins; to form the root region, the cervical loop begins to grow deeper into the surrounding ectomesenchyme of the dental sac, elongating and moving away from the newly completed crown area to enclose more of the dental papilla, forming Hertwig's epithelial root sheath (HERS) dental epithelium