Dentin Desensitizing Agent

# The dentin desensitizing agents that acts by precipitating proteins in dentinal tubular fluid is: (MHCET 2014)
A. Strontium chloride
B. Potassium oxalate
C. Fluoride
D. Hydroxyethyl methacrylate

The correct answer is A. Strontium chloride.

After professional diagnosis, dentinal hypersensitivity can be treated simply and inexpensively by home use of desensitizing dentifrices.

Strontium Chloride Dentifrices

Ten percent strontium chloride desensitizing dentifrices are found effective in relieving the pain of tooth hypersensitivity.

Potassium Nitrate Dentifrices

Five percent potassium nitrate dentifrices are found to alleviate pain related to tooth hypersensitivity.

Fluoride Dentifrices

Sodium monofluorophosphates dentifrices are effective mode of treating tooth hypersensitivity.

Strontium chloride is the most important constituent in home care dentifrices intended to be used for the treatment of dentinal hypersensitivity. Topical application of concentrated strontium chloride on an abraded dentin produces a deposit of strontium that penetrates dentin to a depth of approximately 10-20 micrometers and extend into dentinal tubules. 

Ref: Textbook of OPERATIVE DENTISTRY, Nisha Garg, 3rd Edition, Page 445

Direct Pulp Capping

# Which of the following are true about direct pulp capping?
A. Mechanically exposed teeth have a greater success rate than carious exposures
B. Final restorative materials do not affect success
C. Generally, individual teeth involved in a fixed prosthesis are candidates for direct pulp capping
D. All of the above

The correct answer is A.  Mechanically exposed teeth have greater success rate than carious exposures.

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