MCQs in Oral Histology

Chapter 1: Tooth development

  

 

1-Concrescence is:

  1. An extra root or accessory roots in a formed tooth.
  2. Distorted root or roots in a formed tooth.
  3. A union of root structure of two or more teeth through cementum only.
  4. A spherical projection on the cemental root surface.

 

 

 

 

 

The answer is: C

 

2- What structure is formed in the crown first?

  1. Enamel
  2. Cementum
  3. Pulp
  4. Dentine

 

 

 

 

 

The answer is: D

 

3- Which of the following induces the dental papilla cells to be differentiated into odontoblasts?

  1. Stratum intermedium.
  2. Reduced enamel epithelium.
  3. Inner enamel epithelium.
  4. Outer enamel epithelium.

 

 

 

 

 

 

The answer is: C

 

4- No basal lamina is found between the cells of the:

  1. Stratum intermedium and inner enamel epithelium.
  2. Outer enamel epithelium and the dental sac.
  3. Inner layer of Hertwig's sheath and the dental papilla.
  4. Inner enamel epithelium and the dental papilla.

 

 

 

 

 

 

 

The answer is: A

 

5- Which of the following is not a functional activity of the enamel organ:

  1. Inducing the differentiation of Odontoblasts.
  2. Secretion of enamel matrix.
  3. Maturation of enamel.
  4. Formation of cementum.

 

 

 

 

 

 

The answer is: D

 

6- Which of the following is not derived from the dental organ:

  1. Stellate reticulum.
  2. Hertwig's epithelial root sheath.
  3. Odontoblasts
  4. Ameloblasts

 

 

 

 

 

 

 

The answer is: C

 

7- The stratum intermedium:

  1. Induces dentin formation.
  2. Is separated from the stellate reticulum by a basal lamina.
  3. Develops in cap stage.
  4. Is important for enamel maturation.

      

 

 

 

 

 

The answer is: D

 

8- The dental organ

  1. Develops from cells in the dental follicle.
  2. Is a completely connective tissue structure.
  3. Is a completely epithelial structure.  
  4. Is highly vascular, as ameloblasts require an enriched environment.

 

 

 

 

 

 

The answer is: C

 

9- The enamel cord

  1. Is an extension of the dental lamina.
  2. Is an extension of the outer dental epithelium. 
  3. Is an extension of successional dental lamina
  4. Extends from the stratum intermedium to the stellate reticulum.

 

 

 

 

 

 

The answer is: D

 

10-Dental follicle cells

  1. Differentiate into the ameloblast layer.
  2. Differentiate into the odontoblast layer.
  3. Are found within the dental organ.
  4. Migrate to dentin surface of the root and differentiate into the cementoblast.

                 

 

 

 

 

 

 

The answer is: D

                                                                                                      

11- All of the following is the functions of The Stellate Reticulum except:

  1. Keep Space for The enamel development.
  2. Act as a reservoir for nutritive materials.
  3. Act as a cushioned to protect ameloblasts.
  4. Secretes alkaline phosphatase enzyme.

 

 

 

 

 

 

The answer is: D

 

12- The epithelial root sheath of Hertwig disintegrates:

  1. After odontoblastic differentiation & before dentin matrix formation.
  2. After odontoblastic differentiation & dentin matrix deposition.
  3. Before odontoblastic differentiation.
  4. After cementum formation.

 

 

 

 

 

 

The answer is: B

 

13- All of the following is a function of dental sac except:

  1. Nutrition of enamel organ.
  2. Formation of cementum.
  3. Formation of periodontal ligament.
  4. Formation of supporting alveolar bone.

 

 

 

 

 

 

 

The answer is: D

 

14- The lateral dental lamina gives rise to:

  1. Deciduous teeth .
  2. Permanent successors.
  3. Permanent molars.
  4. Vestibular lamina.

 

 

 

 

 

 

The answer is: A

 

15- The stratum intermedium:

  1. Lies between outer enamel epithelium & stellate reticulum.
  2. Is a transient structure.
  3. Is rich in mucopolysaccharides.
  4. Plays important role in enamel calcification. 

