X ray beam is filtered to:

 # X ray beam is filtered to:

A. Soften the beam

B. Restrict beam size

C. Remove long wavelength  X rays

D. Remove short wavelength x rays

The correct answer is C. Remove long wavelength X rays.

Although an x-ray beam consists of a continuous spectrum of x-ray photon energies, only photons with sufficient energy to penetrate through anatomic structures and reach the image receptor (digital or film) are useful for diagnostic radiology. Low-energy photons that cannot reach the receptor contribute to patient risk but do not offer any benefit. Consequently, it is desirable to remove these low-energy photons from the beam. This removal can be accomplished in part by placing a metallic disk (filter) in the beam path. A filter preferentially removes low-energy photons from the beam, while allowing high-energy photons that are able to contribute to making an image to pass through.

Energy of x-rays depends directly on its frequency (E~f) and inversely related to wavelength (E~1/λ). Electromagnetic waves with higher frequencies have proportionally higher energies. The wave with the shorter wavelength, will have higher frequency. Since we know that the energy scales directly with the frequency we know that the wave that has the shorter wavelength will have higher energy.

Reference: Oral Radiology Principles and Interpretation, 7th Edition, White and Pharoah, Page no 10

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Light appearing X ray film

 # Which of the following factor result in film appearing very  light?

A. Under exposure

B. Over development

C. Developing solution too hot

D. Unsafe illuminations in dark room

The correct answer is A. Underexposure.

CAUSE S OF LIGHT RADIOGRAPHS

Processing Errors

- Underdevelopment (temperature too low; time too short; thermometer inaccurate)

- Depleted developer solution

- Diluted or contaminated developer

- Excessive fixation

Underexposure

- Insufficient mA

- Insufficient kVp

- Insufficient time

- Film-source distance too great

- Film packet reversed in mouth 

Reference: Oral Radiology Principles and Interpretation, 7th Edition, White and Pharoah, Page no 80

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Initial clinical sign of juvenile periodontitis:

 #  Initial clinical sign of juvenile periodontitis:

A. Pathological tooth migration and midline diastema

B. Tooth mobility and bone loss

C. Gingival enlargement and pus formation

D. Pain and bleeding

The correct answer is A. Pathological tooth migration and midline diastema.

Pathologic migration may continue after a tooth no longer contacts its antagonist. Pressures from the tongue, the food bolus during mastication, and the proliferating granulation tissue provide the force.

Pathologic migration is also an early sign of localized aggressive periodontitis. Weakened by the loss of periodontal support,the maxillary and mandibular anterior incisors drift labially and extrude, thereby creating diastemata between the teeth.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 306

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In initial stages, treatment of acute necrotizing ulcerative gingivitis without systemic involvement is:

 # In initial stages, treatment of acute necrotizing ulcerative gingivitis without systemic involvement is:

A. Thorough debridement and H2O2 mouthwashes

B. Penicillin therapy

C. Metronidazole and penicillin therapy

D. Gingivectomy and gingivoplasty

The correct answer is A. Thorough debridement and H2O2 mouthwashes.

The oral cavity is examined for the characteristic lesion of NUG, its distribution, and the possible involvement of the oropharyngeal region. Oral hygiene is evaluated, with special attention to the presence of pericoronal flaps, periodontal pockets, and local factors (e.g., poor restorations, distribution of calculus). Periodontal probing of NUG lesions is likely to be very painful and may need to be deferred until after the acute lesions are resolved.

The goals of initial therapy are to reduce the microbial load and remove necrotic tissue to the degree that repair and regeneration of normal tissue barriers are reestablished.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 460

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