Solitary Radiopacity Associated with Root of Unerupted Supernumerary Tooth - A Case Report and Differential Diagnosis

Introduction

Supernumerary tooth is defined as the presence of additional tooth or teeth in any region of the dental arch.¹ There are several theories that explain about the formation of supernumerary tooth but the etiology is not completely understood. Some theories state that hyperactivity of dental lamina, trauma, and infection could lead to its formation.¹ Supernumerary teeth may occur in one or both the jaws, either as single or multiple, unilateral or bilateral. In majority of cases, supernumerary teeth are impacted and asymptomatic and are detected accidentally during radiographic examination.^1,2 Early diagnosis is essential to minimize the complications of resorption of roots of adjacent teeth, delayed eruption or no eruption, cyst formation, displacement of permanent teeth, and malformation of roots of adjacent teeth.²

Periapical radiopacities can be solitary or multifocal. The internal appearance of the lesion can be either completely radiopaque or may present as radiopacity mixed with radiolucency.³ Periapical radiopacities could be due to developmental conditions, inflammatory disorders, or neoplastic conditions.⁴ For appropriate characterization of radiopaque and mixed lesions of jaws, combination of clinical signs and symptoms, age, location of the lesion and radiographic findings are essential.³

Diagnostic imaging provides essential information about the location of the lesion, locularity, involvement of adjacent teeth, size of the lesion, number [solitary or multifocal], density of the lesion, shape of the lesion, margins [well-defined or ill-defined], internal appearance of the lesion [radiolucent/radiopaque/ mixed], and periosteal reaction.⁴ Radiographic analysis of periapical pathoses is not sufficient for clinicians in decision making for therapeutic approaches. For definitive diagnosis and management of lesions, radiographic findings must be correlated with clinical and histopathological findings.

Case Presentation

A 35-year-old male patient reported to the Department of Oral Medicine and Radiology with a chief complaint of a broken tooth in the upper front teeth region. His past dental history was noncontributory. The patient reported a history of trauma to the orofacial region six years ago and also provided a history of self-fall while playing 20 years ago. On clinical examination, all erupted permanent teeth were noted, except 13 which exfoliated due to trauma. Ellis class III fracture was noted wrt 22. Deep distoocclusal caries with proliferated pulpal tissue was found wrt 46 [Figure 1]. Spacing was noted wrt 11 and 21. Intraoral Periapical Radiograph (IOPA) was taken wrt 46 which showed coronal radiolucency involving pulp, loss of lamina dura, and widening of Pdl space, suggesting a diagnosis of chronic apical periodontitis wrt 46. We could also notice a dense radiopacity overlapping the root of 45 at the mesial corner of the IOPA radiograph. Hence an Orthopantomogram (OPG) was advised to obtain a broader view of the radiopacity. OPG showed a full complement of teeth except 13. Root stump was seen wrt 22 with diffuse periapical radiolucency, suggestive of periapical abscess. OPG wrt 45 and 46 showed an impacted supernumerary tooth-like structure overlapping the root of 45 and also a circular, well-defined radiopacity was observed at the root end of the impacted supernumerary tooth [Figure 2]. The density of this resembled the radiopacity of dentine. Internally, the lesion exhibited uniform density with no evidence of radiolucency or trabeculae. Later the patient was subjected to Cone Beam Computed Tomography (CBCT) imaging for accurate diagnosis of the lesion. CBCT imaging revealed a supplementary tooth resembling a premolar located between the mid and apical thirds of the mesial root of 46 and the distal part of the root of 45, whose apex was in close relation with a solitary dense homogenous radiopacity sized 8.6 x 9.4 x 8.6 mm, displacing the inferior alveolar nerve canal to the buccal side [Figure 3]. Periapical bone rarefaction, mild resorption of the distal root of 46 were noticed. All the features were suggestive of a supplementary tooth with cementoblastoma, correlating the clinical and histopathologic findings.

Discussion

Cementoblastoma is a rare benign odontogenic tumor of ectomesenchymal origin arising from the cementum of the tooth. Proliferation of cementoblasts in an unorganized manner around the apical one-third of the root can lead to the formation of cementum-like tissue.⁵ The etiology of cementoblastoma is unknown. Most of the cases are reported during 2nd and 3rd decades of life, more frequently in the mandible than in the maxilla, and the posterior region is more often involved compared to the anterior region.^6,7 Commonly affected teeth include the mandibular first molar and mandibular second premolar teeth with 50% of cases seen involving mandibular first molar.^5,8 The affected tooth usually preserves pulp vitality, but in some cases obliteration of Pdl space and root resorption is seen. Radiographically cementoblastoma presents as a well delineated round radiopaque mass with a corticated border surrounded by a thin radiolucent rim connected to the tooth root.⁹ The internal structure of the lesion could be radiopaque with uniform density or a mix of radiolucent and radiopaque areas. Involvement of root of one or more teeth, canal invasion, root resorption of adjacent teeth, tooth displacement, and obliteration of periodontal ligament space is seen.⁹ In some cases, if the lesion is large enough, expansion of bone and perforation of the outer cortical plate is seen.^5,6 The radiographic differential diagnosis of a cementoblatoma must be made with fibrous dysplasia, osteoblastoma, cementifying fibroma, osteosarcoma, odontoma, cementoosseous dysplasia, periapical sclerosing osteitis, and dense bone island.^9-11,12

