DENTINAL HYPERSENSITIVITY….

Dr Nida Sumra

Contents.

Introduction Definitions Etiology Mechanism of dentin sensitivity Theories Clinical considerations Methods of measuring hypersensitivity Management of hypersensitivity Summary & conclusion

Introduction.

The term dentine hypersensitivity has been used for many decades to describe a common painful condition of the teeth. Despite this there are many gaps in our knowledge concerning dentine hypersensitivity.

It is perhaps not surprising therefore that one can still

have sympathy with statement made in 1987 by Johnson and Co-workers that dentine hypersensitivity is an Enigma, being frequently encountered yet ill understood.

Definition.

Dentine hypersensitivity is defined as short, sharp pain arising from exposed dentine in response to stimuli, typically thermal, evaporative, tactile, osmotic or chemical and which cannot be ascribed to any other dental defect or pathology.

Dowell and Addy 1983

Prevalence 15-18% of the general populations; 72-98% - In periodontal patients

  Age incidence: – 20-40 yrs peak; range 20-50 yrs. (Reasons – appearance and progression of gingival

recession.)

  Gender: - Proportionately more females affected than

males. Reasons: Related to the better oral hygiene of females

compared with male Differences in diet – favoring healthy but often acidic foods

and drinks in females. Either periodontal disease and / or periodontal treatment

predisposed to dentine hypersensitivity, presumably through both having effects on dentine and gingival recession.

Distribution Buccal cervical area of teeth

Reasons – site of pre-dilection for gingival recessions and the area where enamel is the thinnest.

Most commonly affected are canines and Ist premolars, then incisor and 2nd premolars, least often molars.

Show a negative co-relation with plaque scores recorded by site.

Significantly greater proportions of left side tooth sensitivity compared with their right contralateral tooth types.

Etiology

Two processes need to occur to arise dentine hypersensitivity.

Lesion localization Lesion initiation

A. LESION LOCALIZATION: dentine has to become exposed.

Causes: Enamel loss Gingival recession

Enamel loss

Attrition. Abrasion.

Erosion.

• dietary• environmental

Extrinsic acids

Intrinsic acids

Abfraction.

Other reasons.

Improper instrumentation Enamel and cementum do not meet at the CEJ

Gingival recession

Cause: Tooth brushing ANUG and ANUP, Self- inflicted injury, Periodontal disease, Periodontal surgical and non-

surgical procedures, Dehiscence / fenestrations.

B. LESION INITIATION Require opening of dentinal

tubules Tooth paste remove the smear

layer through abrasive and detergent actions

Erosive agents, particularly acid dietary fluids readily expose tubules

Most soft drinks, some alcoholic beverages and yoghurt all readily remove the dentine smear layer after a few minutes of exposure.

Erosion causes bulk loss of dentine and surface softening, which is very susceptible to physical insults.

Mechanism of action

The neural theory, gate control theory

The odontoblastic transduction theory

The hydrodynamic theory

Direction neural stimulation

According to this theory the dentinal tubules innervated by nerves, which extend upto 100 microns along the dentinal tubules.

Whenever there is injury to these dentinal tubules, the stimuli reach the nerve ending in the inner dentine.

The stimulated nerve causes hypersensitivity.

Since histological examination shows the dentinal tubules does not contain any nerve endings, this theory is not accepted 

Gate control theory. (seltzer)

• A.k.a. vibration theory

• Irritated pulpal nerves get activated & larger myelinated fibres accommodate these sensations.

• But smaller C fibres tend to be maintained hence high intensity gates remain open

• Causing pain

2. Transduction theory Membrane of the odontoblast process is excited by the

stimulus and the impulse is conduct to the nerve ending in the inner dentine i.e. pre-dentine, odontoblast zone and pulp.

Not popular theory since there is no neurotransmitter vesicles in the odontoblast process to facilitate the synapse or synaptic specialization.

3. Hydrodynamic theory

Ist proposed Gysi – 1900,) (Brannstrous 1963,67.)

Rapid shifts of the fluids within the dentinal tubules, following stimulus application, result in activation of sensory nerves in the inner dentin region of the tooth

Clinical assessment of dentine hypersensitivity

  Subjective Evaluation

1. Verbal rating scale is a simple descriptive pain scale

which includes the following:

0 – No discomfort

1 – Mild discomfort

2 – Marked discomfort

3 – Marked discomfort that lasted for more than 10

seconds

2. Visual analogue scale is a line 10 cm in length,

the extremes of the line representing the limits

of pain, a patient might experience from an

external stimulus.

