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DENT 1200 Materials I Lesson 3 Alginate Impression Material

DENT 1200 Materials I Lesson 3 Alginate Impression Material

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Page 1: DENT 1200 Materials I Lesson 3 Alginate Impression Material

DENT 1200 Materials I

Lesson 3 Alginate Impression Material

Page 2: DENT 1200 Materials I Lesson 3 Alginate Impression Material

Introduction

• Alginates are salts of alginic acid (crystalline compounds that are typically water soluble and are extracted from seaweed). When alginate is mixed with water, it has the ability to set or gel. Dental alginates are called irreversible hydrocolloids (have the ability to change from a liquid state (sol) to a semisolid state (gel) but do not have the ability to change from a semisolid to a liquid state). The material is supplied as a powder. Alginate is used for making impressions for study models, primary impressions of edentulous mouths and impressions in areas in which partial dentures are to be fabricated.

Page 3: DENT 1200 Materials I Lesson 3 Alginate Impression Material

1. Main Ingredients

• Potassium Alginate (seaweed, active

ingredient) 15%• Calcium Sulfate ( cause the chemical reaction) 16%• Trisodium phosphate (inhibit) 1%• Diatomaceous earth ( filler) 60%• Zinc Oxide ( filler & set time) 4%• Potassium Titanium Fluoride 3% ( makes compatable with gypsum)

Page 4: DENT 1200 Materials I Lesson 3 Alginate Impression Material

2. Measure, mix and load tray

• 1 scoop of fluffed alginate for 1 ring of water

• Quadrant tray- 1 increments

• Maxillary- 3 increments

• Mandibular- 2 increments

Page 5: DENT 1200 Materials I Lesson 3 Alginate Impression Material

2. Measure, MIX and Load tray

• Add water first

• Sift in powder and wet with spatula

• Hold bowl in palm of left hand and rotate while stroping spatula against the side of the bowl

Page 6: DENT 1200 Materials I Lesson 3 Alginate Impression Material

ALGINATOR

•There is a mechanical device called an

•alginator, in which the bowl spins.

Page 7: DENT 1200 Materials I Lesson 3 Alginate Impression Material

2. Measure, mix and LOAD tray

• Maxillary• 1 increment, load

posterior to anterior

• Mandibular• ½ material into left

flange, ½ into right flange, load from the lingual

Trays should extend into the muccobuccal fold but not inpinge on any Frenum.

Page 8: DENT 1200 Materials I Lesson 3 Alginate Impression Material

Frenum

• Tissue that attaches• Be careful of the

maxillary labial frenum, so the tray does not extend onto it.

Page 9: DENT 1200 Materials I Lesson 3 Alginate Impression Material

3. Dimensional ChangesPour up ASAP

• Syneresis- drying out, shrink, harden

Pour asap or wrap in a moist paper towel.

• Imbibition- take in fluids and swell

Do not immerse in fluid

Page 10: DENT 1200 Materials I Lesson 3 Alginate Impression Material

4. Taking a functional impression of each arch

• Try in trays for size and modify peripheral area with utility wax if needed.

• ALWAYS take MANDIBULAR 1st. Load tray and smooth with a wet finger. Smear some alginate over occlusals to prevent peduncles. Stand in front of patient, center over teeth and seat.

• Stabilize with a finger on each flange.• Remove in a quick snap, protecting the teeth of

the opposing arch.

Page 11: DENT 1200 Materials I Lesson 3 Alginate Impression Material

Wax and Mandibular

Page 12: DENT 1200 Materials I Lesson 3 Alginate Impression Material

4. Functional Maxillary

• Load tray and smooth with wet finger.

• Smear alginate over occlusals

• Seat from BEHIND the patient.

• Seat posterior to anterior.

• Stabilize with finger on palate area.

• Remove with quick snap protecting opposing arch

Page 13: DENT 1200 Materials I Lesson 3 Alginate Impression Material

Maxillary

Page 14: DENT 1200 Materials I Lesson 3 Alginate Impression Material

5. Model Trim

• Pour up and separate• Use a model trimmer• Check Lab sheet for

the Steps

Page 15: DENT 1200 Materials I Lesson 3 Alginate Impression Material

THE END