# Benzodiazepine antagonist is:

# Benzodiazepine antagonist is:
A. Flumazenil
B. Naloxone
C. Furazolidone
D. Dapsone

The correct answer is A. Flumazenil

Benzodiazepine act by enhancing presynaptic or postsynaptic inhibition through a specific receptor which is integral part of gabba receptor Cl-channel complex.

Flumazenil is a BZD analogue which has little intrinsic activity but it competes with BZDs as well as inverse agonists for BZD receptor and reverses their depressant or stimulant effects respectively. Flumazenil is the drug of choice for benzodiazepine overdose.

# To prevent sensitivity caused by acid etching and to protect pulp in deep cavities, which of the following should be used?

# To prevent sensitivity caused by acid etching and to protect pulp in deep cavities, which of the following should be used?
A. Calcium hydroxide liner
B. ZnO liner
C. Light cure GIC liner
D. Lining with varnish

The correct answer is A. calcium hydroxide liner

Deep caries excavation close to the pulp, which may result in either an undetected pulpal exposure or a visible pulpal exposure, should be covered with a calcium hydroxide liner that can stimulate formation of dentin bridges (reparative dentin) over the exposure.

For amalgam restorations, deep excavations not encroaching on the pulp should be covered with a glass-ionomer material that will contribute to thermal protection and provide mechanical protection from amalgam condensation forces at thicknesses of I to 1.5 mm or greater.

Bonding of Composite resin to tooth

# Bonding of composite resins to tooth structure is by: (KAR-01)
a) Covalent bond
b) Ionic bond
c) Mechanical
d) Vander waal forces

The correct answer is C. Mechanical

Bonding of composites to tooth structure occurs by micromechanical retention. Acid etching creates micro porosities into which the resin penetrates resulting in resin tag formation. These tags penetrate to a depth of 5 - 10 µm but their lengths are dependent on the enamel etching time.

Advantages of Dental Composite Resins:

# The main advantage of composites over unfilled direct filling resin is their: (KAR-97)
a) Higher solubility in saliva
b) Lower modulus of elasticity
c) Esthetic excellence
d) Lower thermal co-efficient of expansion

The correct answer is D. Lower coefficient of thermal expansion.

Advantages of composites over unfilled resins:

• Lower coefficient of thermal expansion
• Low polymerization shrinkage
• Low water absorption
• High abrasive resistance

Disadvantages of composites:

• Less color stability
• Less smooth finish than unfilled resins

Hyperplastic Tissue Management in Complete Dentures

# The most common reason why hyperplastic tissue is removed during the construction of a complete denture is that:
a) It interferes with the arrangement of the teeth
b) It is unaesthetic to construct a denture on a hyperplastic tissue
c) It interferes with the stability of the denture
d) All of the above

The correct answer is C. It interferes with the stability of the denture.

The most important reason for the treatment of hyperplastic tissue before the construction of complete or removable partial dentures is to provide a firm, stable base for the denture. 

Functional cusp reduction

# The amount of functional cusp reduction required for metal-ceramic crown is -
a) 1.0 - 2.5 mm
b) 1.5 - 2.0 mm
c) 2.0 - 2.25 mm
d) 1.85 - 2.10 mm

The correct answer is B. 1.5 -2.0 mm. 

Metal ceramic restorations require a 1.5 - 2 mm reduction in the functional cusp and 1.0 - 1.5mm reduction in the non-functional cusp. 

Gutta percha removal

# Best method to remove gutta-percha in retreatment procedures:
A. Hand instrumentation
B. Automated instrumentation
C. Rotatory instruments
D. Ultrasonic instruments

The correct answer is A. Hand instrumentation

The coronal portion of gutta-percha obturations should always be drilled out, preferably by means of endodontic drills such as the Gates-Glidden or Peeso. Gutta-percha may be dissolved (solvent technique) or removed in its solid form (Solid gutta-percha techniques). Dissolving avoids the use of excessive force in the negotiating of gutta-percha-obturated canals.

Extrusion of solvent into the periapical tissues should be prevented.

Solvents of gutta-percha: Gutta-percha is soluble in chloroform, ethyl chloroform, carbon disulfide, carbon tetrachloride, benzene, xylene, eucalyptol oil, halothane, and rectified white turpentine.

Retreatment of solid objects other than gutta-percha, either a silver point or a fragment of an instrument or post, cannot be easily grasped and pulled out. A readily accessible solid object may be withdrawn from the canal by a variety of instruments, including Stieglitz or Perry pliers, a modified Castroviejos needle holder, or a Caulfield silver point extractor. Ultrasonic Vibration, bypassing with hand instruments and Intermittent irrigation, alternating sodium hypochlorite with hydrogen peroxide or RC-Prep, may float the object coronally through the effervescence they create.

Special grasping devices. The Masserann technique- Masserann and alternative extractors. The Masserann kit consists of an extractor into which the object to be retrieved is locked. An assortment of end-cutting trepan burs are used in anticlockwise rotation, to provide access for the extractor.