What is meant by fatigue failure and why is it important for dental materials

Q1: What is meant by fatigue failure and why is it important for dental materials? (250 words)

Define the terms i) fatigue life, ii) fatigue strength and iii) fatigue (endurance) limit.

Q2a: Describe the function of a plasticiser and give an example of a dental material in which one is used.(250 words)

b: Name a plasticiser you know of, and briefly outline its biocompatibility(50 words)