 

 

 

 

 

 

 

The answer is: D

 

16- The down growth of an epithelial thickening buccal to the dental lamina is known as:

  1. Vestibular lamina.
  2. Linguo-alveolar Sulcus.
  3. Lateral dental lamina.
  4. Successional dental lamina.  

 

 

 

 

 

 

 

The answer is: A

 

17- The dental lamina is induced to proliferate into a tooth bud by the:

  1. Basement membrane. 
  2. Nerve endings.
  3. Ecto-mesenchyme.
  4. Oral epithelium.

 

 

 

 

 

 

 

The answer is: C

 

18- Calcified tissues of the tooth are derived from:

  1. Ectoderm only.
  2. Endoderm only.
  3. Mesoderm only.
  4. Ectoderm & Mesoderm.

 

 

 

 

 

 

 

The answer is: D

 

19- A layer of cells that seems to be essential to enamel formation but does not actually secrete the enamel is:

  1. Outer dental epithelium.
  2. Stratum intermedium.
  3. Reduced dental epithelium.
  4. Vestibular lamina.

 

 

 

 

 

 

 

The answer is: B

 

20- The stimulus that initiates the actual formation of enamel matrix seems to be:

  1. Reduction of stellate reticulum.
  2. Influence of increased vascularization of the dental sac.
  3. Disappearance of the cell free zone of dental papilla.
  4. Presence of predentin.

 

 

 

 

 

 

 

The answer is: D

 

21- The number of roots that are formed is determined by the:

  1. Number of root sheaths developed by the enamel organ.
  2. Number of medial ingrowths at the epithelial diaphragm.
  3. Number of root sheaths developed by the dental sac.
  4. Thickness of the cervical loop. 

 

 

 

 

 

 

 

The answer is: B

 

22- Which of the following is the first process to occur in the sequence of tooth development:

  1. Deposition of the first layer of enamel.
  2. Deposition of the first layer of dentin.
  3. Elongation of the inner dental epithelial cells.
  4. Differentiation of odontoblasts. 

 

 

 

 

 

 

 

The answer is: C

 

23-All of the following are involved in the formation of a tooth except:

  1. Epithelial root sheath.
  2. Successional lamina.
  3. Dental lamina.
  4. Vestibular lamina.

 

 

 

 

 

 

 

The answer is: D

 

24- The dental lamina initiating the permanent molars develops:

  1. As successional lamina.
  2. As a distal extension of the dental lamina.
  3. As lateral dental lamina.
  4. As vestibular lamina.

 

 

 

 

 

 

 

The answer is: A

 

25-The cell rests of Malassez are derivatives of:

  1. Cervical ameloblasts.
  2. Outer enamel epithelium.
  3. Dental papilla.
  4. Root sheath. 

 

 

 

 

 

 

 

The answer is: D

 

26- Odontogenesis of the primary dentition begins between:

  1. The sixth & seventh week.
  2. The fifth & sixth week.
  3. The seventh& eighth week.
  4. The fourth & fifth week.

 

 

 

 

 

 

 

The answer is: A

 

27- The embryo's stomodeum is lined by:

  1. Ectoderm
  2. Endoderm
  3. Mesoderm
  4. Ectomesenchyme

 

 

 

 

 

 

 The answer is: A

 

28-  By the 6th week of tooth development, the oral epithelium is:

  1. 2-3 layers thickness.
  2. 3-4 layers thickness.
  3. 4-5 layers thickness.
  4. 2-5 layers thickness.

 

 

 

 

 

 

 

The answer is: A

 

29- The vestibular lamina gives rise to:

  1. The alveolodental sulcus.
  2. The alveolobuccal sulcus.
  3. The alveololingual sulcus.
  4. The alveologingival sulcus.

 

 

 

 

 

 

 

The answer is: B

 

30- The ectomesenchymal cell condensation just beneath the enamel organ is called:

  1. Dental sac.
  2. Dental follicle.
  3. Pulp.
  4. Dental papilla.

 

 

 

 

 

 

The answer is: D

 

31- The cells of the tooth bud have:

  1. High RNA content only.
  2. Low glycogen content only.
  3. Increased oxidative enzyme activity only.
  4. All of the above.

