Restricting size of beam is done by:

 # Restricting size of beam is done by:

A. Collimator

B. Transformer

C. Tube head seal

D. Beam indicating device

The correct answer is A. Collimator.

A collimator is a metallic barrier with an aperture in the middle used to restrict the size of the x-ray beam and the volume of tissue irradiated. Round and rectangular collimators are most frequently used in dentistry. Dental x-ray beams are usually collimated to a circle 4 inches (7 cm) in diameter at the patient’s face. A round collimator is a thick plate of radiopaque material (usually lead) with a circular opening centered over the port in the x-ray head through which the x-ray beam emerges. Typically, round collimators are built into open-ended aiming cylinders. Rectangular collimators further limit the size of the beam to just larger than the x-ray film, further reducing patient exposure. Some types of film-holding instruments also provide rectangular collimation of the x-ray beam. 

Reference: White and Pharoah's Oral Radiology, 7th Edition

In CBCT technology, the speed with which individual images are acquired is called:

 # In CBCT technology, the speed with which individual images are acquired is called:

A. Running rate

B. Frame rate

C. Projection rate

D. Image rate

The correct answer is B. Frame rate.

The number of images constituting the projection data throughout the scan is determined by the detector frame rate (number of images acquired per second), the completeness of the trajectory arc (180 to 360 degrees), and the rotation speed of the source and detector. The number of basis images making up a single scan set may be fixed or variable. Higher frame rates have both desirable and undesirable effects. Higher frame rates increase the signal-to-noise ratio, producing images with less noise and reducing metallic artifacts. However, a higher frame rate is associated with a longer scan time and higher patient dose. In addition, more data are obtained, and primary reconstruction time is increased.

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Hemorrhage secondary to heparin administration can be corrected by administration of:

 # Hemorrhage secondary to heparin administration can be corrected by administration of:

A. Vitamin K

B. Whole blood

C. Protamine

D. Ascorbic acid

The correct answer is C. Protamine.

The half life of intravenous heparin is about one hour and if a patient bleeds, it is usually sufficient just to discontinue the infusion; however if the bleeding is severe, the excess can be neutralized with intravenous protamine.

# Most reliable method of identification of a person is by:

# Most reliable method of identification of a person is by:

A. Anthropometry

B. DNA finger printing

C. Dactylography

D. Dentition

The correct answer is C. Dactylography.

• Derived from GK word daktylose-finger ,graphein- to write

Dactylography is the method of identification based on unique epidermal ridge pattern on the tips of fingers. It is a most accurate and unfailing method of positive identification. No Two Individual will have identical fingerprints It is better method of identification than DNA profiling. DNA profiling would be same in identical twins but fingerprints are different. Fingerprints remain permanent throughout life and even after death and in advance stage of decomposition. Fingerprints have general characteristic ridge patterns that permit them to be systematically classified. Pattern can be easily emailed and printed, enabling intercontinental criminals to be caught easily.

Marked salivary gland hypofunction

 # Stimulated whole salivary flow rate of less than _____ ml/min indicates marked salivary gland hypofunction. 

A. 0.6 

B. 0.7 

C. 0.8 

D. 0.9 

The correct answer is B. 0.7.

It is difficult to define absolute “normal” values for salivary output due to great interindividual variability and, consequently, a large range of normal values exists. About 0.3– 0.4 mL/min for unstimulated flow and 1.5–2.0 mL/min for stimulated flow are considered normal. Unstimulated whole

saliva flow rates of < 0.1 mL/min and stimulated whole saliva flow rates of < 0.7 mL/min are abnormally low and indicative of marked salivary gland hypofunction. Higher levels of output do not guarantee that function is normal, however, as they may represent marked hypofunction for some individuals. Therefore, these stated values represent a lower limit of normal and should serve only as a guide for the clinician.

Reference: Burket’s Oral Medicine, Thirteenth Edition

The presence of fluoride in communal water supplies have demonstrated appreciably lesser benefits, this is due to:

 # The presence of fluoride in communal water supplies have demonstrated appreciably lesser benefits, this is due to 

A. Adverse effect 

B. Halo effect 

C. Bacteriostatic effect 

D. None of the above 

The correct answer is B. Halo effect.

Several studies concerning the reduced prevalence of dental caries associated with the presence of fluoride in communal water supplies have demonstrated appreciably lesser benefits, typically ranging between 18% and 30%. This decrease in attributable benefit is due to the so-called halo effect associated with the preparation of numerous foods and beverages in fluoridated communities and their consumption in nonfluoridated communities.