3. McGill pain questionnaire – the patient is

shown 20 sets of words and asked to select a

word from each set which best describes the

present pain experience.

Objective assessment

Mechanical or tactile stimuli

Pass a sharp dental explorer… grade the response …..scale 0 – 3 Collins used a no 23 explorer Simple yet effective 5 – 10 gm of force…Tip of the explorer … 500/nm2…

compression and deformation of dentin.

Incorporating a calibrated strain gauge in the explorer.

Using a Yeaple probe…. Compact handpiece that contains an explorer … electromagnetic field.

Hand held scratch device… Dr

Kleinberg Torsion gauge

Sharp explorer like probe

Indicator …Records the force of displacement in

centinewtons

Probed at CEJ

A tooth that fails to respond at 80 centi-newtons is non

sensitive.

Scratch device

Thermal Sensitivity

Directing a burst of warm temperature air from a dental syringe onto the test tooth

One second blast from the air syringe …. temperature is b/n 650 and 700F and at a pressure of 60 psi

0 - No discomfort 1 - Mild discomfort, but no severe pain 2 - Severe pain when stimulus is applied 3 - Severe pain occurs and persists even after removal

of stimulus

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.

The Yeh device had a disposible plastic tip, and air emitted at 10 psi could be adjusted to between 1000 and 700F within about 2 minutes.

Cold water testing: varied temperature of 15 ml of water is rinsed.

Thermo-electric device (Biomat-thermal probe)

It provides a continuous application of heat/cold.

Consists of small probe tip to which thermistor is attached. This thermistor measures the temperature at the probe tip.

A current flow is used to regulation air temperature either by increasing or decreasing the current flow in range of 12oC- 82oC

It is preset at temperature of 37.5oC. It can be used for heat and cold testing by increasing or decreasing the temperature by IoC.

Ice – stick. Heat or cold air. Ethyl chloride.

Electrical stimulation Electrical pulp tester Is a battery operated, producing pulses of direct current. The

intensity of the output voltage may be increased by pre-setting various numbered gradations (0-10) on a thumb wheel.

Dental Pulp Stethoscope Developed by Stark et al (1977) Consisted of a digital readout sensitive voltameter connected

to a digital printer teeth was activated by push button control. A conventional battery powered electrical pulp tester was attached to the Voltameter.

The stimulus intensity was measured in volts. The pulp test lip is placed on the gingival 1/3rd of enamel and

tooth stimulated. A electrolytic gel with a pH of 5.4 – 5.6 is used.

When patients feel tingling warm sensation, it is switched off and voltage is read in digital read out. 15 volts and above- range of non sensitivity  

Stark instrument for electrical stimulation

Chemical / osmotic stimulation

Hypertonic solutions. Eg. Sodium chloride glucose, sucrose and calcium chloride.

The use of chemical solution is complicated, because the solute in solution diffuses into the dentine fluid. On repeated applications, the osmotic pressure difference between the tubular fluid and the applied fluid will decrease and reduce the effect of the solution as our osmotic stimulus.

To avoid this, long time intervals must be allowed between the applications of the solutions.

Practically least preferred.

 

Differential Diagnosis

Cracked tooth syndrome.

Fractured restorations.

Chipped teeth.

Dental caries.

Post-restorative sensitivity.

Teeth in acute hyper function.

MANAGEMENT

Classification

According to Scherman A and Jacobeen – 1992. Based on chemical and physical properties as follows.

Chemical agents Physical agents Corticosteroids Composites Silver nitrate Resins Strontium chloride Varnishes Formaldehyde Sealants Potassium nitrate or oxalate Soft tissue

grafts Fluorides Glass inomer

cement Sodium citrate Lasers Iontophoresis with 2% NaF

B. IN-OFFICE PRODUCTS 1. Treatment agents that do not polymerize. a. Varnishes / Precipitants Shellacs 5% NaF varnish 1% sodium fluoride, 0.4% stannous fluorides 3% mono-potassium-monohydrogen oxalate 6% acidic ferric oxalate Calcium phosphate preparations. Calcium hydroxide. b. Primes containing HEMA (Hydroxy ethyl methacrlate) 5% glutaradehyde 35% HEMA in water   II. Treatment agents that undergo setting or polymerization reactions.

