OBS Quiz

Question 1

Jim is an 82 year old bricklayer, has been diagnosed with squamous cell carcinoma of the lower lip.

Which of the following lymph nodes was first involved in the spread of the cancer cells?

Answer 1

Submental nodes

Question 2

Cells that are responsible for the production of reactive dentin are most likely to present in which of the following areas of pulp?

Answer 2

Pulp periphery

Question 3

The oral bacteria that is associated with the initiation of dental caries is:

Answer 3

Mutans streptococci

Further info: lactobacillus is associated with caries progression

Question 4

Which of the following does not provide supportive evidence of the role of mutans streptococci in dental caries?

Answer 4

The ability to breakdown collagen using pro teases.

Question 5

Which pattern of inheritance is the following genetic tree referring to? (Black circles and squares)

Answer 5

Mitochondrial inheritance

Question 6

Regarding odontoblasts and their processes

Answer 6

Odontoblast processes branch dichotomously at the dentinoenamel junction (DEJ) and may sometimes be incorporated into enamel as enamel spindles

Question 7

Eutetic point defines

Answer 7

Binary alloy formulation that has a single melting point

Question 8

Oral fungal infections that appear as a creamy white, loosely adherent membrane covering the various oral surfaces may be caused by:

Answer 8

Candida albicans

Question 9

In relation to bio materials, stiffness refers to

Answer 9

Resistance to elastic deformation

Question 10

Herpangina and hand, foot and mouth disease are infections that have prominent oral manifestations appearing particularly as vesicles. These infections are caused by:

Answer 10

Type A coxsackie viruses

Question 11

Regarding pulp

Answer 11

It includes undifferentiated cells some of which may differentiate into odontoblasts

Question 12

Which statement regarding dental cements is INCORRECT?

Answer 12

Eugenia in zinc oxide-Eugenia cement has inflammatory effect on the tissue

Question 13

The incident laser beam travels through the thickness of human cementum at the incident angle of pi/3. The refractive index of human cementum is 1.58. What is the refractive index of human dentine if the refractive angle was pi/2.87?

Answer 13

1.54

Question 14

The difference in staining between GRam positive and gram negative organisms:

Answer 14

Is determined by their cell wall structure

Question 15

Regarding to Thea quirked tooth pellicle, which of the following statement is NOT TRUE?

Answer 15

Can be readily removed from teeth by tooth brushing

Question 16

Which is NOT correct regarding the chronology of the human development?

Answer 16

Upper lip and palate fusion is complete at six weeks of development

Question 17

Which artery is a branch of the maxillary artery?

Answer 17

Infra-orbital

Question 18

The tongue includes the following features:

Answer 18

Lingual papillae which include vallate papillae and filiform papillae

Question 19

If the facial nerve was cut as it exited the stylomastoid foramen, which of the following muscles would NOT be affected?

Answer 19

Stapedius

Explanation: the facial nerve originates in the pons, traverses the facial canal of the temporal bone, and exits the cranium through the stylomastoid foramen and then extends laterally around the neck of the mandible through th parotid gland. With the exception of the stapedial nerve, all branchiomotor fibres in the facial nerve emerge from the facial canal via the stylomastoid foramen. The branchial motor of facial nerve supplies the muscles of facial expression, posterior or anterior belly of digastric muscle, stylohyoid.

Question 20

HArdness of human dentine specimen was measured using microindentation instrument. The indentation experiment was conducted at 20mN force and resulted in the residual impression area of 18.52 cm^2. What was the hardness of the specimen?

Answer 20

1.08 GPa

Question 21

A person eats a starch rich diet. Saliva from which of the following glands is most likely to produce amylase to digest this food?

Answer 21

Parotid glands

Question 22

Linear coefficient of thermal expansion of human enamel is 25 x 10^-6 C^o-1. What is the human enamel volumetric coefficient of thermal expansion?

Answer 22

75 x 10^-6 C^o-1

Question 23

The structure depicted at the arrow is a: (dental papilla histology image)

Answer 23

Successional laminators

Question 24

Advantages for microorganisms living within a dental plaque (biofilm) include all of the following except:

Answer 24

Production of bacteriocins within the biofilm.

Reason: bacteriocins are antimicrobial agents which suppress competing microorganisms.

Question 25

Vitamin D is a factor in

Answer 25

Calcium absorption

Question 26

Complex muscle of the face, in which most of the fibres run circularly

Answer 26

Orbicularis oris

Question 27

Elevates hyoid bone during swallowing and speech

Answer 27

Digastric

Question 28

Inserts onto the coronoid process of the mandible

Answer 28

Temporalis

Question 29

Insertion is lateral surface of angle and lower ramps of mandible

Answer 29

Mass eater

Question 30

Originates on temporal bone

Answer 30

Stylohyoid

Question 31

The main muscle of the cheek

Answer 31

Buccinator

Question 32

The muscle that wrinkles the forehead horizontally

Answer 32

Frontalis

Question 33

A superficial muscle in neck

Answer 33

Plays a

Question 34

The muscle that protrudes the lower lip

Answer 34

Mental is

Question 35

Causes genital herpes but sometimes the characteristic inflamed Papuans and vesicles can be seen on the lips and oral mucosa

Answer 35

Herpes simplex virus-2

Question 36

Causes hairy oral leukoplakia in immunosuppressed patients

Answer 36

Epstein-Barr virus