Angular cheilosis is frequently associated with the deficiency of:

 # Angular cheilosis is frequently associated with the deficiency of:

A. Thiamine

B. Riboflavin

C. Niacin

D. Folic acid

The correct answer is B. Riboflavin.

Magenta tongue (glossitis), fissures at corners of mouth (cheilosis), are common manifestations of  vitamin B2 deficiency. 

CLICK HERE FOR MORE MCQs

Lazarine leprosy is a variant of:

 # Lazarine leprosy is a variant of:

A. Lepromatous leprosy

B. Tuberculoid leprosy

C. Intermediate leprosy

D. Dimorphic leprosy

The correct answer is A. Lepromatous leprosy.

Lazarine leprosy: This an unusual type of the disease characterized by ulceration and gangrene. The early lesions are bullae, which soon rupture and become gangrenous. It includes achromic and hypochromic spots of the lepra called lazarine (systematized nervous lepra with leprous erythema, pemphigoid and escharotic), and finally of mixed lepra. 

CLICK HERE FOR MORE MCQs

Opsonins are:

 # Opsonins are:

A. C3a

B. IgM

C. Carbohydrate binding proteins

D. Selectins

The correct answer is C. Carbohydrate binding proteins.

Opsonins 

• Chemicals causing opsonisation 

• They are specific carbohydrate binding proteins 

Examples of opsonins 

• C3b 

• Fc fragment of antibody or IgG 

• Some serum proteins (like fibrinogen, mannose binding lectin and C reactive protein) 

CLICK HERE FOR MORE MCQs

Origin and insertion of which of the following muscles can be seen clearly from outside?

 # Origin and insertion of which of the following muscles can be seen clearly from outside?

A. Masseter

B. Platysma

C. Sternocleidomastoid

D. All of the above

The correct answer is C. Sternocleidomastoid.

Sternocleidomastoid forms the most important landmark on the side of the neck. It becomes prominent

when the face is turned to the opposite side and is seen as a raised ridge extending obliquely from the sternum to the mastoid process. It is the key muscle of the neck which extends obliquely across the side of the neck, dividing it into posterior and anterior triangles.

CLICK HERE FOR MORE MCQs

Chronological hypoplasia is:

 # Chronological hypoplasia is:

A. Hypoplasia of local origin

B. Hypoplasia of systemic origin

C. Hypoplasia of hereditary origin

D. None of the above

The correct answer is B. Hypoplasia of systemic origin.

Hypoplasia and hypocalcification may be caused by systemic, local or hereditary factors. Hypoplasia of systemic origin is termed as chronologic hypoplasia, because the lesion is found in the areas of those teeth where the enamel was formed during the systemic disturbance. 

CLICK HERE FOR MORE MCQs

Which of the following is most frequently noted in patient populations suffering from chronic temporomandibular joint disorder?

 # Which of the following is most frequently noted in patient populations suffering from chronic temporomandibular joint disorder?

A. Passive aggressive disorder

B. Borderline personality disorder

C. Sociopathy

D. Schizotypical behavior

E. Depression psychosis

The correct answer is E. Depression psychosis.

Depression psychosis is a condition which may worsen with the presence of TMJ dysfunction.

Several studies suggest that the presence of depression is a common condition among people experiencing chronic pain, especially TMD.

People most prone to TMJ possess a malocclusion. Other factors that cause TMJ disease include grinding teeth during sleep (bruxism), having an overbite, and rheumatoid arthritis.

CLICK HERE FOR MORE MCQs

Eruption time of deciduous maxillary second molar is:

 # Eruption time of deciduous maxillary second molar is:

A. 18 months

B. 20 months

C. 24 months

D. 28 months

The correct answer is D. 28 months.

The range of time for the crowns of primary dentition to fully erupt is between 7 to 30 months, whereas crown formation of all primary teeth is completed by 12 months of age. The range of time for the crowns of permanent dentition to fully erupt is between 6 to 13 years, (except for third molar).

