Acute rheumatic fever occurs most commonly in:

 # Acute rheumatic fever occurs most commonly in:

A. 5-14 years

B. 15-20 years

C. 21-25 years

D. 26-30 years

The correct answer is A. 5-14 years.

The incidence of acute rheumatic fever is highest in school aged children. The highest incidences recorded are in those aged 5-14 years. One study reported a median age of diagnosis of acute rheumatic fever of 10.4 years with an interquartile range between 8.7-14.3 years. 

The active ingredient of anticalculus dentifrices is:

 # The active ingredient of anticalculus dentifrices is:

A. Fluoride

B. Potassium nitrate

C. Ammonia

D. Pyrophosphate

The correct answer is D. Pyrophosphate.

Pyrophosphate has received particular attention in view of its proposed rote in inhibition of crystal growth. Nevertheless, it is unlikely that pyrophosphate in toothpastes will persist for a reasonable length of time in the mouth, because of the presence of considerable amounts of pyrophosphatase enzymes in saliva and oral bacteria. Pyrophosphate, when introduced into a simulated oral environment, is hydrolyzed by various phosphatases with concomitant loss of its inhibitory activity for calcification in vitro. To overcome this problem, a copolymer of vinyl methyl ether maleic anhydride (Gantrez) and NaF has been introduced in order to inhibit the hydrolysis of pyrophosphate. Animal and clinical studies have shown that toothpaste containing a combination of pyrophosphate, NaF and Gantrez, was highly effective in retarding supragingival calculus formation. 

Disease transmitted from father to all daughters would be:

 # Disease transmitted from father to all daughters would be:

A. Autosomal dominant

B. Autosomal recessive

C. X linked dominant

D. Mitochondrial

The correct answer is C. X linked dominant.

Father gives X to daughter and Y to son. Any X linked dominant disorder in father will affect all daughters. 

Compound odontoma shows on a radiograph as:

 # Compound odontoma shows on a radiograph as:

A. Supernumerary teeth

B. Radiolucent and radiopaque areas

C. Mass of calcified areas

D. Distinguishable tooth like structures

The correct answer is D. Distinguishable tooth like structures.

The radiographic appearance of the odontoma is characteristic. Since most odontomas are clinically asymptomatic and are discovered by routine radiographic examination, the dentist should be familiar with their appearance. They are often situated between the roots of teeth and appear either as an irregular mass of calcified material surrounded by a narrow radiolucent band with a smooth outer periphery, or as a variable number of tooth like structures with the same peripheral outline. This latter type of odontoma may contain only a few structures resembling teeth, or it may contain several dozen. Both forms of odontoma are frequently associated with unerupted teeth. It is of interest that the majority of odontomas in the anterior segments of the jaws are compound composite in type, while the majority in the posterior areas are complex composite.