Effect of cervical margin relocation technique with composite resin on the marginal integrity of a ceramic onlay: a case report.

Treatment of a large proximal carious lesion that extends below the cementoenamel junction is challenging. Large defects usually require replacement with indirect restorations (inlays, onlays, or crowns). However, when the gingival cavity margins are deep, procedures such as isolation of the operative field, proper cavity preparation, successful impression-making, and adhesive luting may be hindered unless soft gingival or hard bony tissues are removed to expose the cavity margin. The present case report describes the clinical application of a conservative cervical margin relocation technique for treating deep cavity margins. A patient presented with large distal carious lesions and necrotic pulps in both the maxillary and mandibular right first molars, which were diagnosed with symptomatic apical periodontitis. After root canal treatment of both teeth, the maxillary molar underwent a crown-lengthening surgical procedure and subsequent placement of a zirconia crown. In the mandibular molar, the cervical margin was relocated by placing a composite resin base at the proximal gingival cavity margins under meticulous isolation of the operative field. The tooth was restored with a composite core build-up and bonded ceramic onlay. The satisfactory outcome suggested a promising prognosis for the oral health of the patient.