Impacted permanent incisors associated with compound odontoma

Abstract

Odontomas are the most common odontogenic tumours of the maxillary bones, characterised by a slow growth and benign behaviour. They are usually small, asymptomatic and diagnosed after routine radiographic examination. The aim of this study was to report a case of a compound odontoma in the anterior maxilla of a 7-year-old girl, which was causing the impaction of the maxillary right central and lateral incisors, as well as the prolonged retention of the corresponding primary teeth. We also aimed to review the literature about these tumours, since they are not part of the dentist's day-to-day clinical practice. The clinical and radiographic features, the diagnosis and treatment of the case were discussed in this work.

Background

Odontomas are odontogenic tumours composed of dental tissues, like enamel, dentine, cementum and pulp. They are considered to be hamartomas more than true neoplasms.¹ According to the WHO, they can be classified in compound or complex. Compound odontomas consist of multiple miniature or rudimentary teeth and are more commonly found in the anterior maxilla, whereas complex odontomas appears like an amorphous and disorderly mass of dental tissues, tending to develop in the posterior mandible.^{1 2} The aetiology is not clear, although the occurrence of odontomas have been associated with local trauma, infection and genetic factors.³

Odontomas may be found in any age, but are commonly detected in school-age children, accounting for 22% of all odontogenic tumours found in jaws, with no gender predilection. They are usually discovered through radiographic examination, in order to investigate the reason for a missing permanent tooth.^4–6 The majority of odontomas is asymptomatic, presenting a limited growth potential.⁷

The recommended treatment of compound odontoma is the complete removal of the tumour. An orthodontic approach may be indicated to correct any malocclusion or to perform the traction of the tooth, due to a possible impaction.⁴ It is important for dentists to be aware of the clinical and radiographic features of this type of odontogenic tumour, in order to provide a correct and early diagnosis, as well as the most adequate treatment for each case, resulting in a favourable prognosis.

Case presentation

A 7-year-old girl was referred to the Childhood Pediatric Clinic of the Metropolitan University of Education and Culture with a chief symptom of unerupted maxillary right central incisor. According to the patient's mother, there was no history of trauma to the face or mouth. The patient was taking no medications and had good general health.

During the clinical examination, no facial asymmetry was detected extraorally (figure 1). Intraoral examination revealed a mixed dentition period, and the unerupted central and lateral maxillary right incisors were noticed, as well as the prolonged retention of the corresponding primary teeth. A mild bone bulging was observed in the region of the unerupted teeth (figure 2).

Figure 1.

Extraoral aspect of the patient.

Figure 2.

Intraoral view, showing prolonged retention of primary maxillary right incisors and a mild bulging in the unerupted teeth region.

Investigations

The intraoral periapical radiograph revealed the presence of a radiopaque mass with multiple small structures, obstructing the eruption of the permanent incisors (figure 3).

Figure 3.

Periapical radiograph showing the presence of radiopaque mass in the region of unerupted maxillary central and lateral right incisor.

Differential diagnosis

On the basis of clinical and radiographic findings the provisional diagnosis of compound odontoma was made. After the removal of the tumour, the histopathological report described the presence of enamel and dentine orderly distributed, confirming the provisional diagnosis of compound odontoma.

Treatment

The treatment consisted of surgical removal of the odontoma under local anaesthesia. A mucoperiosteal flap on the labial surface of the maxillary central and lateral right primary incisors was reflected. After the removal of the central primary incisor, the layer of bone overlying the labial surface was removed and the rudimentary denticles were exposed (figure 4A). The tooth-like structures were removed without disturbing the underlying teeth and sent to histopathological examination (figure 4B). The surgical flap was apically positioned and sutured in place (figure 5).

Figure 4.

Surgically exposure of the odontoma (A) and the calcified tooth-like structures surgically removed (B).

Figure 5.

The surgical flap positioned and sutured in place.

Outcome and follow-up

After 3 months, the patient returned for a review appointment. The radiographic examination revealed that the unerupted teeth remained impacted (figure 6). At this moment, the maxillary right lateral primary incisor was removed under local anaesthesia.

