chapter: 47 Laboratory, materials and procedures

Dental laboratory

A separate area of the dental office, where lab procedures are completed

Benefit of having a dental laboratory

Dentist and dental assistant can handle case work without having to send it out to a private dental lab

Model trimmer

Used to trim stone or plaster models, water continuously runs out on wheel to control dust

Vacuum former

Small electric appliance used to contract custom trays

Dental vibrator

Used to remove air bubbles from stone or plaster

Laboratory handpiece

Used to trim custom impression trays, adjust dentures and polish provisional and indirect restoration

Sand blaster (Air abrasion)

A handheld unit that sprays sand at high speed that creates etching on a surface area

Articulator

A mechanical device used to hold maxillary and mandibular models to simulate jaw movement

Face bow

Determines positional relationship of maxillary arch to TMJ

Dental Lathe

Used to trim and polish custom trays, provisional coverage, dentures and indirect restorations

Specialized spatulas and bowls

Used to mix stone

Dental models

A reproduction of the teeth and surrounding soft tissue of a patient’s Arches

Gypsum products

Product used to construct dental models made from the dihydrate form of calcium sulfate

Gypsum Type 1

Impression plaster

Gypsum Type 2

Model Plaster

Gypsum Type 3

Dental stone

Gypsum Type 4

Die Stone

Gypsum Type 5

High-strength stone

Impression plaster & model plaster (type 1 &2)

White, primarily for edentulous models, weakest form, requires more water

Dental stone (type 3)

Typically yellow, used for more diagnostic cast (removable dentures, retainers and custom trays)

Die Stone (type 4)

(densite or improved dental stone). Very strong and hard, used for crowns, bridges & indirect restoration

High strength stone (type 5)

The strongest, requires least amount of water, not used on inlays or onlays

Anatomic portion of dental model

Created from alginate that shows the teeth and surrounding areas

Art portion of dental model

The base of the cast

Double pour method

anatomical portion is poured first, plaster / stone is used for art portion

Box and pour method

Impression is surrounded by a box

Inverted pour method

Poured impression is flipped upside down to invert impression

What is done to a model to give it a professional appearance

Trimming & finishing

Digital models

3D image of a diagnostic model