Dentin hypersensitivity is a common condition caused by exposure of dentin tubules. Various theories have attempted to explain the transmission of pain signals, with the hydrodynamic theory currently favored. It proposes that fluid movement in dentin tubules stimulates nerve fibers. Clinical examination involves tactile, thermal, or chemical stimuli to provoke symptoms. Management focuses on occluding dentin tubules through agents, bonding resins, or lasers to block fluid flow. Further research continues to improve treatment approaches for this painful condition.

1. INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education
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2. Contents
Introduction
Definitions
Historical perspective
Etiology
Nerve Fibers
Theories of dentin sensitivity
Clinical considerations
Methods of measuring Hypersensitivity
Management of Hypersensitivity
Summary & conclusion

3. Dentin

4. Introduction

5. Tooth Hypersensitivity in
the Spectrum of Pain

6. Few Terms…….
Definition: “Exaggerated response to a non noxious
sensory stimuli”
Addy & Urquart (1992) define….
Are pain and sensitivity related??
 Chronic condition with acute exacerbations.
 An enigma

7. Flashback
 2000 years or more - Chinese… by the application of
‘Xiao-Shi’
 3 rd century B.C-The Egyptian Medical Papyrus …red
and yellow vitriol and alum for “teeth that suffer”
 875 A.D - Rhages ….treatment with astringent agents.
 1678 Leeuwenhoek … “tooth canals in dentin”

8. Early years from B.C. to
A.D.

9.  1855 - J.D.White …. movement of fluid in dentinal
tubules
 1857 - Cartwright …. dentine sensitivity was
observed……… that some areas of the tooth were
"exquisitely sensitive" and a source of great discomfort.

10.  1898 - Henry H. Buchard-
 agents to lower the pain perceptive centers of the
brain.
 destroy or coagulate the dentinal protoplasm
 local analgesic agents on the dentin.
 1899 – George.F.Eames.. caused by erosion
 1900 - Alfred Gysi - first to suggest relieving
hypersensitivity

11.  1941-Lukomsky-NaF..desensitizing obtundant.
 1962- Brannstorm- Hydrodynamic Theory
 1966….. Therapies
deposit an insoluble substance on the ends of the fibers
or nerves to act as a barrier
To stimulate secondary dentin formation.
 In 1974… Hodosh…superior desensitizer….. Potassium
nitrate.

12. Etiology & Predisposing
factors
1. Loss of enamel
Abrasion
Erosion Attrition
 Abfraction
2.Gingival Recession

14.  Scaling, Root planing, Periodontal Surgery……
 Question arises whether tooth brushing with or without a
dentrifice will expose dentinal tubules
 Role of plaque – important factor
 Role of saliva and bacterial contamination..
 Loyn et al(1991)..effect of some proprietary mouth rinses
on dentin smear layer.

15. Nerve fibers
 The dental pulp is richly innervated ….
 Myelinated … Non myelinated
 A fibers … C fibers
 B fibers…
 A-ά… proprioception, A-β…touch & pressure, A-γ…motor function
to spinal nerves and A-δ fibers…pain, temp & touch.

17.  A-delta and C-fibers sub odontoblastic plexus…..
 A-δ…. Brief, sharp, well localized pain …. Dentinal
hypersensitivity.
 C fibers… poorly localized pulpal pain.

18. Theorie
s
 Direct stimulation
 Odontoblastic transducer mechanism
 Gate-control theory and vibration
 Hydrodynamic mechanism

19. Direct Stimulation
theory

20. Anderson’s explanation
 No nerve elements….
 Receptor mechanisms in dentin that could be stimulated
indirectly…no direct stimulation… barrier.
 This theory is deficient because neural elements have not
been shown to extend into the peripheral half of-the dentin.
(Forrest et al 1988)

21. Odontoblastic Transduction
theory

22.  Synaptic like relation b/n the terminal sensory nerve endings
& odontoblastic processes.
 No evidence of acetylcholine
 Proponents of dentinal receptor mechanism…. Odontoblasts
has special sensory function and that a functional complex
with the terminal sensory nerve endings … excitatory
synapse…neuro sensitive complex

23. Drawbacks
 Why dentin continues to be sensitive, despite destruction
of odontoblast layer?
 Also does not explain why protein precipitation does not
decrease sensitivity of dentin to osmotic stimuli.
 Abandoned…. Failure to establish a synaptic relation
between the odontoblasts and the pulpal nerves.

24. Gate control theory and vibration
 When the dentin is irritated, all of the pulpal
nerves become activated from the vibrations.
 As the low-intensity "pain gates" from the larger
fibers are closed, the high-intensity "pain gates"
from the smaller fibers are enhanced.

25. Drawbacks
:
 Little to explain how pain responses from the dentin are
transmitted and perceived by the nerve endings of the pulp-
only how they may be centrally interpreted.

26. Hydrodynamic Theory (Brannstrom)
This idea of fluid movement within the dentinal tubules is the
basis for the transmission of sensations according to the
hydrodynamic theory.

