Tooth most likely to not erupt due to overcrowding

# Which of the following teeth is most likely to NOT erupt into the arch due to overcrowding?
A. Canine
B. Central incisor
C. Lateral incisor
D. 2nd premolar
E. 1st premolar

The correct answer is A. Canine.

Canines are the anterior teeth that are most
likely to be unable to erupt within a crowded dentition because the canine erupts after the incisors and premolars have already erupted.

Tooth crowding may occur in patients with
teeth that are too wide mesiodistally or if
their dental arch is too small to
accommodate all the erupted teeth.

Tooth crowding carries a genetic predisposition because it is often a matter of tooth size vs arch size.

Facial profile change with ageing

# The facial profile of most people change as they age and mature through becoming..
A. More convex
B. The same level of convexity
C. Less concave
D. Less convex

The correct answer is D. Less convex. 

The facial profile may vary as we age due to

the loss of facial fat, muscle atrophy and

loss of skin elasticity.

The buccal fact pad is gradually lost in the

cheeks, causing the skin to adapt itself to

the underlying muscle and bone.

During the aging process, metabolism

slows down and the production of skin,

collagen, and muscle fibers is reduced.

The constant pull of gravity also contributes

to the sagging of the face.

Late mesial shift of permanent first molars

# The closure of which of the following spaces results in the late mesial shift of permanent 1st molars?
A. Canine
B. Interocclusal
C. Extraction
D. Leeway
E. Primate

The correct answer is D. Leeway space. 

Leeway space is closed as the 1st permanent molars move mesially after the

exfoliation of the primary 2nd molar and is

usually seen among children from 11-12

years of age.

Leeway space is created from the difference of sizes between the primary canine and molars compared to the erupting premolars and permanent canines.

The discrepancy in size of primary molars and premolars creates a free space that allows the late mesial migration of permanent 1st molar after the exfoliation of the primary 2nd molar.

Pigmented (usually purple) lesions in the skin caused by extravasation of blood from the capillaries

# The category of pigmented (usually purple) lesions in the skin caused by extravasation of blood from the capillaries is known as:
A. Petechiae
B. Purpura
C. Ecchymosis
D. Varicose veins

The correct answer is B. Purpura.

Purpura spots (pinpoint spots) are purplish discolorations in the skin produced by small bleeding vessels near the surface of the skin. Purpura may also occur in the mucous membranes (such as the lining of the mouth) and in the internal organs. Purpura by itself is only a sign of other underlying causes of bleeding. Purpura may occur with either normal platelet counts (non-thrombocytopenic purpuras) or decreased platelet counts (thrombocytopenic purpura). Platelets help maintain the of the capillary lining and are important in the clotting process. Note: Large purpura spots (> 3 mm) are called ecchymoses.

Major kinds of purpura:

- Thrombocytopenic purpura (Werlhof's disease): a bleeding disorder characterized by a deficiency in the number of platelets. This results in multiple bruises, petechiae, and hemorrhage into the tissues

- Thrombotic thrombocytopenic purpura (TTP) : a severe and frequently fatal form characterized by a low platelet count in the blood due to the consumption of platelets by thrombosis in the terminal arterioles and capillaries of many organs.

Oral manifestations of thrombocytopenic purpura:

• Severe and profuse gingival hemorrhage

• Petechiae occur commonly on the palate

Important: Tooth extractions are contraindicated due to the tendency for excessive bleeding.