Dentosphere : World of Dentistry

 # An outstanding oral manifestation of achondroplasia is: A. Rampant caries B. Periodontal disease C. Overcrowding of teeth D. Supernumerary teeth The correct answer is C. Overcrowding of teeth. Achondroplasia is the most common form of short-limb dwarfism. It occurs in all races and with equal frequency in males and females. An individual with achondroplasia has a disproportionate short stature -- the head is large and the arms and legs are short when compared to the trunk length. Other signs are a prominent forehead and a depressed bridge of the nose. Many of these children die during the first year of life. Deficient growth in the cranial base is evident in many children that survive. Important: The maxilla may be small with the resultant crowding of the teeth. Note: A Class III malocclusion is very common. Remember: The oral manifestations of the following disorders in children: • Gigantism: enlarged tongue, mandibular prognathism, teeth are usually tipped to the buccal or lin...

 # 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

# Which out of the following is a contraindication for splenectomy ? A. Iatrogenic splenic rupture B. Thrombocytopenia C. Presence of bone marrow failure D. Hairy cell leukemia The correct answer is C. Presence of bone marrow failure. The only contraindication to splenectomy is the presence of marrow failure, in which the enlarged spleen is the only source of hematopoietic tissue. Ref: Harrison’s 18th Ed. 471

# Weight of a normal spleen is ? A. < 150 grams B. < 250 grams C. < 350 grams D. < 450 grams The correct answer is B. < 250 grams. Normal spleen weighs <250 grams. Ref: Harrison’s 18th Ed. 468