The cyst with the highest recurrence rate is:

  # The cyst with the highest recurrence rate is: 

A. Keratocyst

B. Periapical cyst

C. Nasoalveolar cyst

D. Globulomaxillary cyst

The correct answer is A. Keratocyst.

In 1967, Toller suggested that the OKC may best be regarded as a benign neoplasm rather than a conventional cyst based on its clinical behavior. The WHO has reclassified the lesion as a tumor based on several factors, that formed the basis of this decision.

Behavior: The KOT is locally destructive and has a high recurrence rate.

Histopathology: The basal epithelial layer of KOT shows proliferation and budding into the underlying connective tissue in the form of daughter cysts and mitotic figures are frequently found in the suprabasal layers of the lesional epithelium. 

Dentigerous cyst is suspected if the follicular space is more than:

 # Dentigerous cyst is suspected if the follicular space is more than: 

a. 2-3 mm 

b. 3-4 mm 

C. 1-2 mm 

d. More than 5 mm 

The correct answer is D. More than 5 mm.

One of the most difficult differential diagnoses to make is between a small dentigerous cyst and a hyperplastic follicle. A cyst should be considered with any evidence of tooth displacement or considerable expansion of the involved bone. The size of the normal follicular space is 2 to 3 mm. If the follicular space exceeds 5 mm, a dentigerous cyst is more likely. If uncertainty remains, the region should be reexamined in 4 to 6 months to detect any increase in size or any influence on surrounding structures characteristic of cysts.

Reference: Oral radiology Principles and Interpretation, 7th Edition Stuart C. White, Michael J. Pharoah

Which one of the following conditons is least likely to be associated with an increased risk of oral cancer?

 # Which one of the following conditons is least likely to be associated with an increased risk of oral cancer? 

a. Actinic Cheilosis 

b. Erythroplakia 

c. Leukoedema 

d. Leukoplakia 

The correct answer is C. Leukoedema. 

Leukoedema is a white and veil‐like alteration of the oral mucosa that is merely considered a normal variant. The condition is often encountered bilaterally in the buccal mucosa and sometimes at the borders of the tongue. Leukoedema is less clinically evident after stretching the mucosa, but reappears after this manipulation is discontinued.

Reference: Burket's Oral Medicine

Disadvantages of using a GRID is:

 # Disadvantages of using a GRID is: 

a. Increased patient exposure 

b. Decreased Patient exposure 

c. Increased fogging of the film 

d. Increased secondary radiation 

The correct answer is A. Increased patient exposure. 

Although radiographic grids reduce scattered radiation and improve contrast and resolution, they result

in higher patient exposure. Cephalometry does not require the use of grids. However, grids could improve the radiographic appearance of fine structures, such as trabecular architecture, and aid in the diagnosis of disease.

Reference: Oral radiology Principles and Interpretation, 7th Edition Stuart C. White, Michael J. Pharoah