Dentosphere : World of Dentistry

 # Each milliliter of red cells contain how much elemental iron ? A. 1 mg B. 2 mg C. 3 mg D. 4 mg The correct answer is A. 1 mg. Each milliliter of red cells contains 1 mg of elemental iron. Ref: Harrison’s 18th Ed. 845

# The term "flexural strength" describes a material with the ability do which of the following? A. Be visually detectable in radiographs B. Sustain deformation without permanent change in size or shape C. Resist fracture during bending D. Resist the propagation of a crack The correct answer is C. Resist fracture during bending.  Flexural strength is the ability of a material to resist fracture while bending and is also known as modulus of rupture, bend strength, or fracture strength. The transverse bending test is most frequently employed to evaluate the flexural strength of a material using a 3-point flexural test technique. The flexural strength gives the highest stress experienced within the material at its moment of rupture. The significance of flexural strength is commonly expressed in class V cervical restorations.

# A material with a low tensile strength and high compressive strength can be described as which of the following? A. Ductile B. Malleable C. Resilient D. Brittle E. Tough The correct answer is D. Brittle.  Brittle materials can be hard solid materials that can withstand heavy compression but not tension. Brittle materials exhibit low tensile strength and may fracture or break instead of being deformed when under tensile stress. Ductile materials exhibit high tensile strength and low compressive strength, making them capable of being drawn into wires.

# Excessive segmentation of nucleus of neutrophils is a manifestation of ? A. Folate or vitamin B12 deficiency B. Iron deficiency C. Thalassemia D. Repeated blood transfusion The correct answer is: A. Folate or vitamin B12 deficiency. Nucleus of neutrophils normally contains up to four segments. Excessive segmentation (>5 nuclear lobes) is seen in folate or vitamin B12 deficiency & congenital neutropenia syndrome of warts, hypogammaglobulinemia, infections & myelokathexis (WHIM). Ref: Harrison’s 18th Ed. 473