1. Maximum bends that can gives in which wire before fracture

a. B-Titanium
b. Co-Cr-Ni
c. Stainless steel
d. NiTi

ANSWER b

Co-Cr-Ni

• Elgiloy was developed by Elgin national company as the metal for precision syringe.
• It is also called as ELGILOY.
• The hardness, tensile strength and yield are same as 18-8 steel.
• Tarnish and corrosion resistance are excellent. .
• The main advantage of wire over stainless steel is easier to bend in the received state. So it is preferred in techniques easier to bend in the received state.
• It can also be heat treated afterwhere loops in arch wires are used. It can also be heat treated after manipulation to achieve a hardness approximately equal to that of manipulation to achieve a hardness approximately equal to that of stainless steel.
• Composition of Elgiloy

  Cobalt 40% Manganese 2% Chromium 20% Carbon 15% Nickel 15% Beryllium 0.04% Molybdenum 7%

• Manufactured in four tempers and each are color coded in increasing order of resistance.increasing order of resistance.
• Maximum strength of wire can be strength of wire can be obtained by a heat treatment at 1200F.
• It is recommended for use when considerable bending, soldering or welding in required. Heat treatment of blue Elgiloyin required.
• Heat treatment of blue Elgiloy increases its resistance to deformation.

2. Maximum friction is seen in which orthodontics wire

a. Stainless steel
b. Aj Wilcock
c. NiTi
d. B titanium

ANSWER d

Compared with stainless steel wires, beta-titanium wire has lower force magnitudes, a lower elastic modulus, higher springback (maximum elastic deflection), a lower yield strength, and good ductility, weldability, and corrosion resistance.

3. Tooth most likely to be displacement in case of mandibular arch crowding is

a. 1st molar
b. 2nd molar
c. 1st premolar
d. 2nd premolar

ANSWER d

4. In a patient with cleft lip and palatal speech problems occurs because of

a. Improper seal between palatal and nasal cavity
b. Improper seal between tongue and epiglottis
c. Poor lip muscle function
d. Tongue not able to touch teeth properly

ANSWER a

• Children with a cleft that affects their soft palate (the part towards the back of the throat) may have problems with speech that include sounding nasal.
• This is caused by the soft palate not being able to properly close off the mouth from the nose while speaking and therefore letting air escape through the nose.
• This is known as velopharyngeal impairment (VPI).
• Additionally, if there are still holes (fistulas) in the palate, this makes it difficult to make some consonant sounds such as s, z, sh which require placing the tongue there to make the sound.
• If teeth are missing or not in the right place, some dental sounds such as f and v may be more difficult to articulate.

5. Which of the following orthodontics wire cannot be soldered

a. NiTi
b. B-Titanium
c. Stainless steel
d. Cobalt-chromium

ANSWER b

SOLDERING is defined as the joining of metals by the fusion of filler metal between them, at a temperature below the solidus temperature of the metals being joined and below 450° C.

Titanium is a difficult metal to solder because it has a very low thermal conductivity. This means that heat does not easily pass through the metal, making it hard to create a strong joint