The most common organism causing infective endocarditis following dental manipulation is a:

 # The most common organism causing infective endocarditis following dental manipulation is a:

A. Streptococcus viridans

B. Staphylococcus aureus

C. Group A Streptococci

D. Gram –ve rod

The correct answer is A. Streptococcus viridans.

Bacteremias have been shown to cause Infective endocarditis; viridans group streptococci are part of the normal oral flora and have been commonly found in Infective endocarditis; dental procedures can cause bacteremias because of Streptococcus viridans; a large number of case reports associate dental procedures with subsequent Infective endocarditis.

Reference: Contemporary Oral and Maxillofacial Surgery, James R. Hupp, 6th Edition 2013, Page No: 314

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Knoop Hardness Number of enamel

 # Knoop Hardness Number (KHN) of enamel is:

A. 15

B. 55

C. 25-35

D. 350-430

The correct answer is D. 350-430 

The Knoop hardness test employs a diamond-tipped tool. The impression is rhombic in outline, and the length of the largest diagonal is measured. The load is divided by the projected area to give the Knoop hardness number (usually abbreviated as HK or KHN). 

Knoop hardness number of dentin is 68 and that of enamel is 350-459. Unfilled acrylic has KHN of 15 whereas hybrid composites have a KHN of 55-60. 

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Inducing Omission in Behavior management

#  You are treating a child patient. In the process of managing behavior of your patient you plan to induce omission, which refers to:

A. Pleasant consequence following a response

B. Withdrawal of an unpleasant stimulus after a response

C. Removal of a pleasant stimulus after a particular response

D. Presentation of an unpleasant  stimulus after a response

The correct answer is C. Removal of a pleasant stimulus after a particular response

Omission

Also called as ‘timed-out’, involves removal of pleasant stimulus after a particular response. For example if a child who throws temper tantrum has his favorite toy taken away for a short time as a consequence of this behavior, the probability of similar behavior is decreased. Because children are likely to regard attention by others as a very pleasant stimulus, withholding attention following undesirable behavior is use of omission that is likely to reduce the unwanted behavior.

Reference: Pedodontics Practice and Management, Badrinatheswar GV, First Edition 2010 Page no: 101

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Structures passing through foramen ovale are all EXCEPT:

 # All of the following structures pass through foramen ovale except:

(a) Mandibular nerve

(b) Anterior division of middle meningeal artery

(c) Lesser superficial petrosal nerve

(d) Emissary vein connecting pterygoid venous plexus to cavernous sinus

The correct answer is B. Anterior division of middle meningeal artery.

Foramen ovale contents: (Mnemonic: MALE)

(i) Mandibular nerve.

(ii) Accessory middle meningeal artery.

(iii) Lesser petrosal nerve.

(iv) Emissary vein: connecting the pterygoid venous plexus to the cavernous sinus.

Reference: TEXTBOOK OF ANATOMY HEAD, NECK AND BRAIN, Volume III, 2nd Edition Vishram Singh, Page No.  320

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Area of the lateral aspect of skull that overlies the anterior division of middle meningeal artery:

 # The area of the lateral aspect of skull that overlies the anterior division of middle meningeal artery is called:

(a) Bregma

(b) Asterion

(c) Pterion

(d) Inion

The correct answer is C. Pterion.

The region in the anterior part of the temporal fossa where four bones (frontal, parietal, squamous temporal, and greater wing of the sphenoid) meet to form an H-shaped suture is called pterion. It is situated 4 cm above the midpoint of the zygomatic arch.

The pterion overlies the anterior division of middle meningeal artery, which ruptures following a blow in this region to form an extradural hematoma (a clot formation between the skull bone and the dura mater). The clot, if big, may compress the brain leading to unconsciousness or even death. Therefore, it should be removed as early as possible by trephination or craniotomy.

Reference: TEXTBOOK OF ANATOMY HEAD, NECK AND BRAIN, Volume III, 2nd Edition Vishram Singh, Page No.  18

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Bones of the skull which permit free movement are all except:

 # Bones of the skull which permit free movement are all except:

(a) Mandible

(b) Malleus

(c) Incus

(d) Vomer

The correct answer is D. Vomer.

The vomer is involved in all three types of Le Fort fractures of midfacial skeleton. The vomer is paper thin. A transverse fracture of vomer due to direct blow on the nose leads to deviated nasal septum (DNS).

Reference: TEXTBOOK OF ANATOMY HEAD, NECK AND BRAIN, Volume III, 2nd Edition Vishram Singh, Page No. 40

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Sternocleidomastoid divides the neck into:

 # Sternocleidomastoid divides the neck into which cervical triangles?

(a) Medial and lateral

(b) Superior and inferior

(c) Anterior and posterior

(d) Proximal and distal

The correct answer is C. Anterior and Posterior.

The neck is conventionally divided into various triangles. The sternocleidomastoid muscle transects the side of neck obliquely on each side and divides it into anterior and posterior cervical triangles.

Reference: TEXTBOOK OF ANATOMY HEAD, NECK AND BRAIN, Volume III, 2nd Edition Vishram Singh, Page No. 10

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