1. Alginate Impressions on a Patient
DA 122 Dental Materials

2. Alginate Powder & Scoop
Alginate Tray Set-up
Water Measuring Cup
Spatula
Alginate Powder & Scoop
Mixing Bowl
Mandibular Tray
Maxillary Tray

3. Armamentarium

4. Alginate Trays

5. Adding wax periphery

6. Set-up for Alginate Alginate bowls Alginate spatulas
Fresh, room temperature water
Measuring scoops / water vial
Impression trays (metal-perforated, rimlock) or disposable-perforated
Cup of mouthwash and paper towel
Damp paper towel
Labeled ziplock bag

7. Measure alginate and water
Maxillary arch:
3 scoops alginate 3 lines water (room temperature)
Mandibular arch:
2 scoops alginate 2 lines water
Water is measured and dispensed in the plastic water measurer that comes with the materials
Excess water will weaken the final set

8. Taking the Impression Try tray in patient’s mouth Mix material
Remove excess material
Place gently in patient’s mouth
Hold until set
Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.

9. Try in the tray
Try the tray in the patient’s mouth BEFORE mixing any alginate
Be sure the tray fits properly
It’s best to do mandibular impressions first
Less likely to set off gag reflex!

10. Mixing Alginate

11. Mixing Alginate Put measured powder into rubber bowl
Incorporate water gently until completely moistened
Hold bowl in left hand and spatulate with right hand
Use a wiping motion
Spatulate mix into creamy, homogeneous consistency
Alginate should be mixed for 60 seconds
Increasing the water temperature will shorten the mixing time!

12. Mixing Alginate Undermixing: Mixture will be grainy
Model will have poor detail

13. Loading the Alginate Tray

14. Loading the tray
A useful method is to start at the posterior and push the mix anteriorly by adding more and more to the posterior

15. Alginate Impressions – Taking the Impression
Removal of Small Amount from Palate

16. Alginate Impressions – Taking the Impression
Insertion

17. Alginate Impressions – Taking the Impression
Holding Tray in Position

18. Removing the Impression
Ensure material is set
Carefully rock tray back and forth
Keep fingers steady to protect teeth
Give patient wet paper towel for face
Check impression for landmarks
Rinse impression
Disinfect impression
Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.

19. Alginate Impressions – Removing the Impression
Breaking the Suction-like Seal

20. Alginate Impressions – Removing the Impression
Position of Fingers Protecting Opposing Arch

21. Examine the impression:
Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.

22. Evaluate your alginate impression
Smooth surface?
Rounded periphery?
Centered in tray?
¼ inch depth in tray?
No oral cavity debris?
No tray showing?
No torn or thin places?
Good detail?
Anatomy
Distals of posterior molars
All sides of teeth visible
Retromolar pads/ maxillary tuberosity
Muscle attachment
Abnormalities? (tori, etc.)

23. Alginate Impressions –
Rinsing of Impression with Water

24. Alginate Impressions:
Spray with Disinfectant

25. Alginate Impressions:
Wrapping Alginate with damp paper towel

26. Ziplock bag labeled with patient’s full name
Alginate Impressions – Disinfecting the impression
Ziplock bag labeled with patient’s full name