Purpose

Procedure

Material

What is duplicating? What is duplicating?

Duplicating & wax-upDuplicating & wax-up

AdvantagesAdvantages

Preserve the original castPreserve the original cast Eliminating the danger of fracture or Eliminating the danger of fracture or

abrading the surface of the original master abrading the surface of the original master cast cast

Forming the wax or plastic patternForming the wax or plastic pattern The metal framework is cast against the The metal framework is cast against the

surface of refractory castsurface of refractory cast

Duplicating materials & flasksDuplicating materials & flasks

Duplicating materials & flasksDuplicating materials & flasks

Duplicating materials & Duplicating materials & flasks

Duplicating materials & flasksDuplicating materials & flasks

DuplicatingDuplicating

Materials used for Materials used for dduplicating :uplicating :

Duplicating gelsDuplicating gels SiliconesSilicones

Agar Composition

Agar 12-25 %

Borax 0.2 %

Potassium sulfate 1-2 %

Alkyl benzoate 0.1 %

Water 85 %

Plasticizer glycerin

Filler silica , wax , rubber

Bactericidal Agent Thymol , Quaternary ammonium

Coloring / flavoring agent

HysteresisGel Sol

70-100 °

37-50 °

Agar

liquefaction 100 ° 8-12 min

Storage 65 ° 7 days

Chilling 18-21 ° 3-5 min

Agar

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

Duplicating procedureDuplicating procedure

InvestmentInvestment

Select investments that is compatible Select investments that is compatible

alloys alloys

Investment

Wax pattern shrinkage

Metal shrinkage (~ 1.5-2%)

Wax pattern expansion

Investment expansion• Setting• Hygroscopic• Thermal

ExpansionExpansion Setting ExpansionSetting Expansion

Hygroscopic setting expansion

Thermal Expansion.Thermal Expansion.

““Ideal” Investment:

Expaned to compensate metal shrinkageExpaned to compensate metal shrinkage

not decompose at high temperaturenot decompose at high temperature

Strengthed at various temperatureStrengthed at various temperature

Porous to allow the escape of gasesPorous to allow the escape of gases

Consistent casting temperaturesConsistent casting temperatures

““Ideal” InvestmentIdeal” Investment

Easy to manipulate.Easy to manipulate.

Smooth castings.Smooth castings.

Easy to break out.Easy to break out.

Inexpensive.Inexpensive.

TYPES OF INVESTMENTS

Based on the type of binderBased on the type of binder::

Gypsum-bonded or Calcium-sulfate bondedGypsum-bonded or Calcium-sulfate bonded

Phosphate-bondedPhosphate-bonded

Gypsum-bonded or Calcium-sulfate bondedGypsum-bonded or Calcium-sulfate bonded

CompositionComposition Binder: a-hemihydrate form of gypsum (25-45%)Binder: a-hemihydrate form of gypsum (25-45%)

Ca SO4 ½+3/2 h2o= Ca So4.2H2oCa SO4 ½+3/2 h2o= Ca So4.2H2o

Not to be heated above 700Not to be heated above 700ooC C decomposition decomposition

Phosphate-bonded investmentPhosphate-bonded investment

CompositionComposition::

Filler (refractory) = quartz or cristobalite or both Filler (refractory) = quartz or cristobalite or both (80%)(80%)

Binder = magnesium oxide and acid phosphateBinder = magnesium oxide and acid phosphate

Liquid = colloidal silica suspensionLiquid = colloidal silica suspension

FactorFactor Setting hygroscopic Setting hygroscopic

expansionexpansion Thermal expansionThermal expansion

Water/powder ratio Water/powder ratio increasedincreased

DecreasedDecreased DecreasedDecreased

Time of spatulation Time of spatulation increasedincreased

IncreasedIncreased No effectNo effect

Rate spatulation Rate spatulation increasedincreased

IncreasedIncreased No effectNo effect

Age of investment Age of investment increasedincreased

DecreasedDecreased No effectNo effect

Delay before Delay before immersion increasedimmersion increased

DecreasedDecreased

Water bath Water bath temperature patternstemperature patterns

IncreasedIncreased

DuplicatingDuplicating

DuplicatingDuplicating

Duplicating procedureDuplicating procedure

Refractory castRefractory cast

1

2

3

1-Master cast

2. Refractory cast

3. Master cast

Waxing the frameworkWaxing the framework

Dental waxesDental waxes

Pattern waxPattern waxeses

11..Inlay waxesInlay waxes

3.Baseplate waxes2.Casting waxes

Casting waxCasting wax

The pattern for the metallic framework of RPD.

Casting waxCasting wax

Casting wax : Casting wax : CCompositionomposition

The ingredients are similar to inlay waxes

Casting wax : PropertiesCasting wax : Properties

FlowFlow

Breaking pointBreaking point :: no fractureno fracture

PiPillable and readily adaptableable and readily adaptable

Adapt Adapt accurately accurately to to surface against which it pressed surface against which it pressed

not be brittle on coolingnot be brittle on cooling

VapVappporize, leaving no film orize, leaving no film ratherrather than than ccarbonarbon

Working propertiesWorking properties

Lingual bar waxing

Half-pear-shaped , 6- gauge + 24-gauge sheet wax

Minor connector (guiding plate)Minor connector (guiding plate)

Half round 8-gauge

Minor connectorMinor connector

Round wax 10-gauge

Metal base

24-gauge sheet wax24-gauge sheet wax

RestRest

Half round 8-gauge

Reciprocal armReciprocal arm

Half-round 12 gauge

Half-round 8- gauge

External finish lineExternal finish line

14-gauge round wax

Saddle waxing

Longitudinal pieces12-gauge half round

Saddle waxingSaddle waxing

Buccal loop 18-gauge round wax

External finish lineExternal finish line

14-gauge round wax

Nailhead configurationsNailhead configurations

Round wax 14-gauge

Wrought wire joiningWrought wire joining

Completed wax patternCompleted wax pattern

any questions ?