[Deep Margin Elevations, clinical considerations].

Subgingival restorations are problematic due to reduced visibility at the preparation margins, humidity (saliva, crevicular fluid and/or blood), problems with taking impressions (digital or analogue) and problems with the application of a rubber dam. Solutions, such as the use of a surgical microscope, retraction cord and Teflon tape, are available. Since modern dentistry largely relies upon adhesive techniques with hydrophobic materials, these require a clean and dry working area. One solution is to place the preparation margin supragingivally. This can be done in three ways: a local build-up using a direct composite restoration, a surgical clinical crown lengthening or an extrusion (orthodontic or surgical). Since in practice only a small part is usually located subgingivally, placing a direct composite restoration is often sufficient. The term Deep Margin Elevation is generally used in the international English-language literature for this approach. If the area located subgingivally is larger, then techniques like crown lengthening and extrusion might be better.