Figure 6.

Radiograph of the impacted maxillary central and lateral incisors 3 months after the odontoma removal.

Six months after the last appointment, the clinical evaluation revealed the spontaneous eruption of the maxillary lateral permanent incisor, but the tooth was derotated (figure 7). Based on the new radiographic examination, it was concluded that there was no space on the maxillary arch for the eruption of the permanent central incisor (figures 8 and 9). Therefore, an orthodontic approach was proposed. First, we intend to perform a rapid maxillary expansion, allowing the possible spontaneous erupting of the permanent central incisor. If necessary, the next step will be the achievement of a new surgical procedure for orthodontic traction of the impacted tooth.

Figure 7.

Intraoral aspect 9 months after the surgical procedure. Note the spontaneously eruption of lateral incisor.

Figure 8.

Periapical radiograph of the impacted central incisor, evidencing the lack of space for eruption.

Figure 9.

Panoramic radiograph, 9 months after the odontoma removal.

Discussion

Odontomas are considered mixed odontogenic tumours, since they result from the growth of completely differentiated epithelial and mesenchymal cells that give rise to ameloblasts and odontoblasts. They are basically formed by the hard tissues enamel and dentine, but they can present amounts of cementum and pulp.⁸ It presents a limited potential growth, because like teeth, once fully calcified they do not develop further.

The aetiology of odontoma is not known, but environmental causes such as infection, trauma, family history and genetic mutation are hypothesised.⁹ In the present clinical case, the children's guardian reported no history of trauma or infection, neither revealed any family case of odontogenic tumour. The patient in this case was 7 years old, agreeing with the majority of the reported cases, where the tumours are seen more frequently in the first two decades of life.^{4 10–14}

An odontoma is essentially a benign lesion, but it often causes disturbances in the eruption of its associated tooth. Not rare, the patient search for dental assistance due to the lack of eruption of a permanent tooth. Because the majority of odontomas are asymptomatic, and seldom causes swelling, pain, suppuration and/or bone expansion, this kind of tumour use to be discovered accidentally, after routine radiograph examination.^{7 13 15} In general, odontomas causes the impaction of permanent teeth as presented in this case, but sometimes they can be associated with primary dentition.^10–13

The treatment for odontomas in primary and permanent dentition is their complete surgical removal. It has been suggested that the odontoma, once enucleated, usually does not recur in young children, but a close follow-up is needed.¹¹ If odontomas are extirpated early without disturbing the underlying tooth germ, the eruption of the impacted tooth can be expected spontaneously.^{7 16} In a retrospective investigation of 73 cases of odontomas, 53.2% of the impacted teeth erupted after the surgical removal of the odontogenic tumours.¹⁵ According to Hisatomi,¹⁷ the impacted teeth tend to erupt regardless of the degree of root formation after extirpation of the odontoma. However, there have been other reports where the orthodontic traction was necessary to lead the impacted teeth to a satisfactory occlusion.^{11 18–20}

In this case report, the overlying odontoma was removed and the impacted permanent teeth kept under observation to monitor its eruption. Although out of its correct position in maxillary arch, the lateral incisor erupted spontaneously after the surgery. After a 6-month follow-up, the radiographic examination revealed that there was no space in arch for the eruption of the central incisor. Therefore, an orthodontic approach was planned, including the rapid maxillary expansion and perhaps the traction of the impacted tooth.

Patient's perspective.

• I was worried about the delay in tooth eruption in my daughter, but then I became confident and relieved because the treatment is being carried out.

Learning points.

• Since the compound odontoma is a common cause of missing incisors, any change in the chronology of eruption of permanent teeth should be carefully investigated.

• Once diagnosed, the treatment of choice is the complete surgical removal of the tumour, followed by a close monitoring of the impacted teeth.

• If the odontoma is detected in early stages, an interceptive treatment can be provided, effectively enhancing aesthetic, function and structural balance in developing dentition.