EXAMINATION SAMPLE

• Course: 253 DDS ORAL BIOLOGY & HISTOLOGY

Please Read the Questions Carefully and Answer Accordingly

• The primitive oral cavity is lined by

  1. endoderm

  2. mesoderm

  3. ectoderm

  4. ectoderm and mesoderm

• The lower lip develops from

  1. maxillary processes and median nasal process

  2. lateral nasal process and maxillary process

  3. maxillary process and mandibular process

  4. two mandibular processes

• Prior to the formation of the palate ,the oronasal cavity of the embryo is occupied by

  1. tongue

  2. frontonasal process

  3. buccopharyngeal membrane

  4. lateral palatine process

• The line of fusion between the maxillary process and lateral nasal process is termed

  1. primitive palate

  2. median nasal septum

  3. nasolacrimal groove

  4. copula

• Rupture of the oropharyngeal membrane

  1. joins the pharynx to the trachea

  2. joins the oral cavity to the pharynx

  3. joins the two medial nasal processes

  4. joins the two lateral palatine processes

•

The Branchial arches are separated externally by

1. Branchial grooves

2. pharyngeal pouches

3. oropharyngeal membrane

4. Branchial fistula

The head and neck is formed around

1. 7 days of intrauterine life

2. 15 days of intrauterine life

3. 28 days of intrauterine life

4. 50 days of intrauterine life

During the development of the nose, nasal placodes are considered as

1. neural crest cells

2. ectodermal thickening

3. mesodermal thickening

4. endodermal thickening

Denticles could by:

1. single or multiple

2. true or false

3. free, attached or embedded

4. all of the above

5. none of the above

The odontoblastic processes act as a receptor that conveys the stimulus to the near nerve endings.

a. True b. False

 The cementum:

1. thickness at the root apex 150-200 μm

2. contains 67% - 70% inorganic minerals

3. in 10% of all teeth cementum meets the enamel in a sharp line

4. all of the above

The cellular cementum covers the apical third of the root and most of the processes of the cementocytes are directed toward the periodontal ligament.

a. True b. False

The matrix of the acellular cementum consists of:

1. cementoblasts, cementocytes and Tome’s fibres

2. collagen fibres and elastic fibres

3. Tome’s fibres and collagen fibres

4. Collagen fibres and calcified ground substance

Fontanelles are bone free spaces that appear in the skull between the bones enabling the skull to undergo alterations in shape

a. True b. False

The first sign of human tooth development is seen during the :

1. 6th week intrauterine

2. 7th week intrauterine

3. 8th week intrauterine

4. 12th week intrauterine

Bell stage of tooth development refers to

1. dental lamina

2. initiation

3. proliferation

4. histodifferentiation and morphodifferentiation