MDS PREP
Occluded submandibular salivary duct can be best observed by
1. Palpation
2. Sialography
3. Occlusal X-ray
4. Thermography
An occluded submandibular salivary duct can be best observed by sialography.
Overexposure of film results in
1. Increased density and dark film
2. Increased density and light film
3. Decreased density and light film
4. Decreased density and dark film
Radiology
Answer: 1
Overexposure of film results in increased density and dark film.
An intraoral periapical X-ray is taken for evaluation of impacted third molar. Another X-ray is taken with downward angulation to first one. If third molar is lingual impaction it will appear to
1. Move downward in relation to inferior alveolar canal
2. Move upward in relation to inferior alveolar canal
3. Be stable in relation to inferior alveolar canal
4. None of the above
Radiology
Answer: 1
If a third molar is lingually impacted, it will appear to move downward in relation to the inferior alveolar canal when taking a second X-ray with downward angulation.
Zygoma fractures can be best viewed by
1. Occipitomental view
2. Lateral oblique
3. Towne"s view
4. True lateral
Radiology
Answer: 1
Zygoma fractures can be best viewed by occipitomental view.
Light radiographic film is due to
1. Overdeveloping
2. Overfixing
3. Directly putting in fixer
4. Exposure to sunlight
Radiology Answer: 2
Overfixing occurs when the radiographic film remains in the fixing solution for an extended period, leading to excessive clearing of the image. Fixing agents, such as sodium thiosulfate, dissolve unexposed silver halide crystals. Prolonged exposure results in a lighter image as even some of the developed silver may be affected. Other options, such as overdeveloping, directly putting in fixer, or sunlight exposure, typically lead to other issues like dark films or fogging.
The radiograph showing one of the best view of a fracture of
1. The orbital rim is the 30 degree occipitomental view
2. The orbital floor is the 10 degree occipitomental view
3. The orbital medial wall is the lateral skull view
4. The orbital roof is the lateral skull view
The radiograph showing the best view of a fracture of the orbital floor is the 10-degree occipitomental view.
All of the following are radiolucent except
1. Osteomalacia
2. Osteopetrosis
3. Ameloblastoma
4. Central giant cell granuloma
Radiology
Answer: 2
All of the following are radiolucent except osteopetrosis.
Filament in X-ray tube is heated by
1) Step-up high voltage transformer
2) Auto transformer
3) Step-down low voltage transformer
4) Ammeter
Radiology
Answer: 3
In an X-ray tube, the filament (cathode) is heated to produce electrons through a process called thermionic emission. This heating is accomplished by a step-down low voltage transformer, which reduces the high voltage from the power supply to a lower voltage suitable for heating the filament. The step-down transformer ensures that the filament receives the correct amount of current to achieve the necessary temperature for electron production.