CLICK HERE FOR MORE MCQs

The major connector of choice in a patient with high lingual frenum is:

 # The major connector of choice in a patient with high lingual frenum is:

A. Lingual bar

 B. Labial bar

C. Lingual plate

D. None of the above

The correct answer is C. Lingual plate.

Indications of Lingual plate mandibular major connector:

- When most posterior teeth are lost and additional indirect retention is required.

- When remaining teeth are not periodontally sound.

- When there is no space for lingual bar.

- Presence of inoperable mandibular tori.

- When patient has bilateral distal extension edentulous areas and resorbed ridges and when anterior teeth lack bony support.

- When one or more incisor teeth have to be replaced in the future. The lingual plate is preferred because additional teeth can be added by attaching retention loops to it.

- When there is excessive vertical ridge resorption in Kennedy’s class I cases to resist horizontal rotations.

CLICK HERE FOR MORE MCQs

Polyene antibiotics exhibit their action on:

 # Polyene antibiotics exhibit their action on:

A. Cell membrane

B. Cell wall

C. Cell nucleus

D. Ribosomes

The correct answer is A. Cell Membrane.

Amphotericin, the polyenes antibiotics, have high affinity for ergosterol of fungal cell membranes to orient themselves to produce micropore through which ions, amino acids and water-soluble substances move out. It is not effective against bacteria as it does not contain sterol in their cell membrane. 

CLICK HERE FOR MORE MCQs

Early bell stage is associated with:

 # Early bell stage is associated with:

A. Initiation

B. Proliferation

C. Histodifferentiation

D. Apposition

The correct answer is C. Histodifferentiation.

Morphologic stages and physiologic process related to each stage: 

• Dental lamina & Bud stage -Initiation 

• Cap stage -Proliferation 

• Early bell stage - Histodifferentiation 

• Advanced bell stage - Morpho-differentiation 

• Formation of enamel & dentin matrix - Apposition 

CLICK HERE FOR MORE MCQs

Treatment of dehydrated child patient is:

 # Treatment of dehydrated child patient is:

A. 0.9% normal saline

B. 5% dextrose

C. 10% dextrose

D. 50% dextrose

The correct answer is B. 5% dextrose.

5% dextrose supplies calories, but not electrolytes. The solution can only be used when the patient does not require any electrolytes but a solution to replenish his blood volume along with some nutrition.

CLICK HERE FOR MORE MCQs

Conjugated and unconjugated bilirubins are increased in:

 # Conjugated and unconjugated bilirubins are increased in: 

A. Prehepatic jaundice 

B. Hepatocellular jaundice 

C. Posthepatic jaundice

D. Hemolytic jaundice 

The correct answer is B. Hepatocellular jaundice.

In hepatocellular jaundice, bilirubin transport across the hepatocytes may be impaired at any point between uptake of unconjugated bilirubin into the cells and transport of conjugated bilirubin into the canaliculi. So the concentrations of both conjugated and unconjugated bilirubin in the blood increase. 

CLICK HERE FOR MORE MCQs

Strict vegetarian diet results in the deficiency of:

 # Strict vegetarian diet results in the deficiency of:

A. Vitamin B1

B. Biotin

C. Vitamin B12

D. Vitamin D

The correct answer is C. Vitamin B12.

Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It is important in the normal functioning of the nervous system via its role in the synthesis of myelin, and in the circulatory system in the maturation of red blood cells in the bone marrow. Plants do not need cobalamin and carry out the reactions with enzymes that are not dependent on it.

Vitamin B12 is the most chemically complex of all vitamins, and for humans, the only vitamin that must be sourced from animal-derived foods or supplements. Only some archaea and bacteria can synthesize vitamin B12. Most people in developed countries get enough B12 from the consumption of meat or foods with animal sources. Foods containing vitamin B12 include meat, clams, liver, fish, poultry, eggs, and dairy products. Grain-based foods can be enriched with the vitamin. Supplements and medications are available to treat and prevent vitamin B12 deficiency. They are taken by mouth, but for the treatment of deficiency may also be given as an intramuscular injection.

