MDS PREP
What is the primary use of zinc oxide-eugenol (type III) temporary cement?
1) For permanent cementation
2) For immediate post-operative treatment of sensitivity
3) For long-term temporary cementation
4) For trial of the metal framework
The general use of type III zinc oxide-eugenol temporary cement is for immediate post-operative treatment of sensitivity and to reduce post-operative sensitivity before placing a permanent restoration.
What is the typical particle size range of the fillers in conventional, microfilled, and hybrid composites?
1) Conventional: 8-12 µm, Microfilled: 0.04-0.4 µm, Hybrid: 0.1-0.01 µm
2) Conventional: 1-5 µm, Microfilled: 0.04-0.4 µm, Hybrid: 0.01-0.1 µm
3) Conventional: 8-12 µm, Microfilled: 0.01-0.05 µm, Hybrid: 0.5-1 µm
4) Conventional: 0.01-0.1 µm, Microfilled: 0.1-0.5 µm, Hybrid: 0.5-1 µm
The particle size of the fillers in composite materials affects their physical and handling properties. Conventional composites have larger filler particles, while microfilled and hybrid composites have smaller ones. The text provides the typical ranges for each type of composite.
What is the primary function of a luting agent in the context of dental restorations?
1) To bond the restoration to the tooth
2) To provide a protective barrier against bacteria
3) To insulate the tooth from thermal changes
4) To fill in gaps caused by tooth decay
A luting agent's primary function is to bond the restoration to the tooth and enhance its retention.
What is the typical range of pH for acidic dental cements?
1) pH > 7
2) pH 7-10
3) pH 4-7
4) pH < 4
Acidic dental cements typically have a pH less than 7.
What is the effect of adding potassium sulfate to gypsum-based materials?
1) It accelerates the setting reaction.
2) It retards the setting reaction.
3) It increases the porosity.
4) It has no effect on the setting reaction.
Potassium sulfate acts as an accelerator by increasing the solubility of the hemihydrate and promoting the formation of dihydrate, which speeds up the setting process.
What is the minimum 24-hour compressive strength required for dental cement according to ANSI/ADA Specification No. 96 (ISO 9917)?
1) 50 MPa
2) 70 MPa
3) 100 MPa
4) 150 MPa
The text states that the standard luting consistency of dental cement must exhibit a minimum 24-hour compressive strength of 70 MPa.
In orthodontic wire selection, what is the benefit of using a wire with a high load deflection rate?
1) It provides a constant force over a wider range of tooth movements.
2) It is more suitable for areas requiring minimal tooth movement.
3) It is less prone to permanent deformation during activation.
4) It has a steeper force-deflection curve.
In orthodontics, wires with a high load deflection rate are beneficial in areas where minimal tooth movement is desired, such as in maximum anchorage extraction cases or during finishing.
Which of the following is NOT a type of zinc phosphate cement?
1) Type I
2) Type II
3) Type III
4) Type IV
Type IV is not a recognized classification for zinc phosphate cements.