Introduction
Cone Beam Computed Tomography (CBCT) is an invaluable tool in dental diagnostics, often providing critical insights that can prevent unnecessary interventions, such as extractions or biopsies. The ability to accurately diagnose common pathologies within the jaws is essential for ensuring optimal patient outcomes, as misinterpretation can lead to invasive procedures that may not be warranted. This case report challenges you to apply your diagnostic skills to a lesion identified in a small field of view CBCT scan. The patient, a 42-year-old female, was referred by an endodontist after oral surgery recommended extraction and biopsy of a lesion at the apex of tooth #31. Let’s explore this case and see if you can identify the pathology before proceeding with any intervention.
Case Report
A 42-year-old female was referred by an endodontist for CBCT evaluation prior to a planned extraction and biopsy, following a recommendation from oral surgery. The doctor notes stated: “Please evaluate the mixed lesion at the apex of tooth #31. All lower right teeth respond normally to pulp testing, and she is asymptomatic. She has been advised by Oral Surgery to extract and biopsy the lesion. Prior to biopsy, we recommended an Oral Radiology review prior to any extraction/biopsy.” The CBCT scan was performed using a Carestream CS 8100 3D CBCT with a 41.8 x 49.9 x 51.5 mm field of view and 0.07 mm voxel size.
The CBCT images revealed a well-defined, round, mixed density lesion around the apices of tooth #31. The internal structure was largely hypodense, with a ground-glass, cloudy appearance. Two round hyperdensities were noted within the lesion: one at the mesial apex, where the PDL space remained intact and uniform (PDLN), and a second toward the buccal aspect, slightly distal to the first. The lesion’s border showed sclerotic bone, and it encompassed the inferior alveolar canal without affecting the canal’s borders, path, or size. The lesion extended slightly into the buccal and lingual cortices, resulting in slight thinning but no expansion. Additional findings included a partially visualized tooth #27, teeth #28-31 fully within the volume, and the crowns of the opposing maxillary dentition partially visualized. The distal portion of the restoration on tooth #30 appeared absent. A well-defined, ovoid hyperdensity surrounded by a thin, uniform hypodense rim was noted within the alveolar bone distal to tooth #31, consistent with a residual root of #32, with no associated inflammation. The remainder of the dentition and paradental bone within the field of view appeared unremarkable, with no radiologic signs of infection or pathosis. The dentition was separated from occlusion.
Radiographic Images
Take a moment to examine the CBCT images provided. Focus on the mandibular right region, specifically around the apices of tooth #31. Since this is a dental-specific finding, you have the Axial, Curved, and Cross-sectional slices. Scroll through the different views to observe the lesion’s characteristics: a well-defined, round, mixed density lesion with a hypodense ground-glass appearance, two hyperdense foci, a sclerotic border, and its relationship with the inferior alveolar canal. Pay close attention to the PDL space around tooth #31 and the lesion’s effect on the surrounding cortices. What do you notice?
Differential Diagnosis
Q: What is the most likely diagnosis for this mixed density lesion at the apex of tooth #31?
- Periapical Cyst
Incorrect. A periapical cyst typically presents as a well-defined hypodensity associated with a non-vital tooth. In this case, tooth #31 tested vital, and the lesion’s mixed density with a ground-glass appearance and hyperdense foci is not characteristic of a periapical cyst.
- Ameloblastoma
Incorrect. Ameloblastomas often show a multilocular, expansile pattern with cortical thinning or perforation, which is not seen here. The lesion’s sclerotic border and lack of expansion make this diagnosis unlikely.
- Cemento-Osseous Dysplasia
Correct! The mixed density lesion, with a hypodense ground-glass appearance, hyperdense foci, sclerotic borders, and no effect on the inferior alveolar canal, is consistent with focal cemento-osseous dysplasia (FCOD). The patient’s asymptomatic presentation and vital tooth further support this diagnosis.
- Squamous Cell Carcinoma
Incorrect. Squamous cell carcinoma (SCC) in the jaws typically presents with irregular borders, cortical destruction, and possible soft tissue involvement, often accompanied by clinical symptoms like pain or paresthesia. In this case, the lesion’s well-defined sclerotic border, lack of cortical expansion, and the patient’s asymptomatic status make SCC unlikely.
