Ⅰ. INTRODUCTION
Ectopic supernumerary teeth can occur in many different forms and locations including mandibular condyle1), coronoid process2), maxillary sinus3), palate4), orbit5), skin6), and nasal cavity7,8). Most commonly reported type is found in the palate of central incisor region, known as mesiodens9), and although rare, ectopic eruption of tooth in the nasal cavity has been reported in previous literatures7,8). In addition, formation of dentigerous cyst surrounding the supernumerary tooth in the nasal cavity is even more an uncommon finding10). This paper reports a case of supernumerary tooth associated with dentigerous cyst that is impacted both palatally and nasally and discusses the management of this rare developmental anomaly.
Ⅱ. CASE REPORT
A 7-year-old boy was referred to the Department of Pediatric Dentistry at Seoul National University Dental Hospital due to a palatally impacted mesiodens located in the maxillary central incisor region. Other than prior history of rhinitis, the patient’s medical history was noncontributory.
Upon initial radiographic examination, 2 impacted mesiodens were located palatal to each maxillary central incisor; one behind right maxillary central incisor was inverted, and one behind left maxillary central incisor was horizontally impacted.(Fig. 1) Because the permanent maxillary central incisors were still at their development stage, a follow-up with cone beam computed tomography (CBCT) was planned 5 months later.
1. 1st surgical extraction
The CBCT taken 5 months after the initial examination revealed that the root of the supernumerary tooth located behind left maxillary central incisor extended through the nasopalatine canal to the floor of the left nasal cavity, forming another crown.(Fig. 2A) Under local anesthesia, the patient underwent extraction of supernumerary tooth located in the right maxillary central incisor region via palatal approach. The patient was put on a 6-month recall before deciding to extract the remaining supernumerary tooth to monitor the spontaneous eruption of right maxillary central incisor.
2. 2nd surgical extraction
Another panoramic radiograph was taken after 6 months, and delayed eruption of right maxillary central incisor and retained deciduous right lateral incisor were observed.(Fig. 2B) The patient was referred to the Department of Oral and Maxillofacial Surgery for surgical extraction of the palatonasally impacted supernumerary tooth. The supernumerary tooth was extracted under general anesthesia. Attempt was made via palatal approach, but only the palatal portion was removed as it broke off from the root. Nasal speculum was used on the left nostril to approach remaining of the supernumerary tooth, which was composed of crown in the nasal floor and root located within the nasopalatine canal. Flap was reflected to expose the tooth after making an incision on the left nasal floor mucosa, and saline irrigation was done to examine the tooth. However, the tooth was dislodged into the oropharynx upon saline irrigation and removed intraorally. Hemostasis was achieved, and the patient was discharged on the same day. At 1-week postoperative follow-up, uneventful wound healing without complications was observed.
The inverted supernumerary tooth in the left nasal cavity floor had conical shape with curved root which was fused to the non-inverted supernumerary tooth in the palate with tuberculate crown shape.(Fig. 3A) The pericoronal granulation tissue was submitted to the Department of Oral Pathology for biopsy. Upon histological examination, the cyst wall was composed of chronic inflammatory cells in fibrous connective tissue lined by non-keratinized stratified squamous epithelium, and the diagnosis was confirmed to be dentigerous cyst.(Fig. 3B)
Ⅲ. DISCUSSION
Supernumerary tooth in the nasal cavity is an unusual ectopic eruption affecting only 0.1 to 1% of the general population11). Although patients may be asymptomatic, these teeth should be extracted as early as possible due to potential morbidities it may cause, such as nasal obstruction3,8,11), epistaxis12), foul-smelling nasal discharge8), headache13), facial pain14), and oronasal fistula15).
Many theories have been proposed on the development of supernumerary tooth, yet the etiology still remains controversial. One of the oldest theory is atavism theory which states that supernumerary teeth result from phylogenetic reversion of the extinct primates’ dentition that had 3 pairs of incisors16). Another theory is dichotomy theory, suggesting that the tooth bud divides into 2 parts17). There is also dental lamina hyperactivity theory, which assumes that supernumerary teeth develop as a consequence of local, independent, and conditioned hyperactivity of the dental lamina18).
The cause of ectopic growth in the nasal cavity is not well-understood, but some of the proposed assumptions are crowding of the dentition leading to obstruction of eruption path, retained deciduous teeth, abnormally dense bone, genetic predisposition, cleft palate, infection, or dislodgment of tooth due to trauma or cysts7,16).
In this present case, other than prior history of rhinitis, the patient had no history of trauma, infections, craniofacial anomalies, or nasal symptoms such as nasal obstructions and epistaxis. Despite lack of symptoms, supernumerary tooth in the nasal cavity was detected incidentally during periodic dental radiographic examination.
The optimal timing of extraction of supernumerary tooth is usually after complete root formation of permanent teeth, in order to prevent developmental disturbance. However, since there were delayed permanent teeth eruption and presence of cystic lesion in the nasal cavity, treatment was necessary. The depth of the impaction and thin root anatomy complicated the procedure as the palatal portion broke off at the tip of the root, and the nasal portion slipped into the oropharynx.
After surgical removal of tooth, granulation tissue around the nasal portion of the tooth was submitted for biopsy and was diagnosed as dentigerous cyst. Dentigerous cyst that develops around a nasal tooth is a unique finding. According to Vele et al., cysts can form in the nasal cavity from the nasal mucosa or from surrounding dental tissues19). Another exceptional finding of the present case was that the supernumerary tooth had 2 crowns impacted both palatally and nasally joined by a root within the nasopalatine canal. To the extent of our knowledge, there has not been a case of palato-nasally impacted supernumerary tooth with this type of anomaly. The most likely cause of palato-nasally impacted supernumerary tooth in this case is developmental. Ectopic growth of teeth in the premaxilla can be induced by failure of neural crest cells in the frontonasal area to migrate by the completion of the 5th embryonic week. Regarding the inverted orientation of the tooth, it might have been displaced and grew inside the incisive suture into the nasal cavity throughout the early stages of palate and teeth development14,20).
For extraction of palato-nasally impacted supernumerary tooth, both nasal and palatal approaches are required for successful removal of the tooth. While attempting to extract the tooth through nasal approach, tooth in the nasal cavity may be dislodged into the pharynx, leading to risk of an airway obstruction. Careful attention is needed especially when the patient is under sedation or general anesthesia due to loss of gag and cough reflexes. Also, copious irrigation of the nasal cavity is highly recommended to make sure that there are not any leftover tooth fragments.