Reference: Mc Donald 2nd South Asian Edition

The reversal agent used in clinical practice to treat benzodiazepine overdose:

 The reversal agent used in clinical practice to treat benzodiazepine overdose

A. Romazicon 

B. Naloxone

C. Sublimaze

D. Demerol

The correct answer is A. Romazicon.

-Flumazenil (Romazicon) is a direct, specific reversal agent used in clinical practice to treat benzodiazepine overdose. Pharmacologically, it acts as a competitive antagonist at the benzodiazepine receptor sites in the CNS. 

-Naloxone is a life-saving medication that can reverse an overdose from opioids, including heroin, fentanyl, and prescription opioid medications.

-Fentanyl (Sublimaze) is a potent synthetic opiate agonist. A dose of 0.1 mg is approximately equivalent to 10 mg of morphine or 75 mg of meperidine. Fentanyl acts rapidly, and after intramuscular injection the onset occurs in 7–15 min; duration of effects is 1– 2 h.

-Meperidine (Demerol) is a synthetic opiate agonist, closely related to fentanyl in chemical structure.

Reference: Mc Donald 2nd South Asian Edition

Genetic factors play a role in the aetiology of:

 # Genetic factors play a role in the aetiology of: 

A. Chronic periodontitis 

B. Aggressive periodontitis 

C. Both of the above 

D. None of the above 

The correct answer is C. Both of the above.

Though genetic factors play a dominant role in Aggressive cases, they are considered to be the aetiological factors in all kinds of periodontitis. 

Incisor liability in maxillary arch

 # Incisor liability is about ………..in maxillary arch.

A. 4.6 mm 

B. 5.4 mm 

C. 6.2 mm 

D. 7.6 mm 

The correct answer is D. 7.6 mm.

Incisor liability is about 7.6 mm in maxillary arch and 6 mm in mandibular arch. The incisor liability is compensated by three mechanisms:

a. Increased intercanine width: During the period of permanent incisor eruption, significant amount of increase in intercanine arch width occurs. It is about 3–4 mm.

b. Interdental spacing: Spacing present in primary dentition helps in alignment of incisor. The primate space present in the upper arch mesial to primary canine is also used.

c. Labial eruption of incisor: Primary incisor stand upright. The permanent incisors, which replace them, are labially proclined placing them in a wider arch.

Source: Mc Donald 2nd South Asian Edition

Salt and pepper appearance in radiograph is seen in:

# Salt and pepper appearance in radiograph is seen in:

A. Osteoporosis

B. Osteopetrosis

C. Sickle cell anemia

D. Thalassemia

The correct answer is D. Thalassemia.

"Crew - cut" or "Hair - on - end" appearance of skull is characteristic of both sickle cell anemia and thalassemia. In thalassemia radiographs of maxilla and mandible shows characteristic apparent coarsening of some trabeculae and the blurring and disappearance of others, resulting in "salt and pepper" effect.

Primary HSV infection for first few days is associated with elevated level of immunoglobulin:

 # Primary HSV infection for first few days is associated with elevated level of immunoglobulin: 

A. IgG 

B. IgA 

C. IgM 

D. IgE 

The correct answer is C. IgM.

Primary HSV infection is associated with elevated immunoglobulin (Ig)M titers that occur within days, followed several weeks later by permanent IgG titers (seroconversion) that indicate previous infection but confer no protection against reactivation. Recurrent infection is associated with a rise in IgG antibody titer in acute and convalescent sera, but a fourfold rise (a criterion that indicates active infection) is seen in only 5% of patients. The assay for HSV IgM is not particularly reliable for diagnostic purposes and overall, the use of serology to diagnose recurrent infection is not advised.

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HSV-1 infection spreading through the sport of wrestling

 # HSV-1 infection of skin spread through the sport of wrestling. This is called: 

A. Herpetic whitlow 

B. Herpes gladiatorum 

C. Herpes zoster sine 

D. Herpetic shingles 

The correct answer is B. Herpes gladiatorum.

HSV‐1 or ‐2 may cause herpes whitlow, an infection of the fingers when virus is inoculated into the fingers through a break in the skin. This was a common occupational hazard (including within the dental profession) before the widespread use of gloves. Other HSV‐1 infections include herpes gladiatorum (infections of the skin spread through the sport of wrestling), herpes encephalitis, HSV esophagitis, HSV pneumonia and neonatal and disseminated infection.

