Department of Orthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran


Introduction: Tooth eruption is a complex procedure and many theories has been proposed to describe the nature of this process. Some studies, have shown that in contrast to traditional thoughts, root development is not necessary for tooth eruption and have been focused on the role of dental follicle. Eruption of the permanent teeth with no or little root development has been reported in a few cases. Dentin dysplasia is a rare genetic disorder of the teeth that affect dentin formation. Dentin dysplasia type I or radicular dentin dysplasia is characterized by normal appearance of crowns, but severe tooth mobility. Radiographically, very short or absent roots, periapical lesions and spontaneous pulp obliteration are seen.
Case Presentation: This paper describes two patient with dentin dysplasia type I that despite of rootless tooth, normal eruption has occurred.
Conclusions: These cases are good example to support that eruption procedure is an independent event from root formation.