Deep margin elevation: rescuing teeth that look unrestorable

A subgingival cavity does not always mean the tooth needs crown lengthening or extraction. Deep margin elevation makes restoration possible — when used correctly.

A young woman in her thirties walks in with a swollen cheek and a tooth she has been told three things about: extract it, crown-lengthen surgically first, or "leave it and watch." The cavity has extended 2 to 3 mm below the gum line on the distal of an upper second molar. The dentist who quoted extraction was not wrong by old standards. By current standards, the tooth is restorable — with a technique called deep margin elevation. Deep margin elevation (DME) is one of the most under-used techniques in modern dentistry. It is the difference between losing a tooth and keeping it, between an open-flap surgery and a single composite layer at the chair, between a crown that fails at the gum line in five years and an onlay that lasts twenty. What deep margin elevation actually is The technique was formalised by Dietschi and Spreafico in the late 1990s and refined by Magne, Veneziani, and others in the 2010s. The principle: when a cavity margin sits below the gum line where bonding is impossible, a controlled increment of bonded composite is placed at the floor of the box to elevate the margin upward to a supragingival level. From that elevated, accessible margin, the rest of the restoration — a direct composite, an indirect onlay, or eventually a crown — is built using normal isolation and standard bonding protocols. Veneziani's 2017 protocol in the International Journal of Esthetic Dentistry is the current clinical reference; the cumulative survival data at 12 years sits around 95% for the elevated-margin restorations themselves. A 1 to 2 mm bonded composite layer at the floor of a subgingival cavity converts an unrestorable margin into a restorable one. Why it matters clinically Before DME, a subgingival margin had three options. Surgical crown lengthening to expose the margin, which sacrifices supporting bone on adjacent healthy teeth and adds a healing cycle. Orthodontic extrusion, which is precise but slow and not always tolerated. Or extraction. Each of those was a major intervention to manage a 2 mm geometry problem. DME solves it with a single composite layer placed under rubber dam isolation with a deep-margin matrix system (we use Garrison Composi-Tight 3D Fusion and Bioclear matrices depending on the case). The technique respects the biology. The biological width — the connective tissue and junctional epithelium that protect the bone — is not violated a…

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