Dentosphere : World of Dentistry

Oblique ridge at the centre of occlusal surface is reduced to the level of:

# Oblique ridge at the centre of occlusal surface is reduced to the level of:

A. Central groove

B. Marginal ridges

C. Cusp tips

D. All of the above

The correct answer is B. Marginal ridges.

The oblique ridge is a ridge that crosses the occlusal surface obliquely. The union of the triangular ridge of the distobuccal cusp and the distal ridge of the mesiolingual cusp forms it. This ridge is reduced in height in the center of the occlusal surface, being about on a level with the marginal ridges of the occlusal surface. Sometimes it is crossed by a developmental groove that partially joins the two major fossae by means of its shallow sulcate groove.

CLICK HERE FOR MORE MCQs

Which Premolar develops from five lobes?

# Which of the following premolars develop from five lobes?

A. Maxillary first premolar

B. Maxillary second premolar

C. Mandibular first premolar

D. Mandibular second premolar

The correct answer is D. Mandibular second premolar.

The mandibular first premolars are developed from four lobes, as were the maxillary premolars. The mandibular second premolars are, in most instances, developed from five lobes, three buccal and two lingual lobes.

Reference: Wheeler's, 10th Edition, Page 151

Parahemophilia is due to deficiency of :

# Parahemophilia is due to deficiency of :

A. Clotting factor VIII

B. Clotting factor IX

C. Clotting factor V

D. Clotting factor XI

The correct answer is C. Clotting factor V.

Parahemophilia: a congenital deficiency of factor V in the blood that is associated with hemorrhagic diathesis and abnormally slow clotting time. — called also Owren's disease.

CLICK HERE FOR MORE MCQs

In the anteroposterior bar major connector, the shape of the bars are:

# In the anteroposterior bar major connector, the shape of the bars are:

A. Anterior bar – flat strap; posterior bar- half oval

B. Anterior bar – half pear shape; posterior bar- half pear shape

C. Anterior bar – half oval; posterior bar- flat strap

D. Anterior bar – flat strap; posterior bar- flat strap

The correct answer is A. Anterior bar – flat strap; posterior bar- half oval.

The anterior component is a flat strap located as far posteriorly as possible to avoid rugae coverage and tongue interference. The anterior border of this strap should be located just posterior to a rugae crest or in the valley between two crests. The posterior strap is thin, a minimum of 8 mm wide, and located

as far posteriorly as possible, yet entirely on the hard palate. It should be located at right angles to midline rather than diagonally.

Posterior palatal component: a strap of 22-gauge thickness, 8 to 10 mm wide (a half-oval form of approximately 6-gauge thickness and width) may also be used.

CLICK HERE FOR MORE MCQs

The space maintainer which is contraindicated in a child suffering from subacute bacterial endocarditis is:

# The space maintainer which is contraindicated in a child suffering from subacute bacterial endocarditis is:

A. Removable

B. Crown and loop

C. Band and loop

D. Distal shoe

The correct answer is D. Distal shoe.

A distal shoe space maintainer is indicated when the primary 2nd molar is lost before eruption of the permanent 1st molar.

Distal shoe space maintainer is contraindicated in:

• Patient with heart diseases

• Patients with poor oral hygiene

• Hemophilic patients

CLICK HERE FOR MORE MCQs

Middle concha of nose are a part of:

# Middle concha of nose are a part of:

A. Nasal bone

B. Ethmoid

C. Vomer

D. Maxilla

The correct answer is B. Ethmoid.

The nasal conchae are curved bony projections directed downward and medially.

The 3 conchae are:

i) Inferior concha: It is an independent bone.

ii) Middle concha: It is a projection from the medial surface of the ethmoidal labyrinth.

iii) Superior concha: It is also a projection from the medial surface of the ethmoidal labyrinth. This is the smallest concha situated just above the posterior part of middle concha.

CLICK HERE FOR MORE MCQs