A. Tooth buds and salivary glands
B. Nerve and muscle tissue
C. Hair and nails
D. Cartilage
# The most radiosensitive cells in the body are:
A. Endothelial cells
B. Epithelial cells
C. Red blood cells
D. White blood cells
# Radiation caries is caused by irradiation of:
A. Salivary glands
B. Enamel
C. Enamel and dentin
D. Oral mucosa
# Teeth affected by radiation hazard show:
A. Occlusal caries
B. Proximal caries
C. Chronic caries
D. Rampant caries
# The most radioresistant organ is:
A. Cartilage
B. Gonads
C. Lungs
D. Lymphoid
# Which type of radiation effect results in radiation induced thyroid cancer?
A. Somatic
B. Genetic
C. Teratogenic
D. Autosomal
# Most susceptible to radiations are:
A. Nucleic acids
B. Nerve cells
C. Muscle cells
D. Epithelial cells
# The skin of a patient undergoing radiotherapy will show after two weeks:
A. Erythema
B. Depigmentation
C. Radiation induced carcinomas
D. No change
# Effect of radiation is:
A. Cumulative
B. Fractionalized
C. Concentrated
D. Dependent on genetic makeup of individuals
# Decay of enamel following radiotherapy is initiated due to:
A. Decrease in salivary flow
B. Direct radiations contacting the enamel
C. Dessication of tooth structure
D. Hypocalcification and pitting of enamel
# A patient requires tooth extractions from an area that has been subjected to radiation therapy. Which of the following represents the greatest danger to this patient?
A. Alveolar osteitis
B. Osteoradionecrosis
C. Prolonged healing time
D. Fracture of the mandible
# Complication of irradiation of mouth may include all except:
A. accelerated caries activity
B. caries in unusual sites
C. accelerated periodontal diseases
D. Xerostomia
# X rays causes radiation damage primarily by their property of:
A. Penetration
B. Radioactivity
C. Electromagnetic induction
D. Ionisation
# The somatic non stochastic effect of radiation is seen:
A. as effects on the body irradiated
B. as effect of mutation
C. as hereditary phenomenon
D. all of the above
# Radiation's effect on blood supply:
A. Anemia
B. Endarterities of small blood vessels
C. Infection
D. All of the above
# Which of the following cells is most radioresistant?
A. Early precursor cells of erythroblastic series
B. Muscle cells
C. Fibroblasts
D. Vascular endothelial cells
# Osteoradionecrosis is due to:
A. Endarteritis of blood vessels
B. Damage to periosteum
C. Damage to Lymphatics
D. All of the above
# Compared with calcium tungstate screens, rare earth screens decrease patient exposure by about:
A. 15%
B. 35%
C. 55%
D. 75%
# Radiation injury to the hematopoietic system of the bone marrow occurs when the whole body exposure ranges between:
A. 50-100 rads
B. 200-1000 rads
C. 1000-5000 rads
D. 10000 rads and more
# Radiation causes cell death by:
A. Charring of nucleoproteins
B. Destroying their mitochondria
C. Ionization
D. Disruption of cytosol
# A patient who has been given tumoricidal dose of radiotherapy recently reports to dental clinic with painful carious exposed mandibular first molar with periapical abscess. The treatment of choice should be:
