Information about ZINC PHOSPHATE CEMENT.......

2.  INTRODUCTION
 CLASSIFICATION
 AVAILABLE AS
 COMMERCIAL NAME
 COMPOSITION
 MANUFACTURE
 SETTING REACTION
 PROPERTIES
 MANIPULATION
 ADVANTAGES
 DISADVANTAGES
 APPLICATION

3.  ADA SPECIFICATION NUMBER- 96.
 Zinc phosphate is the oldest of the
luting cements and thus serves as
a standard with which newer
cements can be compared.

4.  ADA Spa. No. 96. designates them as:
 Type I: Fine grained for luting.
Film thickness should be
25micrometer.
 Type II: Medium grained for luting and
filling.
Film thickness should not more
then 40micrometer.

5. 1. Powder and liquid system.
2. Capsules of preproportioned
powder and liquid.

6.  - Confit.
 - Harvard.
 - Zinc Cement Improved.
 - Modern Tenacin.

7. )(. POWDER:
- Zinc Oxide- 90.2%.
>. Principal constituent.
- Magnesium Oxide- 8.2%.
>. Aids in sintering.
- Other Oxide- 0.2%.
>.Improve smoothness of mix.
- Silica- 1.4%.
>.Filler.

8. )(. LIQUID:
- Phosphoric Acid- 38.2%.
>.React with zinc oxide.
- Water- 36.0%.
>.Control rate of reaction.
- Aluminium Phosphate- 16.2%.
>.Buffer.
- Aluminium- 2.5%.
- Zinc- 7.1%.

9.  The ingredients are mixed and heated at
temperatures bw 1000‘C. and 1400’C.
[SINTERING].
 After sintering ,the cake formed is cooled
quickly.
 This cause the material to crack which
helps in grinding of the material to a fine
powder.
 This process is known as FRITTING.

10. @. When the powder is mixed with liquid,
phosphoric acid attacks the surface of the
particles and releases zinc ions.
@. The aluminum in the liquid is essential for
cement formation.
@. The aluminum complexes with the
phosphoric acid and the zinc ions to form
a zinc aluminophosphate gel.

11. @. The reaction is EXOTHERMIC.
@. Setting Time: 2.5-8 mins.

12. #. COMPRESSIVE STRENGTH:
103.5MPa.[15,000GPa].
#. TENSILE STRENGTH:
5.5MPa.[800psi].
#. MODULUS OF ELASTICITY:
13.5GPa.
#. SOLUBILITY:
0.06%.

13. #. THERMAL PROPERTIES:
Good Thermal Insulator.
#. ADHESION PROPERTIES:
Not form a chemical bond with
enamel or dentin.
#.BIOLOGICAL PROPERTIES:
-At the time of cementation the pH is 2.
-Starting pH is 3.5.
-After 24 hours the pH is 5.5.

14. #. OPTICAL PROPERTIES:
OPAQUE.

15. 1. Stainless steel spatula and clean cool
glass slab are use for mixing.

16. 2. Mixing Time:- 1 min. 15 sec.
3. P/L Ratio:- 1.4gm/0.5ml.

17. 4. The powder is added in small increments.

18. 5. Mixing is done with stainless steel spatula
using brisk circular motion.
6. Each increments is mixed for 15-20 sec.

19. 7. A large area is covered during mixing in
order to dissipate the exothermic heat.

21. }{. Good compressive strength.
}{. Good thermal insulation ability.
}{. Dose not dissolve in oral fluids.

22. }{. No chemical adhesion.
}{. Pulp irritation.
}{. Poor esthetics.

23. ::- Luting for restoration.
::- High strength bases.
::- Temporary restoration.
::- Luting for orthodontic bands and
brackets.