Crepitus will be seen in the tissues surrounding an infection by:

 # Crepitus will be seen in the tissues surrounding an infection by:

A. Staphylococcus

B. Streptococcus

C. Clostridium tetani

D. Clostridium perfringes

The correct answer is D. Clostridium perfringes. 

■ Clostridium perfringens causes gas gangrene or myonecrosis. 

■ Gas gangrene is characterized by skin colour change from pallor to bronze/purple discoloration and the skin is tense and exquisitely tender. 

■ Gas in the tissues may be obvious with crepitus on clinical examination or visible on radiograph. 

■ Surgical debridement, antibiotic therapy with high-dose I.V penicillin, clindamycin and metronidazole and hyperbaric oxygen therapy are used for treating gas gangrene [Note: Hyperbaric oxygen therapy is also used for osteoradionecrosis and chronic osteomyelitis]. 

■ Cl. tetani causes tetanus and cl. difficile causes pseudomembranous colitis. 

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.

APC gene is mutated in:

 # APC gene is mutated in:

A. Hereditary intestinal polyposis syndrome

B. Gardner’s syndrome

C. Gorham stout syndrome

D. Caffey Silverman Syndrome

The correct answer is B. Gardner's syndrome.

Gardner syndrome, inherited as an autosomal-dominant disorder, is characterized by intestinal polyposis, multiple osteomas, fibromas of the skin, epidermal and trichilemmal cysts, impacted permanent and supernumerary teeth, and odontomas. The genetic defect is found in a small region on the long arm of chromosome 5 (5q21), where the familial adenomatous polyposis (APC) gene resides. Most patients with Gardner’s syndrome do not exhibit the complete spectrum of clinical disease expression. Osteomas associated with this syndrome may be found in the jaws (especially the mandibular angle) and in facial and long bones. Intestinal polyps associated with Gardner syndrome are commonly located in the colon and rectum. Significantly, these polyps, found microscopically to be adenomas, exhibit a very high rate of malignant transformation to invasive colorectal carcinoma.

Reference: ORAL PATHOLOGY: CLINICAL PATHOLOGIC CORRELATIONS, SEVENTH EDITION, Joseph A. Regezi, DDS, MS, James J. Sciubba, DMD, PhD, Richard C.K. Jordan, DDS, MSc, PhD, FRCD(C), FRCPath

Obstructive sleep apnea syndrome (OSAS) often results in all of the following except:

 # Obstructive sleep apnea syndrome (OSAS) often results in all of the following except: 

A. Excessive daytime sleepiness 

B. Aggressive behavior 

C. Personality changes 

D. Depression 

The correct answer is B. Aggressive behavior.

Signs and symptoms

Generally, symptoms of OSA begin insidiously and are often present for years before the patient is referred for evaluation.

Nocturnal symptoms may include the following:

• Snoring, usually loud, habitual, and bothersome to others
• Witnessed apneas, which often interrupt the snoring and end with a snort
• Gasping and choking sensations that arouse the patient from sleep, though in a very low proportion relative to the number of apneas they experience
• Nocturia
• Insomnia; restless sleep, with patients often experiencing frequent arousals and tossing or turning during the night

Daytime symptoms may include the following:

• Nonrestorative sleep (ie, “waking up as tired as when they went to bed”)
• Morning headache, dry or sore throat
• Excessive daytime sleepiness that usually begins during quiet activities (eg, reading, watching television); as the severity worsens, patients begin to feel sleepy during activities that generally require alertness (eg, school, work, driving)
• Daytime fatigue/tiredness
• Cognitive deficits; memory and intellectual impairment (short-term memory, concentration)
• Decreased vigilance
• Morning confusion
• Personality and mood changes, including depression and anxiety
• Sexual dysfunction, including impotence and decreased libido
• Gastroesophageal reflux
• Hypertension

Reference: https://emedicine.medscape.com/article/295807-overview