This document provides instructions for making final impressions for complete dentures. It discusses: - The objectives of final impressions including preservation of tissue and bone, support, stability, and retention. - Techniques for recording tissues at rest to avoid displacement and damage, including selective pressure and border molding. - Steps for making custom trays including design, tray materials, and border molding sequences. - Considerations for final maxillary impressions including mobile tissues, tori, and seal areas. - Selection and application of impression materials to achieve an accurate final impression.

1. 7. Final Impressions John Beumer III, DDS, MS, Robert Duell, DDS and Eleni Roumanas Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry UCLA School of Dentistry This program of instruction is protected by copyright ©. No portion of this program of instruction may be reproduced, recorded or transferred by any means electronic, digital, photographic, mechanical etc., or by any information storage or retrieval system, without prior permission.

2. Final Impressions

5. We attempt to record the tissues at rest. The only exception is the posterior palatal seal area Maxillary tuberosity Posterior palatine glands Posterior Palatal Seal

16. Maxillary tray sequence of border molding: The posterior palatal seal area is added last and the tray is tested for peripheral seal.

17. Border Molding Heat the modeling compound over a flame

25. Area “A” has been refined. Note that the denture extension in this area is thinner and flatter. What structure limits the thickness and length of the denture border in this region? A Border Molding Coronoid Process

26. Note the difference Before After

28. Don’t pull down on the lip . This maneuver will foreshorten the denture flange. Border Molding

32. Pull on the tray handle to test retention. If retention is lacking check the following: 1) Check buccal pouch, hamular notch and posterior palatal seal area 2) Check the length and thickness of the denture extensions Testing Peripheral Seal

33. Compare the extensions of the border molded tray with those of the old denture.

34. If the retention is adequate you are ready to cut back the compound. Border Molding-Cut Back

64. Mandibular Sequence of Border Molding

69. Section “A” on one side is complete. This defines the proper tray extension for this area. Completed Buccal Flange

70. Add compound to area “B” (buccinator insertion, masseter groove region and area defining the posterior border associated with the retromolar pad). Temper, carefully rotate the tray into the mouth, and ask the patient to close while holding the tray in position, resisting the closure with your forefingers on the finger rests. Border molding the posterior flange-Area “B”

71. Area “A” and area “B” have been completed and trimmed. Avoid displacing the tissues associated with the retromolar pad. Border Molding –Completed Areas “A &C”

76. Border molding is completed. Inspect carefully to ensure that the extensions are well defined. The borders should be smooth and rounded . Note the varying thickness of the lingual flange. The thinnest border extends into the retromylohyoid space. Border Molding Completed