alginate - 104

imbibition

addition or absorption of water

syneresis

shrinkage of the impression from water loss

sol

liquid phase

gel

semi solid

colloid

glue like material composed of 2 or more substances. one substance does not go into solution but remains suspended within another substance

Potassium alginate

extracted from seaweed and kelp

reverse hydrocolloid or ‘agar hydrocolloid’

when reheated it returns to sol state

irreversible hydrocolloid or ‘alginate hydrocolloid’

is permanent - can not be changed once set

gelatin time

time it takes to completely set after mixed with water

generic name for alginate

irreversible hydrocolloid

methods to alter set time

warmer water - set faster

cooler water - set slower

advantages of alginate

economical

ease of manipulation

minimal equipment

rapid setting

disadvantages of alginate

lose accuracy due to syneresis and imbibition

alginate derived from

seaweed

alginate packaged

airtight plastic container

pre-measured sealed bag

premixed package w/ dispensing unit

purpose of alginate

making opposing models for fixed and removable prosthesis - used when less accuracy is needed

common use of alginate

impressions

mixing alginate

1 min

loading max / mandibular tray

try before loaded to make sure it fits

max - back of tray - smooth to front if needed

man - 2 separate parts loaded in midline

seating max/ man tray

line up to midline - retract lip - back teeth first

removing max/ man tray

break seal snapping motion

infection control

rinse under water to remove any debris

spray with disinfectant

wrap in paper towel

label container

what tray is placed first

mandibular - build patient confidence