Incisor liability in maxillary arch

 # Incisor liability is about ………..in maxillary arch.

A. 4.6 mm 

B. 5.4 mm 

C. 6.2 mm 

D. 7.6 mm 

The correct answer is D. 7.6 mm.

Incisor liability is about 7.6 mm in maxillary arch and 6 mm in mandibular arch. The incisor liability is compensated by three mechanisms:

a. Increased intercanine width: During the period of permanent incisor eruption, significant amount of increase in intercanine arch width occurs. It is about 3–4 mm.

b. Interdental spacing: Spacing present in primary dentition helps in alignment of incisor. The primate space present in the upper arch mesial to primary canine is also used.

c. Labial eruption of incisor: Primary incisor stand upright. The permanent incisors, which replace them, are labially proclined placing them in a wider arch.

Source: Mc Donald 2nd South Asian Edition

Salt and pepper appearance in radiograph is seen in:

# Salt and pepper appearance in radiograph is seen in:

A. Osteoporosis

B. Osteopetrosis

C. Sickle cell anemia

D. Thalassemia

The correct answer is D. Thalassemia.

"Crew - cut" or "Hair - on - end" appearance of skull is characteristic of both sickle cell anemia and thalassemia. In thalassemia radiographs of maxilla and mandible shows characteristic apparent coarsening of some trabeculae and the blurring and disappearance of others, resulting in "salt and pepper" effect.

Primary HSV infection for first few days is associated with elevated level of immunoglobulin:

 # Primary HSV infection for first few days is associated with elevated level of immunoglobulin: 

A. IgG 

B. IgA 

C. IgM 

D. IgE 

The correct answer is C. IgM.

Primary HSV infection is associated with elevated immunoglobulin (Ig)M titers that occur within days, followed several weeks later by permanent IgG titers (seroconversion) that indicate previous infection but confer no protection against reactivation. Recurrent infection is associated with a rise in IgG antibody titer in acute and convalescent sera, but a fourfold rise (a criterion that indicates active infection) is seen in only 5% of patients. The assay for HSV IgM is not particularly reliable for diagnostic purposes and overall, the use of serology to diagnose recurrent infection is not advised.

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HSV-1 infection spreading through the sport of wrestling

 # HSV-1 infection of skin spread through the sport of wrestling. This is called: 

A. Herpetic whitlow 

B. Herpes gladiatorum 

C. Herpes zoster sine 

D. Herpetic shingles 

The correct answer is B. Herpes gladiatorum.

HSV‐1 or ‐2 may cause herpes whitlow, an infection of the fingers when virus is inoculated into the fingers through a break in the skin. This was a common occupational hazard (including within the dental profession) before the widespread use of gloves. Other HSV‐1 infections include herpes gladiatorum (infections of the skin spread through the sport of wrestling), herpes encephalitis, HSV esophagitis, HSV pneumonia and neonatal and disseminated infection.

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