MDS PREP
What is the primary function of a base material in dental restoration?
1) To seal the tooth from microleakage
2) To provide insulation from thermal changes
3) To reinforce the tooth structure
4) To enhance the aesthetics of the restoration
A base material in dental restoration is primarily used to provide a seal against microleakage.
What is the chemical structure of Giomers?
1) They contain fluoraluminosilicate glass and silica-filled urethane resin.
2) They are purely organic ceramic-filled polymers.
3) They are a combination of glass ionomer and resin-modified glass ionomer.
4) They have a matrix of polyacrylic acid and ceramic filler particles.
Giomers are a combination of fluoraluminosilicate glass and silica-filled urethane resin. This unique composition allows for the release of fluoride and improved physical properties compared to traditional composites.
What is the maximum allowable level of mercury in the blood according to the given information?
1) 1 µg/L
2) 3 µg/L
3) 5 µg/L
4) 10 µg/L
The maximum allowable level of mercury in the blood is specifically mentioned as 3 µg/L in the provided text.
What is the ideal consistency of a luting agent according to ANSI/ADA Specification No. 96 (ISO 9917)?
1) Thixotropic
2) Plastic
3) Thin film
4) Putty
The ideal luting agent consistency is not explicitly mentioned in the text, but it should be able to flow into a film less than 25 µm thick without fragmentation.
Which of the following cements bonds to tooth structure, which has an anticariogenic effect, has a degree of translucency and does not irritate the pulp?
1) Polycarboxylate cement
2) Resin cement
3) Silicate Cement
4) Glass ionomer cement
Dental Materials Answer: 4
Chelation of carboxyl groups of the polyacids with the calcium in the apatite of enamel and dentin is the main mechanism through which glass ionomer bonds to tooth structure.
Glass ionomers release fluoride which results in the inhibiton of the progression of secondary caries. GIC is relatively biocompatable.
They elicit a greater pulp reaction as compared to ZnoE but generally less compared to zinc phosphate cement.
How does the degree of polymerization affect the strength of resin?
1) There is no correlation between the two
2) Higher degree of polymerization results in increased strength
3) Lower degree of polymerization results in increased strength
4) The strength is unaffected by the degree of polymerization
A higher degree of polymerization in resins generally correlates with greater strength, as more polymer chains are formed and cross-linked.
If a partially set material is seated, the die material obtained from such impression will be
1) Oversized
2) Undersized
3) Retains its dimension due to elasticity of the material
4) Dimensions will be un changed but may leave a rough surface
Dental Materials Answer: 2
If Impression tray comprising of elastomeric impression material is seated too late as elasticity starts to develop, raised seating pressure is applied to overcome the stiffness of impression material.
Because of recovery of excessive elastic deformation there is development of distortion
The die produced in the inaccurate impression is too narrow and too short.
What is the function of ZnO in Gutta Percha?
1) To increase flexibility
2) To improve thermal insulation
3) To enhance radio-opaque properties
4) To form the matrix of Gutta Percha
ZnO is a filler in Gutta Percha, and it improves the strength and flexibility of the material.