Gypsum

Question 1

Study Model

Answer 1

used to plan treatment and observe progress

Question 2

Cast

Answer 2

replica on which appliances are fabricated. more accurate, more than 1 tooth (quad or full arch)

Question 3

Die

Answer 3

working replica of a single tooth. removable part of a cast

Question 4

Study Model Components

Answer 4

Art Portion + Anatomical Portion. Base/Front/Side/Heel

Question 5

Study Model Qualities

Answer 5

accuracy, stability, fine detail, strength, compatible w impression material

Question 6

Types of Gypsum

Answer 6

5 Types: 1. Impression Plaster 2. Plaster (weakest) 3. Dental Stone (we use) 4. Improved Stone 5. High Strength

Question 7

Chemical Formula of Gypsum b4 manufacturing

Answer 7

Calcium Sulfate Dihydrate

Question 8

Chemical Formula AFTER manufacturing

Answer 8

Calcium Sulfate Hemihydrate! Powder form, 1.5 moles water removed

Question 9

Type 3 Stone

Answer 9

what we use, yellow or white; heated under pressure - particles uniform, less pourus, denser, stronger

Question 10

Type 4 High Strength Stone

Answer 10

boiled w chloride; denser, harder, stronger, cuboidal particles

Question 11

Exothermic Reaction

Answer 11

liberation of heat during setting, post mixing hemihydrate w water = dihydrate

Question 12

Water Ratios

Answer 12

higher strength, smoother particles = less water

Question 13

Type 3 Stone W/P Ratio

Answer 13

28-30mL / 100gms

Question 14

Working Time

Answer 14

5-7 minutes

Question 15

Initial Set

Answer 15

loss of gloss, no longer flows

Question 16

Final Set times

Answer 16

45-60 min, 24 hrs to harden completely

Question 17

Setting time Retarders

Answer 17

borax, blood, saliva, hydrocolloids (alginates). room temp/humidity ^ = ^ setting time

Question 18

Setting time Accelerators

Answer 18

potassium sulfate, didydrate crystals (dried stone pieces), slurry water