The diets of vegetarians and vegans may not provide sufficient B12 unless a dietary supplement is consumed. A deficiency in vitamin B12 may be characterized by limb neuropathy or a blood disorder called pernicious anemia, a type of megaloblastic anemia, causing a feeling of tiredness and weakness, lightheadedness, headache, breathlessness, loss of appetite, pins and needles sensations, changes in mobility, severe joint pain, muscle weakness, memory problems, decreased level of consciousness, brain fog, and many others. If left untreated in infants, deficiency may lead to neurological damage and anemia. Folate levels in the individual may affect the course of pathological changes and symptomatology of vitamin B12 deficiency.

CLICK HERE FOR MORE MCQs

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. 

CLICK HERE FOR MORE MCQs

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 

CLICK HERE FOR MORE MCQs

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 

CLICK HERE FOR MORE MCQs

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

CLICK HERE FOR MORE MCQs

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. 

CLICK HERE FOR MORE MCQs

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

CLICK HERE FOR MORE MCQs

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. 

CLICK HERE FOR MORE MCQs

Intracoronal retainer placed in the abutment tooth has the following disadvantage:

 # 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

A minor connector contacting the axial surface of an abutment should not be located on a:

 # A minor connector contacting the axial surface of an abutment should not be located on a:

A. Flat surface

B. Concavo-convex surface

C. Convex surface

D. Concave surface

The correct answer is C. Convex surface.

Minor connector contacting the axial surface of an abutment should not be located on a convex surface. Instead, it should be located in an embrasure. 

CLICK HERE FOR MORE MCQs

The first step in surveying the cast for RPD is:

 # The first step in surveying the cast for RPD is: 

A. Establishment of guiding plane

B. Establishments of undercuts for retention

C. Establishment of tooth contour for esthetics

D. Establishment of interferences for major connector

The correct answer is A. Establishment of guiding plane.

The step by step procedures in surveying are:

- Guiding planes

- Retentive areas

- Interferences

- Esthetics

CLICK HERE FOR MORE MCQs

A wrought wire clasp is considered most effective in Kennedy Class:

 # A wrought wire clasp is considered most effective in Kennedy Class: 

A. III cases for periodontally weakened abutment teeth

B. I cases for periodontally weakened abutment teeth

C. II cases for the non edentulous side

D. IV cases with periodontally weakened teeth

The correct answer is B. I cases for periodontally weakened abutment teeth.

The wrought wire clasp is generally considered to flex and be kinder to the abutment tooth periodontally although it engages the undercuts about two to three times greater than a cast clasp. 

CLICK HERE FOR MORE MCQs

# Cotton wool appearance is seen in:

 # Cotton wool appearance is seen in:

A. Paget’s disease

B. Osteomyelitis

C. Fibrous dysplasia

D. Achondroplasia

The correct answer is A. Paget's disease.

The radiographic appearance of chronic diffuse sclerosing osteomyelitis is, as the name suggests,

that of a diffuse patchy, sclerosis of bone often described as ‘cotton-wool’ appearance. This radiopaque lesion may be extensive and is sometimes bilateral. In occasional cases, there is bilateral involvement of both the maxilla and the mandible in the same patient. Because of the diffuse nature of the disease, the border between the sclerosis and the normal bone is often indistinct. The pattern may actually mimic Paget’s disease of bone or cemento-osseous dysplasia.

Reference: Shafer's 

CLICK HERE FOR MORE MCQs

Pathological calcification is seen in:

 # Pathological calcification is seen in:

A. Scleroderma

B. Lichen planus

C. Dystrophic epidermolysis bullosa

D. Lupus erythematosus

The correct answer is A. Scleroderma.

Pathologic calcification is a common process in a wide variety of disease states; it implies the abnormal deposition of calcium salts, together with smaller amounts of iron, magnesium, and other minerals. When the deposition occurs in dead or dying tissues, it is called dystrophic calcification; it occurs in the absence of derangements in calcium metabolism (i.e., with normal serum levels of calcium). In contrast, the deposition of calcium salts in normal tissues is known as metastatic calcification and is almost always secondary to some derangement in calcium metabolism (hypercalcemia). Of note, while hypercalcemia is not a prerequisite for dystrophic calcification, it can exacerbate it.