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Stieglitz pliers are used to:

 # Stieglitz pliers are used to:

A. Contour matrix bands

B. Hold the silver point

C. Remove roots during hemisection

D. Place rubber dam clamp on the tooth

The correct answer is B. Hold the silver point.

Stieglitz forceps come with carbide tips for extra grip and are used for retrieving separated files, silver points, and root fragments.

For the orientation use the following:

North South (N/S) - bucco-lingual chamber orientation of anteriors and bicuspids

East West (E/W) - mesio-distal chamber orientation of molars

Penetration of sealers into the detinal tubules mainly depends on:

 # Penetration of sealers into the dentinal tubules mainly depends on:

A. Sealer thickness

B. Method of obturation

C. Type of final irrigant used

D. Type of sealer

The correct answer is B. Method of obturation.

The smear layer may interfere with the adhesion and penetration of root canal sealers. It also may prevent gutta-percha penetration during thermoplastic techniques. Significant tubular penetrations of gutta-percha and sealers have been reported with thermoplasticized obturations and with dentin-bonded composite resins. Removal of the smear layer also enhances the adhesion of sealers to dentin and tubular penetration. Root canal filling materials adapt better to the canal walls after smear layer removal.

Which of the following statements applies to globular dentin?

 # Which of the following statements applies to globular dentin? 

a. Deposited first along the dentinoenamel junction. 

b. Mineralized by matrix vesicles. 

c. Separates mantle dentin from circumpulpal dentin. 

d. Secreted by immature odontoblasts. 

The correct answer is C. Separates mantle dentin from circumpulpal dentin.

Sometimes mineralization of dentin begins in small globular areas that fail to coalesce into a homogeneous mass. This results in zones of hypomineralization between the globules. These zones are known as globular dentin or interglobular spaces. This dentin forms in the crowns of teeth in the circumpulpal dentin just below the mantle dentin, and it follows the incremental pattern. The dentinal tubules pass uninterruptedly through interglobular dentin, thus demonstrating defect of mineralization and not of matrix formation. 

Which is NOT a paired bone of the skull?

 # Which is NOT a paired bone of the skull?

a. Nasal.

b. Maxilla.

c. Lacrimal.

d. Sphenoid.

The correct answer is D. Sphenoid. 

Out of the 8 cranial bones, Parietal and Temporal are only paired. Occipital, Sphenoid, Frontal and Ethmoid are unpaired bones of the skull. Nasal, Maxilla and Lacrimal bones are paired though they don't constitute the cranium, they are facial bones.

Admixed high copper alloy powder contains:

  # Admixed high copper alloy powder contains:

A. 9-20% copper

B. 13-20% copper

C. 9-30% copper

D. 13-30% copper

The correct answer is A. 9-20% copper.

In low copper alloys, copper is less than 6% by weight. In high copper single composition alloys, 13-30% copper by weight is present whereas in high copper admixed alloys, 9-20% copper is present.



Back pressure porosity can be avoided by:

  # Back pressure porosity can be avoided by:

A. Using asbestos liners

B. Placing the sprue at least one quarter inch away from the end of casting ring

C. Preventing rapid heating of investment

D. Using a short and wide sprue

The correct answer is B. Placing the sprue at least one quarter inch away from the end of casting ring

Entrapped air bubbles on the inner surface of the casting, sometimes referred to as back-pressure porosity, can produce large concave depressions. This is caused by the inability of the air in the mold to escape through the pores in the investment or by the pressure gradient that displaces the air pocket toward the end of the investment via the molten sprue and button. The incidence of entrapped air can be increased by the use of the dense modern investments.

All castings probably contain a certain amount of porosity, as exemplified by the photomicrographs. This should be minimized because it may adversely affect the physical properties of the casting. Proper burnout, an adequate mold and casting temperature, a sufficiently high casting pressure, and a proper investment L/P ratio can minimize or eliminate entrapped air porosity. It is good practice to make sure that the thickness of investment between the tip of the pattern and the end of the ring is not greater than 6 mm. 



Dull aching, continuous pain is transmitted by which of these nerve fibers

  # Dull aching, continuous pain is transmitted by which of these nerve fibers?

A. A delta fibers

B. B fibers

C. C fibers

D. A alpha fibers

The correct answer is C. C fibers.

C fibers transmit late, dull pain due to its high threshold. The C fibers are unmyelinated, have slower conduction velocity and are associated with a dull, aching or burning sensation.



First number in the instrument formula indicates:

  # First number in the instrument formula indicates:

A. Length of the blade in centimeters

B. 1/10th of the width

C. Angulation of the blade in degrees

D. Primary cutting edge angle

The correct answer is B. 1/10th of the width.

