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What Can Medical Office Personnel Do to Assist the Physician in Maintaining Compliance with the Controlled Substances Act?

  • Date Submitted: 03/12/2015 08:28 AM
  • Flesch-Kincaid Score: 36.6 
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Abstract
Zinc oxide-eugenol cements are considerably better tolerated by tissue than other dental materials. As they alleviate pain and are bacteriostatic and antiseptic, they are well tolerated by patients. The cements are good insulators and possess better sealing properties than zinc phosphate cements. Because of their poor mechanic properties, the conventional zinc oxide-eugenol cements are mainly used as temporary fixing contents and filling materials, for gingival dressings and together with filling materials as impression materials. Recently, reinforced zinc oxide-eugenol cements and cements containing ethoxy benzoic acid (EBA) have been developed. These new cements have considerably better mechanic properties and are therefore used for cement bases, indirect capping, long-term temporary fillings and in selected cases as definite fixing cements.
CHEMISTRY
Constituents of a typical zinc oxide eugenol paste are:
BASE PASTE
Zinc oxide
Inert oils (plasticiser)
  * Hydrogenated resins (increases setting time and improves cohesion)
REACTOR PASTE
  * Eugenol
  * Zinc acetate (accelerator)
  * Fillers (talc or kaolin)
Some pastes contain a substitute for eugenol e.g. a carboxylic acid.
The 2 pastes come in contrasting colours and are dispensed in a 1:1 ratio. They are mixed to give a paste of even colour. The setting reaction is shown below:
ZINC OXIDE (excess) | | ZINC OXIDE (UNREACTED) |
+ |  | + |
EUGENOL | | EUGENOL |
The set material contains both some unreacted zinc oxide and eugenol.
Any movement of the tray as the paste is hardening will lead to a deformed, inaccurate impression.
Setting time depends on:
1. Accelerator additives (e.g. zinc acetate, acetic acid)
2. Exposure to moisture on mixing or the addition of water will accelerate the reaction
3. Increasing temperature causes a faster setting reaction
Setting time is normally 4-5 minutes.
PROPERTIES
  * Non toxic
  * Adherence to tissues
  * Mucostatic or...

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