How many premolars are in each quadrant? - correct answer 2
Why do we use bases and liners? - correct answer We use them to protect the pulp, aid in
... [Show More] its recovery, or both.
What is important to place on tooth before you place the acrylic to make a squash temporary? - correct answer Vaseline
Basers and Liners may be used as what? - correct answer Sealers, Reinforcers, Insulators, Obtundents, and Pulp Stimulators.
What is the function of sealers? - correct answer To seal off the cavity preparation. Since they are very thin layers, they are known as liners.
Basic Functions of Sealers: - correct answer Seal off the openings of the cut Dentinal tubules and prevent chemical irritants from reaching the pulp. These materials seal off the microscopic space between the tooth surface and restoration while reducing the leakage of fluids around the restoration. This helps to prevent post operative sensitivity by reducing the infiltration or leakage of fluids and saliva at the margins of a new restoration.
Disadvantage of Sealers: - correct answer They cannot provide thermal insulation because they are too thin.
Types of Sealers: - correct answer Cavity Varnishes such as copalite.
Can Varnish be placed under an amalgam restoration? - correct answer Yes
No, because the solvent in the varnish may react with, or soften the resin and the monomer of the resin may dissolve the varnish. - correct answer Can varnish be placed under a composite restoration?
How do you apply varnish? - correct answer 1. Flush the completed preparation with water and air spray to remove all debris.
2. Dry the preparation.
3. Apply a thin coat of varnish with a microbrush. Cover all surfaces of the preparation. Be sure that if calcium hydroxide is indicated, it is placed prior to cavity varnish, and is set before applying the varnish.
4. Dry the varnish.
5. Reapply a second coat and dry.
What are Reinforcers? - correct answer Reinforcers are bases used to protect the pulp from the pressures exerted during amalgam placement (condensing).
Can a material be an insulator and reinforcer at the same time? - correct answer Yes. Example: ZOE (Zinc Oxide Eugenol).
What is the function of reinforcers? - correct answer The functions a material serves depend on its composition and how it is used in the cavity preparation; however, one basic function is to protect the pulp from the pressures exerted on the tooth during amalgam condensing.
Types of Reinforcers - correct answer Reinforcers can be any material that is placed in a relatively thick layer between the restorative material and the dentin and may be referred to as a base regardless of the purpose it serves. Any material placed as a thin coating between the restoration and the walls of the preparation may be called a liner and may not necessarily be a reinforcer. Insulators are reinforcers, BUT stimulators (calcium hydroxide) do not have the strength to be reinforcers, therefore they are liners.
What are insulators? - correct answer Insulators are also referred to as bases (cements used in thick layers) and are placed to insulate the pulp from thermal irritation. The material used as an insulator must be a poor thermal conductor. Because the insulation value of an insulator increases with its thickness, this material must have some body and strength to withstand the pressure used during condensation of amalgam restorations.
What are types of Insulators - correct answer ZOE: Zinc Oxide Eugenol is used as an insulating base and a reinforcer. The Eugenol in the liquid has a soothing effect on a painful, irritated pulp.
When can you use ZOE (Zinc Oxide Eugenol)? - correct answer You can use it as a base under amalgam restorations or as a temporary restoration.
Can ZOE be placed under composite restorations? - correct answer No because it interferes with the setting reaction of unfilled and filled composite resin materials.
What is Zinc Phosphate Cement and how is it used? - correct answer This material is used as an insulator and reinforcer. This powder-liquid system is primarily zinc oxide with smaller amounts of silicon dioxide and magnesium oxide. The main ingredient is phosphoric acid. This phosphoric acid is chemically irritating to the pulp. This material has the strength to function as a reinforcer. The setting reaction is exothermic (heat releasing).
When using Zinc Phosphate Cement, what can happen during the setting reaction process? - correct answer It can be irritating to the pulp. Because cements are placed in deep prepared areas, the pulp should be protected from these problems by using varnish or a non irritating liner between the Zinc phosphate cement and the dentin.
What are zinc poly acrylic cements? - correct answer Also called carboxylate or polycarboxylate cements, used and insulators and reinforcers. The liquid solution is a viscous mixture of polyacrylic acid (40%) in water. This material is weaker than Zinc Phophate Cement, but it is less irritating to the pulp.
What is an example of Zinc Poly Acrylic Cement? - correct answer Durelon
What is a disadvantage of polycarboxylate cement? - correct answer Poor handling characteristics.
What are Obtundents? - correct answer They have the ability to soothe the sensitive pulp or reduce the irritability of a pulp. In a situation where a tooth has undergone trauma that caused pulpitis and pain, these will decrease the reaction and reduce the pain. Eugenol or (oil of clove) commonly serves as these in dentistry and is found in the ZOE cements.
What are Pulp Stimulators? - correct answer Are used in deep cavity preparations to stimulate a thickening of the dentin layer. [Show Less]