Synonyms: Crown and bridge cement, Zinc oxyphosphate
APPLICATIONS:
Luting of restoration and orthodontic bands & brackets
Thermal insulation
Root canal restoration
High strength bases
Temporary restoration
CLASSIFICATION:
PARTICLE SIZE | FILM THICKNESS | USE | |
TYPE 1 | Fine | 25um | Luting |
TYPE 2 | Medium | 40um | Luting, base |

SETTING OF THE CEMENT:
Phosphoric acid in the liquid dissolves zinc oxide and reacts with aluminium phosphate to form aluminium phosphate gel on the remaining undissolved zinc oxide particles.

SETTING TIME: 2.5 to 8 minutes
MANIPULATION:
It is an exothermic process.
Zinc oxide cement is dispensed on the glass slab and divided into 6 increments(1/16, 1/16, 1/8, 1/4, 1/4, 1/4). It is followed by dispensing of the liquid.
Mixing of the cement should be initiated by the smallest increment with a thin spatula. There should be brisk spatulation with large, wide circular motions to dissipate the heat.
When the spatula is drawn away from the mixture, a strand of 12-19 mm should be produced. Such cement is suitable for cementation.
MIXING TIME:
For each increment: 15-20 sec
Total mixing time: 1.5-2 min
PROPERTIES:
MECHANICAL PROPERTIES: Compressive strength = 104 MPa, Tensile strength = 5.5 MPa, Elastic modulus = 13 GPa
SOLUBILITY: Less soluble in water (0.06%). Soluble in lactic, acetic and citric acids (in-vivo)
ADHESION TO TOOTH: Mechanical bonding ( In case of application of a cavity liner before applying zinc phosphate, it does not bond well due to less retention as it will create smoother surface with less interlocking)
BIOLOGICAL PROPERTIES: Phosphoric acid is acidic and cytotoxic. Younger patients are more susceptible to it because of more open dentinal tubules. Older patients with sclerotic dentin have a tortuous path for the entry of acid.