Part 1 : Border Molding and Secondary Impression Mandible

Summary

The video discusses the process of making a final denture impression for edentulous patients using a custom tray. It emphasizes capturing all denture-bearing surfaces for proper fit, support, retention, and stability. Steps include tray preparation, border molding with impression compound, and final impression using zinc oxide eugenol. The guide details how to adjust and mold soft tissues, ensuring accurate anatomical recording, especially around the labial, buccal, and lingual frena. The summary also highlights essential tips like removing excess material and checking for overextensions to ensure a comfortable, well-fitted denture.

Takeaways

• 🦷 The objective of impression making is to capture all potential denture-bearing surfaces to ensure support, retention, and stability of the denture.
• 🛑 The denture should extend peripherally to record the resiliency of surrounding structures, ensuring proper border length and width.
• 🛠️ A custom tray is used to make the final impression for edentulous patients, allowing control over movable soft tissues and minimal displacement of denture-bearing areas.
• 🔍 Before proceeding, check the custom tray extensions to ensure coverage of the buccal shelf area, retromolar pad, and sufficient clearance for frenum areas.
• 🖊️ Overextended tray borders should be marked with an indelible pencil and adjusted using a straight handpiece to ensure accurate extensions.
• 🔥 Impression compound, a mixture of waxes and thermoplastic resin, is used for border molding, and it can be added incrementally and reshaped with heat.
• 💧 The material should be heated and tempered in hot water before being applied to the tray, and Vaseline can be used to shape borders before inserting into the patient’s mouth.
• 👄 Border molding includes retracting the lips and cheeks and having the patient move their tongue to record the correct shape and depth of the sulcus and surrounding areas.
• 🕵️ Once border molding is complete, inspect the tray for accuracy by checking for loss of gloss, which indicates proper recording of the tissues.
• 🧪 Zinc oxide eugenol is used for the final impression, mixed in equal lengths and loaded gradually to avoid air bubbles, followed by repeating border molding movements before setting.

Q & A

What are the primary objectives of impression making for dentures?

The objectives of impression making are to capture all potential denture-bearing surfaces and tissues to provide support, retention, and stability of the denture under function. It also improves the appearance of the lips and ensures that the denture base acts as a proper foundation.

Why is it important for the denture to extend peripherally?

The denture should extend peripherally to record the resiliency of surrounding limiting structures, ensuring proper length and width of the final denture borders. This helps achieve adequate support, retention, and stability of the denture.

What is the role of a custom tray in making the final impression for an edentulous patient?

A custom tray is used to make the final impression for an edentulous patient. It allows control over the movable soft tissues around the impression and ensures minimal or selective displacement of the tissues covering the denture-bearing area, especially in primary denture-bearing zones.

How should the tray be checked before making the impression?

Before making the impression, check that the tray covers the buccal shelf area and the retromolar pad. Ensure there is clearance for the labial, buccal, and lingual frenum, and that there is 1.5 to 2 millimeters of space between the tray and the full depth of the sulcus when the lip is moved horizontally.

What does it mean if the tray is displaced when the patient elevates and protrudes their tongue?

If the tray is displaced when the patient elevates and protrudes their tongue, it indicates that the lingual borders of the tray are overextended and need to be adjusted.

Why is an indelible pencil used during the impression process?

An indelible pencil is used to mark the labial and buccal frenum as well as to draw any overextensions on the tray. These markings guide the clinician in making accurate adjustments during the reduction process.

What are the advantages of using impression compound for border molding?

Impression compound is ideal for border molding because it can be placed incrementally, allowing for easy observation, trimming, and adaptation. It also has the property of becoming rigid at room temperature, which helps in achieving accurate borders without distortion.

What is meant by 'loss of gloss' in the impression compound?

'Loss of gloss' refers to the dull appearance of the impression compound once it contacts the tissues, indicating that the material has recorded the correct depth and width of the sulcus. This signifies successful border molding.

How is the zinc oxide eugenol impression material prepared for use?

Zinc oxide eugenol is prepared by mixing equal lengths of two pastes: zinc oxide (white) and eugenol (red). The material is spread over a mixing pad using a figure-eight motion until a homogeneous mixture is achieved. It has an initial set time of 3-5 minutes and fully sets in 10 minutes.

What is the purpose of applying Vaseline to the patient's face before seating the tray with zinc oxide eugenol?

Vaseline is applied to the patient's face to prevent the zinc oxide eugenol impression material from adhering to the skin, making it easier to clean after the impression process is complete.