27. Two mechanisms
Diffusion ……
Convection, transport or filtration

28. Hydraulic conductance of dentin………

31. Alternative mechanism (Modified
Hydrodynamic theory)
Application of various chemical solutions
Raising the intratubular potassium content,
Interdental nerves less excitable to further stimuli by
depolarizing the nerve fiber membrane.

32. To summarize….

33. Clinical considerations

34. Physiologic & Pathologic
pulpal defense mechanisms
 Formation of secondary dentin
 Peritubular dentin calcification…
 Natural occlusion of the dentinal
tubules
 Plaque adhesion and salivary
occlusion of the surface of the dentin

35. Methods of measuring
Dental Hypersensitivity
Tactile sensitivity
Thermal Sensitivity
Electrical Sensitivity
Osmotic Sensitivity
Chemical Sensitivity

36. Subject Assessment

37. Questions

38. Tactile Method
 Tactile-sharp explorer over sensitive area. CEJ
 Smith & Ash…(1964)

39. Tactile Method
 Using a Yeaple probe…. Compact hand
piece that contains an explorer tine …
electromagnetic field.
Scratchometer
Courtesy : Kleinberg{1988}

40. Thermal Sensitivity

41. Thermal Sensitivity
 An air thermal device devised by Dr. K.C. Yeh used a
temperature controlled stream of air as the stimulus.
 Air was heated to 1000F close to temperature of the
mouth. Its temp was then reduced until the subject felt
pain or discomfort.
Drawbacks : Moisture content

42. Thermoelectric device
Devices…. Electrical cooling or heating of direct contact
metal probes.

43. Electrical Sensitivity
 Pain response from both non sensitive and sensitive teeth.
 Lower organic resistance material to enamel, cementum and
dentine.
 Access of electrical stimulus via open tubules

44. Stark instrument for electrical
stimulation
Intensity:0-25 RMS

45. Osmotic Method
An osmotic method….. McFall and Hamrick(1987)
Fresh saturated solution of sucrose and allowing it to
reach room temperature
Solution is then applied to the root surface of the tooth
…..in place for 10 sec

46.  Popularized by Anderson and his colleagues
 Effective because the chemical activity of water in these
solutions is less than the chemical activity of water in
dentinal fluid
 Calcium chloride excites intra dental nerves owing to
osmotic movement of fluid
 Sodium chloride excite nerves owing to indirect osmotic
effects on superficial dentin & direct effects on intra
dental nerves in deep dentin.

47. Chemical
sensitivity

48. Differential Diagnosis
 Chipped teeth..
 Fractured restorations.
 Cracked tooth syndrome
 Dental caries.
 Post-restorative sensitivity.
 Teeth in acute hyper function
 Galvanism, marginal leakage, Palatogingival groove

49. Treatment
Modalities

50. Current approaches to the
Management
1.Fluid formation of smear layer
2.Topical application
3.Impregnation of tubules
4.Dentin bonding agents

51.  Most agents that are effective in reducing dentinal
hypersensitivity are also effective in partially occluding
the dentinal tubules
 Greenhill and Pashley found potassium nitrate to be
ineffective, but it is effective as a desensitizing agent.
 Most in-office procedures are aimed at obturating the
tubules

52. Mechanism of actions of desensitizing
agents
The methods of tubule occlusion are,
1. Formation of calcium over sensitive tubules
2. Formation of intra tubular crystals from salivary mineral
3. Formation of intra tubular crystals from dentinal fluid.
4. Progressive formation of peritubular dentin
5. Invasion of tubules by bacteria
6. Formation of intratubular collagen plugs

53. 7. Formation of irritation dentin
8. Leakage of large plasma proteins into tubules.
9. Formation of smear layer by brushing, use of tooth
picks etc
10. Resin impregnation or covering
11. Topical application of Calcium hydroxide, sodium
fluoride and oxalate
12. Restorations

54. Criteria
 Selecting desensitizing procedures
 Desensitizing agents
 Instructions to the patients

55. Office treatments for dentinal
hypersensitivity
1. Cavity varnishes
2. Anti inflammatory agents
3. Treatment that partially obturate dentinal tubules
o Burnishing of dentin
o Silver nitrate
o Zinc chloride - potassium ferro cyanide
o Formalin
o Calcium compounds
 Calcium hydroxide
 Dibasic calcium phosphate

56. Office treatments for dentinal
hypersensitivity
– Fluoride compounds
• Sodium fluoride
• Sodium silico fluoride
• Stannous fluoride
– Iontophoresis
– Strontium chloride
– Potassium oxalate
4. Restorative resins
5. Dentin bonding agents

57. Cavity varnishes
 Wycoff(1982) advocated the use of a cavity varnish such
as Copalite

58. Corticosteroids
 Anti-inflammatory effect of glucocorticoids …. decrease
dentinal sensitivity
 Mjor and Furseth …..
 Use is based on the assumption that hypersensitivity is
linked to pulpal inflammation

59. Burnishing of dentin
 Tooth pick or "orange wood stick …
 Pashley et al(1987)….Reduced fluid movement by 50% to
80%

60. Formation of insoluble
precipitates
 Calcium oxalate dihydrate
 Calcium fluoride
 Silver nitrate.
 Zinc chloride potassium Ferro cyanide impregnation
 Formalin

61. Silver nitrate
 Powerful protein precipitant
 Precipitated in solution with formalin or eugenol
 It may cause pulpal inflammation in shallow cavities.