 

 

 

 

 

 

 

The answer is: D

 

32- Regulatory genes play a significant role in tooth development, they:

  1. Control the tooth position.
  2. Control the tooth number.
  3. Determine the tooth shape.
  4. a & b.

 

 

 

 

 

 

 

The answer is: D

 

33- Initiation of dental lamina is induced by:

  1. Neural crest cell.
  2. Endoderm
  3. Ectoderm
  4. Mesoderm

 

 

 

 

 

 

 

The answer is: D

 

34- Primordium for the permanent dentition appears as an extension of dental lamina into the ectomesenchyme:

  1. Lingual to the developing primary tooth germ.
  2. Labial  to the developing primary tooth germ.
  3. Mesial to the developing primary tooth germ.
  4. Distal to the developing primary tooth germ.

 

 

 

 

 

 

The answer is: A

 

35- The region where the inner and outer enamel epithelium meets at the rim of the enamel organ is known as:

  1. Zone of Flection.
  2. Cervical loop.
  3. Epithelial Diaphragm.
  4. Root Sheath of Hertwing's.

 

 

 

 

 

 

 

The answer is: A

 

36- Which the followings is not a  function of stellate reticulum:

  1. Protection of the underlying dental tissues.
  2. Maintenance of tooth shape.
  3. Support the production of enamel.
  4. Control the position & number of tooth germs.

 

 

 

 

 

 

 

The answer is: D

 

37- The epithelial pearls are derived from:

  1. Dental lamina.
  2. Dental pulp.
  3. Dental sac.
  4. Dental organ.

 

 

 

 

 

 

 

The answer is: A

 

38- Odontoblasts start their secretory activity:

  1. Before enamel matrix production.
  2. After enamel matrix production.
  3. During enamel matrix production.
  4. During & after enamel matrix production.

 

 

 

 

 

 

 

 

The answer is: A

 

39- Preameloblasts differentiate into ameloblasts:

  1. After the differentiation of odontoblasts.
  2. Before the differentiation of odontoblasts.
  3. During the differentiation of odontoblasts.
  4. During & after the differentiation of odontoblasts.

 

 

 

 

 

 

 

 

The answer is: A

 

40- During the early stages of tooth development three transitory structures may be seen, these structures are:

  1. Enamel knot, enamel organ & enamel niche.
  2. Enamel knot, enamel cord & enamel niche.
  3. Enamel knot, enamel organ & enamel epithelium.
  4. Enamel niche, enamel organ & enamel knot.

 

 

 

 

 

 

 

 

The answer is: B

 

41- The epithelial rests in the periodontal ligament are derived from:

  1. Dental pulp.
  2. Epithelial root sheath of Hertwing's.
  3. Vestibular lamina.
  4. Dental sac.

 

 

 

 

 

 

 

 The answer is: B

 

42- Appositional stage is confined to:

  1. Cap stage.                                      
  2. Bud stage.
  3. Bell stage.                                      
  4. Dental lamina.

 

 

 

 

 

 

 

The answer is: C

 

43- Concresense usually occurs with:

  1. Permanent maxillary molars.
  2. Permanent maxillary premolars.
  3. Permanent mandibular premolars.
  4. Permanent mandibular premolars.

 

 

 

 

 

 

 

 

The answer is: A

 

44- Supernumerary roots occur mainly with:

  1. Permanent third molars.
  2. Permanent second  molars.
  3. Permanent first molars.
  4. Permanent second premolars.

 

 

 

 

 

 

 

The answer is: A

 

45- Enamel pearls occur in:

  1. Apical third of molars roots.
  2. Furcation area of molars.
  3. Cervical third of molars roots.
  4. Furcation area of premolars.

 

 

 

 

 

 

 

 

The answer is: B

 

46- The process of differentiation of mesenchymal cells into Odontoblasts is called:

  1. Initiation
  2. Induction
  3. Apposition
  4. Morphodifferentiation

 

 

 

 

 

 

 

The answer is: A

 

47- The epithelial root sheath of Hertwing's is composed of:

  1. Outer enamel epithelium & inner enamel epithelium.
  2. Inner enamel epithelium & stratum intermedium.
  3. Outer enamel epithelium & stellate reticulum.
  4. Stellate reticulum & stratum intermedium.

