Use of intensifying screen is:

 # Use of intensifying screen is:

a. to decrease scattered radiation 

b. to decrease patient radiation 

c. to increase contrast 

d. to increase number of photons striking the anode filament 

The correct answer is B. To decrease patient radiation.

The presence of intensifying screens creates an image receptor system that is 10 to 60 times more sensitive to x-rays than the film alone. Consequently, the use of intensifying screens substantially reduces the dose of x radiation to the patient. Intensifying screens are used with films for virtually all extraoral radiography, including panoramic, cephalometric, and skull projections.

Digital radiography differs from conventional in:

 # Digital radiography differs from conventional in:

a. X-rays not used 

b. Rays other than X-rays are used 

c. Radiation receptors are different 

d. No hard copy is formed 

The correct answer is C. Radiation receptors are different.

Digital image receptors encompass numerous different technologies and come in many different sizes and shapes. Numerous different and sometimes confusing names are in use to identify these receptors in medicine and dentistry. The most useful distinction is that between two main technologies: (1) solid-state technology and (2) photostimulable phosphor (PSP) technology. Although  solid-state detectors can be subdivided further, these detectors have in common certain physical properties and the ability to generate a digital image in the computer without any other external device.

In medicine, the use of solid-state detectors is referred to as digital radiography. In dentistry, intraoral solid-state detectors are often called sensors. The other main technology, PSP, consists of a phosphor-coated plate in which a latent image is formed after x-ray exposure. The latent image is converted to a digital image by a scanning device through stimulation by laser light. This technology is sometimes referred to as storage phosphor on the basis of the notion that the image information is temporarily stored within the phosphor. Other times the term image plates is used to differentiate them from film and solid-state detectors. The use of PSP plates in medical radiology is referred to as computed radiography.

Tzanck smear test is used in the diagnosis of:

 # Tzanck smear test is used in the diagnosis of :

a. Pemphigus 

b. ANUG 

c. Aphthous disease 

d. Lichen planus 

The correct answer is A. Pemphigus.

Pemphigus as an entity is characterized microscopically by the formation of a vesicle or bulla entirely intraepithelially, just above the basal layer producing the distinctive suprabasilar ‘split’. Prevesicular edema appears to weaken this junction, and the intercellular bridges between the epithelial cells disappear. This results in loss of cohesiveness or acantholysis, and because of this, clumps of epithelial cells are often found lying free within the vesicular space. These have been called ‘Tzanck cells’ and are characterized particularly by degenerative changes which include swelling of the nuclei and hyperchromatic staining. These changes are particularly obvious in cytologic smears taken from early, freshly opened vesicles. 

A flat, circumscribed discoloration of skin or mucosa that may vary in size and shape is referred to as:

 # A flat, circumscribed discoloration of skin or mucosa that may vary in size and shape is referred to as: 

a. epulis 

b. macule 

c. nodule 

d papule 

The correct answer is B. Macule.

Macules: These are lesions that are flush with the adjacent mucosa and that are noticeable because of their difference in color from normal skin or mucosa. They may be red due to increased vascularity or inflammation, or pigmented due to the presence of melanin, hemosiderin, and foreign material (including the breakdown products of medications). A good example in the oral cavity is the melanotic macule.

Papules: These are lesions raised above the mucosal surface that are smaller than 1.0 cm in diameter (some use 0.5 cm for oral mucosal lesions). They may be slightly domed, or flat‐topped. Papules are seen in a wide variety of diseases, such as the yellow‐white papules of pseudomembranous candidiasis.

Plaques: These are raised lesions that are greater than 1 cm in diameter; they are essentially large papules.

Nodules: These lesions are present within the deep mucosa. The lesions may also protrude above the mucosa forming a characteristic dome‐shaped structure. A good example of an oral mucosal nodule is the irritation fibroma.

Vesicles: These are small blisters containing clear fluid that are less than 1 cm in diameter.

Bullae: These are elevated blisters containing clear fluid that are greater than 1 cm in diameter.

Erosions: These are red lesions often caused by the rupture of vesicles or bullae, or trauma and are generally moist on the skin. However, they may also result from thinning or atrophy of the epithelium in inflammatory diseases such as lichen planus. These should not be mistaken for ulcers, which are covered with fibrin and are yellow.

Pustules: These are blisters containing purulent material and appear yellow.

Ulcers: These are well‐circumscribed, sometimes depressed lesions with an epithelial defect that is covered by a fibrin membrane, resulting in a yellow‐white appearance. A good example is an aphthous ulcer.

Purpura: These are reddish to purple discolorations caused by blood from vessels leaking into the connective tissue. These lesions do not blanch when pressure is applied and are classified by size as petechiae (less than 0.3 cm), purpura (0.4–0.9 cm), or ecchymoses (greater than 1 cm).

Bismuth intoxication is manifested as:

 # Bismuth intoxication is manifested as: 

a. Pigmentation in areas of inflammation 

b. Burtonian line 

c. Gingiva 

d. Blackish line in the mucosa 

The correct answer is D. Blackish line in the mucosa.

Oral Manifestations: Bismuth pigmentation of the oral mucosa, particularly of the gingiva and buccal mucosa, is the most common oral feature of bismuth therapy and is reported to occur in a high proportion of patients receiving preparations containing the metal.

The pigmentation appears as a ‘bismuth line’, a thin blue-black line in the marginal gingiva which is sometimes confined to the gingival papilla. There may also be the same type of pigmentation of the buccal mucosa, the lips, the ventral surface of the tongue, or in any localized area of inflammation such as around partially erupted third molars or around the periphery of an ulcer as an anachoretic phenomenon.

Cyst without a lining is :

 # Cyst without a lining is : 

a Radicular cyst 

b. Nasopalatine duct cyst 

c. Dentigerous cyst 

d. Hemorrhagic/traumatic bone cyst 

The correct answer is D. Hemorrhagic/Traumatic bone cyst.

The traumatic cyst is a pseudo cyst (lacks an epithelial lining) and an uncommon lesion comprises about 1% of all jaw cysts. It occurs in other bones of the skeleton as well.

Etiology. The etiology of the solitary bone cyst is unknown, although a number of theories have been proposed and at least one, the trauma—hemorrhage theory has been rather widely accepted. Howe and also Sieverink have carried out extensive reviews of the literature and pointed out the wide acceptance

of the theory of origin from intramedullary hemorrhage following traumatic injury. Hemorrhage occurring within the medullary spaces of bone after trauma heals in most cases by organization of the clot and eventual formation of connective tissue and new bone. According to the traumatic theory, the

clot breaks down and leaves an empty cavity within the bone. Steady expansion of the lesion occurs secondary to altered or obstructed lymphatic or venous drainage. This expansion tends to cease when the cyst-like lesion reaches the cortical layer of bone, so that expansion of the involved bone is not a common finding in the solitary bone cyst.

Giant cell fibroma occurs commonly on:

 # Giant cell fibroma occurs commonly on:

A. Maxillary gingiva

B. Mandibular gingiva

C. Tongue

D. Palate

The correct answer is B. Mandibular gingiva.

Most common benign soft tissue neoplasm is fibroma (oral fibroma or fibromatosis fibroma) and its most common site is buccal mucosa. Giant cell fibroma is a distinctive entity from a conventional fibroma. The most common site is the mandibular gingiva, followed by the maxillary gingiva, the tongue, and the palate