Shade selection for composite restoration

# Shade selection for composite restoration in anterior teeth should be done:
 A. After end of etching
 B. After prolonged drying
 C. Before prolonged drying
 D. After applying bonding agent

The correct answer is C. Before prolonged drying.

For shade selection, the teeth should be moist and should not be dehydrated. A dehydrated tooth gives a whiter appearance due to scattering and reflection of light. Bleaching procedures if any should be done before shade selection.

Permanent dentition stage normally begins with:

# The permanent dentition stage normally begins with which of the following?

A. Exfoliation of the primary mandibular central incisor

B. Exfoliation of the primary maxillary 2nd molar

C. Eruption of the permanent mandibular 1st molar

D. Eruption of the permanent maxillary 1st molar

E. Exfoliation of the primary mandibular 1st molar

The correct answer is B. Exfoliation of the primary maxillary 2nd molar. 

The permanent dentition stage does not

begin until the final primary tooth is

exfoliated.

The term "'mixed dentition" describes the

time between the eruption of the permanent 1st molars until the exfoliation of the last primary tooth.

Patients who retain primary teeth don't

leave the mixed dentition stage until the

primary teeth are lost.

Primary dentition: 6 months- 6 years

Mixed dentition: 6 years- 12 years

Permanent dentition: 12 years +

Most effective topical anesthetic

# Which of the following is most effective as a topical anesthetic?
A. Lidocaine
B. Bupivacaine
C. Procaine
D. Prilocaine
E. Articane

The correct answer is A. Lidocaine.


Lidocaine is proven to be an effective
topical anesthetic drug that can effectively
numb the mucosal surfaces the oral cavity.

It is a strong anesthetic drug usually
delivered in gel, liquid, lotion, spray or
cream form.

Lidocaine topical anesthetic can penetrate
approximately 2-3mm deep into the
mucosal layer when applied properly.

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.