 

 

 

 

 

 

 

The answer is: A

 

48- Inner dental epithelium:

  1. Consists of a single layer of cuboidal epithelial cells.
  2. Consists of a single layer of columnar epithelial cells.
  3. Consists of a single layer of polyhedral epithelial cells.
  4. Consists of a single layer of polygonal epithelial cells.

 

 

 

 

 

 

 

The answer is: B

 

49- Determination of the initial position of the first cusp of the tooth during crown pattern formation may be achieved by:

  1. The enamel knot.                             
  2. The enamel cord.
  3. Both enamel knot and cord.                
  4. None of the above.

 

 

 

 

 

 

 

The answer is: A

 

50- Before enamel formation begins:

  1. Enamel knot disappears and enamel cord remains.
  2. Enamel knot remains and enamel cord disappear.
  3. Both knot and cord disappear.
  4. Both knot and cord remain.

 

 

 

 

 

 

 

The answer is: C

 

51- Concerning the stellate reticulum one of the following statements is wrong:

  1. Occupies the central portion of the dental organ.
  2. Lies between outer and inner dental epithelia.
  3. Synthesizes and secretes glucoseaminoglycans.
  4. Becomes polyhedral in shape.

 

 

 

 

 

 

 

The answer is: D

 

52- The dental sac is:

  1. The condensation of the ectomesenchymal cells surrounding the dental organ.
  2. The condensation of the ectomesenchymal cells surrounding the dental papilla.
  3. The condensation of the ectomesenchymal cells surrounding the dental organ and dental papilla.
  4. None of the above.

 

 

 

 

 

 

 

The answer is: C

 

53- The main difference between bell and apposition stage is:

  1. The formation of first layer of E.
  2. The formation of first layer of D.
  3. The formation of first layer of C.
  4. The formation of first layer alveolar bone.

 

 

 

 

 

 

 

 

The answer is: B

 

54- Concerning the stratum intermedium, one of the following statements is incorrect:

  1. It is composed of 2-3 layers of squamous epithelial cells.
  2. It is differentiated between the inner enamel epithelium and stellate reticulum.
  3. It is connected to each other and to the cells of stratum intermedium by desmosomes.
  4. It is essential for enamel formation as it contains acid phosphatase enzyme.

 

 

 

 

 

 

 

The answer is: D

 

55- Which one of the following functions of the inner dental epithelium is wrong?

  1. It exerts an organizing influence on the undifferentiated cells of the dental papilla to differentiate into ameloblasts.
  2. It shares in the transport of the nutritive materials.
  3. It determines the future incisal or occlusal crown pattern.
  4. It lays down enamel matrix and helps in its mineralization.

 

 

 

 

 

 

 

 

The answer is: A

 

56- The epithelial root sheath of Hertwig can't be seen as a continuous layer in the developing root because:

  1. The rapid epithelial sheath proliferation.
  2. The dentin formation.
  3. The rapid epithelial sheath destruction after dentin formation.
  4. All of the above.

 

 

 

 

 

 

 

The answer is: C

 

57- Epithelial rests of Malassez are:

  1. Epithelial strands and may undergo degeneration only.
  2. Epithelial remnants of the epithelial root sheath of Hertwig only.
  3. Network or isolated islands in the P.L. only,
  4. All of the above.

 

 

 

 

 

 

 

The answer is: D

 

58- If Hertwig's epithelial root sheath does not disintegrate:

  1. No cementum will be formed on the radicular dentin.
  2. It is likely that some of the enamel will be resorbed.
  3. The apical end of the junctional epithelium will lie occlusal to the cemento-enamel junction.
  4. Predentine will form on the outer surface of the radicular dentin.

 

 

 

 

 

 

 

The answer is: A

 

59-The reduced enamel epithelium is derived from:

  1. Maturative ameloblasts and stratum intermedium.
  2. Stratum intermedium, stellate reticulum and outer dental epithelium.
  3. Stratum intermedium, stellate reticulum and inner epithelium.
  4. Protective ameloblasts, stratum intermedium, stellate reticulum and outer dental epithelium.

 

 

 

 

 

 

 

The answer is: D

 

60-Which of the following is not component of the enamel organ?

  1. Ameloblasts
  2. Odontoblasts
  3. Outer enamel epithelium.
  4. Stratum intermedium.

 

 

 

 

 

 

 

The answer is: B

 

61- Which of the following indicates the major components of a tooth germ?

