Zinc Oxide Eugenol Cement
July 9th, 2008 / No Comments » / by admin
These cements have been in dentistry since 1890’s, and these are low strength cements they are of 4 types depending of use of the cement.
Classification
Type 1 ZOE - For temporary cementation
Type 2 ZOE - For permanent cementation
Type 3 ZOE - Temporary filling and thermal insulation
Type 4 ZOE - Cavity liners
These cements are available in forms of powder/liquid or in 2-paste systems. They are available in commercial names Tempac, Cavitic and Tempbond. There are other special type of cements such as EBA Alumina modified ZOE Cement, Polymer modified ZOE Cement and Non-Eugenol cement.
Composition
Powder has ingredients such as Zinc oxide, White rosin, Zinc stearate, Zinc acetate and Magnesium oxide. White rosin is helpful in reducing the brittleness of the cement. Compounds of zinc are used as accelerators.
Liquid has ingredients such as Eugenol and Olive oil. Eugenol reacts with Zinc oxide during setting and Olive oil acts a plasticizer.
Properties
- This cement sets in a time of 4-10 minutes.
- The compressive strength of the cement depends on its type, i.e. luting cements have lower strength that restorative cement. Generally the compressive strength varies from 3-55 MPa.
- These are not used in final cementation of crowns and bridges as they do not adhere well to the dentin/enamel of the tooth.
- These are the least irritataing cements of all the dental cements. pH of these cements range from 6.6 to 8.0
- ZOE cements have property of inhibiting bacterial growth, and also provides soothing effect on the deep cavities of the pulp, thus reducing pain.
Modified Zinc Oxide-Eugenol Cements
These cements were introduced to provide the improved mechanical properties of traditional ZOE cement.
There are 2 kinds of modified ZOE cements -
1. EBA-Alumina modified cements
2. Polymer reinforced ZOE cements
EBA-Alumina modified cement has Zinc oxide and Alumina in Powder and EBA, Eugenol in liquid. These have higher compressive strengths. And setting time is near to 9-10 minutes.
Polymer reinforced cements have Zinc oxide, natural and synthetic resins in Powder and Eugenol, acetic acid, thymol in Liquid.
