Oral Biology Exam-1 (Quiz MCQ)
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19/12--------24/12: Exam 1:Quiz (MCQ in: studied subjects + Slides identification).
- 1.
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.
Correct Answer
A. Stratum intermedium and inner enamel epithelium.Explanation
The basal lamina is a thin layer of extracellular matrix that separates epithelial cells from underlying connective tissue. In this case, the correct answer is "Stratum intermedium and inner enamel epithelium" because no basal lamina is found between these two cell layers. The basal lamina is present between the outer enamel epithelium and the dental sac, as well as between the inner layer of Hertwig's sheath and the dental papilla. However, it is absent between the stratum intermedium and inner enamel epithelium.Rate this question:
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- 2.
Passive eruption is:
- A.
Growth in the length of the root.
- B.
Apical migration of the junctional epithelium.
- C.
Deposition of bone at the fundus.
- D.
The formation of cellular cementum.
Correct Answer
B. Apical migration of the junctional epithelium.Explanation
Passive eruption refers to the natural process where the junctional epithelium, which is the tissue that attaches the gum to the tooth, migrates apically or towards the root of the tooth. This migration exposes more of the tooth's surface, resulting in an increase in the length of the clinical crown. It is a normal physiological process that occurs as a person ages. The other options mentioned, such as growth in the length of the root, deposition of bone at the fundus, and the formation of cellular cementum, are not related to passive eruption.Rate this question:
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- 3.
Which of the following has the highest mineral content?
- A.
Predentin.
- B.
Peritubular dentin.
- C.
Intertubular dentin.
- D.
Cementum.
Correct Answer
B. Peritubular dentin.Explanation
Peritubular dentin has the highest mineral content among the given options. Dentin is a calcified tissue that makes up the majority of the tooth structure. It consists of tubules, and peritubular dentin surrounds these tubules. Peritubular dentin is highly mineralized, containing a higher concentration of hydroxyapatite crystals compared to other types of dentin. This high mineral content gives it greater hardness and resistance to decay. Therefore, peritubular dentin is the correct answer as it has the highest mineral content among the options listed.Rate this question:
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- 4.
The complex arrangement of rods over the cusps of teeth is termed:
- A.
Prismless enamel.
- B.
Prenatal enamel.
- C.
Gnarled enamel.
- D.
Postnatal enamel.
Correct Answer
C. Gnarled enamel.Explanation
Gnarled enamel refers to the complex arrangement of rods over the cusps of teeth. This term is used to describe the twisted and interwoven pattern of enamel rods that form the outer layer of the tooth. It is a characteristic feature of the occlusal surface of molars and premolars, providing strength and resistance to wear and tear. Prismless enamel, prenatal enamel, and postnatal enamel do not specifically refer to the complex arrangement of rods over the cusps of teeth.Rate this question:
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- 5.
Dilaceration is:
- A.
Distorted root or roots in a formed tooth.
- B.
An extra root or accessory 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.
Correct Answer
A. Distorted root or roots in a formed tooth.Explanation
Dilaceration refers to the condition where the root or roots of a formed tooth are distorted. This means that the root structure is not in its normal, straight form but instead appears twisted or bent. This can occur due to trauma or developmental abnormalities during tooth formation.Rate this question:
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- 6.
Ameloblasts having ruffled borders are:
- A.
Secretory ameloblasts.
- B.
Maturative ameloblasts.
- C.
Protective ameloblasts.
- D.
Transitional ameloblasts.
Correct Answer
B. Maturative ameloblasts.Explanation
Ameloblasts are cells that are responsible for the formation of tooth enamel. They go through different stages during enamel formation. The stage where ameloblasts have ruffled borders is known as the maturative stage. During this stage, the ameloblasts are actively secreting enamel proteins and mineralizing the enamel matrix. The ruffled borders increase the surface area of the ameloblasts, allowing for more efficient secretion and mineralization. Therefore, the correct answer is maturative ameloblasts.Rate this question:
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- 7.
The inter-globular dentin is found:
- A.
Near the amelo-cemental junction.
- B.
In the root dentin.
- C.
Near the amelo-dentinal junction.
- D.
Near the dentino-cemental junction.
Correct Answer
C. Near the amelo-dentinal junction.Explanation
The inter-globular dentin is found near the amelo-dentinal junction. This junction is the area where the enamel and dentin meet in the tooth. Inter-globular dentin refers to areas of dentin where the mineralization process was incomplete, resulting in small gaps or spaces between the dentin globules. These gaps can be seen as dark spots or lines on a microscopic level. The inter-globular dentin is more commonly found near the amelo-dentinal junction because this is where the dentin formation starts during tooth development.Rate this question:
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- 8.
Which of the following is most likely to be found in the dentinal tubules:
- A.
Tomes' fibers.
- B.
Oxytalan fibers.
- C.
Tomes' process.
- D.
Thick collagen fibers.
Correct Answer
A. Tomes' fibers.Explanation
Tomes' fibers are most likely to be found in the dentinal tubules. Tomes' fibers are long cytoplasmic processes of odontoblasts that extend into the dentinal tubules. They are responsible for the secretion of dentin matrix and play a crucial role in dentin formation. Oxytalan fibers are found in the elastic fibers of connective tissues and are not typically present in dentinal tubules. Tomes' process refers to the secretory end of the odontoblast, which is also found in the dentinal tubules. Thick collagen fibers are not typically found in dentinal tubules.Rate this question:
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- 9.
Shrinkage of stellate reticulum begins:
- A.
At the cervical loop of the dental organ.
- B.
After complete formation of the crown.
- C.
At the middle portion of dental organ.
- D.
At the height of incisal edge or cusp.
Correct Answer
D. At the height of incisal edge or cusp.Explanation
The correct answer is "at the height of incisal edge or cusp." The stellate reticulum is a layer of cells in the enamel organ of a developing tooth. It starts to shrink at the highest point of the tooth, which is the incisal edge or cusp. This shrinkage is a part of the process of enamel formation and helps to shape the tooth's final structure.Rate this question:
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- 10.
The formation of the enamel matrix between two short increments needs:
- A.
One day.
- B.
Two days.
- C.
Three drays.
- D.
Four days.
Correct Answer
A. One day.Explanation
The formation of the enamel matrix between two short increments needs one day. This means that it takes one day for the enamel matrix to form between two small sections of enamel.Rate this question:
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