Conventional glass ionomer cement. Resin-modified glass ionomer cement / Compomers Adhesive resin primers Adhesive resin bonding system.

III. Use of mouth guards. IV. Iontophoresis. V. Lasers.

Mechanisms The most likely mechanisms of action is the reduction

in the diameter of the dentinal tubules so as to limit the displacement of fluid in them.

According to Trowbridge and Silver (1990) this can be attained by

Formation of a smear layer produced by burnishing the exposed surface.

Topical application of agents that forms insoluble precipitates with in the tubules.

Impregnation of tubules with plastic resins. Sealing of the tubules with plastic resins.   Act via precipitates of crystalline salts on the dentine

surface, which blocks dental tubules. Desensitizing agents are effective when used

continuously for a period of at least 2 weeks.

A. Home use products

Rationale. Home use ‘over the counter’ desensitizing products

appear to be the most realistic and practical means of treating most patients with tooth dentine hypersensitivity and should be the 1st step in routine management.

 

Several reasons exit to prescribe these products.

They are readily and widely available in pharmacies The products are cost effective. The ‘over the counter’ products an simple to use and non-

invasive The habit of tooth brushing is almost universal the patients

are not required to do anything.

Strontium chloride Dentifrice containing 10% strontium chloride

hexahydrate as the desensitizing agent

Sensodyne tooth paste was formulated with

strontium chloride hexahydrate in 1961 In vitro studies report that strontium chloride

only slightly reduces dentinal fluid flow, the occurrence thought to be produced by the abrasive filler occluding the tubule orifices.

Skurnick in an uncontrolled study, found that it decreased dentinal sensitivity short term in 93% of cases.

However, Anderson and Matthews found it ineffective as a densitizing agent.

Possible detrimental pulpal effects of strontium chloride have also been suggested.

Minkoo et al regular at-home use of a dentifrice containing 10% strontium chloride hexahydrate is an effective means for reducing the discomfort and pain engendered by thermal and tactile stimuli.

Potassium Nitrate Greenhill and Pashleyfound potassium nitrate - ineffective in

decreasing any dentinal fluid flow in in vitro coated dentin, even at a 30% concentration.

But many investigators have found 5% potassium nitrate an excellent dentinal desensitizing agent.

Hodash (1974) called potassium nitrate a superior desensitizer and found it to be highly effective at concentrations of 1 to 15 %

In a controlled study, Tarbet et al found 5% potassium nitrate-paste able to desensitize the dentin effectively at 1 week and up to 4 weeks compared to the control (paste without potassium nitrate) in 92% of the subjects. In a follow-up report, which histologically examined the pulpal effects of the previous study, it was determined that "potassium nitrate did not induce any pulpal tissue change

Sodium monoflurophospate

In a study by Arowojolu (2001) , the desensitizing effect of sodium monoflurophosphate was better than srontium chloride.

In conclusion a commercially available dentrifice of Na monoflurophospahte as its active ingredient - effective results after 6 weeks.

A. Varnish /Precipitants 5% sodium fluoride in a thick varnish – by Clark et

al (1985).

HEMA containing primers like GULMA [5% gluteraldehyde and 35% HEMA]

Corticosteroids Anti-inflammatory effect of glucocorticoids …. decrease

dentinal sensitivity

Mjor and Furseth ….. application of corticosteroid preparation to dentin caused complete obliteration of tubules .

Mosteller …. liner consisting of 1% prednisolone in combination with 25% parachlorophenol, 25% m-cresyl acetate and 50% gum camphor prevented postoperative thermal sensitivity

Mjor showed that steroid application to dentin increased peritubular dentin mineralization.

Thus, the tubule lumen would be decreased, resulting in less dentin tubule fluid movement, reducing the dentinal sensitivity.

Green et al compared steroid application to Ca(OH)2 in their ability to induce mineralization. The results were very similar for both compounds, with the steroid causing "completely obturated tubules" and calcification "in an area of the dentine where no highly mineralized peritubular matrix is normally found."

Burnishing of dentin

Tooth pick or "orange wood stick … creates a partial smear layer on

dentin surface .

Reduced fluid movement by 50% to 80% .

More effective in reducing dentin permeability than burnishing

with glycerin alone or glycerin in combination with sodium flouride.

