What is an example of chemical retraction?

Chemical retraction involves using a substance that causes the tissues to shrink away from the tooth, allowing for better visibility and access during dental procedures, especially in preparation for impressions. Impregnated cords are the prime example of this method. These cords are often treated with astringent chemicals such as aluminum chloride or ferric sulfate, which help to control bleeding and facilitate the retraction of gingival tissues. This allows for clearer margins for the dentist to work with, improving the accuracy of impressions and the overall outcome of dental restorations.

Other methods mentioned, while useful, do not involve chemical means of retraction. Foam retraction caps and silicone pastes are typically non-invasive mechanical methods that assist in holding tissues back. Mechanical clips also do not involve any chemical interaction with the tissue, making impregnated cords the clear example of chemical retraction in this context.