Oral Biology Exam-3 (Quiz MCQ)

2.

Neonatal lines are present in:

All permanent teeth.
Permanent canines.
All deciduous & first permanent molar.
Premolars.

Correct Answer

A. All deciduous & first permanent molar.

Explanation

Neonatal lines are present in all deciduous and first permanent molars. Neonatal lines are growth lines that form in the enamel of teeth during the first few weeks of life. They are caused by the physiological stress experienced by the developing tooth during birth. These lines can be used by forensic scientists to determine the age of an individual at the time of birth. Since neonatal lines are only present in teeth that are present at birth, they are not found in permanent canines or premolars.

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3.

The downgrowth of an epithelial thickening buccal to the dental lamina is known as:

Vestibular lamina.
Linguo-alveolar Sulcus.
Lateral dental lamina.
Successional dental lamina.

Correct Answer

A. Vestibular lamina.

Explanation

The downgrowth of an epithelial thickening buccal to the dental lamina is known as the vestibular lamina. This structure plays a role in the development of the oral cavity and helps to form the vestibule, which is the space between the teeth and the inner lining of the cheeks and lips. The vestibular lamina is important for the proper alignment and eruption of the teeth. It is distinct from the other options provided, which are not directly related to the downgrowth of the epithelial thickening buccal to the dental lamina.

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4.

Calcified tissues of the tooth are derived from:

Ectoderm only.
Endoderm only.
Mesoderm only.
Ectoderm & Mesoderm.

Correct Answer

A. Ectoderm & Mesoderm.

Explanation

The calcified tissues of the tooth, such as enamel, dentin, and cementum, are derived from both the ectoderm and mesoderm. The ectoderm gives rise to the enamel organ, which forms the enamel, while the mesoderm contributes to the dental papilla, which develops into dentin and cementum. Therefore, both germ layers are involved in the formation of the calcified tissues of the tooth.

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5.

When prismless enamel is formed, the secretory ameloblast does not contain:

Rough endoplasmic reticulum.
Tome's process.
Tome’s fibers.
Secretory granules.

Correct Answer

A. Tome's process.

Explanation

Tome's process is a specialized extension of the ameloblast that is responsible for the deposition of enamel matrix during tooth development. It plays a crucial role in the formation of enamel. However, when prismless enamel is formed, the ameloblasts do not develop Tome's process. This absence of Tome's process is characteristic of prismless enamel formation. The other options, including rough endoplasmic reticulum, Secretory granules, and Tome's fibers, are all present in the secretory ameloblasts during enamel formation.

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6.

Hypocalcified areas in enamel are:

Enamel spindles.
Dentino-enamel junction.
Interprismatic substances.
Enamel tufts.

Correct Answer

A. Enamel tufts.

Explanation

Enamel tufts are hypocalcified areas in enamel. They are small, darkly stained areas that extend from the dentino-enamel junction towards the enamel surface. Enamel tufts are thought to result from irregularities during enamel development and are considered a normal variation in enamel structure. They are not associated with any pathological condition and do not cause any functional or aesthetic problems in the tooth.

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1

7.

Which of the following occurs during the early stage of eruption of a tooth:

Differentiation of the stratum intermedium.
Formation of the dental sac.
Formation of stellate reticulum.
Maturation of enamel.

Correct Answer

A. Maturation of enamel.

Explanation

During the early stage of tooth eruption, the maturation of enamel occurs. Enamel maturation is a process in which the enamel layer of the tooth becomes fully mineralized and hardened. This process involves the deposition of hydroxyapatite crystals, which give enamel its strength and durability. It is an important step in tooth development as it ensures that the tooth enamel is strong enough to withstand the forces of chewing and protect the underlying dentin and pulp. The differentiation of the stratum intermedium, formation of the dental sac, and formation of stellate reticulum are all processes that occur at later stages of tooth development.

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8.

During shedding of deciduous teeth, the pulp:

Plays an active role in the process.
Show sings of degeneration throughout.
Contain pulp stones.
Remains vital.

Correct Answer

A. Remains vital.

Explanation

During the shedding of deciduous teeth, the pulp remains vital. This means that the pulp, which is the innermost part of the tooth containing blood vessels and nerves, continues to be alive and functional. It provides nourishment to the developing permanent tooth underneath and helps in the process of tooth eruption. Unlike in permanent teeth where the pulp degenerates and forms pulp stones, the pulp in deciduous teeth does not show signs of degeneration and remains active.

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9.

Which would not be present in a ground section?

Inorganic crystals.
Odontoblast.
Interglobular space.
Dentinal tubules.

Correct Answer

A. Odontoblast.

Explanation

The ground section of a tooth typically includes various structures such as inorganic crystals (such as hydroxyapatite), interglobular spaces (areas with less mineralization), and dentinal tubules (microscopic channels within the dentin). However, odontoblasts are not part of the ground section. Odontoblasts are specialized cells found in the pulp of the tooth, responsible for producing dentin. Therefore, odontoblasts would not be present in a ground section.

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10.

In a developing tooth, if Hertwig's sheath and the epithelial diaphragm were cut before odontoblasts diffrentiation, the resulting tooth would exhibit:

No radicular dentin.
Intermediate cementum.
Bare dentin.
Accessory root canals.

Correct Answer

A. Bare dentin.

Explanation

If Hertwig's sheath and the epithelial diaphragm were cut before odontoblasts differentiation, the resulting tooth would exhibit bare dentin. Hertwig's sheath and the epithelial diaphragm are important structures that play a role in the formation of dentin and cementum. Hertwig's sheath guides the differentiation of odontoblasts, which are responsible for producing dentin. The epithelial diaphragm helps in the formation of cementum. If these structures are cut before odontoblasts differentiation, the tooth would lack the necessary guidance and support for dentin formation, resulting in bare dentin.

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1

Oral Biology Exam-3 (Quiz MCQ)

Shedding is predominantly the:

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Neonatal lines are present in:

The downgrowth of an epithelial thickening buccal to the dental lamina is known as:

Calcified tissues of the tooth are derived from:

When prismless enamel is formed, the secretory ameloblast does not contain:

Hypocalcified areas in enamel are:

Which of the following occurs during the early stage of eruption of a tooth:

During shedding of deciduous teeth, the pulp:

Which would not be present in a ground section?

In a developing tooth, if Hertwig's sheath and the epithelial diaphragm were cut before odontoblasts diffrentiation, the resulting tooth would exhibit: