Introduction

Clinicians frequently encounter the sequlae of trauma, but are rarely present when the trauma actually occurs. It is important to be aware of possible healing responses after dental trauma has occurred. Spontaneous natural closure of an open apex in an immature tooth with a hard tissue barrier (HTB) is rare. To our knowledge, this is the first time 3D images of such a tooth are reported. 3D images were also done on the follow-up visit (30 month) to confirm healing. Treatment was successfully done according to the principles of regenerative endodontics. This demonstrates the relevance of this treatment in immature teeth with arrested root development in the adult patient.

This work was done by a resident in Endodontics at Indiana University School of Dentistry (IUSD). The 3D imaging was done in collaboration with the Department of Orthodontics & Oral Facial Genetics at IUSD. Each author has contributed to this work.

Introduction

Closure of the open apex in an infected immature tooth is usually achieved after disinfection of the root canal and dressing it with calcium hydroxide or other materials. Spontaneous natural closure of an open apex in an immature tooth with a hard tissue barrier (HTB) has been observed following luxation injuries, but it is not commonly seen.^{(1, 2)}

A single-visit endodontic treatment was performed in a 22-year-old man who presented with asymptomatic apical periodontitis (AP) in an immature maxillary lateral incisor (#10) with spontaneous root closure and a dens invaginatus Oehlers II. The research done on apexification and in regenerative endodontics provided the background for the treatment provided. The nature of the unusual anatomy of this tooth was assessed using Cone Beam Computed Tomography (CBCT) imaging. The treatment aims were to address the AP by disinfecting the RCS and yet not harm the HTB created or the cells responsible for its creation and maintenance. Disinfection of the canal was to be done solely by copious irrigation with sodium hypochlorite, ethylenediaminetetra-acetic acid (EDTA) and chlorhexidine (CHX), and mineral trioxide aggregate (MTA) was to be placed over the HTB. After the MTA had set, the tooth was to be restored with resin restoration and a fiber post.