The complete instrument formula (four numbers) is expressed as the blade width (1) in 0.1-mm increments, cutting edge angle (2) in centigrades, blade length (3) in millimeters, and blade angle (4) in

centigrades.

Reference: Sturdevant's, 2018, Mosby



Nasolabial cyst is thought to arise from:

  # Nasolabial cyst is thought to arise from:

A. Remnant of cell rest of Serres

B. Remnant of cell rest of Malassez

C. Remnant of cell rest of embryonic lacrimal duct

D. Maxillary sinus lining epithelium

The correct answer is C. Remnant of cell rest of embryonic lacrimal duct.

Nasolabial cyst is a very uncommon cyst which forms outside the bone in the soft tissues, deep to the nasolabial fold. It probably arises from the lower end of the nasolacrimal duct and is occasionally

bilateral. It presents over a wide age range, mostly in middle-aged adults, and much more commonly in females. The cysts form soft tissue swellings in the upper lip, distort the nostril and cause pressure resorption of the anterior maxilla if large. 



Buccal cusp of maxillary tooth placed lingual to the lingual cusp of mandibular posterior teeth is referred to as:

 # Buccal cusp of maxillary tooth placed lingual to the lingual cusp of mandibular posterior teeth is referred to as: 

A. Buccal occlusion

B. Buccal non occlusion

C. Lingual non occlusion

D. Lingual occlusion

The correct answer is C. Lingual non occlusion.

The standard probing depth, which requires referral to periodontist, at the time of evaluation of phase 1:

 # The standard probing depth, which requires referral to periodontist, at the time of evaluation of phase 1: 

A. 5 mm 

B. 6 mm 

C. 7 mm 

D. 8 mm 

The correct answer is A. 5 mm.

Pocket depth of 5 and above should be referred to a periodontist.

The deficiency of which of the following nutrients is well tolerated by humans?

 # The deficiency of which of the following nutrients is well tolerated by humans?

A. Carbohydrate

B. Lipid

C. Protein 

D. Vitamins

The correct answer is A. Carbohydrate.

Carbohydrates are the polyhydroxyaldehydes or ketones, or campounds which produce them on hydrolysis. The term sugor is applied to carbohydrates soluble in water and sweet to taste. Carbohydrates are the major dietary energy sources, besides their involvement in cell structure and various other functions.

Carbohydrates are broadly classified into 3 groups- monosaccharides, oligosoccharides, and polysaccharides. The monosacchsrides are further divided into different categories based an the presence of functional groups (aldoses or ketoses) and the number of carbon atoms (trioses, tetroses, pentases, hexoses and heptoses).

Glyceraldehyde (triose) is the simplest carbohydrate and is chosen as a reference to write the configuratian of all other monasaccharides (D- and L- forms). If two monosaccharides differ in their structure around a single carbon atom, they are known as epimers. Glucose and galactose are C4-epimers. 

Maltose which is produced as a breakdown product of starch is:

 # Maltose which is produced as a breakdown product of starch is:

A. Monosaccharide

B. Disaccharide

C. Trisaccharide

D. Polysaccharide

The correct answer is B. Disaccharide.

Sucrose, lactose and maltose are disaccharides.

Sucrose = Glucose + Fructose

Lactose = Galactose + Glucose

Maltose = Glucose + Glucose

Which of the following is a monosaccharide?

 # Which of the following is a monosaccharide? 

a. Galactose 

b. Lactose 

c. Maltose 

d. Sucrose 

The correct answer is A. Galactose.

Sucrose, lactose and maltose are disaccharides.

Sucrose = Glucose + Fructose

Lactose = Galactose + Glucose

Maltose = Glucose + Glucose

In the plasma membrane, glycolipids are usually situated in:

 # In the plasma membrane, glycolipids are usually situated in:

a. Cannot be predicted, it varies according to the cell types. 

b. Inner leaflet of plasma the membrane. 

c. Outer leaflet of the plasma membrane. 

d. Evenly distributed in both outer and inner leaves of plasma membrane. 

The correct answer is C. Outer leaflet of the plasma membrane.

Glycolipids are found on the outer leaflet of cellular membranes where it play not only a structural role to maintain membrane stability but also facilitates cell to cell communication acting as receptors, anchors for protein and regulators of signal transduction. Cell surface carbohydrates play major roles in cell substrate recognition in oncogenesis, cell adhesion in metastasis.

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