  1. The dental lamina, the stellate reticulum and the stratum intermedium.
  2. The dental organ, the dental papilla and the dental sac.
  3. The dental pulp, the dental sac and the dental lamina.
  4. The cervical loop, Hertwig's sheath and the inner enamel epithelium.

 

 

 

 

 

 

 

The answer is: B

 

62- Which of the following is not ectodermal in origin?

  1. Epithelial rests of Malassez.
  2. Anterior pituitary gland.
  3. Stellate reticulum.
  4. Enamel spindles.

 

 

 

 

 

 

 

The answer is: D

 

63- Which of the following appear FIRST in a developing tooth?

  1. Predentin
  2. Cementoid
  3. Tome's process.
  4. Secondary dentin.

 

 

 

 

 

 

 

The answer is: A

 

64- The last hard dental tissue to be deposited is:

  1. Enamel
  2. Outer layers of cementum.
  3. Mantle dentin.
  4. Primary dentin.

 

 

 

 

 

 

 

The answer is: B

 

65- Which of the following is associated with an erupted tooth?

  1. Outer Enamel epithelium.
  2. Cervical loop.
  3. Epithelial rests of Malassez.
  4. Stratum intermedium.

 

 

 

 

 

 

 

The answer is: C

 

66- Which of the following is not true of Hertwig's epithelial root sheath?

  1. It lacks a stellate reticulum.
  2. It is derived from stomodeal ectoderm.
  3. Its remnants form epithelial rests.
  4. It remains intact until a layer of cementum has been formed.

 

 

 

 

 

 

 

The answer is: D

 

67- Which of the following contain blood vessels?

  1. Cartilage
  2. Enamel
  3. Dental lamina.
  4. Dental sac.

 

 

 

 

 

 

 

The answer is: D

 

68- Which group of structures is entirely derived from the dental sac?

  1. Dentin, pulp, cementum.
  2. Cementum, alveolar bone, pulp.
  3. Cementum, enamel, pulp.
  4. Periodontal ligament, cementum, alveolar bone.

 

 

 

 

 

 

 

The answer is: D

 

69-The development of the root begins when

  1. The inner and outer dental epithelium reaching the future C.E.J.
  2. The crown is completely formed.
  3. The development of the supporting bone begins.
  4. The development of the periodontal ligament begins.

 

 

 

 

 

 

 

The answer is: B

 

70- The function of the inner dental epithelium is……..

  1. Exerts organization influence on the dental papilla cells.
  2. Lays down dentin matrix             
  3. Protects the enamel after eruption.
  4. Provides the enamel organs with alkaline phosphatase

 

 

 

 

 

 

The answer is: A

 

71-The tooth germ is composed of 

  1. Dental papilla, dental follicle, dental organ.
  2. Dental follicle, dental lamina, vestibular lamina.
  3. Dental papilla, dental lamina, dental organ.
  4. Dental organ, dental follicle, dental lamina. 

 

 

 

 

 

 

 

The answer is: A

 

72-The apposition stage of tooth development begins 

  1. When the root of the tooth begins to develop.
  2. When the first layer of dentine is deposited.
  3. When odontoblast start to differentiate.
  4. When the first layer of enamel lay down.

 

 

 

 

 

 

 

The answer is: B

 

73- What statement about epithelial diaphragm is Not true?

  1. It produces narrowing of the wide cervical opening. 
  2. Its proliferation is accompanied by proliferation of pulp cells adjacent to diaphragm.
  3. It's growing end  is located coronal to the root sheath.
  4. It grows in a horizontal plane.

 

 

 

 

 

 

 

The answer is: C

 

74- The cells of the stratum intermedium:

  1. Have a stellate outline.
  2. Are not yet differentiated in the bell stage.
  3. Are in direct contact with the outer dental epithelium.
  4. Are characterized by high alkaline phosphatase enzyme activity.

 

 

 

 

 

 

 

The answer is: D

 

75-The dental follicle:

  1. Is an epithelial structure.
  2. Give rise to the radicular pulp.
  3. Is not present in permanent teeth.
  4. give rise to cementum.