Systemic sclerosis can be classified into two groups on the basis of its clinical course:

• Diffuse scleroderma, characterized by initial widespread skin involvement, with rapid progression and early visceral involvement

• Limited scleroderma, with relatively mild skin involvement, often confined to the fingers and face. Involvement of the viscera occurs late, so the disease in these patients generally has a fairly benign course. This clinical presentation is also called the CREST syndrome because of its frequent features of calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia.

CLICK HERE FOR MORE MCQs

# Non disjunction of chromosome occurs in which stage?

 # Non disjunction of chromosome occurs in which stage?

A. Prophase

B. Metaphase

C. Anaphase

D. Telophase

The correct answer is C. Anaphase.

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (mitosis/meiosis). There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and failure of sister chromatids to separate during mitosis.

Meiosis II

Ovulated eggs become arrested in metaphase II until fertilization triggers the second meiotic division. Similar to the segregation events of mitosis, the pairs of sister chromatids resulting from the separation of bivalents in meiosis I are further separated in anaphase of meiosis II. In oocytes, one sister chromatid is segregated into the second polar body, while the other stays inside the egg. During spermatogenesis, each meiotic division is symmetric such that each primary spermatocyte gives rise to 2 secondary spermatocytes after meiosis I, and eventually 4 spermatids after meiosis II. Meiosis II-nondisjunction may also result in aneuploidy syndromes, but only to a much smaller extent than do segregation failures in meiosis I. 

Mitosis

Division of somatic cells through mitosis is preceded by replication of the genetic material in S phase. As a result, each chromosome consists of two sister chromatids held together at the centromere. In the anaphase of mitosis, sister chromatids separate and migrate to opposite cell poles before the cell divides. Nondisjunction during mitosis leads to one daughter receiving both sister chromatids of the affected chromosome while the other gets none. This is known as a chromatin bridge or an anaphase bridge. Mitotic nondisjunction results in somatic mosaicism, since only daughter cells originating from the cell where the nondisjunction event has occurred will have an abnormal number of chromosomes. Nondisjunction during mitosis can contribute to the development of some forms of cancer, e.g., retinoblastoma. Chromosome nondisjunction in mitosis can be attributed to the inactivation of topoisomerase II, condensin, or separase. Meiotic nondisjunction has been well studied in Saccharomyces cerevisiae. This yeast undergoes mitosis similarly to other eukaryotes. Chromosome bridges occur when sister chromatids are held together post replication by DNA-DNA topological entanglement and the cohesion complex. During anaphase, cohesin is cleaved by separase. Topoisomerase II and condensin are responsible for removing catenations. 

CLICK HERE FOR MORE MCQs

Mediators of inflammation are all EXCEPT:

 # Mediators of inflammation are all EXCEPT:

A. TNF

B. IFN

C. PG

D. Myeloperoxidase

The correct answer is D. Myeloperoxidase.

Myeloperoxidase is not an inflammatory mediator. It is an enzyme in neutrophils that convert Cl-, I- and SCN- ions to corresponding acids -HOCl etc. These acids are potent oxidants and help in destroying the invading organisms. 

CLICK HERE FOR MORE MCQs

Complication of duodenal ulcer:

 # Complication of  duodenal ulcer: 

A. Hypoacidity

B. Pernicious anemia

C. Stenosis

D. Malignant transformation

The correct answer is C. Stenosis.

Obstruction from edema or scarring occurs in about 2% of the patients. Most often due to pyloric channel ulcers. May also occur with duodenal ulcers.

CLICK HERE FOR MORE MCQs

Gluconeogenesis occurs in the liver and:

 # Gluconeogenesis occurs in the liver and ________.

 A. Kidney

 B. Muscle

 C. Heart

 D. Fat

The correct answer is A. Kidney.

Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose from certain non-carbohydrate carbon structures. 

