Dentosphere : World of Dentistry

 # 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  CLICK HERE FOR MORE MCQs

 # 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  CLICK HERE FOR MORE MCQs

 # 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 CLICK HERE FOR MORE MCQs

 # 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.  CLICK HERE FOR MORE MCQs

 # 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 CLICK HERE FOR MORE MCQs

 # 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.  CLICK HERE FOR MORE MCQs

 # Intracoronal retainer placed in the abutment tooth has the following disadvantage: A. It is unaesthetic B. They cannot provide support and stability C. Difficult laboratory procedures D. Difficult to repair and replace The correct answer is D. Difficult to repair and replace. The advantages of internal or precision attachments are improved esthetics by elimination of a visible retentive component and vertical support. Its disadvantages are difficulty in repair and replacing, greater cost to the patient and inability to use in teeth having short clinical crowns and tissue supported distal extension denture bases.  CLICK HERE FOR MORE MCQs