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

there is 2 different short answer questions

answer them with detail as much as possible

NO in-text referencing just at the bottom of the text

no intro or conclusion needed

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)