Impurity found in nitrous oxide

# The impurity that is theoretically found in nitrous oxide that is considered slightly toxic is:
A. Methane
B. Cyclohexane
C. Ethylene oxide
D. Nitric oxide

The correct answer is D. Nitric oxide.

Nitrous oxide is a gas that creates
analgesia and dissociated anesthesia and
is commonly used in dentistry.

Nitrous oxide was first used by Horace
Wells for his own tooth extraction by his
assistant.

Nitrous oxide is used in general anesthesia
to enhance the effect of other drugs being
administered by allowing the concentration
of other drugs to be decreased without
decreasing their effect.

When nitrous oxide reacts with oxygen and
is converted into nitric oxide, causing
vasodilation.

Causes of Dark appearance of radiograph

# After processing a film, you notice that it appears too dark. What is the most likely cause of this problem?
A. Inadequate development time
B. Developer solution too cool
C. Depleted developer solution
D. Excessive developing time

The correct answer is D. Excessive developing time.

The causes underlying dark appearance of a radiograph are:
- Excessive developing time
- Developer solution too hot
- Inaccurate timer or thermometer
- concentrated developer solution

Solutions for the dark appearance of radiograph
- Chcck development time.
- Check developer temperature.
- Replace faulty timer or thermometer.
- Replenish developer with fresh solutions as needed.

Coronoid process of the mandible often appears in periapical x-rays of:

# The image of the coronoid process of the mandible often appears in periapical x-rays of:
A. The incisor region of the mandible
B. The molar region of the mandible
C. The incisor region of the maxilla
D. The molar region of the maxilla

The correct answer is D. The molar region of the maxilla.

As the mouth is opened, the coronoid process moves forward, and therefore it comes into  view

most often when the mouth is opened to its fullest extent at the time the exposure is made.

It is evidenced by a tapered or triangular radiopacity, which may be seen below, or in some instances superimposed on the molar teeth and maxilla.

The coronoid process appears as a triangular-shaped radiopacity.

Contraindication of Pulpotomy

# Pulpotomies are CONTRAINDICATED on primary molars with which of the following?
A. Radiographic evidence of deep caries approximating the pulp chamber
B. Radiographic evidence of internal resorption
C. Sensitivity to sweets
D. Exposure of the pulp during caries excavation

The correct answer is B. Radiographic evidence of internal resorption.

Root canal therapy is indicated to treat
cases involving internal resorption.

When a carious lesion approximates or
extends into the pulp chamber of a
deciduous tooth, removal of coronal pulp is
performed to prevent the spread of the
infection into the radicular pulp.

Pulpotomies are performed on deciduous
teeth to prevent premature tooth loss and
potential loss of space.

Careful clinical and radiographic
assessment along with the child's medical
and dental history are necessary before
performing a pulpotomy.

Pulpotomy is contraindicated where there is:
- Internal resorption (root canal therapy
indicated)
- Perforation of pulp chamber floor
- Over 2 root resorption
- Cellulitis
- Localized abscess
- Draining sinus
- Inability to isolate the tooth
- Inability to properly restore tooth after the
procedure