Pashley et al - The effects on dentin permeability of burnishing NaF, kaolin, or glycerin, alone and in various combinations, were determined using an in vitro system. The results indicate that the important variable was not any of the constituents of the paste but the burnishing process itself.

Silver nitrate

Powerful protein precipitant .

Greenhill and Pashley found that the silver nitrate either alone or in combination with formalin ppted silver chloride or elemental silver

It may cause pulpal inflammation in shallow cavities.

Naylor and Anderson and Matthews measured dentin sensitivity before and after silver nitrate application and found no significant difference in pain response.

Thus, silver nitrate may be ineffective and is possibly deleterious in the management of dentin sensitivity.

Calcium hydroxide It may block dentinal tubules or promote peritubular dentin formation .

Brannstrom (1976) … construction of the dentinal tubules… depth of 0.1mm .

Mjor (1967)…micro radiography… increased radio density

In a study by Greene et al hydroxide was an effective desensitizing agent over the control to mechanical, hot and cold stimulation .Calcium hydroxide out-performed potassium nitrate at all time intervals throughout cold stimulation and therefore is especially recommended as a desensitizing agent for those patients who are sensitive only to cold.

Jorkjend and Tronstad applied calcium hydroxide to sensitive teeth following periodontal surgery, sealing it in with polymethacrylate and a periodontal pack. They found best results were obtained after 7 days, with the teeth no longer sensitive to cold, air, carbohydrates, toothbrushing, toothpicks, scaling or ultrasonic devices

In a 3-month clinical study, Green et al found calcium hydroxide applications consistently effective in relieving cervical hypersensitivity

Hydroxyapatite

Shetty et al evaluated Hydroxyapatite as an In-Office Agent for Tooth Hypersensitivity - showed definite potential as an effective desensitizing agent providing quick relief from symptoms. None of the patients reported any adverse responses to the agent

Fluoride Mechanism of action….

increasing the amount of reparative dentin, or

by precipitating calcium fluoride in the tubules

Johnson et al (1981) stannous fluoride with the ionizing brauh provided significantly greater relief than did the stannous fluoride alone.

Clement and Hoyt and Bibby (using 33.3% NaF) found sodium fluoride very effective in reducing dentinal hypersensitivity in subjective, noncontrolled studies. However, sodium fluoride may produce severe pulpal inflammation when applied to dentin.

Fluoride Iontophoresis A low voltage electric current is used to impregnate the tooth with

fluoride ions. Two to six times more fluoride can be impregnated into dentine

than when treated with topical sodium fluoride. Manning described an iontophoretic device which would work

electrophoretically to desensitize dentin. Using 2% NaF with iontophoresis, Carlo (in a noncontrolled study)

found "significant relief from sensitivity“ in 90% of cases. Singal et al - 2% NaF was comparatively better than HEMA-G in

providing long-term relief

Intra oral fluoride releasing device.

Sodium fuoride in an acrylic polymer releasing fluoride at the rate of 0.04mg/day,

This device is fast , painless and cost effective (marini et al 2010)

Orsini et al (2013) compared - Three dentifrices [1) containing 8% arginine,

1450ppm sodium monofluorophosphate; 2) containing 8% strontium acetate, 1040ppm sodium fluoride; 3) containing 30% micro-aggregation of zinc-carbonate hydroxyapatite nanocrystals] were compared after 3-day treatment .

This study documented that the three tested dentifrices significantly reduced DH after 3-day treatment, supporting their utility in clinical practice. This is the first report documenting the rapid relief from DH of a zinc-carbonate hydroxyapatite dentifrice.

Oxalates

used popularly as desensitizing agent

inexpensive

easy to apply and

well tolerated by the patients

Potassium oxalate and ferric oxalate solutions -calcium ions

in the dentinal fluid to form insoluble calcium oxalate crystals.

Muzzin et al compared 30% dipotassium Oxalate (DO) and 3% monohydrogen-monopotassium Oxalate (MO) on the reduction of dentin hypersensitivity in vivo. Results suggested - decrease in dentin hypersensitivity following the application of 3% MO alone, and 30% DO followed by 3% MO.

Lasers

Studies have reported that the neodymium:YAG laser, the erbium:YAG laser and galium-aluminium-arsenide, erbium, chromium-doped:yttrium, scandium, gallium, and garnet all reduce DH

A more expensive and complex treatment modality.