Discussion
Cemento-osseous dysplasia (COD) is a relatively common benign fibro-osseous lesion of the jaws, often presenting diagnostic challenges due to its evolving radiographic appearance. COD predominantly affects middle-aged females, with a higher prevalence in Blacks, Asians, and Hispanics, and is most commonly found in the anterior mandible (Neville et al., 2016). It is classified into three types: periapical COD (PCOD), involving the apices of anterior teeth; focal COD (FCOD), a solitary lesion often in the posterior mandible, which some studies suggest is more common in Caucasians (Su et al., 1997); and florid COD, involving multiple quadrants with extensive involvement. COD lesions typically begin as hypodense, resembling periapical inflammatory lesions, which can lead to unnecessary root canal therapy on vital teeth (Alsufyani & Lam, 2014). As COD matures, it calcifies from the inside out, with calcifications starting in the center and progressing outward, forming hyperdense foci within a ground-glass matrix. This pattern distinguishes COD from condensing osteitis, where sclerotic bone forms around a periapical hypodense lesion, almost always accompanied by a radiolucency at the tooth apex due to inflammation. In COD, as calcifications increase and the lesion abuts the root or apex, a regular, uniform periodontal ligament (PDL) space becomes evident, indicating the tooth’s vitality and lack of inflammatory involvement.
In this case, the lesion at the apices of tooth #31 was initially concerning enough for oral surgery to recommend extraction and biopsy. However, the CBCT findings—hypodense with a ground-glass texture, hyperdense foci, sclerotic borders, and lack of cortical expansion—aligned with the known progression of FCOD. The presence of a regular, uniform PDL space (PDLN) around tooth #31, along with its vitality, confirmed the absence of inflammatory pathology, distinguishing it from conditions like condensing osteitis. The patient, a 42-year-old female, fits the typical age range for COD, and the posterior mandibular location is consistent with FCOD, which may be more prevalent in Caucasians (Su et al., 1997). A critical aspect of this case is the lesion’s relationship with the inferior alveolar canal, which it encircled without affecting its borders, path, or size. Attempting to excise this lesion, as initially recommended, would have posed a significant risk of nerve injury, potentially leading to permanent numbness—a devastating outcome for an asymptomatic patient. This underscores the importance of recognizing COD’s benign nature and radiographic evolution to avoid invasive procedures, as supported by Neville et al. (2016), who note that COD lesions often mature into calcified masses without requiring intervention.
Panoramic Reformat of the CBCT
Summary and Conclusion
In this case, a 42-year-old female presented with a mixed density lesion at the apex of tooth #31, initially recommended for extraction and biopsy by oral surgery. CBCT evaluation identified the lesion as focal cemento-osseous dysplasia (FCOD), a benign condition that did not require intervention. The tooth tested vital, the patient was asymptomatic, and the lesion showed no effect on the inferior alveolar canal, leading to a recommendation for continued monitoring with periapical imaging rather than surgery. This approach saved the patient’s tooth and avoided the risk of nerve injury, which could have resulted in permanent numbness.
This case highlights the responsibility of radiologists to interpret CBCT scans with precision, even in small fields of view where findings can be easily misinterpreted. It also emphasizes the value of collaboration between endodontists, oral surgeons, and radiologists to ensure optimal patient outcomes, reinforcing the need to treat every CBCT scan with the diligence it deserves.
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References
Neville, B. W., Damm, D. D., Allen, C. M., & Chi, A. C. (2016). Oral and Maxillofacial Pathology (4th ed.). Elsevier.
Su, L., Weathers, D. R., & Waldron, C. A. (1997). “Distinguishing features of focal cemento-osseous dysplasia and cemento-ossifying fibromas.” Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, 84(3), 301-309. https://pubmed.ncbi.nlm.nih.gov/9377196/
Alsufyani, N. A., & Lam, E. W. N. (2014). “Cemento-osseous dysplasia: A review of the literature and imaging features.” Imaging Science in Dentistry, 44(3), 169-176. https://pmc.ncbi.nlm.nih.gov/articles/PMC3611451/