The document provides instructions for taking preliminary alginate impressions and alternative Accu-Dent impressions. For preliminary impressions, an extended stock tray is used to capture peripheral landmarks. Alginate is mixed, the tray is loaded and seated to capture ridges and borders. For Accu-Dent impressions, different viscosity materials are used and loaded into a custom tray to capture details without requiring extensive border molding. Both techniques aim to accurately record ridges, borders and anatomical landmarks to create a preliminary cast.

1. 5. Preliminary Impressions John Beumer III, DDS, MS Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry UCLA School of Dentistry and Frank Lauciello DDS Ivoclar Vivadent 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. Preliminary Impressions

4. Preliminary Impressions

7. Warm the periphery wax in a warm water bath, insert in patients mouth and mold the periphery wax to the intraoral contours. **Note: the pts existing denture can be used to help select an appropriate size tray. Preliminary Impressions

16. Alternate Technique- Accu-dent

18. Tray Selection

20. Mix the Syringe Gel using 70 °F water measured to the designated line on the vial. Back load the syringe Replace the plunger and express out any air. Set aside Syringe Gel

21. Mix the Tray Gel using 70 °F water measured to the designated line on the vial. The mix will appear dry at first but do not add additional water. Tray Gel

22. Accu-Dent Maxillary Impression Make sure a small amount of Tray Gel is pushed through the large holes in the tray for retention. Hold the tray under cold running water and smooth the surface with your fingers. The proper shape of the Tray Gel material is very important: most of the material should be in the front sloping to very little in the back. Loading the tray

23. Wipe dry the vestibules and palate with a 2x2 gauge. Express a line of the Syringe Gel into the vestibule from the hamular notch to the midline. Continue from opposite posterior to midline. Do not go all the way around in a single pass. Taking the Impression Accu-Dent Maxillary Impression

24. Taking the Impression Place a small amount of Syringe Gel in the anterior vault of the palate. Seat the tray from front to back. Stop seating the tray when a small amount of Syringe Gel appears in the distal edge of the tray. Accu-Dent Maxillary Impression

25. Pull straight down once on the filtrum at the vermilion border. Massage the cheeks very lightly downward with the fingers. Have the patient open wide Border Molding Accu-Dent Maxillary Impression

26. Tray Removal When set, break the seal at the distal buccal periphery and carefully remove the impression. Using the handle alone to remove the impression might dislodge the material. Disinfect according to OSHA guidelines and immediately pour the model Accu-Dent Maxillary Impression

27. Impression tray acts only as a method of delivering the impression material Accu-Dent Maxillary Impression

28. Accu-Dent Mandibular Impression

29. The lower Accu-Tray selection is accomplished in two steps, 1) tray type and 2) tray size Chose the tray that best suits either a normal ridge, or a highly resorbed ridge. Trays # 26-30 are designed with a moderate distal rise to accommodate the moderately resorbed ridge . Trays #20-24 are designed with a high distal rise to help accommodate the severely resorbed ridge . Accu-Dent Mandibular Impression Tray Type Tray Selection

30. Use the supplied calipers to measure the width of the residual ridge in the first molar region. This can be done on the existing denture, as shown, or in the patients mouth. Use this measurement to select the correct size lower tray. The caliper measurement should line up with the large holes in the first molar region of the lower tray. When in doubt use a smaller tray. Accu-Dent Mandibular Impression Tray Size Tray Selection

31. Mix the Syringe Gel using 70 °F water measured to the designated line on the vial. Back load the syringe Replace the plunger and express out any air. Set aside Syringe Gel

32. Mix the Tray Gel using 70 °F water measured to the designated line on the vial. The mix will appear dry at first but do not add additional water. Tray Gel

33. Mix the Tray Gel and place half on each side of the tray. Make sure that some of the tray material is pushed through the holes. This is the correct shape of the loaded tray. More material should be in the posterior of the tray. Give the Tray Gel a surface wash and rub smooth under cold running water with your fingers. Accu-Dent Mandibular Impression Loading the Tray

34. Express Syringe Gel from the retromolar pad forward to the midline. Repeat on the other side of the arch. It is not necessary to place Syringe Gel into the lingual vestibules. Place tray front to back until Syringe Gel appears in the posterior of the tray. Have the patient bring their tongue forward as you rotate the tray backward into position. When the Tray Gel rises up in the distal, Stop. Accu-Dent Mandibular Impression Taking the Impression