A restorative material which has a high proportional limit, compared with one with a lower proportional limit would have:: (A) Greater ductility, (B) Greater toughness, (C) A higher modulus of elasticity, (D) More resistance to permanent deformation
Answer is D. Proportional limit—Magnitude of elastic stress above which plastic deformation occurs.
A restorative material which has a high proportional limit, compared with one with a lower proportional limit would have more resistance to permanent deformation.
Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, 12th ed page no 48