Clinical evaluation of deep margin elevation in CAD/CAM indirect restorations: A 24-month follow-up study

To evaluate the two-year clinical performance and survival rate of CAD/CAM-fabricated endocrowns with and without deep margin elevation (DME) in endodontically treated posterior teeth.

This prospective clinical study included 88 patients (100 teeth) treated at Hacettepe University. Patients were divided into two groups: supragingival margins (SGM, n = 50) and subgingival margins restored using DME (SubGM, n = 50). All teeth had previously completed standardized endodontic treatment performed according to routine clinical protocols. Endodontic procedures were not part of the study protocol. In SubGM cases, the cervical margin was elevated using a highly filled flowable composite (G-ænial Universal Injectable, GC) prior to digital impression and adhesive luting with hybrid ceramic restorations (Cerasmart 270, GC). Clinical outcomes, including marginal integrity, marginal discoloration, and gingival inflammation, were evaluated using modified USPHS criteria at baseline, 6, 12, and 24 months. Survival analysis was performed using the Kaplan-Meier method.

The overall 24-month survival rate was 97%. The SGM and SubGM groups showed survival rates of 98% and 96%, respectively, with no statistically significant difference (p > 0.05). Modified USPHS criteria revealed minimal degradation across parameters. No secondary caries were detected. Slightly lower Alpha scores in gingival health and patient satisfaction were observed in the SubGM group but were not statistically significant.

DME is a clinically viable technique for restoring deep subgingival margins in endodontically treated molars. Provided proper isolation and adhesion protocols are followed, its short-term performance is comparable to restorations with supragingival margins.

Deep margin elevation in CAD/CAM indirect restorations may allow clinicians to manage subgingival margins more conservatively, potentially improving restoration longevity and facilitating adhesive procedures without surgical crown lengthening.