Dentosphere : World of Dentistry

# Among the natural radiation, the one that contributes to more radiation exposure of general population: A. Cosmic B. Terrestrial C. Radon D. Consumer products # X rays cause radiation damage primarily by their property of: A. Penetration B. Radioactivity C. Electromagnetic induction D. Ionisation

# The most radiosensitive cells in the body are: A. Endothelial cells B. Epithelial cells C. Red blood cells D. White blood cells The correct answer is D. White blood cells.

# Identical twins are produced by fertilization of: A. 1 ovum by 1 sperm B. 2 ova by 1 sperm C. 1 ovum by 2 sperms D. 2 ova by 2 sperms The correct answer is: A. 1 ovum by 1 sperm Twins can be either  monozygotic  ('identical'), meaning that they develop from one  zygote , which splits and forms two  embryos , or  dizygotic  ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell.

# The leading cause of childhood gingivostomatitis in children aged 1 to 3 is: A. Herpes Simplex B. Chicken pox C. Influenza D. Rubella The correct answer is A. Herpes simplex The primary infection (primary herpetic gingivostomatitis) usually occurs in a chlld  under ten years of age who has had no contact with the Type I herpes simplex virus  and who therefore has no neutralizing antibodies. It may also affect young adults (15-25).  Nearly all primary infections are of the subclinical type (they may only have flu-  like symptoms) and one or two mild sores in the mouth which go unnoticed by the  parents. In other children, the primary infection may be manifested by acute symptoms (acute  herpetic gingivostomatitis). These include fever; irritability; cervical lymph adenopathy; fiery red gingival tissues; and small, yellowish vesicles that rupture  and result in painful ulcers on the free and attached mucosa. The most serious  potentia...