In vertebrates, gluconeogenesis occurs mainly in the liver and, to a lesser extent, in the cortex of the kidneys. It is one of two primary mechanisms – the other being degradation of glycogen (glycogenolysis) – used by humans and many other animals to maintain blood sugar levels, avoiding low levels (hypoglycemia). Although most gluconeogenesis occurs in the liver, the relative contribution of gluconeogenesis by the kidney is increased in diabetes and prolonged fasting.

Gluconeogenesis is a pathway consisting of a series of eleven enzyme-catalyzed reactions. The pathway will begin in either the liver or kidney, in the mitochondria or cytoplasm of those cells, this being dependent on the substrate being used. Many of the reactions are the reverse of steps found in glycolysis. 

CLICK HERE FOR MORE MCQs

Fluid mosaic model of membrane structure was proposed by:

 # Fluid mosaic model of membrane structure was proposed by:

A. Watson and Crick

B. Edward H. Angle

C. G.V. Black

D. Singer and Nicolson

The correct answer is D. Singer and Nicolson.

The fluid mosaic model explains various observations regarding the structure of functional cell membranes. According to this biological model, there is a lipid bilayer (two molecules thick layer consisting primarily of amphipathic phospholipids) in which protein molecules are embedded. The phospholipid bilayer gives fluidity and elasticity to the membrane. Small amounts of carbohydrates are also found in the cell membrane. The biological model, which was devised by SJ Singer and G. L. Nicolson in 1972, describes the cell membrane as a two-dimensional liquid that restricts the lateral diffusion of membrane components. 

CLICK HERE FOR MORE MCQs

Which of the following does not occur in mitochondria?

 # Which of the following does not occur in mitochondria?

A. TCA

B. HMP shunt

C. Urea cycle

D. Beta oxidation of fatty acids

The correct answer is B. HMP shunt.

HMP shunt or hexose monophosphate pathway or pentose phosphate pathway (PPP) or phosphogluconate pathway : for oxidation of glucose as an alternative pathway to glycolysis and TCA cycle. Enzymes for HMO shunt are located in cytosol/cytoplasm.

CLICK HERE FOR MORE MCQs

Muller’s muscle is seen in:

 # Muller’s muscle is seen in:

A. Nose tip

B. Upper eye lid

C. Lower eye lid

D. Mid canthus

The correct answer is B. Upper eyelid.

Posterior to the levator aponeurosis is the underlying Muller's muscle complex- Orbitalis muscle or the circular fibres of the ciliary muscle, both of which are also known as Muller's muscle. 

CLICK HERE FOR MORE MCQs

Why is morphine contraindicated in maxillofacial injury or head injury?

 # In patients with maxillofacial injury, narcotics like morphine are contraindicated because:

A. Morphine causes miosis

B. Morphine causes mydriasis

C. Morphine is respiratory irritant

D. Morphine is circulatory depressant

The correct answer is A. Morphine causes miosis.

Miosis masks the neurological signs of cerebral hemorrhage.

  Morphine is a phenanthrene derivative opioid analgesic. It is contraindicated in head injuries due to:

- Retention of carbondioxide leading to increased intracranial pressure

- exaggerated depression of respiration and the potential need to control ventillation of the patient must be considered

- vomitting, miosis (miosis will interrupt in monitoring the eye signs in case of probable head injury in the patients of maxillofacial injury), and altered mental state interfere with assessment of prognosis in patients with head injury

CLICK HERE FOR MORE MCQs

‘Chicken-wire’ appearance of enlarged bone marrow spaces is seen in:

 # ‘Chicken-wire’ appearance of enlarged bone marrow spaces is seen in:

A. Fetal alcohol syndrome

B. Sickle cell anemia

C. Hemophilia A

D. Beta thalassemia major

The correct answer is D. Beta thalassemia major.

Radiographic changes of thalassemia include generalized rarefaction of alveolar bone, chicken-wire appearance of enlarged marrow spaces and coarse trabeculation. In the skull, proliferation of marrow may completely erode the cortex, leaving only periosteum, and produce a ‘hair-on-end’ radiographic appearance.

CLICK HERE FOR MORE MCQs

Enamel can act in a sense like a:

# Enamel can act in a sense like a:

A. Permeable membrane

B. Impermeable membrane

C. Semipermeable membrane

D. Infrapermeable membrane

 

The correct answer is C. Semipermeable membrane.

