What purpose does a gingival retraction cord serve during an impression procedure?

The purpose of a gingival retraction cord during an impression procedure is primarily to help expose the finished tooth preparation by temporarily displacing the gingival tissue. This allows for a clear impression of the tooth and the surrounding areas by extending the impression area slightly below the finished preparation.

This is crucial as it ensures that the impression captures both the contours of the preparation and the margins of the restoration, leading to better adaptation of the final prosthetic. By providing access to the subgingival areas, the retraction cord facilitates detailed reproduction of the tooth and surrounding soft tissues, which is essential for accurate crown or bridge placement.

In contrast, while the other choices mention various functionalities, they do not accurately capture the primary role of the retraction cord in impression procedures. For example, extending the impression 2mm below the gingival margin implies a specific measurement, which is not the main intent of the cord. Preventing impression material from entering into the sulcus and ensuring no gingival overgrowth are important considerations but do not specifically reflect the main function of a gingival retraction cord during the impression process.