What is Fluoride bomb?

# The ‘FLUORIDE BOMBS’ is related to:
A. A fluoride  capsule with high ppm of fluoride varnish
B. A hypoplastic lesion on tooth seen in fluorosis areas
C. Undiagnosed hidden caries
D. Procedure to treat rampant caries

The correct answer is C. Undiagnosed hidden caries.

• Occult or hidden caries is used to describe such lesion which is not clinically diagnosed but detected only on radiographs.
• Occult lesions are seen with low caries rate which is suggestive of increased fluoride exposure.
• It is believed that increased fluoride exposure encourages remineralization and slows down the progress of the caries in the pit and fissure enamel while the cavitation continues in dentin, and the lesions become masked by a relatively intact enamel surface.
• These hidden lesions are called 'fluoride bombs' or fluoride syndrome.

# Calcium hydroxide is advocated as an inter appointment intracanal medication because of

# Calcium hydroxide is advocated as an inter appointment intracanal medication because of:
A. Its ability to dissolve necrotic tissue
B. Its antimicrobial property
C. Its ability to stimulate hard tissue formation
D. Its powerful bleaching effect

The correct  answer is B. Its antimicrobial property. 

Most studies report culture reversals during the interappointment period when active antibacterial dressing is not used in the root-canal system between appointments. The reversals are due to regrowth of residual bacteria or recontamination by bacterial leakage around the access cavity

dressing. 

Classical and well-controlled studies (Sundqvist’s group) evaluated the effect of various root-canal treatment procedures on the microbiota both qualitatively and quantitatively. They tested the effect of mechanical preparation, saline or sodium hypochlorite irrigation (0.5%, 5.0%, 5.0% with EDTA), the addition of ultrasonic activation to the irrigation and calcium hydroxide dressing; each addition to the chemical canal preparation improved the antibacterial effect, reducing residual bacteria further. They found the antibacterial action to reduce the number of bacteria from an initial range of 10^2–10^8 cells to 10^2–10^3 fewer cells after initial debridement, further reducing down to no recoverable cells (from the prepared part of the root-canal system) after interappointment dressing with calcium hydroxide.

Reference: Endodontics, 4th Edition, Kishor Gulabivala, Yuan-Ling Ng, Page no. 83

Initial dissolution of Tooth Substance by Acid

# In the carious process, the initial dissolution of the tooth substance by acid takes place in which of the following place?
A. Below the dentin Surface
B. Below the enamel surface
C. On the enamel surface
D. Towards the dentin

The correct answer is B. Below the Enamel Surface.

The top portion of the tooth remains intact and it's the subsurface which looses the minerals. This is the stage where it's called as incipient lesion. Once the top protion breaks, it's called a cavitated lesion.

Digestive System and Nutrition - MBBS BDS Entrance Examination

The correct answers are highlighted in green.

# Micelles are the bodies related to:
 A. Secretion of hormones
 B. Secretion of enzymes
 C. Absorption of minerals
 D. Absorption of fat

# Movements of circular muscles in the stomach is called
 A. Digestion
 B. Absorption
 C. Excretion
 D. Peristalsis