Eugenol Based Cement Classification, Composition And Uses

Eugenol Based Cement

Zinc Oxide Eugenol Cement:

Classification of Zinc Oxide Eugenol Cement:

ISO 3107:2004:

• Type I ZOE — For temporary cementation
  • Class I – Settng cement
  • Class II – Non-setting cement
• Type II ZOE — For permanent cementation
• Type III ZOE — Temporary filing and thermal base
• Type IV ZOE — Cavity liners

The above classification of ISO 3107:2004 recently has been replaced by ISO 3107: 2011 in which only two classes are described.

ISO 3107: 2011:

• Type I: For temporary cementation
• Type II: For bases and temporary restorations

Type I ZOE cements: 

They are meant for short-term luting. They are used to cement provisional restoration for the period it takes to make a definitive restoration. Permanent restorations are also sometimes for a short period for the patient to try it. They have low strength which allows easy removal of restoration without damage to the restoration or tooth.

Type II ZOE cement:

They are used for interim periods when a tooth is undergoing treatment or until it is ready for permanent restoration. They can also be used as bases under non-resin-based permanent restorations.

Composition of  Zinc Oxide Eugenol Cement:

Powder:

Liquid:

Chemistry of Setting Zinc Oxide Eugenol Cement:

The setting reaction and microstructure are the same as that of the zinc oxide eugenol impression paste. In the first reaction, hydrolysis of zinc oxide to its hydroxide take place. Water is essential for the reaction.

ZnO + H₂O  →  Zn (OH)₂
The reaction proceeds as a typical acid-base reaction.

Zn (OH)₂      +       2HE   →   ZnE₂  +  2H₂O
Base             Acid          Salt
(Zinc hydroxide)   (Eugenol)  (Zinc eugenolate)

The chelate formed is an amorphous gel that tends to crystallize imparting strength to the set mass.

Manipulation of  Zinc Oxide Eugenol Cement:

Powder/liquid ratio 4: 1 to 6: 1 weight. Bottes are shaken gently. A measured quantity of powder and liquid is dispensed into a cool glass slave bulk of the powder is incorporated into the liquid and spatulated thoroughly in a circular motion with a stiff-bladed stainless steel spatula Smaller increments are then added until the mix is complete.

Properties  of  Zinc Oxide Eugenol Cement:

• Mechanical Properties:
  • The compressive strength of the cement ranges from 5 to 55 MPa.
    1. For Type I—6 to 28 MPa
    2. For Type II—45 to 55 MPa
  • Tensile strength ranges from 0.32 to 5.3 MPa
  • The modulus of elasticity is 0.22 to 5.4 GP

• Thermal Properties:
  • Thermal conductivity: Its thermal insulating properties are excellent. Thermal conductivity is in the range of insulators such as cork and asbestos.
  • Its coefficient of thermal expansion is 35 × 10–6/°C

• Solubility: Its solubility is highest among the cement. These cements disintegrate in oral fluids.
• Film Thickness: The film thickness of zinc oxide eugenol cement is 25 µm which is higher than other cement.
• Adhesion: It does not adhere to enamel or dentin.
• Biological Properties:
  • Effect on pulp: Its pH is 6.6 to 8.0. It is the least irritating to all the cement. Its effect on pulp is mild.
  • Bacteriostatic and obtundent properties: It stops the growth of bacteria and provides a soothing effect to the pulp.
  • Eugenol is irritating to the skin and eyes and can cause allergic dermatitis.
• Optical Property: Set cement is opaque.

Uses  of  Zinc Oxide Eugenol Cement: 

• For temporary cementation
• For temporary restoration
• Cavity liners and base
• Pulp capping agent
• Secondary use:
• Root canal restorations
• A periodontic bandage or surgical pack.