ZINC PHOSPHATE CEMENT DENTAL MATERAIL

1. ZINC PHOSPHATE
CEMENT

2. Introduction
 Oldest of the luting cements thus serves as a
standard with which newer cements can be
compared over 100 yrs of clinical experience
 Routine application
 Low hardness cement
 High solubility
 pH low initial pH
 it may cause pulpal irritation

3.  There two types of zinc phosphate are present
1. Type I (fine grain)
2. Type II (medium grain)
 This material creates the very thin film layer
that is necessary for accurate seating of
castings.
 Recommended for use as an insulating base for deep
cavity preparations
Classification

4.  Powder and liquid system
 Capsules or preproportioned
(powder/liquid)
 There are two common mode of
supply
Mode of Supply

5.  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)
 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%
Powder Liquid
Composition

6.  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.
 The reaction is Exothermic
 Setting Time: 2.5-8 mins
Setting Reaction

7. Compressive strength 103.5mpa
Tensile strength 5.5mpa
Modulus of elasticity 13.5gpa
Solubility 0.06%
Thermal properties Good thermal insulator
Adhesion properties Not form a chemical bond with enamel or dentin
pH At the time of cementation the ph is 2.
Starting ph is 3.5.
After 24 hours the ph is 5.5.
Properties

8.  Stainless steel spatula and clean cool glass slab are use
for mixing.
 Mixing Time:- 1 min. 15 sec.
 P/L Ratio:- 1.4gm/0.5ml.
 The powder is added in small increments.
 Mixing is done with stainless steel spatula using brisk
circular motion.
 Each increments is mixed for 15-20 sec.
 A large area is covered during mixing in order to
dissipate the exothermic heat.
Manipulation

9.  Good compressive strength.
 Good thermal insulation ability
 Dose not dissolve in oral fluids.
Advantages

10.  No chemical adhesion
 Pulp irritation
 Poor esthetics.
Disadvantages

11. THANK YOU