tooth development Flashcards
Concrescence is:
a- An extra root or accessory roots in a formed tooth.
b- Distorted root or roots in a formed tooth.
c- A union of root structure of two or more teeth through cementum only.
d- A spherical projection on the cemental root surface.
C
What structure is formed in the crown first?
a- Enamel.
b- Cementum.
c- Pulp.
d- Dentine.
D
Which of the following induces the dental papilla cells to be differentiated into
odontoblasts?
a- Stratum intermedium.
b- Reduced enamel epithelium.
c- Inner enamel epithelium.
d- Outer enamel epithelium.
C
No basal lamina is found between the cells of the:
a- Stratum intermedium and inner enamel epithelium.
b- Outer enamel epithelium and the dental sac.
c- Inner layer of Hertwig’s sheath and the dental papilla.
d- Inner enamel epithelium and the dental papilla.
A
Which of the following is not a functional activity of the enamel organ:
a- Inducing the differentiation of Odontoblasts.
b- Secretion of enamel matrix.
c- Maturation of enamel.
d- Formation of cementum.
D
Which of the following is not derived from the dental organ:
a- Stellate reticulum.
b- Hertwig’s epithelial root sheath.
c- Odontoblasts.
d- Ameloblasts.
C
The stratum intermedium:
a- Induces dentin formation.
b- Is separated from the stellate reticulum by a basal lamina.
c- Develops in cap stage.
d- Is important for enamel maturation.
D
The dental organ
a- Develops from cells in the dental follicle.
b- Is a completely connective tissue structure.
c- Is a completely epithelial structure.
d- Is highly vascular, as ameloblasts require an enriched environment.
C
The enamel cord
a- Is an extension of the dental lamina.
b-Is an extension of the outer dental epithelium.
c- Is an extension of successional dental lamina
d-Extends from the stratum intermedium to the stellate reticulum.
D
Dental follicle cells
a- Differentiate into the ameloblast layer.
b- Differentiate into the odontoblast layer.
c- Are found within the dental organ.
d- Migrate to dentin surface of the root and differentiate into the cementoblast.
D
All of the following is the functions of The Stellate Reticulum except:
a- Keep Space for The enamel development.
b- Act as a reservoir for nutritive materials.
c- Act as a cushioned to protect ameloblasts.
d- Secretes alkaline phosphatase enzyme.
D
The epithelial root sheath of Hertwig disintegrates:
a- After odontoblastic differentiation & before dentin matrix formation.
b- After odontoblastic differentiation & dentin matrix deposition.
c- Before odontoblastic differentiation.
d- After cementum formation.
B
All of the following is a function of dental sac except:
a- Nutrition of enamel organ.
b- Formation of cementum.
c- Formation of periodontal ligament.
d- Formation of supporting alveolar bone.
D
The lateral dental lamina gives rise to:
a- Deciduous teeth .
b- Permanent successors.
c- Permanent molars.
d- Vestibular lamina.
A
The stratum intermedium:
a- Lies between outer enamel epithelium & stellate reticulum.
b- Is a transient structure.
c- Is rich in mucopolysaccharides.
d- Plays important role in enamel calcification.
D
The down growth of an epithelial thickening buccal to the dental lamina is
known as:
a- Vestibular lamina.
b- Linguo-alveolar Sulcus.
c- Lateral dental lamina.
d- Successional dental lamina.
A
The dental lamina is induced to proliferate into a tooth bud by the:
a- Basement membrane.
b- Nerve endings.
c- Ecto-mesenchyme.
d- Oral epithelium.
C
Calcified tissues of the tooth are derived from:
a- Ectoderm only.
b- Endoderm only.
c- Mesoderm only.
d- Ectoderm & Mesoderm.
D
A layer of cells that seems to be essential to enamel formation but does not actually secrete the enamel is:
a- Outer dental epithelium.
b- Stratum intermedium.
c- Reduced dental epithelium.
d- Vestibular lamina.
B