Alginate & Gypsum

Why do we make mounted study models?

1. Treatment planning

2. Dental legal records (possible legal defense)

3. provisional restorations (putty)

Criteria for proper tray size

1. Maxillary tray extend to distal most tooth

2. Mandibular tray extend retromolar pad

3. Capture vestibule

Loading mandibular tray

Load material in 3 increments from lingual side

Seating for tray insertion

Maxillary = 12

Mandibular = 9 if R

Fixed Prosthodontics

restoration not done directly in the mouth

ex. crowns, fixed partial dentures, taking impressions

Category of disease preventation

1. Primary = prevent disease before happening (sealant, fissure, fluoride treatment)

2. Secondary = eliminate or reduce when occuring (composite or amalgam restoration)

3. Tertiary = rehabilitate after disease happens (prosthodontics, crowns, fixed bridge, dentures, dental implants)

Alginate

irreversible hydrocolloid impression material

hydrocolloid

mixture within water

colloid = particle of substance evenly dispersed throughout another substance

Alginate composition

- Mucous extract from brown algae

- 15% potassium alginate = active

- 16% calcium sulfate = react with potassium to make insoluble calcium alginate

- 2% trisodium phosphate (Na3PO4) = slows down rxn time for mixing

- 60% diatomaceous earth = filler

- 4% zinc oxide = add bulk

- 3% potassium titanium fluoride = surface strength

potassium alginate

water soluble salt of alginic acid

trisodium phosphate

Na3PO4

purpose = slows down reaction time for mixing

reacts = calcium sulfate

what does regular or fast set types depend on

level of trisodium phosphate

phases of alginate setting

1. sol (solution phase) = liquidy ish

2. gel phase (semisold, gelatinous)

purpose of diagnostic impression

replicate teeth including vestibules & palate

advantages of alginate

- biocompatible