Gingival retraction, the process of displacing the gingiva to expose the tooth margin, is crucial for obtaining precise digital impressions. To achieve ideal gingival retraction, controlling bleeding and achieving hemostasis is very important. Light cannot penetrate bleeding, so it’s essential to stop the bleeding before a scan.
Below is a scan with bleeding around the margin. It’s very difficult to record the margin and to determine the final margin of the restoration.
Selecting the Ideal Tissue Management Protocol
Our role is to select the ideal tissue management protocol. We aim for vertical and horizontal displacement and ideal hemostasis without soft tissue trauma, preventing further recession. The three main protocols are chemo-mechanical, chemical, and surgical. The chemo-mechanical method uses retraction cords. The chemical method relies on retraction-based chemicals. The surgical method involves laser or electrosurgery.
Using Retraction Cord to Achieve Hemostasis and Gingival Retraction
Retraction cords are a popular chemo-mechanical method among dentists. They come in sizes 000, 00, 0, 1, 2, and 3. Cords are either impregnated or non-impregnated and have knitted, twisted, or braided designs.
Dentists prefer the knitted design because it absorbs crevicular fluid and bleeding after placement in the sulcus. This absorption causes the cord to expand, aiding in further horizontal and vertical soft tissue retraction. Because of these benefits, knitted retraction cords are the most commonly used.
Applying the Retraction Cord
To apply the retraction cord, start at the deepest sulcus and move to the shallowest, either interproximally, buccally, or lingually, based on probing depths. Use a serrated or rounded-end retraction cord packer and apply gentle pressure to avoid soft tissue recession or trauma.
Achieving Ideal Hemostasis with Retraction Cord
Retraction cord can achieve good vertical and horizontal displacement. For hemostasis, whether the cord is impregnated or non-impregnated, soak the retraction cord in a hemostatic solution like ViscoStat Clear, which contains 25 percent aluminum chloride. Soak the cord in this gel for around five minutes, then dry it to avoid trauma from excessive chemicals. Place the cord into the sulcus to achieve effective hemostasis.
Aluminum chloride is effective in hemostasis and will not cause discoloration or pigmentation to the soft tissue or the tooth, unlike ferric sulfate, which can cause discoloration. Therefore, using an aluminum chloride gel or solution is better for both posterior and anterior teeth to avoid discoloration from ferric sulfate.
Detecting the Margins
After achieving gingival retraction and hemostasis, margins can be detected using manual margin detection or tools like Medit’s automatic margin detection. If the margins are clear and the gingiva is sufficiently retracted, automatic margin detection can detect the margin in one second.
Using a retraction cord is an effective method for achieving both gingival retraction and hemostasis. By carefully selecting the right type of cord and applying it correctly with a hemostatic solution, dentists can ensure clear margins and accurate digital impressions without causing trauma to the soft tissue. This process is crucial for successful dental restorations and maintaining overall oral health.
For a more detailed explanation of how to optimize digital scans with ideal gingival retraction, please watch the full webinar here.
