Impressions and in complete dentures.pptx

complete notes

1. Impressions in complete dentures

2. **Q1: What is the purpose of taking impressions for complete dentures?** **A1:** The purpose of taking impressions for complete dentures is to capture the detailed and accurate contours of the patient's oral tissues, including the gums and the underlying bone structure. This information is essential for creating a denture that fits well, is comfortable, and functions effectively. The impressions help the dental lab fabricate a denture that replicates the natural anatomy of the patient’s mouth.

3. **Q2: What are the two main types of impressions used in complete denture fabrication?** **A2:** The two main types of impressions used in complete denture fabrication are: 1. **Preliminary Impressions:** These are taken with a more flexible material and are used to create preliminary models or casts. These models are used to plan the denture design and make a custom tray for the final impression. 2. **Final Impressions:** These are taken with a more precise material and capture the detailed contours of the oral tissues. Final impressions are used to create the definitive models on which the final denture will be based.

4. **Q3: What materials are commonly used for preliminary and final impressions in complete dentures?** **A3:** For preliminary impressions, materials like alginate (irreversible hydrocolloid) are commonly used due to their ease of use and ability to capture a general impression of the oral tissues. For final impressions, more accurate materials such as polyvinyl siloxane (PVS), polyether, or elastomeric materials are used. These materials provide greater detail and accuracy necessary for a well-fitting denture.

5. **Q4: Why is it important to use a custom tray for final impressions?** **A4:** A custom tray is important for final impressions because it provides a more accurate and consistent thickness of impression material and ensures a precise fit. It is tailored to the individual’s mouth, which helps in capturing the fine details of the oral tissues. This results in a more accurate final impression and ultimately a better-fitting denture. --- **Q5: How does the impression technique affect the fit of the complete denture?** **A5:** The impression technique significantly affects the fit of the complete denture. Proper technique ensures that all areas of the oral tissues are accurately captured, including the denture borders and the functional contours. Inaccurate impressions can lead to ill-fitting dentures, which may cause discomfort, reduced function, and poor esthetics. The goal is to capture the exact anatomical details to ensure the denture fits snugly and comfortably.

6. **Q6: What are some common issues that can arise with impressions in complete denture fabrication?** **A6:** Common issues that can arise include: - **Inaccurate Impressions:** Due to inadequate material coverage or patient movement, leading to poor denture fit. - **Distortion:** If the impression material is not handled properly or if it sets too quickly. - **Air Bubbles:** These can cause imperfections in the final impression, affecting the accuracy. - **Patient Discomfort:** Improper tray selection or incorrect technique can cause discomfort during the impression-taking process.

7. *Q7: What steps can be taken to ensure an accurate impression for complete dentures?** **A7:** To ensure an accurate impression, the following steps can be taken: 1. **Proper Tray Selection:** Use a well-fitting custom tray or appropriate stock tray. 2. **Adequate Material Handling:** Mix and handle impression materials according to manufacturer instructions to avoid issues like bubbles or incomplete setting. 3. **Ensure Full Coverage:** Make sure the impression material covers all necessary areas, including the vestibular regions. 4. **Patient Preparation:** Instruct the patient properly to minimize movement and ensure cooperation during the impression-taking process. 5. **Check the Impression:** Inspect the impression for any defects or inaccuracies before sending it to the lab.

8. **Q8: How can an impression be evaluated for quality before proceeding with denture fabrication?** **A8:** An impression can be evaluated for quality by checking:+ - **Detail Reproduction:** Ensure all anatomical features are clearly captured. - **Complete Edges:** Verify that the impression material extends to the vestibular areas and the entire denture border. - **No Distortions:** Look for any signs of distortion or defects in the impression material. - **Cleanliness:** Ensure the impression is clean and free of debris or air bubbles. If any issues are detected, a new impression may be required to ensure a proper fit for the complete denture. Feel free to ask if you need more information or have other questions!