Another physical property of enamel is its permeability. It has been found with radioactive tracers that the enamel can act in a sense like a semipermeable membrane, permitting complete or partial passage of certain molecules: 14C-labeled urea, I, etc. The same phenomenon has also been demonstrated by means of dyes.

Reference: Orban's

CLICK HERE FOR MORE MCQs

All primary teeth would have begun to calcify by:

 # All primary teeth would have begun to calcify by:

A. 14 weeks of intrauterine life

B. 18-20 weeks of intrauterine life

C. 6 months of gestation

D. 6 months of age

The correct answer is B. 18-20 weeks of intrauterine life.

Calcification of the primary teeth begins in utero from 13 to 16 weeks postfertilization. By 18 to 20 weeks, all the primary teeth have begun to calcify. Primary tooth crown formation takes only about 2 to 3 years from initial calcification to root completion. However, mineralization of the permanent dentition is entirely postnatal, and the formation of each tooth takes about 8 to 12 years.

Reference: Wheeler's

CLICK HERE FOR MORE MCQs

Major salivary buffer is:

 # Major salivary buffer is:

A. Protein buffer

B. Carbonic acid and bicarbonate

C. Phosphate buffer

D. Albumin

The correct answer is B. Carbonic acid and bicarbonate.

The maintenance of the physiologic hydrogen ion concentration (pH) at the mucosal epithelial cell surface and the tooth surface is an important function of salivary buffers. The primary effect of these buffers has been studied in relationship to dental caries. In saliva, the most important salivary buffer is the bicarbonate– carbonic acid system. Saliva also contains coagulation factors (i.e., factors VIII, IX,

and X; plasma thromboplastin antecedent; and Hageman factor) that hasten blood coagulation and that protect wounds from bacterial invasion. An active fibrinolytic enzyme may also be present. 

CLICK HERE FOR MORE MCQs

Gingival enlargement can be expected in all of the following patients EXCEPT:

 # Gingival enlargement can be expected in all of the following patients EXCEPT:

A. A patient who has undergone kidney transplant

B. A patient with COPD

C. An epileptic patient

D. Patient on antihypertensive therapy

The correct answer is B. A patient with COPD.

Gingival enlargement is a well-known consequence of the administration of some anticonvulsants (epileptic patient), immunosuppressants (organ transplant recipient), and calcium channel blockers (antihypertensive). The condition may create speech, mastication, tooth eruption, and aesthetic problems.  

CLICK HERE FOR MORE MCQs

Which of the following cytokeratin is not found in orthokeratinized epithelium?

 # Which of the following cytokeratin is not found in orthokeratinized epithelium?

A. K9

B. K10

C. K11

D. K19

The correct answer is D. K19

Keratins K1, K2, and K10 through K12, which are specific to epidermal-type differentiation, are immunohistochemically expressed with high intensity in orthokeratinized areas and with less intensity in parakeratinized areas. K6 and K16, which are characteristic of highly proliferative epithelia, and K5 and K14, which are stratification-specific cytokeratins, also are present. Parakeratinized areas express K19, which is usually absent from orthokeratinized normal epithelia.

CLICK HERE FOR MORE MCQs

PDL fibers that prevent extrusion are:

 # PDL fibers that prevent extrusion are: 

A. Horizontal

B. Oblique

C. Transseptal

D. Alveolar crest fibers

The correct answer is D. Alveolar crest fibers.

Alveolar crest fibers extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest. Fibers also run from the cementum over the alveolar crest and to the fibrous layer of the periosteum that covers the alveolar bone. The alveolar crest fibers prevent the extrusion of the tooth and resist lateral tooth movements. The incision of these fibers during periodontal surgery does not increase tooth mobility unless significant attachment loss has occurred.

Reference: Carranza's

CLICK HERE FOR MORE MCQs

Elastic fiber component of periodontal ligament with age:

 # Elastic fiber component of periodontal ligament with age:

A. Remains same

B. Increases

C. Decreases

D. Either increases or decreases with age

The correct answer is B. Increases. 

