Revision on Practical Dental Materials

RDM211

DENTAL BIOMATERIALS

Mechanical properties

DIAMETRAL TENSILE STRENGTH TEST

THREE POINT BENDING (TRANSVERSE STRENGTH TEST

Testing compressive strength of a material:

• Specimen shape: Cylindrical

• Type of force used: compression

•Tester: Universal Testing Machine

Dumbell shaped specimen

Disc shaped specimen for diametral TS

Diametral compression test of brittle materials:

• Specimen shape: Disk-shaped

• Type of force applied: Compression

• Resultant force: Tension

• Tester: Universal Testing Machine

Stress = 2P Load π D T

Diameter XThickness

Hardness testers

STOCK TRAYS

Acrylic special tray

1-IMPRESSION MATERIALS

Impression compound low fusing sheets and sticks(green)

compound(

• 1) An impression compound disc

• 2) An impression compound impression taken in an upper edentulous stock tray

LOW FUSING COMPOUND (GREEN COMPOUND).

ZINC OXIDE EUGENOLIMPRESSION PASTE

Glass slab and spatula

ZINC OXIDE EUGENOL SECONDRY IMPRESSION

ACRYLIC SPECIAL TRAY WITH BORDER MOULDED (USING LOW FUSING

COMPOUND) READY FOR MAKING ZOE IMPRESSION

PRIMARY COMPOUND IMPRESSION

INPRESSION COMPOUND SHEETS

Agar syringe and tray material

• Syringes:Syringes: low viscosity – high flow. low viscosity – high flow.

• Tubes:Tubes: high viscosity – heavy body: low flow. high viscosity – heavy body: low flow.

AGAR-AGAR CONDITIONER

Three compartments conditioning bath

Water cooling system tray for agar impression

Alginate

Rubber bowl and broad bladed spatula

Alginate impression

polysulphide

•Mixing on paper pad or glass slab with medium blade spatula.

Manipulation

•Kneading

Addition siliconeHow many consistency

Vinyl glovesLatex gloves

Condensation silicone

• Condensation silicon– By-product

– ethyl alcoholInaccuracy (shrinkage)Poured as soon as

possibleNeed very dry field

(hydrophobic) Advantages:

Clean, pleasant odour

Addition silicon:No byproduct

Release H2 gas after settingDelayed pouring

Hydrophobic

Advantages:Good dimensional stability

Tray adhesive

Auto mixing gun and cartridges

Static mixing tips

Rubber base impression

Light body

Heavybody

2 -GYPSUM MATERIALS

STONE CAST

Die

Rubber bowl and spatula

Semi mechanical mixer

Vacum mixing machine