contains thousands of microscopic tubular structures that radiate outwards from
the pulp, these dentinal tubules are typically 0.5–2 micrometres in diameter.
Changing in the flow of the dentinal fluids present in the dentinal tubules can
trigger a mechano-receptors present on nerves located at the pulpal aspect,
thereby provoking a pain response. This hydrodynamic flow can be increased by
cold, air pressure, drying, sugar, sour (dehydrating chemicals), or forces
acting onto the tooth. Hot or cold food or drinks, and physical pressure are
typical stimuli in those individuals with teeth sensitivity.
Modes of desensitization of hypersensitive dentin
There are so many different approaches regarding desesnstization
of the hypersensitive dentin that have been viewed in literature. These
different modes could be categorized into nerve desensitization by blocking
neural transmission (eg. potasium nitrate), protien precipitation (eg.
glutraldehyde, silver nitrate and zinc chloride), plugging patent dentinal
tubules (eg. sodium fluoride, stannous fluoride and calcium phosphate), the use
of dentin adhesive sealers (eg. fluoride varnishes, glass ionomer, composites
and dentin bonding agents) and finally the introduction of laser therapy for
treatment of dentin hypersesntivity (eg. Nd: YAG laser). The following are some
reviews for the modes of desensitizing hypersensitive dentin.
Ochardson and Gilliam (2000) discussed a method
for reducing sensory nerve activity in a hypersensitive tooth and for
desensitizing hypersensitive dentin involved applying to the surface of exposed
dentin of a subject’s tooth a potassium salt,
in this way the pain resulting from stimulation of hypersensitive nerve tissue
may be reduced or relieved. It was concluded that Potassium
bicarbonate is the required agent for desensitizing hypersensitive dentin and
for inhibiting increased sensory nerve activity.(9)
Pereira et al. (2001) compared a 3% potassium
nitrate 0.2%, sodium fluoride mouthwash with a 0.2% sodium fluoride control
mouthwash in a six-week double-blind study. There was a statistically
significant difference in reducing sensitivity between the groups. The study
concluded that a 3% potassium nitrate 0.2% sodium fluoride mouthwash appears to
have therapeutic potential to reduce the severity of dental hypersensitivity.(10)
Kishore et al.
a study to evaluate the efficacy of desensitizing agents for the treatment of
dentin hypersensitivity. Results showed that 10% strontium chloride solution,
2% sodium fluoride solution, and 40% formalin solution significantly reduced
dentin hypersensitivity, whereas a 5% solution of potassium nitrate did not.(11)
Corona et al. (2003) evaluated the use of
low-level gallium–aluminum–arsenide (GaAlAs) laser and sodium fluoride varnish
in treating of cervical dentin hypersensitivity in vivo. There was no significant
difference for the fluoride varnish at the three examination periods,
immediately, 15 and 30 days after first application and for laser therapy,
significant difference was found solely between the values obtained before the
treatment and 30 days after the first application. It may be concluded
that both treatments may be effective in reducing cervical dentinal hypersensitivity.
Moreover, the low-level GaAlAs laser showed better results for treating teeth
with higher degree of sensitivity.(12)