Question

Which of the following has the lowest modulus of elasticity?

• A. Co Cr
• B. M NiTi
• C. SS
• D. Beta titanium

Hint:

In orthodontic wires: SS and CoCr are stiffBeta titanium is intermediateNiTi has the lowest modulus and highest flexibility.

Answer 1

The Correct Option is B

Step 1: Understanding modulus of elasticity.
The modulus of elasticity (Young’s modulus) measures the stiffness of a materialA lower modulus means the material is more flexible and delivers lighter continuous forces
Step 2: Compare the materials.
(A) Co Cr (Cobalt Chromium): Has a high modulus of elasticityIt is relatively stiff and similar to stainless steel in rigidity
(C) SS (Stainless Steel): Has a high modulus of elasticity around 200 GPaIt is stiff and less flexible
(D) Beta titanium: Has a lower modulus than stainless steel but is still stiffer than NiTi
(B) M NiTi (Martensitic Nickel Titanium): Has the lowest modulus among theseIt is highly flexible and exhibits superelastic propertiesMaking it ideal for delivering light continuous forces
Step 3: Conclusion.
Since M NiTi is the most flexible and has the lowest stiffness among the given options, it has the lowest modulus of elasticity