Perfusion of oxygen supply in a free flap can be correctly estimated by:

 # Perfusion of oxygen supply in a free flap can be correctly estimated by:

a) Pulse oximetry 

b) Laser Doppler flowmetry 

c) Prick test 

d) Fluroscopy

The correct answer is B. Laser doppler flowmetry.

Let's go through each option:

a) Pulse oximetry: Pulse oximetry measures the oxygen saturation of hemoglobin in arterial blood non-invasively. However, it may not provide an accurate estimation of oxygen supply in a free flap because it only measures the oxygen saturation of blood and does not directly assess tissue perfusion. While it can indicate overall oxygenation status, it may not reflect the oxygen supply to a specific tissue like a free flap.

b) Laser Doppler flowmetry: Laser Doppler flowmetry is a non-invasive technique used to measure tissue perfusion by detecting the movement of red blood cells. It can provide real-time information about blood flow in the microcirculation of tissues, including free flaps. Therefore, it is often used to monitor the perfusion of oxygen supply in free flaps during surgery and postoperative care. This option is correct because it directly assesses tissue perfusion, which is crucial for evaluating the viability of free flaps.

c) Prick test: A prick test, also known as a pinprick test, is typically used to assess sensory nerve function by evaluating the patient's ability to perceive pain or touch in a specific area. It is not a suitable method for estimating oxygen supply in a free flap. While changes in sensation may indicate compromised blood flow to the flap, the prick test itself does not directly measure tissue perfusion or oxygen supply.

d) Fluoroscopy: Fluoroscopy is a medical imaging technique that uses a continuous X-ray beam to create real-time moving images of the internal structures of a patient. While fluoroscopy can provide valuable information about blood flow and vascular anatomy, it is not commonly used to estimate oxygen supply in free flaps. Fluoroscopy is more often utilized for guiding interventional procedures or diagnosing vascular issues but is not specifically tailored for assessing tissue perfusion in free flaps.

Hence, Laser Doppler flowmetry is the correct choice for estimating the perfusion of oxygen supply in a free flap as it directly measures tissue perfusion and is commonly used in clinical practice for this purpose.

The teeth most likely to be transposed are:

 # The teeth most likely to be transposed are:

A. Mandibular Premolars and maxillary incisors

B. Maxillary premolars and mandibular incisors

C.  Maxillary molars and canines

D. Mandibular molars and canines

The correct answer is B. Maxillary premolars and mandibular incisors.

Transposition is a rare positional interchange of two adjacent teeth. It occurs with a prevalence of approximately 0.3% and equally affects males and females. The teeth most likely to be transposed

are mandibular incisors and maxillary premolars, and this usually occurs as a consequence of ectopic eruption. There appears to be a genetic component to this problem. In the early mixed dentition years, transposition can develop when distally directed eruption of the permanent mandibular lateral incisor leads to loss of the primary mandibular canine and primary first molar. If left untreated, this can result in a true transposition of the permanent lateral incisor and canine.

The first material used for orthodontic TADs was:

 # The first material used for orthodontic TADs was:

A. Titanium

B. Stainless Steel 

C. Vitallium

D. Nickel - Chromium

The correct answer is C. Vitallium.

To date, three types of materials have been used for orthodontic TADs: titanium alloy, stainless steel

and vitallium. Vitallium was the first material used for orthodontic TADs. However, due to undesirable biocompatibility and a higher failure rate, vitallium was gradually replaced by titanium alloy. Stainless steel is also used for orthodontic mini-implants and recent evidence indicates that the success rate is similar between titanium alloy and stainless steel mini-implants. Nowadays, due to high biocompatibility of titanium, orthodontic TADs made of titanium alloy are most frequently used in clinical practice.

Reference: Clinical Insertion Techniques of Orthodontic Temporary Anchorage Devices, Wiley Blackwell

Who first advocated the opening of mid palatal suture to expand the dental arch?

 # Who first advocated the opening of mid palatal suture to expand the dental arch?

Emerson C. Angell 

B. Pierre Fauchard

C. Edward H. Angle 

D. Raymond Begg

The correct answer is A. Emerson C. Angell.

In 1860 Emerson C. Angell was probably the first person to advocate opening of the midline suture to provide space in the maxillary arch, because he took a very strong stand against extraction.

Ref: Graber, 7th Edition

Double lip is a feature of:

 # Double lip is a feature of:

 A. Aschers syndrome

B. Parry Romberg syndrome

C. Pierre Robin Syndrome

D. Mieschers syndrome

The correct answer is A. Aschers syndrome.

Ascher syndrome was first described in 1920 by an ophthalmologist. This syndrome presents as blepharochalasis(swelling of the eyelids), double lip and nontoxic thyroid enlargement. The thyroid enlargement is not present in all cases of this syndrome. The syndrome is often undiagnosed because of its rarity.

Otocephaly is a developmental disorder of:

 # Otocephaly is a developmental disorder of:

 A. Zygoma

B. Jaw bone

C. Occipital bone

D. Parietal bone

The correct answer is B. Jaw bone.

Otocephaly, also known as agnathia–otocephaly complex, is a very rare and lethal cephalic disorder characterized by the absence of the mandible (agnathia), with the ears fused together just below the chin (synotia). It is caused by a disruption to the development of the first branchial arch. It occurs in every 1 in 70,000 embryos.  

Reference: WIKIPEDIA

MCQs on Pharmacology - Drugs acting on Autonomic Nervous System

# The highest seat of regulating autonomic functions is located in:
A. Hypothalamus
B. Medulla
C. Spinal cord
D. Midbrain

# Catecholamines are synthesized from which amino acid?
A. Histamine
B. Phenylalanine
C. Tryptophan
D. Glycine