Changes in the periodontal ligament that have been reported with aging include decreased numbers of fibroblasts and a more irregular structure, thus paralleling the changes seen in the gingival connective tissues. Other findings include decreased organic matrix production, epithelial cell rests, and increased amounts of elastic fiber.

CLICK HERE FOR MORE MCQs

All of the following conditions affect oral and perioral tissues and are self-limiting EXCEPT:

 # All of the following conditions affect oral and perioral tissues and are self-limiting EXCEPT:

A. Varicella

B. Herpangina

C. Erythema multiforme

D. Hand, foot and mouth disease

E. Lupus erythematosus

The correct answer is E. Lupus erythematosus.

Lupus erythematosus (LE) may be seen in one of two well recognized forms: systemic (acute) lupus erythematosus (SLE) and discoid (chronic) lupus erythematosus (DLE), both of which may have oral manifestations. A third form, known as subacute lupus, has also been described. In the spectrum of LE, SLE is of particular importance because of the profound impact it has on many organs. DLE is the less aggressive form, predominantly affecting the skin and rarely progressing to the systemic form. It may, however, be of great cosmetic significance because of its predilection for the face. Subacute cutaneous LE, described as lying intermediate between SLE and DLE, results in skin lesions of mild to moderate severity. It is marked by mild systemic involvement and the appearance of some abnormal autoantibodies.

DLE is usually treated with topical corticosteroids. Highpotency corticosteroid ointments can be used intraorally. In refractory cases, antimalarials or sulfones may be used. Systemic steroids may be used in the treatment of SLE. The prednisone dose is generally dependent on the severity of the disease, and prednisone may be combined with immunosuppressive agents for their therapeutic and steroid-sparing effects. Antimalarials and nonsteroidal antiinflammatory drugs may help control this disease.

Reference: Oral Pathology Clinical Pathologic Correlations, Regezi, Sciubba, Jordan (2016)

CLICK HERE FOR MORE MCQs

Microscopic feature responsible for the clinical appearance of Wickham striae

 # Which of the following microscopic features is responsible for the clinical appearance of Wickham striae?

A. Fibrin deposition

B. Reduced vascularity

C. Acantholysis

D. Hyperkeratosis

E. Intracellular keratinocyte edema

The correct answer is D. Hyperkeratosis.

Several types of lichen planus within the oral cavity have been described. The most common type is the reticular form, which is characterized by numerous interlacing white keratotic lines or striae (so-called Wickham’s striae) that produce an annular or lacy pattern. The buccal mucosa is the site most commonly involved. 

CLICK HERE FOR MORE MCQs

Legally dental records are the property of:

 # Legally dental records are the property of:

A. The patient

B. The dentist

C. The state

D. None of the above

The correct answer is B. The Dentist.

Dental radiographs should be kept indefinitely. The dental record must include documentation of informed consent and the exposure of radiographs (e.g., the number and type of films, the rationale for exposure and the interpretation). Legally, dental radiographs are the property of the dentist. Patients do,

however, have a right to reasonable access to the dental radiographs, which includes having a copy of the radiographs forwarded to another dentist.

Patients may refuse dental x-rays, however the dentist must decide whether an accurate diagnosis can be provided and whether treatment can provided.

*** No document can be signed by the patient that releases the dentist from liability.

CLICK HERE FOR MORE MCQs

The biggest advantage of pulp revascularization in endodontics is:

 # The biggest advantage of pulp revascularization in endodontics is:

A. Achieving continued root development

B. No additional material such as TCP or MTA is required

C. No obturation is needed

D. After control of infection, it can be completed in a single visit

The correct answer is A. Achieving continued root development.

Revascularization is a new treatment method for immature (open apex) necrotic permanent teeth. This technique allows the growth of root even when the pulp is necrotic. This helps in strengthening and avoiding damage to the remaining thin and fragile walls of the immature apex. The main aim of this technique is stimulating the residual apical pulp stem cells which are able to survive due to the abundant blood supply in the open apex cases.

