Objectives

At the end of this case the reader should appreciate the pathogenesis, diagnosis and management of external cervical resorption (ECR).

Introduction

A 22‐year‐old male medical student presented with persistent bleeding on brushing teeth and spontaneous pain localised to the lower left canine (LL3).

Chief Complaint

Hot/cold foods and liquids resulted in a localised throbbing pain lasting approximately 20 minutes. The symptoms had been present for three weeks and had been getting progressively worse.

Medical History

Unremarkable.

Dental History

Attended annually for dental check‐up appointments and twice a year for hygienist maintenance. The patient recalled having the tooth restored with a direct plastic restoration two to three years ago after his dentist detected a buccal caries. The patient had Invisalign orthodontic treatment 10 years ago for 18 months.

Clinical Examination

The extraoral examination was unremarkable. The patient had a minimally restored dentition and his oral hygiene status was satisfactory.

The LL3 was restored with a buccal composite restoration that extended subgingivally. Periodontal probing resulted in significant bleeding; the base of the restoration did not feel like it was very well adapted to the base of the cavity. Sensibility testing with EndoFrost reproduced the patient’s symptoms. The adjacent teeth were healthy and responded normally to sensibility testing (Table 8.1.1).

A periapical radiograph of the tooth revealed a radiopaque restoration in the cervical region of the LL3, the inferior border of which appeared to be poorly adapted (Figure 8.1.1a). Beneath the restoration was a radiolucency extending across the width of the tooth; the root canal borders can be traced through the radiolucency. There were no other signs of endodontic or periodontal disease detected on the radiograph. Small field‐of‐view cone beam computed tomography (CBCT) confirmed a poorly adapted restoration and ECR in close proximity to or even perforating the root canal (Figure 8.1.1b–d).

There are no ‘classic’ symptoms or signs for ECR. The radiographic symptoms are also highly variable (Table 8.1.2).

Would a parallax radiograph have been beneficial?

Parallax radiographs may be indicated if a CBCT is not possible. With ECR, a second (parallax) radiograph will result in a change in position of radiolucency, while with internal inflammatory resorption the radiolucency will stay centred. Parallax radiographs can also be used to locate the position of ECR using the ‘SLOB’ (Same Lingual Opposite Buccal) rule (Figure 8.1.2).

In this case, the clinical examination confirmed the position (buccal) of the ECR defect. The CBCT scan revealed that the lesion was confirmed to the buccal aspect of the tooth. There is good evidence that CBCT overcomes the limitations of periapical radiographs, thus improving the diagnosis and/or management of ECR, by giving the clinician a precise appreciation of the nature and extent of the lesion; that is, three‐dimensional (3D) morphology, degree of circumferential spread and proximity to the root canal.