 

 

 

 

 

 

 

The answer is: D

 

76-If the process of morphogenesis is disturbed:

  1. Changes will occur in the shape of crown and root.
  2. Enamel formation will be abnormal.
  3. Dentin formation will be abnormal.
  4. Absence of cementum.

 

 

 

 

 

 

The answer is: A

 

77- The mesenchymal cells lying adjacent to the inner enamel epithelium:

  1. Differentiate into ameloblasts.
  2. Differentiate into odontoblasts.
  3. Are under the influence of stellate reticulum.
  4. Become markedly folded.

 

 

 

 

 

 

The answer is: B

 

78- The dental lamina:

  1. Breaks at the cap stage.
  2. Has no branching.
  3. Has no remnants.    
  4. Develops from the oral epithelium.

 

 

 

 

 

 

The answer is: D

 

79- Advanced bell stage of tooth development refers to:

  1. Histodifferentiation , morphodifferentiation.
  2. Initiation & Proliferation.
  3. Mesenchymal condensation.
  4. Apposition of dental tissues. 

 

 

 

 

 

 

 

The answer is: D

 

80- The epithelial component of the tooth germ is known as:

  1. Dental lamina.
  2. Dental papilla.
  3. Enamel organ.
  4. Dental follicle.

 

 

 

 

 

 

 

The answer is: C

 

81- Which of the following is not part of the tooth germ?

  1. Dental papilla.
  2. Dental follicle.
  3. Dental lamina.
  4. Enamel organ. 

 

 

 

 

 

 

 

The answer is: C

 

82- The dental sac plays an important role in the formation of all of the following except:

  1. Periodontal ligament.
  2. Dentin of the root.
  3. Alveolar bone proper.
  4. Cementum.

 

 

 

 

 

 

The answer is: B

 

83- After the crown of the tooth is formed, the dental papilla is called:

  1. Dental pulp.
  2. Pulp stone.
  3. Dental sac.
  4. Dentin.

 

 

 

 

 

 

The answer is: A

 

84- In a developing tooth, if Hertwig's sheath and the epithelial diaphragm were failed to form, the resulting tooth would exhibit:

  1. No radicular dentin.
  2. Malformed or fused roots.
  3. Acellular, but no cellular, cementum.
  4. Defective enamel in the cervical region.

 

 

 

 

 

 

 

The answer is: A

 

85- The reduced enamel epithelium:

  1. Lacks cells derived from the stellate reticulum.
  2. Contains protective ameloblasts.
  3. Overlies immature enamel which has not yet reached its full thickness.
  4. Does not cover enamel located at the cervical end of the crown.

 

 

 

 

 

 

The answer is: B

 

86- Which of the following is a component of tooth germ?

  1. Lateral dental lamina.
  2. Successional lamina.
  3. Vestibular lamina.
  4. Dental sac.

 

 

 

 

 

 

 

The answer is: D

 

87- The origin of enamel is:

  1. Endoderm
  2. Mesoderm
  3. Ectoderm
  4. Ectomesenchyme

 

 

 

 

 

 

The answer is: C

 

88-Which statement about early dental development is incorrect?

  1. Cap stage is accomplished by unequal growth in different parts.
  2. In the cap stage the inner and outer enamel epithelial cells are completely alike.
  3. The transition from cap stage to bell stage is particularly marked by the full differentiation of stellate reticulum.
  4. The dental papilla and the dental sac develop in the cap stage. 

 

 

 

 

 

 

 

The answer is: B

 

89- The dental sac gives rise to:

  1. Cementoblasts and periodontal ligament.
  2. Periodontal ligament and dental pulp.
  3. Dental pulp and attachment epithelium.
  4. Odontoblasts and Cementoblasts.

 

 

 

 

 

 

 

The answer is: A

 

90- Which of the following is true about the initiation of calcification of teeth:

  1. Initiation of calcification of primary teeth is complete at the time of birth
  2. Initiation of calcification of all primary teeth and permanent incissors complete at birth
  3. Initiation of calcification of all primary and permanent teeth completes at birth except 3rd molars
  4. Calcification of primary teeth starts after birth

 

 

 

 

 

 

 

The answer is: A

 

91- Root resorption of maxillary deciduous central incisors starts by:

 

  1. 3 years
  2. 4 years
  3. 5 years
  4. 6 years

 

 

 

 

 

 

The answer is: B