A 7-year-old male visited a dental office for an initial examination and prophy. Oral examination revealed a missing left mandibular permanent first molar.
Joen Iannucci Haring, DDS, MS
The patient`s parent denied any history of signs or symptoms associated with the left mandibular molar region. The patient appeared to be in a general good state of health, with no significant medical history. At the time of the dental appointment, the patient was not taking medications of any kind.
Extra-oral examination of the head and neck region revealed no enlarged or palpable lymph nodes. Intra-oral examination revealed a transitional dentition with no other suspect areas of delayed tooth eruption. No unusual soft tissue findings were noted.
After a thorough clinical examination, a panoramic radiograph was ordered to evaluate the suspect area of delayed eruption. Examination of the panoramic radiograph revealed a large, well-defined radiopacity surrounded by a radiolucent border with a smooth periphery in the left mandibular molar area (See radiograph). The lesion appeared to be located in the bone distal to the erupted deciduous second molar and superior to the impacted permanent first molar. The radiopacity measured approximately 3.0 centimeters by 1.5 centimeters in diameter.
Based on the clinical and radiographic information available, which of the following is the most likely diagnosis?
- ossifying fibroma
- cementifying fibroma
- complex odontoma
- compound odontoma
__ complex odontoma
Odontomas are the most common type of odontogenic tumors. Odontomas are developmental in origin and are comprised of varying amounts of enamel, dentin, pulp and cementum. Based on the amount of differentiation present, odontomas are classified as either compound or complex. The compound odontoma (RDH, July 1990) is characterized by a high degree of tissue differentiation and consists of a collection of dwarfed, mis-shapen tooth-like structures with a normal enamel, dentin and cementum relationship.
The complex odontoma is characterized by an amorphous conglomeration of hard tissue and consists of a haphazard arrangement of enamel, dentin and cementum. No identifiable tooth-like forms are seen.
The odontoma is a tumor of children and teen-agers. Most odontomas are discovered during the first two decades of life. Some studies suggest that odontomas occur more frequently in males than in females while other studies suggest there is no sex predilection.
Odontomas may occur in the maxilla or mandible. The compound type is most likely to occur in the anterior maxilla while the complex type is most likely to be found in the molar region of either jaw. Complex and compound odontomas occur with about equal frequency. The typical odontoma is asymptomatic and discovered during routine radiographic examination. This lesion is also detected when radiographic examination is used to evaluate an area where a tooth has failed to erupt.
The radiographic appearances of the compound and complex odontomas are very different.
The compound odontoma has a characteristic appearance that is seldom confused with other lesions. On a dental radiograph, this lesion appears as a collection of radiopaque tooth-like structures surrounded by a thin radiolucent rim at the periphery. The compound odontoma is typically small and is found in tooth-bearing areas, often in association with an impacted or unerupted tooth.
Unlike the compound odontoma, the complex odontoma does not have a characteristic appearance. On a dental radiograph, this lesion appears as an amorphous radiopaque mass. The mass is well-circumscribed and surrounded by a thin radiolucent band that separates the lesion from the adjacent bone. The complex odontoma varies in size and is often seen in association with the crown of an unerupted tooth.
The radiographic features of the compound odontoma are diagnostic. In contrast, a biopsy and histologic examination of the complex odontoma are necessary to establish a definitive diagnosis. Histologically, the complex odontoma will exhibit mature dentin with small amounts of immature enamel. The osteoma and other highly calcified bony lesions should be considered in the differential diagnosis for the complex odontoma.
Odontomas can prevent the eruption of permanent teeth and cause a malpositioning of the adjacent teeth. In addition, a lesion such as the dentigerous cyst may arise from the epithelial components of the odontoma. For such reasons, all odontomas must be removed. The treatment is simple surgical excision. Following surgical removal, this lesion does not recur and the prognosis is excellent.
Joen Iannucci Haring, DDS, MS, is an associate professor of clinical dentistry, Section of Diagnostic Services, The Ohio State University College of Dentistry.