A. Produced by ameloblasts
B. Found in the region of cusps
C. Surrounded by inter prismatic enamel
D. Terminated as rounded process
# Ionic exchange between enamel surface and environment :
A. Does not take place once enamel matures
B. Stops after 2 years of eruption
C. Continues till adult life
D. Continues throughout life
# Approximately how many enamel rods will be present in maxillary molar?
A. 5 million
B. 7 million
C. 9 million
D. 12 million
# All are true about the striae of Retzius except:
A. Constitute the rest lines within the enamel rods
B. Have high inorganic content
C. They are areas of increased porosity
D. Allow the movement of water and small ions
# Neonatal lines are found in all of the following except :
A. Enamel of primary incisors
B. Enamel of premanent canines
C. Enamel and dentin of permanent first molars
D. Dentin of permanent mandibular incisors
# On microscopic examination, enamel rods have :
A. Keyhole appearance in cross section
B. Paddle appearance in cross section
C. Lanullate appearance in cross section
D. None of the above
# Which of the following structures is not of ectodermal origin ?
A. Hunter Schreger bands
B. Enamel spindles
C. Enamel Tufts
D. Enamel lamellae
# The formative cells of which of the following dental tissues disappear once tissue is formed ?
A. Enamel
B. Dentin
C. Periodontal ligament
D. Cementum
# Which of the following tissues have no reparative capacity ?
A. Enamel
B. Dentin
C. Cementum
D. Periodontal ligament
# The enamel has no capacity of self repair because :
A. It has only small percent of organic content
B. Its formative cells are lost once it is completely formed
C. It is essentially a keratin tissue and has no blood vessels
D. It has no direct connection with the active cells of the dental pulp