1. •In the Name of Allah Who is the most Merciful and the
most
•Beneficial

2. MIXING TECHNIQUES OF FIVE DENTAL
PRODUCTS
• By
Najib Ahmad Dawar
Roll #: 66
Khyber College Of Dentistry
Peshawar (Pakistan)

3. • The Process by which two or more
components are mixed together in order
to get a homogeneous mix. e.g.
• Mixing of powder & liquid components,
• Mixing of two pastes &
• The mixing of paste & liquid
components.
Wor king Time
• The time available for mixing and
manipulating a material.

4. Mixing Techniques Of Five Dental
Products Which I Covered In
Presentation
1 Gypsum
2 Glass Ionomer Cement
3 Alginate
4 Zinc Phosphate Cement
5 Zinc Polycarboxylate Cement

5. 1-Gypsum mixinG:
• Mixed by two pr ocess:
• Manual Pr ocess ( Hand Mix)
• Mechanical Pr ocess

6. Requirements:
Robber Bowl, Spatula, Water &
Powder.
Pr ocedure::
• Take a measured quantity of
water in the r ubber bowl
• Add powder to the Bowl.

7. • Settle it for 30 sec with out spatulation.
• This technique minimize the chances of
Air interruption.
• Then spatulation starts and wipe the
powder with the inside of the bowl with a
spatula to insure wetting of the powder
and minimizes the Air entrapped.
• Spatulation continues until all the powder
is uniformly wetted and mix..
• Mixing time is 1min at 2rev/sec.
• Two setting Times:
• Initial setting time
• Final setting time

9. • Mechanical mixing
is done under
vacuum mixer.
• It gives stronger
and denser Mix.
• No chances for Air
to entrap in the Mix.

10. Precautions:
• The mixing equipment must be clean.
• Flexible plastic bowl should be used.
• Wide bladed spatula should be used.
• No air should be trapped in the Mix.
• The material should be used as soon
as possible after mixing since its
viscosity increases and will reach a
stage where the material is
unworkable.

11. 2-GLAss iOnOmER
CEmEnT mixinG
Requir ements:
Powder & Liquid, Glass slab or Non absorbable
Treated paper pad & plastic or ceramic
spatula.
• Consists of Powder & liquid
• If the liquid is the viscous carboxylic acid then
P/L ratio of 1.3:1 to 1.35:1 is used,
• If the liquid is water then W/P ratio 3.3:1 to
3.4:1 is used.
• The P/L ratio also depends on application of
the cements…
• lining consistency
• luting consistency

12. • For lining consistency the P/L ratio is 3:1
• And
• For luting consistency the P/L ratio is 1.5:1
• Powder should be divided into two equal
parts….
• Half of the powder will be carried and
mixed with liquid with a stiff spatula so that
powder is covered with liquid..
• After this the 2nd half is added and keep on
mixing. Until get the desired consistency.
• mixinG TimE:
• 30-60sec.
• WORKinG TimE:
• 2 minutes
• Immediately carry to the prepared cavity
b/c the working time after mixing is only
2min.

13. Encapsulated products are usually mixed for 10sec in
mechanical mixer and dispensed directly onto the
tooth restoration.

14. Precautions:
• There should be no evaporation of water.
• A good mix should have a glassy surface, this
indicates the presence of poly acids which
ensures bonding with the tooth, but a mix with
a dull surface is discarded as it indicates
prolong mixing which reduces the adhesion.
• If the liquid contains polyacids, it should not
be placed in a refrigerator as it becomes very
viscous.
• The glass slab should not be below the dew
point, as moisture may condense on the slab
and changes the acid water balance.
• Never use stainless steel spatula as it is
composed of metals which may react with
Glass Ionomer cement .Always use plastic or
ceramic spatula…

15. 3-ALGinATE mixinG
• Requirements: A clean flexible plastic Bowl,Wide
bladed spatula and a Plastic tube containing
water
• Alginate are supplied as powder which are mixed
with water
• A plastic measuring cylinder is used for the
correct volume of water
• An alginate powder is also supplied in small
sachets.
• Each sachet are sufficient for one impression.

16. • After proportioning the water and powder
are mixed together in a plastic mixing bowl
using a wide bladed spatula
• Rapid spatulation is required to give
thorough mixing and an alginate sol of
creamy consistency is formed.
• Then pour a water in the measuring cylinder
up to point 1 leaving 1 part in the cylinder…
• Mixing is started with a stirring motion to
wet all the powder.
• Once the powder has been moistened then
rapid spatulation with the side should be
done…

17. • Spatulation with sides will help to:
• Remove most of the air bubbles…
• Dissolve alginate from the surface and
complete their dissolution.
• After the material gain creamy consistency
…stop spatulation…
• Mechanical devices are also available for
spatulation alginate. their main advantage
are…
• Speed
• Convenience
• Elimination of human variables.

18. • Pr ecautions::
• Rapid spatulation is required
• Spatulation with the sides is done
• Correct volume of water and powder is
required.
• The water powder ratio specified by the
manufacturer should be used.

19. 4-ZinC phOsphATE
CEmEnT mixinG
Mixing Requirements:
Large Narrow Bladed Stainless
steel
spatula, Cooled Thick Glass slab,
mixinG::
• Its Mixing is an exothermic process.
• Incorporate the proper amount of powder
into the liquid slowly on a glass slab to
attain desired consistency…
• For Cavity Lining P/L is 3.5:1
• For luting a more thinner

20. • We divide the powder into increments
Smaller, larger and then smaller for
proper dissipation of heat.
• 1st incorporate a small increment of
powder into liquid minimum heat is
evolved.
• Then larger increment of powder is
added to further saturate the mix.
• Finally a smaller increment of powder
is added to achieve the desired
consistency of cement.

21. • The mix procedure begins with a Small
one, then larger one and ends with a
small one to compensate heat and to
achieve slow neutralization.
• The reaction is neutralization type.
• Always use thick glass slab to slow
down the process of temperature
change
• For increasing the working time we use
cold glass slab or frozen glass slab.
• Mixing Time:
• 60-90 sec are enough for mixing.
• Working Time
luting -2.5 minutes
lining – 2 minutes

22. • Mix over a large area to dissipate
the generated heat as this heat
will accelerate the setting time.
• The cap from the liquid bottle
should be removed enough to
dispense sufficient liquid for one
mix. ,and then replaced
immediately

23. • If the liquid is placed open for a
long time the water will be
either lost or gained depending
upon the humidity. which will
alter the setting characteristics
and physical properties.

24. 5-ZinC pOLy
CARbOxyLATE CEmEnT
mixinG
Requirements:
Mixing Requirements:
Large Narrow Bladed Stainless
steel
spatula, Cooled Thick Glass
slab,

25. Mixing::
• Available as powder and liquid or
precapsulated form.
• Powder is shaken gently
• Powder is dispensed on paper pad or
glass slab
• A bulk of powder i.e. 90% Of the powder
is added to the Liquid immediately so
that the liquid particles do not
evaporate.
• P/L ratio is 1.1,1.5:1 or 2:1and it can be
increased according to the demand.
• The remainder of the powder is mixed in
order to achieve the desired
consistency.
• It should be spread over a small area.

26. • It should be used immediately after
mixing b/c working time is only 3min at
22 centigrade.
• Working time can be increased by using a
cool glass slab.
• Normally it ranges b/w 2.5-6 mins but can
be increased up to 10-15 mins by using
chilled glass slab.