Revascularization procedure aids in:

- Stimulation of odontoblasts or undifferentiated mesenchymal cells at the periapex

- Deposition of the calcific material at the apex as well as lateral dentinal walls

- Normal maturation of the entire root

CLICK HERE FOR MORE MCQs

MTA can be dissolved by adjunct solution of:

 # Set white MTA can be dissolved by adjunct solution of:

A. Carbonic acid

B. Normal saline

C. Sodium hypochlorite

D. Hydrogen peroxide

The correct answer is A. Carbonic acid. 

Carbonic acid can be effectively used as an adjunct to set white MTA even after 21 days.

CLICK HERE FOR MORE MCQs

Indications for Prenatal Diagnosis by lnvasive Testing

 Principal Indications for Prenatal Diagnosis by lnvasive Testing

- Advanced maternal age (greater than 35 years)

- Previous child with de novo chromosomal aneuploidy

- Presence of structural chromosome abnormality in one of the parents

- Family history of a genetic disorder that may be diagnosed or ruled out by biochemical or DNA analysis

- Family history of an X-linked disorder for which there is no specific prenatal diagnostic test

- Risk of a neural tube defect (first degree relatives of patients with neural tube defects)

- Fetal abnormalities are suspected on Maternal serum screening and ultrasound examination 

Which of the following is not a sporicidal disinfectant?

 # Which of the following is not a sporicidal disinfectant?

A. Glutaraldehyde

B. Formaldehyde

C. Ethylene oxide

D. Benzalkonium chloride

The correct answer is D. Benzalkonium chloride.

Sporicidal agents are: 

E- Ethylene oxide

F- Formaldehyde

G- Glutaraldehyde

H- Halogens 

Benzalkonium chloride is quartenary ammonium antiseptic which is not sporicidal. Only aldehydes, halogens and ethylene oxide are sporicidal disinfectants. 

Formaldehyde is active against the amino group in the protein molecule. In aqueous solutions, it is marked bactericidal, sporicidal and virucidal. It is used to preserve anatomical specimens and for destroying anthrax spores in hair and wool. 10% formalin containing 0.5% sodium tetraborate is used to sterilize clean metal instruments. 

Glutaraldehyde has an action similar to that of formaldehyde. It is especially effective against the tubercle bacilli, fungi and viruses. 

Ethylene oxide is a colorless liquid with a boiling point of 10.7 degree centigrade and highly penetrating at normal temperature and pressure. Therefore, ethylene oxide can be used for sterilization of heat sensitive equipments like heart lung machine, respirators and dental equipment. 

CLICK HERE FOR MORE MCQs

Which of the following cannot be reliably used for handwashing?

# Which of the following cannot be reliably used for handwashing?

A. Lysol

B. Cresol

C. Isopropyl alcohol

D. Chlorhexidine

The correct answer is A. Lysol.

Lysol is a phenolic compound derived from coal tar and is highly toxic to humans. It is recommended for disinfection of surfaces in hospital. 

These can be reliably used for handwashing: 

- Chlorhexidine

- Alcohols (isopropyl alcohol, ethyl alcohol)

- Iodine

- Cresol

- Chloroxylenol (dettol)

- Hexachlorophane

- Tincture of iodine

CLICK HERE FOR MORE MCQs

Pseudomonal infection should not be cleaned by:

 # Pseudomonal infection should not be cleaned by:

A. Dettol

B. Hypochlorite

C. Chlorine

D. Betadine

The correct answer is A. Dettol.

Pseudomonas aeruginosa is heat-labile bacteria, readily killed at 55 degrees celcius in 1 hour. It is also highly susceptible to acid, silver salts, 2% alkaline glutaraldehyde, and disinfectants. 

Due to its sensitivity to silver salts, silver sulphonamide compounds have been used as topical cream in burns. However, Pseudomonas aeruginosa is very strongly resistant to common antiseptics and disinfectants, such as chloroxylenol (dettol), hexachlorophane and quartenary ammonium compounds. Indeed, selective media have been devised for isolation of Pseudomonas aeruginosa incorporating dettol or cetrimide. 

CLICK HERE FOR MORE MCQs