Impaction of a Primary Mandibular Canine

Introduction

Unerupted teeth are seen more commonly in the permanent and early mixed dentition.Unerupted primary teeth are far less common and commonly involve the lower and upper second molars. Thecauses for the unerupted tooth may include another supernumerary tooth,odontoma, a cyst or tumor and inadequate space foreruption.Primary failure of eruption though uncommon may exist as do syndromic and non-syndromic associations like Gardeners syndrome and Cleido-cranial Dysostosis where often multipleteeth remain unerupted.

Odontomas are developmental anomalies due to complete differentiation of epithelial and mesenchymal cells resulting in fully functional ameloblasts and odontoblasts. They are further classified into compound and complex odontomas depending on the level of differentiation of the hard tissue. Often, they are asymptomatic presenting as routine radiographic findings or may hamper the eruption of teeth. There are very few case reports indicating the association of an odontoma and an unerupted primary tooth, especially a primary canine.

Themost common technique of management of these unerupted primary teeth is surgical exposure or surgical exposure followed by extraction of the unerupted tooth. In this case report, an unerupted primary mandibular canine is managed via a combined surgical – orthodontic approach to ensure optimum position of the tooth. This report documents the first instance of use of use of orthodontic forces to aid in eruption of an impacted primary tooth.

Case report

A 48-month-oId female presented with a chief complaint of anunerupted mandibular right primary canine.The parents reported that the mandibular left primary canine had erupted almost a year previously. Prenatal, natal and postnatal history from the hospital records did not show any need for neonatal laryngoscopy or endotracheal intubation. Nor was there any history of natal/neonatal tooth which might have warranted early extraction. This was the patients first dental visit and patient’s medical history was unremarkable. Patient’s parents did not reveal any family history of similarly unerupted teeth.There was no history of any trauma that might have caused premature loss or intrusion of the tooth.

On examination the patient was found to be uncooperative with a Frankels behavior rating of negative.

Clinical examinationrevealed a flush terminal plane occlusion, adequatearch length, and normal relationships in the verticaland transverse dimensions. The whole complement of primary dentition was erupted except for the right mandibular canine despite presence of adequate space for its normal eruption. Adiscrete hard swelling could be palpated in the gingiva overlying the unerupted tooth.

Anorthopantomogram was advised which revealed the presence of the unerupted primary canine with one third root formation was complete and an age-appropriate complement of developing permanent teeth. A small single discrete mixed radiopacity overlying the unerupted caninecrown was visible on examination of the OPG.The radiopacity was surrounded by a thin radiolucent line. The left mandibular canine was on the other hand was fully erupted with root formation almost complete. The lower right permanent canine tooth germ was also visible on the radiograph. On the basis of clinical and radiographic examination a provisional diagnosis of odontoma was made impeding the eruption of the tooth.

Considering the young age of the child and heruncooperativebehavior, the parents were counselled about the various treatment options available i.e. adopt a wait and watch approach, consider only surgical exposure and surgical exposure followed by immediate bracket bonding and application of orthodonticforces. As per the parents’ wishes, surgical exposure followed by orthodontics under GA was chosen as line of therapy.

The patient was referred to a physician for pre-anesthetic clearance following which the procedure was scheduled in a hospital OT setting. Theentire surgical procedure was done under GA. An incision was made over the edentulous ridge fromthe distal of the right central incisor to the mesial of thesecond molar. A full thickness mucoperiosteal flap wasreflected labially and the overlying alveolar bone wasremoved to expose the crown of the canine. During surgery, a small calcified mass was located labial to and separate from the canine crown which was removed with a periosteal elevator under saline irrigation.

Before closing the surgical site, the option of allowing spontaneouseruption of the canine was considered. The canine in addition to being prevented from eruption appeared to have been rotated around its axis. Since exposurehad been accomplished, in consultation with the parents, we chose to initiateorthodontic treatment immediately.

After ensuring adequate isolation of the deciduous canine, an acid etchant was applied for a period of 20 seconds followed by the bonding agent application and light cured for 20 seconds.In caseof contamination due to blood or saliva was suspected the whole sequence of etching and bonding was repeated.A small amount of orthodontic light cure composite was placed on the bonding surface of orthodontic bracket. The bracket was then oriented on the exposed canine and cured with light curing unit. Followingthis orthodontic bracket were bonded on all the remaining teeth with banding of the 75 and 85.

The surgical incision was closed after bonding a bracket on the surgically exposed canine which was united by an arch wire to the remaining erupted mandibular primary teeth. Surgical suturing was done with 3-0 silk sutures.Force application was delayed for one week to allow the site to heal. The patient was seen everythree weeks, to monitor the status of eruption.

At the time of debonding after six months the teeth had erupted perfectly into occlusion with correction of the initial minor rotation. The OPG indicated the normal development of the permanent canine underneath with continued root formation of the deciduous canine. At follow up after one year the patient was asymptomatic with no changes in the occlusion. Normal development of the underlying permanent canine was also evident from the OPG.

Conclusion

In conclusion, early detection and management of unerupted primary teeth is essential to prevent problems in the eruption of their permanent successors. In this report the combined use of surgical exposure and excision of overlying odontoma under GA followed by orthodontic therapy has improved the chances of tooth eruption into a proper occlusion. This report presents a case for early application of orthodontic forces to ensure an optimum outcome.