The lack of food massage will cause gingival atrophy. This is mainly due to the()
A. zero convexity of the dental crown
B. oversized convexity of the dental crown
C. undersized convexity of the dental crown
D. normal convexity of the dental crown
E. irregular dental crown
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Which of the following is not one of the anatomical features of the mandibular central incisor?()
A. It has flat and straight incisal margin.
B. There is almost identical medial incisal angle and distal incisal angle.
C. There is pronounced developmental groove on the labial surface.
D. The incisal ridge is close to the dental long axis.
E. It has flat single root and the elongated depression is deeper on the distal surface than on the medial surface.
Which of the followings is the predilection site of the caries?()
A. the developmental groove
B. the fissure
C. the accessory groove
D. the fossa
E. all of the above
Which of the following descriptions about the developmental groove of the maxillary central incisor is correct?()
A. There are two longitudinal developmental grooves at the incisal half.
B. There are two longitudinal developmental grooves at the incisal third.
C. There is one longitudinal developmental groove at the incisal half.
D. There is one longitudinal developmental groove at the incisal third.
E. There is no developmental groove.
Which of the following is not the characteristics of the deciduous teeth?()
A. short and broad crown
B. small size
C. milky white color
D. narrow occlusal surface and protruded cervical ridge
E. broad crown and broad root of the deciduous anterior teeth
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