Deep margin elevation in permanent incisors with crown-root fractures: A laboratory study.

OBJECTIVES

This laboratory study evaluated the effect of deep margin elevation (DME) on the marginal integrity and fracture resistance of anterior teeth with crown-root fractures. MATERIALS AND

METHODS

Fifty-two extracted permanent human maxillary central incisors were randomly divided into four groups. All teeth received a standardized simulated crown-root fracture, selective enamel etching followed by universal adhesive application, resin-based composite (RBC) build-up (conventional or bulk-fill), root canal treatment, and glass fiber post placement. Crown preparations were performed either entirely in natural tooth structure with subgingival finish lines (DME absent) or partially on the RBC build-up, yielding supragingival finish lines (DME present). Marginal integrity was assessed microscopically at baseline, after initial thermomechanical loading (TML), and after extended TML. Fracture resistance was determined by load-to-fracture testing. Statistical analyses included Kruskal-Wallis, Dunn’s post hoc, and Fisher’s exact tests (α = 0.05).

RESULTS

Median marginal continuity remained 100% across all groups. Fracture resistance (1,305-1,595 N) showed no significant differences between groups. Fractures during TML occurred exclusively in groups without DME.

CONCLUSIONS

Within the limitations of this in vitro study, DME did not adversely affect marginal integrity or fracture resistance of restored anterior teeth. In contrast to non-DME groups, specimens with DME did not exhibit failures during TML. CLINICAL RELEVANCE: DME restorations can maintain high marginal integrity and load-bearing capacity in anterior teeth with crown-root fractures. These findings provide preliminary evidence supporting DME as a conservative approach for managing anterior crown-root fractures in select cases, with confirmation needed from clinical studies.