Wernicke’s encephalopathy is due to the deficiency of:

 # Wernicke’s encephalopathy is due to the deficiency of:

A. Thiamine

B. Vitamin B12

C. Niacin

D. Vitamin B2

The correct answer is A. Thiamine. 

■ Thiamine deficiency in its early stage induces anorexia and nonspecific symptoms (e.g., irritability, decrease in short-term memory). 

■ Prolonged thiamine deficiency causes beriberi, which is classically categorized as wet or dry, although there is considerable overlap. In either form of beriberi, patients may complain of pain and paresthesia. 

■ Wet beriberi presents primarily with cardiovascular symptoms due to impaired myocardial energy metabolism and dysautonomia and can occur after 3 months of a thiamine deficient diet. Patients present with an enlarged heart, tachycardia, high-output congestive heart failure, peripheral oedema and peripheral neuritis. 

■ Patients with dry beriberi present with asymmetric peripheral neuropathy of the motor and sensory systems with diminished reflexes. The neuropathy affects the legs most markedly, and these patients have difficulty rising from a squatting position. 

■ Alcoholic patients with chronic thiamine deficiency also may have central nervous system (CNS) manifestations known as Wemicke's encephalopathy, consisting of horizontal nystagmus, ophthalmoplegia (due to weakness of one or more extraocular muscles), cerebellar ataxia, and mental impairment. 

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Rule of Ten is for:

 # Rule of Ten is for:

A. Pheochromocytoma

B. MEN-I syndrome

C. Adrenal hyperplasia

D. Parathyroid

The correct answer is A. Pheochromocytoma.

Pheochromocytoma:- 

For diagnosis and management of this disease classic "rule of tens is applicable." 

• 10% of these neoplasms occur in children 

• 10% of these neoplasms associated with familial syndromes 

• 10% of sporadic cases of these neoplasms are bilateral 

• 10% of these neoplasms are extra-adrenal 

• 10% of these neoplasms are malignant 

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Supporting cells of taste buds are called as:

 # Supporting cells of taste buds are called as:

A. Sustentacular cells

B. Taste cells

C. Von Ebner cells

D. Acini

The correct answer is A. Sustentacular cells.

The taste bud is composed of about 50 modified epithelial cells, some of which are supporting cells called sustentacular cells and others of which are taste cells. New taste sensation described in some texts is UMAMI. Its receptor is glutamate receptor - mglu R4 

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Matrix vesicles are derived from:

 # Matrix vesicles are derived from:

A. Elastin fibres

B. Collagen

C. Osteoblast

D. Inflammatory cells

The correct answer is C. Osteoblast.

The term matrix vesicles (MV) refers to small (20-200 nm) spherical bodies observed in the pre-mineralized matrix of dentin, cartilage and bone. They appear to be bounded by a lipid bilayer, and are often found associated with small crystals of calcium phosphate mineral. They are derived from the plasma membrane of mineral forming cells i.e. chondrocytes, osteoblasts, odontoblasts. The matrix vesicles promotes the formation of apatite by increasing the concentration of alkaline phosphatase that play a role in calcification. 

Reference: Orban's

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Discoloration of a denture constructed from cold cure acrylic resin is due to:

 # Discoloration of a denture constructed from cold cure acrylic resin is due to: 

A. Absorption of oral fluids 

B. PH changes in saliva 

C. Leaching out of tertiary amines 

D. Leaching out of excess monomer 

The correct answer is C. Leaching out of tertiary amines.

The color stability of chemically activated resins is generally inferior to the color stability of heat activated resins. This property is related to the presence of tertiary amines with in the cold cure resins, which are highly susceptible to oxidation. 

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Most common reason for failure of rest seat in RPD is :

 # Most common reason for failure of rest seat in RPD is : 

A. Improper rest seat preparation 

B. Contaminated metal 

C. Distorted occlusal rest 

D. Excessive occlusal forces 

The correct answer is A. Improper rest seat preparation.

The most common reason for failure of rest seat in RPD is improper rest seat preparation. Inadequate preparation will result in either occlusal interference or perforation of the metal due to lack of clearance. Failure of rest seat due to contaminated metal or distortion is very rare. 

Reference: McCracken's

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The function of reciprocal clasp arm is:

 # The function of reciprocal clasp arm is:

A. To balance the denture 

B. To act as a direct retainer 

C. To counteract the movement of denture which is caused during engagement of retentive arm  

D. None of the above 

The correct answer is C.  To counteract the movement of denture which is caused during engagement of retentive arm 

The rigid reciprocal arm helps in reciprocating stress generated against the tooth by the retentive arm. It also stabilizes the denture against horizontal movement and is always situated above the height of contour. 

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