Radiographic Differential Diagnosis of Cemento-blastoma

Odontoma^3,9

Radiographically, complex odontoma presents as an irregular periphery with a fairly homogeneous radiopaque mass. The density of the lesion might vary reflecting on the amount of hard tissue formed. The radiopaque mass of the lesion is usually seen surrounded by a radiolucent halo. The association of odontoma with impacted teeth, supernumerary teeth, or retained teeth is evident in some cases.

Dense Bone Island^3,10

The periphery of the lesion is usually well defined, occasionally blending with trabeculae of surrounding bone. The internal structure of the lesion varies from ground glass appearance to a uniform radiopaque mass. The shape of the lesion may be round, oblong, or oval.

CementoOsseous Dysplasia¹¹

Radiographically, mature inactive lesions present a well-defined periphery with a mineralized radiopaque mass surrounded by a thin radiolucent halo.

Cementoossifying Fibroma⁹

The periphery of the lesion is usually well-defined with a sclerotic border. The internal structure of the lesion may be radiolucent in the early stage. As the lesion matures, mixed radiolucent and radiopaque mass is seen. A thin radiolucent line separates the lesion from the surrounding normal bone. The important diagnostic feature of the lesion is centrifugal growth pattern, expanding equally in all directions, forming a solid round tumor mass.

Osteoblastoma³

Radiographically, solitary round or oval-shaped radiolucent or mixed lesions with foci of radiopacities surrounded by sclerotic rim are evident. In mature lesions, radiolucent rim surrounding the dense radiopaque structure in the center is evident.

Fibrous Dysplasia^3,9,13

Radiographically fibrous dysplasia presents a poorly defined border with a wide zone of transition between the lesion and adjacent normal bone trabeculae. In some cases, the periphery of the lesion appears corticated in young lesions. The density of lesion and internal structure can vary from radiolucent to entirely radiopaque or mixed, that blends with adjacent bone giving a ground glass appearance. In the maxilla, the lesion appears more radiopaque compared to the mandible where it appears heterogenous with internal septa. Displacement of teeth, interference in normal eruption pattern, root resorption, expansion of bone, and thinning of cortex can be seen.

Osteosarcoma^14,12

Radiographically it appears as a mixed lytic/blastic lesion. Depending on the degree of ossification, the density of the lesion varies. External root resorption and widening of Pdl space may be seen. In some lesions, typical sunray or hair-on-end appearance may be evident. A case report of misdiagnosis of osteosarcoma as cementoblastoma, involving the roots of premolar and molar teeth, with benign bone growth and no typical sunray or hair-on-end appearance has been reported.

Multiple molecules such as bone morphogenic protein, paired box gene 9, FGF activin, transcription factor 2, and lymphoid enhancer binding factor 1 are involved in the transcription and signaling of tooth morphogenesis and expressed during the development of tooth germs. Denovo tooth formation by stimulation of the Wnt pathway leads to the formation of supernumerary teeth and teeth-like structures.¹⁵

Various therapeutic options for the management of cementoblastoma depend on the location and impact of the lesion and its relationship with surrounding anatomical structures. Surgical enucleation of lesions and removal of supernumerary teeth is the most widely used therapeutic approach. Another therapeutic approach considered in cases of asymptomatic lesions or when the patient is not willing for surgical treatment is lesion monitoring. Both cementoblastoma and the involved tooth are preserved and monitored in this approach.⁷

In our case, a final diagnosis of cementoblatoma was made based on radiographic features. Radiographic and clinical findings must be correlated for appropriate diagnosis of the condition. Since the lesion was asymptomatic and the patient was not willing for a biopsy, we decided to adopt lesion monitoring approach.

The present case report discussed a rare instance of an unerupted radiopaque lesion associated with the root of a supernumerary tooth in a 65-year-old male patient. For appropriate delineation of lesion, clinical presentation was correlated with panoramic imaging and cone beam computed tomography. Biopsy is essential to differentiate various radiopaque lesions of mixed density to obtain a definitive diagnosis. In the present case, the lesion on the right side was treated in a conservative manner, without surgical enucleation of the lesion and extraction of the supernumerary tooth, and was closely monitoring.

Source of Support

Nil

Conflict of Interest

Nil