Kumar et al - The combination of Nd:YAG laser and 5% sodium fluoride varnish seems to show an impressive efficacy, when compared to either treatment alone, in treating dentin hypersensitivity.

Yilmaz et al (2011) evaluate the efficacy of er cr ysgg laser on reduction in dh. Immediately after treatment the er cr ysgg laser had a significant higher desensitizing effect and the results were stable after 3 months

Dentine bonding agents Bonding agents are applied to the exposed dentine

Easy to apply Aesthetically acceptable

Brannstrom et al. obtained "immediate and lasting blockage of sensitivity" in 20 patients studied from 2 to 12 months. This is in agreement with Dayton et al. who tested various unfilled resins in 44 teeth.

Narhi et al. recorded nerve activity directly in cat teeth when dentin was mechanically stimulated. He found no neural activity after resin impregnation.

Composite/ glass ionomer restorations

Long lasting, yet more invasive procedure

Is indicated when there is significant loss of tooth structure

GC tooth mousse

Kowalczyk A et al GC Tooth Mousse for dentine hypersensitivity was

evaluated - cold air stream Min. 6 weeks of topical application would reduce

hypersensitivity.

CPP-ACP: Casein Phosphopeptide – Amorphous Calcium Phosphate).

Nano structures bioactive glass.

-Mitchell et al(2011) Nano structured sol gel bioactive glass with carrier

fluid showed a significant change in reduction of conductance…

Produced an immediate reduction in

fluid conductance, and maintaining it for at least 7 days

Conclusion.

Much has been learnt about hypersensitivity since it has been described as an enigma 20 years ago.

The ultimate goal in the treatment of dentine hypersensitivity is the immediate and permanent relief of pain

Professionals should identify the causative factors so that prevention can also be included in the treatment plan

References. Calcium Hydroxide and Potassium Nitrate as Desensitizing Agents

for Hypersensitive Root Surfaces, GREEN et al , jop J. Periodontol. October, 1977.

Clinical Evaluation of a New Treatment for Dentinal Hypersensitivity, Tarbet et al , J. Periodontol. September. 1980

The Effectiveness of an Electro-Ionizing Toothbrush in the Control of Dentinal Hypersensitivity, Johnson et al, J. Periodontol: June, 1982.

Dentinal Sensation and Hypersensitivity A Review of Mechanisms and Treatment Alternatives, Berman, Volume 56, Number 4, i. Periodontol. April, 1984.

The Effects of Burnishing NaF/Kaolin/Glycerin Paste on Dentin Permeability, Pashley et al, J Periodontol. January, 1987. Volume 58 Number 1

Efficacy of Strontium Chloride in Dental Hypersensitivity, Minkof et sl , J. Periodontol. July, 1987 Volume 58 Number 7.

Effects of Potassium Oxalate on Dentin Hypersensitivity in Vivo, Muzzin et al, J. Periodontol. March 1989, Volume 60 Number 3.

Intraora fluoride releasing device: a new clinical therapy for dentin sensitivity, merini et al , JOP 2000 vol 71, 90-95.

2% Sodium Fluoride-Iontophoresis Compared to a Commercially Available Desensitizing Agent. Singal et al , J Periodontol 2005;76:351-357.

Short-Term Assessment of the Nd:YAG Laser With and Without Sodium Fluoride Varnish in the Treatment of Dentin Hypersensitivity – A Clinical and Scanning Electron Microscopy Study, Kumar et al , J Periodontol 2005;76:1140-1147.

Hydroxyapatite as an In-Office Agent for Tooth Hypersensitivity: A Clinical and Scanning Electron Microscopic Study, shetty et al, J Periodontol 2010;81:1781-1789.

A 3-Day Randomized Clinical Trial to Investigate the Desensitizing Properties of Three Dentifrices, Orsini et al, Journal of Periodontology; 2013 , DOI: 10.1902/jop.2013.120697 .

BIOMIMETIC DENTIN DESENSITIZER BASED ON NANO-STRUCTURED BIOACTIVE GLASS, Mitchell et al J Dental materials 2011;27:386–393.

Yilmaz HG, Cengiz E, Kurtulmus-Yilmaz S, Leblebicioglu B. Effectiveness of Er,Cr:YSGG laser on dentine hypersensitivity: a controlled clinical trial. J Clin Periodontol. 2011 Apr;38(4):341-6.

Thank you