ZINC PHOSPHATE CEMENT - CLASSIFICATION,COMPOSITION,SETTING REACTION,MANIPULATION
Zinc Phosphate Cement ADA Specification number of Zinc Phosphate is 96. Zinc phosphate cement was originally developed more than 100 years ago and was extremely popular during most of the twentieth century. CLASSIFICATION: TYPE 1 : Fine grained for luting Type 2: medium grained for luting and restorative purpose. COMPOSITION: Zinc Phosphate cement contains powder and liquid containers which comes separately. powder: zinc oxide 75%,magnesium oxide 13%,silicone dioxide-2%,bismuth trioxide-0.1% liquid: phosphoric acid 38-59% in water 30-50% and is buffered with aluminium and zinc salts to control the ph.,zinc- 7%,aluminium-2% CHEMISTRY AND SETTING : REACTION TYPE- ACID-BASE REACTION SETTING REACTION: Phosphoric acid dissolve in zinc oxide react with aluminum phosphate to form zinc aluminophosphate gel on undissolved zinc oxide particles set cement: unreacted zinc oxide particles gets encased in amorphous matrix of zinc aluminophosphate. loss of water from liquid increases the settin