A. Extraction of the offending tooth
B. Root canal treatment if possible
C. No treatment should be given
D. Incision and drainage of abscess
# A patient with a history of radiation therapy requires special consideration because:
A. The vascularity of the bone may be disrupted
B. Salivary function may be increased
C. Plaque accumulation greater than normal can be expected
D. The potential for periodontal disease is greatly increased
# In radiobiology, the 'latent period' represent the perio of time between:
A. Cell rest and cell mitosis
B. The first and last dose in radiation therapy
C. Film exposure and image development
D. Radiation exposure and onset of symptoms
# The component of cell most affected by radiation is:
A. Cell wall
B. Cell membrane
C. Cytoplasm
D. DNA
# Which of the following is most sensitive to radiation induced cancer?
A. Skin
B. Thyroid
C. Nerve
D. Female Breast
# First complication after radiotherapy is:
A. Mucositis
B. Candidiasis
C. Alopecia
D. Xerostomia
# Osteoradionecrosis results from:
A. Infection, trauma, radiation
B. Radiation, trauma, infection
C. Trauma, radiation, infection
D. None of the above
# Radiation caries occurs due to all of the following EXCEPT:
A. Bone defects
B. Fibrosis of salivary glands
C. Decreased flow of saliva
D. Low pH of saliva
# Phase of cell division most sensitive to radiation is:
A. G1 phase
B. G2 phase
C. S phase
D. None of the above
# Mitotic delay is longer with:
A. Smaller dose
B. Moderate dose
C. Large dose
D. Both A and B
# Most radiosensitive cells are:
A. Vegetative intermitotic cells
B. Differential intermitotic cells
C. Reverting post mitotic cells
D. Fixed post mitotic cells
# One of the following is not capable of replication:
A. Neuron
B. Liver
C. Kidney
D. None of the above
# Reduced salivary flow following irradiation is dose dependent. At what dose does the flow reach essentially zero?
A. 4000 rads
B. 5000 rads
C. 6000 rads
D. 7000 rads
# Which layer of epithelium of oral mucous membrane is more sensitive to radiation ?
A. Stratum spinosum
B. Stratum granulosum
C. Stratum basale
D. Stratum corneum
# Which consequence does not occur due to radiation?
A. Decreased visual acquity
B. Altered taste
C. Xerostomia
D. Mucositis
# Which of the following is not a type of particulate radiation?
A. Alpha particles
B. Beta particles
C. Protons
D. Nucleons
# Fixed post mitotic cells are:
A. Spermatocytes
B. Fibroblasts
C. Endothelial cells
D. Muscle
# All of the following are true except:
A. Use of speed-E film reduces radiation exposure
B. Use of rectangular collimator decreases density
C. Use of rectangular collimator is indicated to decrease the radiation exposure
D. Use of collimator is recommended to reduce the size of X-ray production
# The best method to reduce radiation caries is application of viscous:
A. 0.5% neutral Sodium Fluoride gel
B. 1% neutral sodium fluoride gel
C. 0.5% stannous fluoride gel
D. 1% Stannous fluoride gel
# Deterministic effects of radiation are those effects in which the severity of response:
A. is proportional to the dose.
B. is determined by the operator.
C. depends on composition of tissue.
D. depends on volume of exposed tissue.
# In case of nasal fracture, the following radiograph is used:
A. Submentovertex view
B. Lateral skull view
C. Transorbital view
D. OPG
# Cells are most sensitive to radiation in:
A. G2 phase
B. G1 phase
C. G1 phase and early S phase
D. G2 phase and late S phase
# Months or years following radiotherapy, the irradiated oral mucosa:
A. undergoes necrosis
B. Develops candidiasis
C. Becomes atrophic
D. Develops granulomatosis
# The most common type of radiation caries is:
A. Cervical surface involvement of teeth
B. Widespread superficial lesion attacking buccal, occlusal, incisal, and palatal surfaces
C. Spreading to occlusal and palatal surfaces
D. Dark pigmentation of the entire crown
# Marx-University of Miami protocol for osteoradionecrosis is related to:
A. High dose antibiotic therapy
B. Hyper baric oxygen therapy
C. Both A and B
D. None of the above
# Following organ is least radiosensitive to the effects of exposure to radiation:
A. Testis
B. Bone marrow
C. Muscle
D. Intestine
# Management of osteoradionecrosis would require all of the following except:
A. Antibiotic coverage
B. Hyperbaric oxygen
C. Fluoride application
D. Non removal of sequestrum
# True about X rays is:
A. X rays do not damage structure of all kind of biologic cells
B. In adult cell, the effect of radiation are short term and reversible
C. Only central rays are harmful to patients
D. None of the above
# Which of the following is least radiosensitive tissue?
A. WBC, Bone, cells, Epithelial cells
B. Muscle cells, nerve cells, bone cells
C. Connective tissue cell, endothelial cell, muscle cell
D. RBC, Muscle cell, nerve cell
#