Complex odontome in posterior maxilla: A rare occurrence

Odontomas are the most common benign tumor of jaw constituting 22% of all odontogenic tumors. They are categorised under the benign calcified odontogenic tumors. It is considered to be hamartoma, that is, tumor like malformations. Odontomas are usually small resembling the size of the tooth. Large odontomas are rare. Complex odontomas are usually located in the posterior region of the mandible. In this case, complex odontoma was large with the size of approx. 5 cm and located in the posterior maxilla. The sole management depends upon the early diagnosis, histopathological examination and excision of these tissues. © 2020 Published by Innovative Publication. This is an open access article under the CC BY-NC license (https://creativecommons.org/licenses/by-nc/4.0/)


Introduction
A 40 years old female patient complained of swelling of face over the cheek region on the right side since 2 months and pain in right upper back jaw region since 1 month. The swelling was insidious in onset, slowly progressing in size, was not associated with any other signs and symptoms. No history of epistaxis, nasal obstruction, headache or visual disturbance was reported. No history of trauma was revealed. Pain was insidious in onset, intermittent, moderate, dull aching type, aggravates on mastication and at night, temporarily relieved on taking over-the-counter medications, radiating to right ear. No history of previous episode of similar pain. Patient reported associated sensitivity in teeth in that region on drinking water. No history of any discharge intra-orally from that region. Her medical history and past dental history were non-significant. She has mixed diet, brushes her teeth once daily with toothbrush and toothpaste and has no abusive habits history.
On general physical examination, she was moderately built, well oriented to time, place and person with no signs of pallor, icterus, cyanosis, clubbing and organomegaly. On extra-oral examination, a solitary swelling was noted over the right side of her face involving the middle third ( Figure 2). It was roughly oval in shape, measuring approx. 5cm in diameter, extending superio-inferiorly from 2cm below infra-orbital margin till the level of corner of the mouth and mesio-distally from ala of the nose till the level of outer canthus of the eye. The borders were diffuse. Skin over it was normal in color as the surrounding skin. Surface was smooth. On palpation, all the inspectory findings were confirmed. The swelling presented with no local rise in temp, was bony hard in consistency, non-tender and skin over it was pinchable. It was non-mobile. Bilateral submandibular lymph nodes were palpable. They were solitary, roughly oval in shape, approx. 1cm in diameter, firm, mobile and tender. On intra-oral examination, the labial mucosae and buccal mucosae were apparently normal ( Figure 3). Solitary swelling was seen involving the right side of the palate (Figure 4). It was roughly oval in shape, measuring approx. 4-5 cm in greatest diameter, extending antero-posteriorly from the level of 15 till maxillary tuberosity and mesio-distally from the palatal gingiva irt 15, 16, 17 and distal to it till approx 2cm short of the midline. The borders were well-defined. The mucosa over it was pink in color. The surface was smooth. On palpation, all inspectory findings were confirmed. It was bony hard in consistency and non-tender. Vestibular obliteration irt 17 and distal to it was noted. Buccal cortical plate expansion was present irt 17 and distal to it ( Figure 3). The swelling was bony hard on palpation. No mobilty present irt 15, 16 and 17.
On the basis of history and examination, provisional diagnosis of Benign Odontogenic Tumor Involving Right Posterior Maxilla was given. The differentials were listed as:

Benign non-odontogenic tumors:
1. Central ossifying fibroma.  Figure 5) revealed solitary radiopaque lesion roughly oval in shape, measuring approx. 5 cm in diameter, located in the right posterior maxilla. It had well defined borders and was surrounded by a radiolucent rim with a sclerotic border. The internal structure is homogeneously radiopaque. It was covering the root of 17.

Investigations
IOPA irt 18 ( Figure 6) reveals solitary radiopaque lesion roughly oval in shape, measuring approx. 5 cm in diameter, located in the right posterior maxilla. It had well defined borders and was surrounded by a radiolucent rim. The internal structure is homogeneously radiopaque. It was covering the root of 17.
The lesion was managed as excision of the lesion with surgical removal of 18 and and extraction of 17. The biopsy report at 20x, decalcified and H&E stained sections revealed presence of irregular mature tubular dentin enclosing clefts and hollow circular spaces surrounded by a layer of cementum. There was also evidence of connective tissue surrounding the dentin (Figure 7). Hence, the final diagnosis was given as Complex Composite Odontomeirt impacted 18.

Discussion
Odontomes are mixed odontogenic tumorsbecause they have both epithelial and ectomesenchymal components. Both these components are morphologically normal but have defect in their structural arrangement. Hence called as Hamartomas or malformations rather than true neoplasms. 1 The term "odontome" was first coined by Broca in 1866. He defined it as "growth in which both the epithelial and connective tissue components exhibit complete differentiation, with the result that functional ameloblasts and odontoblasts form enamel and dentin". Still lesion takes place because dental components are laid down in a disorganized manner, due to failure of normal morphodifferentiation. 2 WHO classifies odontomas as a benign odontogenic tumor composed of odontogenic epithelium and odontogenic ecto-mesenchyme with dental hard tissue formation. 3

Classification
In 1914, Gabell, James, and Payne grouped odontome according to their developmental origin: Odontome can occur in one or more of three ways: 1. By interference with the mechanism whereby genes control tooth formation and formed. 2. By a mutation in the genes concerned. 3. By inheritance of those abnormal genes.

Hitchin proposed
Mutation in the epithelial cells of the tooth germ.
↓ Changes inherent capacity of odontogenic epithelium to go through the cap and bell stages of tooth formation, but retains ability to stimulate mesenchymal differentiation to form functional ameloblasts and odontoblasts. in the bone, having density greater than that of bone and equal or greater than that of tooth surrounded by a radiolucent halo (Figure 9). 3. Two appearances of compound odontome are ( Figure 10): a. Cluster of small shapeless dense masses having no resemblance to a tooth in shape but equal or greater in density, depending upon the size of the mass. b. Presence of two or more tooth like masses having conical enamel like capped crowns and with fusion of radiolucent portions. 16 1. Well-delineated, roughly spherical mass of a haphazard conglomerate of mature hard dental tissues. 2. The degree of morphodifferentiation varies from lesion to lesion. 3. There is predominantly dentine of an irregular variety, cementum or cementum-like tissue in small amounts and there is an admixture of dentine with round or ovoid spaces containing pulp tissue, enamel epithelium and remnants of enamel matrix. 9 2.11. Management 1. Complex odontomas can be associated with other more aggressive odontogenic lesions such as cysts and

Conclusion
Odontome is a common lesion to occur in the jaws. Radiopacities in the posterior maxilla can include odontome as one of the differentials considering the location, association with a missing tooth and the radiographic appearance of the lesion. Hence, as an oral physician and radio-diagnostician, we should know the clinical features and radiographic appearance of this lesion.

Source of Funding
None.