The probability of rejecting the null hypothesis when it is true:

 # The probability of rejecting the null hypothesis when it is true:

A. Type 1 error

B. Type 2 error

C. Power of a statistical test

D. Level of significance

The correct answer is A. Type I error.

In statistical hypothesis testing, a type I error is the mistaken rejection of an actually true null hypothesis (also known as a "false positive" finding or conclusion; example: "an innocent person is convicted"), while a type II error is the failure to reject a null hypothesis that is actually false (also known as a "false negative" finding or conclusion; example: "a guilty person is not convicted"). Much of statistical theory revolves around the minimization of one or both of these errors, though the complete elimination of either is a statistical impossibility if the outcome is not determined by a known, observable causal process. By selecting a low threshold (cut-off) value and modifying the alpha (α) level, the quality of the hypothesis test can be increased. The knowledge of type I errors and type II errors is widely used in medical science, biometrics and computer science.

The immunoglobulin which is produced first by the fetus in response to infection is:

#  The immunoglobulin which is produced first by the fetus in response to infection is:

A. IgG

B. IgA

C. IgM

D. IgD

The correct answer is C. IgM.

Phylogenetically, IgM is the oldest immunoglobulin class. It is also the earliest immunoglobulin to be synthesized by the fetus beginning by about 20 weeks of age. As it is not transported across the placenta, the presence of IgM in the fetus or newborn indicates intrauterine infection and its detection is useful in the diagnosis of congenital infections such as syphilis, rubella, HIV infection and toxoplasmosis. 

Normal submandibular salivary gland in sialograph shows

 # Normal submandibular salivary gland in sialograph shows

a. Tree in winter appearance

b. Bush in winter appearance

c. Herb in winter appearance

d. Shrub in winter appearance

The correct answer is B. Bush in Winter Appearance.

Normal sialographic appearances of the submandibular gland

These include:

• The main duct is of even diameter (3-4 mm wide) and should be filled completely and uniformly.

• This gland is smaller than the parotid, but the overall appearance is similar with the branching duct structure tapering gradually towards the periphery — the so-called bush in winter appearance.

Minor salivary gland found along the lateral border of tongue is:

#  Minor salivary gland found along the lateral border of tongue is:

A. Gland of Von Ebner

B. Gland of Weber

C. Gland of Blandin and Nuhn

D. Foliate glands

The correct answer is B. Gland of Weber.

Gland of von Ebner are posterior lingual glands, glands of Blandin and Nuhn are anterior lingual glands while Foliate is papilla present in lateral border of tongue. 

The Weber's glands are muciparous glands on the side of the tongue. They are a minor salivary gland in the peritonsillar space. The glands are named after German anatomist Moritz Ignaz Weber. They clear the peritonsillar space of debris.

Coleman sign is seen in :

 # Coleman sign is seen in :

a. Hard palate 

b. Soft palate 

c. Floor of mouth 

d. None 

The correct answer is C. Floor of Mouth.

During mandibular anterior region fracture submuosal haematoma is seen the lingual surface of mandible at the floor of mouth known as coleman sign.

Break up time test is done for:

# Break up time test is done for:

a. Sjogren’s syndrome

b. Scleroderma

c. Myasthenia gravis

d. Guillian barre syndrome

The correct answer is a. Sjogren's syndrome.

Tear break-up time (TBUT) also known as tear film break-up time (TFBUT) is the time taken for the first dry spot to appear on the cornea after a complete blink. TFBUT measurement is an easy and fast method used to assess the stability of tear film. It is a standard diagnostic procedure in the dry eye clinics. 

Tear film break-up time is abnormal in several conditions like aqueous tear deficiency, keratoconjunctivitis sicca, mucin deficiency, and meibomian gland disorders. Evaporative dryness can also be seen in conditions like lagophthalmos, proptosis, Parkinson's disease, computer vision syndrome, contact lens use, drugs (antihistamines, beta blockers, antispasmodics, diuretics) and vitamin A deficiency, amongst others. 

First order bends are:

 # First order bends are: 

a) Tipping bends. 

b) Torquing bends. 

c) In and out bends. 

d) Anchorage bends. 

The correct answer is C. In and out bends.

First Order Bends

The first order bends or in-out bends are placed to compensate for differences in the buccolingual prominence of the teeth. They comprise of the lateral inset, the canine offset and the molar offset.

Second Order Bends

The second order bends are placed to achieve correct mesiodistal axial inclination of teeth. They comprise the tip back bends placed in the posterior segments.

Third Order Bends

The third order bends or torque are placed to get correct buccolingual position by moving the roots. They are placed by twisting the arch wire.