62. Calcium hydroxide
 Block dentinal tubules or promote peritubular dentin
formation
 Brannstrom (1976) … constriction of the dentinal tubules…
depth of 0.1mm
 Following periodontal surgery, Jorkjend and
Tronstad(1972)……

63. Fluoride
 First proposed …. Lukomsky (1941)
 Bolden and Hezen et al have indicated that sodium
monofluorophosphate dentifrice…. Effective
 Ranouse and Ash….. 0.76% of sodium
monofluorophosphate

64.  Mechanism of action….
 Clement and Hoyt and Bibby found sodium fluoride
very effective in reducing dentinal hypersensitivity
 It may produce severe pulpal inflammation when
applied to dentin.

65. Acidulated sodium fluoride
 Laufer et al(1981) ……Concentration of fluoride in
dentin … greater
 No difference after samples were washed with synthetic
saliva
 A small fraction of the fluoride initially deposited on the
root surfaces was retained in the insoluble apatite form.

66. Sodium silico fluoride
 Bhatia …. saturated solution of sodium silico fluoride
for 5 min …..potent than 2% solution of NaF in
desensitizing painful cervical areas of teeth.
 Everett et al…. that silicic acid forms a gel with the
calcium of the tooth, thus producing an insulating
barrier

67. Stannous fluoride
 Blank and Charbeneau(1986) advocated burnishing a 10%
solution of stannous fluoride
 Ellingsen and Rolla(1987) examined SnF2 treated dentin
surface using S.E.M. and observed a dense layer of tin and
fluoride containing globular particles blocking the dentinal
tubules.
 Blong and associates(1985)…0.4% SnF2 gel effective

68. Fluoride Iontophoresis
 Iontophoresis …
 Iontophoresis of fluoride … controversial
 Induction of Secondary dentin formation by Iontophoresis
…. Murthy et al
 Lefkowitz et al reported on the pulpal response to 1%
sodium fluoride Iontophoresis

69.  Gangarosa recommends that teeth be isolated with plastic
strips and cotton rolls rather than a rubber dam
Induction of parasthesia on odontoblast process by
Iontophoresis …Gangarosa and Park (1978)
produce parasthesia by a direct effect on the
odontoblastic process or by alteration of the sensory
mechanism of pain conduction
Singhal(2005)……

71. Nd-YAG Laser treatment
 Effective in reducing dentine hypersensitivity to cold
stimuli.
 The mechanism of action has yet to be confirmed
 Lier et al (2002)…Nd:YAG laser…not significant
 Shwartz et al (2002)… Er:YAG laser…. Dentin
Protector

72. Kimura et al (2000)…..

73. Oxalates
 Calcium ions in the dentinal fluid to form insoluble
calcium oxalate crystals
Formaldehyde
 Formalin is an agent … control of dentin
hypersensitivity
 During late 1940s, Emoform tooth paste was introduced.

74. Resins and Adhesives
 Brannstrom and Nordenvall ….. impregnating it with
resin (the unfilled dentin bonding agent)
 Bowen & Cobb … composite resin bonded to dentin
decreased dentin permeability.
 Objective-

75.  Javid & co workers… 6 week study …. Isobutyl
cyanoacrylate with 33% of NaF paste….
 Immediate desensitization..
 Sensitivity slowly returned
 Glass ionomer cement…. Hydrophilic
 GLUMA…dentin bonding system …includes 5%
glutaraldehyde primer & 35 % HEMA

76. Strontium chloride

77. Potassium Nitrate
Wara-swapati(2005)…

78. To summarize….

80. References
 DCNA on Tooth hypersensitivity 1990, 34:3
 Text book of Clinical Periodontology –Carranza
 Clincal Periodontology & Oral Implantology –
Jan Lindhe
 Text book of conservative dentistry – Sturdevent
 Dentinal Sensation and Hypersensitivity A
Review of Mechanisms and Treatment
Alternatives (Louis H. Berman) Journal of
Periodontology 1985 Apr (216 - 222):
 Role of dentin bonding agent in reducing
cervical dentin hypersensitivity – JCP 1998

81.  JCP 2002 “desensitizing effects of an Er:YAG
laser on hypersensitive dentin”
 JISP 1997… Comparative evaluation of Gluma
primer & 10% pot nitrate in treating cervical
dentin hypersensitivity.
 JCP 2002.. Treatment of dentin hypersensitivity
by Nd:YAG laser
 JP 2001…. Efficacy of 3% pot nitrate
desensitizing mouthwash in the treatment of
dentin hypersensitivity.
 Dentine Hypersensitivity: new perspectives on
an old problem. International Dental Journal
(2002) 52, 367–375