Introduction

The most commonly encountered odontogenic tumors are odontomas. These tumors account for 22% of all odontogenic tumors of the jaws.₁ The term odontoma is used for describing the growth in which functional amoloblasts and odontoblasts forming the enamel and dentin, or in other words both the epithelial and mesenchymal cells co-differentiate simultaneously.₂

The etiology of odontoma has not been fully explained ₂,₃. It has been proposed that local traumas or infections may cause odontomas.₁,₂,₃ Odontomas are commonly encountered in the first and second decades of life, and are accepted as developmental anomalies (hamartomas) rather than true neoplasms.₄,₅,₆,₇ They consist particularly of enamel, dentin, cement and occasionally pulpa tissue. Odontomas are generally asymptomatic, and are detected accidentally during routine radiographic examinations.₅ These tumors are classified into complex odontomas and compound odontomas depending on their radiographic and microscopic characteristics. Both odontomas are found in the bone tissue.₈ However, in very rare cases, they can extend into the oral cavity.

In radiographic examinations, odontomas appear as dense radio-opaque lesions with prominent external margins surrounded by a thin radiolucent zone.₈,₉ Compound odontomas are in forms of clusters of tooth-like structures of different sizes and volumes that are surrounded by a narrow radiolucent zone, while complex odontomas display irregular and disorganized radio-opacity.₂,₅,₈,₉ Odontomas are frequently accompanied by a yet non-erupted tooth, and prevent tooth eruption ₁. Some small odontomas are found within the roots of an erupted tooth. These do not prevent tooth eruption.₅

Microscopically compound odontomas are formed by multiple structures resembling teeth with single roots that comprise loose fibrous matrices.₅ The mature enamel coat disappears during the decalcification procedure for preparation of microscopic slides; however, enamel matrices are frequently found in varying amounts. Pulpa may frequently be observed in the crown and root zones of the tooth-like structures. The complex odontomas predominantly include mature tubular dentin and are composed of randomly assembled dentin, enamel, enamel matrix, cement and pulpa tissues.₅ In about 20% of the odontomas, small islets of eosinophilic-staining epithelial ghost cells are present.₅

Case Report

In the clinical examination of a 20-year-old male patient admitted to our clinic with the complaint of toothache, the right maxillary central incisor tooth was absent, and a lesion covered with gingival and normal mucosa was found between the maxillary central incisors, expanding the bone outwards. The left central and both right and left lateral maxillary and the canine teeth were tested for vitality. The right lateral maxillary tooth was found to be non-vital. In the panoramic radiogram of the patient, a radio-opaque mass surrounded by a radiolucent zone was found in the root region of the right central maxillary incisor tooth, preventing the eruption of the right central incisor tooth (Figure 1).

Figure 1

Figure 1: Radiographic appearance of case.

A computed tomography imaging was ordered for the patient. In the evaluation of the coronal and axial computed tomography slides of the maxillary bone, a smoothly-demarcated hyperdense lesion sized 12 mm 10 mm was observed, located at the level of the apices of neighboring teeth in the region of right central maxillary incisor tooth (Figure 2).

Figure 2

Figure 2: Axial CT image of patient.

The lesion was suspected to be a “compound odontoma” and the case was referred to the clinic of surgery in our faculty. In the surgery clinic, the mass was excised. In the microscopic examination, the mass was reported to include mature dentin and pulpa tissue. The mass was concluded to be a compound odontoma. During the follow-up of the patient in 1-year intervals, no alteration in the state and direction of eruption of the embedded tooth was observed (Figure 3,4).

Figure 3

Figure 3: Radiographic appearance after 6 months.

Figure 4

Figure 4: Radiographic appearance after 1 year. No eruption was seen the right maxillary incisor.

Discussion

Odontomas are usually asymptomatic, and are detected during routine radiographic examinations. Both types of odontomas are located within the bone tissue.₅,₉,₁₀ Compound odontomas are encountered about 2 folds more frequently than complex odontomas, and most frequently between the maxillary incisor and canine teeth, while the complex odontomas are most commonly found in the mandibular molar regions.₅,₁₁In our case of compound odontoma, the location was in the region of maxillary incisors. This was in accordance with literature. Although compound odontomas are distributed equally among sexes, complex odontomas are more frequently found in women.₁₁The patient in our case was male. In 70% of the odontomas, pathologic alterations are observed in the neighboring teeth such as devitalization, malformation, aplasia, malposition and remaining embedded.₁₁In our case, the right lateral maxillary tooth neighboring the odontoma was non-vital, while the central incisor was embedded.

Correspondence to

Dt. Mustafa GOREGEN Atatürk University Faculty of Dentistry Oral Diagnosis and Radiology 25240, Erzurum, Turkey. Fax: +90 442.2360945 Email: mgoregen@atauni.edu.tr