MCQs on Oral Histology - Dentin Part 3

# Formula of hydroxyapatite crystal is :
A. Ca3(Po4)2.CaCO3
B. 3Ca3(Po4)2. Ca(OH)2
C. CaPo4. Ca(OH)2
D. None of the above

# The type of dentin that is formed prior to root completion is :
A. Inter tubular dentin
B. Peritubular dentin
C. Circumpulpal dentin
D. Secondary dentin

# Accentuated incremental lines in dentin due to disturbances in matrix and mineralisation process is:
A. Incremental lines of Retzius
B. Incremental lines of von Ebner
C. Contour lines of Owen
D. None of the above

# The pain transmission through dentin is :
A. Direct neural stimulation
B. Fluid or hydrodynamic theory
C. Transduction theory
D. All of the above

# Which of the following is correct ?
A. Reparative dentin is characterized by having fewer and more twisted tubules than normal dentin and may include odontoblasts
B. Dead tracts appear black in transmitted and white in reflected light
C. Sclerotic/transparent dentin appears transparent or light in transmitted light
D. All of the above


# First formed dental tissue :
A. Enamel
B. Dentin
C. Cementum
D. Bone

# Dentinal tubules are calcified in:
A. Sclerotic dentin
B. Secondary dentin
C. Primary dentin
D. Interglobular dentin

# Dentin formed throughout the life is:
A. Sclerotic dentin
B. Secondary dentin
C. Repartive dentin
D. All of the above

# Regarding teeth which statement is wrong ?
A. Enamel is harder than dentin
B. Enamel has no cells
C. Ameloblast secrete enamel and dentin
D. Odontoblast produce dentin

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MCQs on Oral Histology - Dentin Part 2

# The dentin receptors are unique because:
A. They elicit pain to hot and cold
B. They elicit pain to touch and pressure
C. They elicit pain to chemicals
D. Elicit only pain as a response

# The main bulk of dentin is formed by :
A. Peritubular dentin
B. Mantle dentin
C. Inter tubular dentin
D. Predentin

# The zone of dentin most recently formed and uncalcified is known as:
A. Mantle dentin
B. Circumpulpal dentin
C. Predentin
D. Secondary dentin

# Inter globular dentin results due to:
A. Failure of coalescence of calcospherites
B. Fracture of the dentin
C. Artifact in light microscopy
D. Disturbance in dentinal tubules

# Dentinogenesis by odontoblasts first behins at :
A. Pulpal end
B. Cusp tip
C. Tooth bud stage
D. Cervical area


# Sclerotic dentin has following features :
A. Caries susceptible
B. Insensitive
C. Hypersensitive
D. Resistant to caries

# The microhardness of dentin is about:
A. 1/2 that of enmel
B. 1/7 that of enamel
C. 1/4 that of enamel
D. 1/5 that of enamel

# Shape of the crown and the size of the roots is determined by:
A. Pulp
B. Dentin
C. Enamel
D. Cementum

# Physically and chemically, the dentin is closely related to:
A. Bone
B. Acellular cementum
C. Enamel
D. None of the above

# Organic portion can be separated from the mineral by :
A. Incineration / Organic chelation
B. Decalcification
C. Devitrification
D. Combustion

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MCQs on Oral Histology - Dentin

# Dentinal tubules are :
A. Concave
B. Straight
C. S-Shaped
D. None of the above

# The cells that form secondary dentin are:
A. Cementoblasts
B. Fibroblasts
C. Odontoblasts
D. Osteoblasts

# Dead tracts in ground section appears as:
A. Dentinal tubules
B. Coarse fibril bundles arranged at right angle to the dentinal surface
C. Black in transmitted light and white in reflected light
D. White in transmitted light and dark in reflected light

MCQs on Dental Caries Part 4

# Chemico-parasitic theory of dental caries is proposed by :
A. G.V. Black
B. Miller
C. Gottlieb
D. Schwartz

# Which of the following organisms is found in deep carious lesions rather than in incipient lesions ?
A. Streptococci
B. Lactobacilli
C. Veillonella
D. Bacteroides

# Pioneer bacteria in dental caries are in:
A. Enamel
B. Dentin
C. Pulp
D. Cementum

# The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a :
A. Significant increase in number of oral bacteria
B. Shift towards more acidogenic microflora
C. Significant decrease in number of oral bacteria
D. shift towards more aerobic microflora

# Ammonia causes:
A. increase in plaque formation
B. increase in calculus formation
C. decrease in plaque formation
D. precipitation of salivary proteins

# Cavity formation in a tooth, due to dental caries is due to:
A. Destructive potential of Streptococcus mutans
B. Destructive potential of Lactobacillus acidophilus
C. Lateral spread of caries along DEJ and weakening of the outer covering enamel
D. Mastectomy force and unrelated to the extent of carious process


# Animals maintained in a germ free environment did not develop caries fed on a high carbohydrate diet is given by:
A. Gottlieb
B. Miller
C. Snyder
D. Orland and Fizgerald

# Which of the following factors in the Stephan's curve is related to the caries incidence and sugar intake ?
A. Physical form of sugar
B. Frequency of sugar intake
C. pH of plaque
D. Quantity of sugar intake

# Initiation of caries by Streptococcus mutans is by the production of the :
A. Dextranase and soluble dextran
B. Insoluble dextran and glycosyl transferase
C. Soluble dextran and glycosyl transferase
D. None of the above

# The attachment of Actinomyces species to the tooth surface is facilitated by:
A. Fimbriae
B. Cilia
C. Flagella
D. Pseudopodia

# Caries associated with pre-eruptive enamel hypoplasia:
A. Secondary caries
B. Chronic caries
C. Occult caries
D. Incipient caries

# Bacteria free zone of dentinal caries is :
A. Zone of decomposed dentin
B. Zone of bacterial invasion
C. Zone of decalcification
D. Zone of dentinal sclerosis

# The legend of worms, endogenous theories, chemical theories and parasitic theory are early theories explaining:
A. Dental caries
B. Gingivitis
C. Periodontitis
D. Osteomylitis

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