MDS PREP
What is the typical depth of corrosion for most amalgam alloys?
1) 50 to 100 µm
2) 100 to 500 µm
3) 500 to 1000 µm
4) 1000 to 2000 µm
The average depth of corrosion for most amalgam alloys is 100 to 500 µm.
What is the maximum allowable creep for a 1-day-old amalgam specimen under a 36 MPa stress at 37°C according to ANSI/ADA Specification No. 1 (ISO 24234)?
1) 0.5%
2) 1%
3) 2%
4) 3%
The maximum allowable creep is 1% for amalgam quality according to the specification.
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 peak wavelength for light-activated dental composite resins?
1) 300-400 nm.
2) 400-500 nm.
3) 500-600 nm.
4) 600-700 nm.
Light-activated dental composite resins are usually cured with blue light at a peak wavelength of about 470 nm, which is absorbed by the photoinitiator, such as camphorquinone.
The impression for a diagnostic cast of a partial edentulous mouth should be taken in:
1) Impression wax
2) Modelling compound
3) Hydro-colloid
4) Hydro cal
Dental Materials Answer: 3
For making impressions of edentulous ridges, impression plaster and impression compound are considered to be useful. For partial edentulous mouth impressions, hydrocolloids are useful.
What is the minimum compressive strength required for lining materials?
1) 1.0 MPa
2) 3.0 MPa
3) 5.0 MPa
4) 10 MPa
Lining materials must have a minimum compressive strength of 5 MPa to withstand the forces in the oral cavity.
Which of the following shows highest permanent deformation following strain in compression :
1) Polysulphide impression material
2) Polyether impression material
3) Condensation silicones
4) Addition silicones
Dental Materials Answer: 1
For permanent deformation following strain in compression, ranking is mentioned below:
Polysulfide > polyethers > condensation silicone > addition silicone
What is the effect of acid etching on dentin bond strength?
1) It decreases bond strength.
2) It has no effect on bond strength.
3) It increases bond strength.
4) It is unpredictable.
Acid etching of dentin creates a micro porous surface that allows for better infiltration and mechanical interlocking of the bonding agent, leading to improved bond strength between the restorative material and the tooth structure.