Which of the following description of the mandibular first premolar is incorrect? ()
A. They are the smallest premolars.
B. The difference of the buccal cusp and the lingual cusp height is the largest.
C. There are transverse ridges on the occlusal surface.
D. The buccal cusp is offset toward the distal.
E. There is a crescent-shaped bucco-cervical ridge.
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Which of the following description of the maxillary canine is incorrect? ()
A. The labial axial ridge is on the labial surface.
B. The lingual axial ridge is on the lingual surface.
C. The cusp tip is offset toward the distal.
D. The cusp tip is offset toward the mesial.
E. The cross section of tooth root is rounded triangle
The permanent teeth that erupt at the age of six and do not to replace any deciduous teeth are the ()
A. central incisors
B. lateral incisors
C. canines
D. premolars
E. first molars
What will cause gingival atrophy when the teeth are impacted directly by food? ()
A. Irregular crown shape
B. Normal crown convexity
C. Undersized crown convexity
D. Oversized crown convexity
E. None of the above is true.
As for the physiological characteristics of tooth eruption, which one is incorrect? ()
A. It follows certain order.
B. It happens within a specific period of time.
C. The left and right teeth erupt symmetrically at the same time.
D. The mandibular teeth erupt a little earlier than the maxillary counterparts.
E. The same type of teeth of the mandibular and maxillary counterparts erupt simultaneously
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