The Importance of Careful Evaluation of Periapical Radiographs: A Case of External Cervical Resorption

In endodontics, a subtle and seemingly insignificant finding on a periapical radiograph can sometimes completely change the diagnosis and treatment plan. Careful radiographic interpretation should go far beyond simply looking for a periapical radiolucency. The root contours, pulp space, periodontal ligament (PDL), lamina dura, and any unusual changes in tooth structure should all be systematically evaluated.

The following case highlights the importance of a thorough radiographic assessment and demonstrates how an early and subtle radiographic finding led to the diagnosis of external cervical resorption (ECR).

Patient History and Clinical Findings

The patient reported occasional episodes of spontaneous pain originating from the area of the second premolar, accompanied by mild tenderness during chewing.

The second premolar responded normally to cold testing but showed slight sensitivity to percussion. In contrast, the first molar was not sensitive to percussion.

Interestingly, another clinician had previously recommended retreatment of the first molar.

At this point, careful correlation between the patient’s symptoms, clinical tests, and radiographic findings was essential before proceeding with retreatment. Take a look at the patient’s previous radiograph:

A Radiopaque Finding Around the First Molar: Hypercementosis or Condensing Osteitis?

A distinct radiopaque area was visible surrounding the distal root of the first molar.

At first glance, such a finding could potentially be mistaken for condensing osteitis. However, a closer examination revealed an important detail: the PDL space was clearly visible around the entire radiopaque area, and the lamina dura remained intact.

These findings were more consistent with hypercementosis rather than condensing osteitis.

Hypercementosis is characterized by excessive deposition of cementum on the root surface while maintaining the normal PDL space and lamina dura. In contrast, condensing osteitis represents a localized sclerotic bone response generally associated with pulpal or periapical inflammation.

Therefore, considering the clinical findings as well as the radiographic appearance, the first molar was unlikely to be the source of the patient’s symptoms. Retreatment of this tooth without further investigation could potentially have resulted in unnecessary treatment.

The Finding That Should Not Have Been Overlooked

The more significant finding was located in the second premolar.

The appearance of the pulp chamber and the surrounding cervical tooth structure was unusual. Although the change was subtle, careful evaluation revealed an abnormal alteration in the normal anatomy of the cervical portion of the tooth.

This radiographic appearance was consistent with the early stages of external cervical resorption (ECR).

ECR is a progressive pathological resorptive process that typically begins in the cervical region of the tooth. In its early stages, the radiographic changes can be extremely subtle, making early diagnosis challenging.

The Importance of Early Diagnosis

One of the major challenges associated with ECR is that the condition may remain relatively asymptomatic during its early stages. As a result, the diagnosis may be delayed until a significant amount of healthy tooth structure has already been lost.

In this case, the patient had brought a previous radiograph from another office. The early radiographic changes were already present, but the unusual appearance of the second premolar had gone unnoticed.

Several months later, a new radiograph taken at our office demonstrated clear progression of the resorptive defect, with further loss of healthy tooth structure.

This progression highlights an important principle:

Any unexplained alteration in the normal morphology of the root or pulp space deserves careful evaluation, even when the finding does not initially appear to explain the patient’s symptoms.

Treatment

The treatment was aimed at removing the resorptive tissue while preserving as much healthy tooth structure as possible.

The resorptive lesion was accessed through the access cavity and debrided using a diamond-coated ultrasonic tip. The area was then thoroughly irrigated with NaOCl.

During the same appointment, the entire root canal system was treated. A small lingual perforation associated with the resorptive defect was also repaired.

The resorptive defect and the perforation were repaired and filled with MTA.

Following completion of the endodontic treatment and repair of the affected areas, the access cavity was restored with glass ionomer and subsequently with composite resin.

A Clinical Lesson in Radiographic Interpretation

This case is a reminder that interpreting a periapical radiograph should not be limited to searching for a periapical lesion.

A systematic evaluation should include:

• Root morphology and contour
• The shape and continuity of the pulp space
• The periodontal ligament space
• The lamina dura
• The surrounding alveolar bone
• Any unusual radiolucent or radiopaque changes
• Cervical and root surface abnormalities
• Correlation between radiographic findings and clinical signs and symptoms

It is also important not to allow an obvious but unrelated finding to distract us from a more subtle and clinically significant abnormality.

In this case, the radiopaque area around the first molar was a relatively straightforward finding consistent with hypercementosis. The more clinically significant finding was the subtle alteration in the second premolar, which represented an early stage of ECR.

Conclusion

Accurate endodontic diagnosis is based on the integration of patient history, clinical examination, pulp and periapical testing, and careful radiographic interpretation.

In this case, the patient’s symptoms did not correlate with the first molar, and the radiopaque finding around its distal root was consistent with hypercementosis rather than an inflammatory periapical lesion.

More importantly, a subtle change in the cervical region of the second premolar represented early external cervical resorption. Failure to recognize such changes at an early stage can allow the resorptive process to progress and result in significant loss of healthy tooth structure.

Clinical Pearl

When evaluating a periapical radiograph, don’t simply look for what you expect to find. Look carefully for what doesn’t look right. Sometimes, the most important finding is the one that is easiest to overlook.