dentin hypersensitivity

Periodontics Seminar

Chithira. E4th year part 1

Reg.no: 100020239

Dentinal hypersensitivity

Dentin hypersensitivity 3

Algorithm Introduction Definition Mechanism of dentin sensitivity Incidence and distribution Etiology and predisposing factors Clinical features Diagnosis Differential diagnosis Treatment strategies Management Conclusion References

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Introduction

• The term tooth hypersensitivity, dentinal sensitivity or hypersensitivity is often used intermittently to describe clinical condition of an exaggerated response to an exogenous stimulus.

• The exogenous stimuli may include thermal, tactile or osmotic changes.

• The response to stimulus varies from person to person due to difference in pain tolerance, environmental factors, and psychology of patient.

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Definition: Holland et al in 1997: Sharp, short pain arising from exposed dentin in response to stimuli typically thermal, chemical, tactile or osmotic and which can not be ascribed to any other form of dental defect or pathology.

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• Sensitivity or hypersensitive dentin implies an abnormal sensitiveness of an exposed area of dentin, exhibiting itself in the form of reflex or localized pain, sometimes in the absence of apparent external sources of irritation or otherwise as a result of the contact of heat and cold, salts, sweets, and acid substances or of foods and instruments. – MC Gee.

• Pain is described as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.

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Mechanism of dentin sensitivity

Theories:1) Neural theory2) Odontoblastic transduction theory3) Hydrodynamic theory

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Neural theory:

o This theory states that dentin hypersensitivity occurs due to the direct stimulation of nerve fibers present in the dentin.

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• No nerve fibers could be demonstrated going to DEJ, which is the most sensitive area. Thus dentin sensitivity does not solely depend up on the stimulation of such nerve endings.

Drawbacks:• Rejected because: outer dentin which is devoid of nerve

fibers is more sensitive than inner dentin.• Newly erupted tooth doesn’t posses nerve endings even

though it is sensitive.

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Odontoblastic transduction theory:

o Odontoblasts are derived from neural crest cells. They retain the ability to transmit and propagate an impulse.

o Theory states that: dentin hypersensitivity occurs due to direct stimulation of odontoblastic processes that are present in dentinal tubules.

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Mechanical, chemical or osmotic

stimulus

Direct stimulation of odontoblastic

process in dentinal tubules

Painful response hypersensitivity

• This is not a popular theory since there are no neurotransmitter vesicles present in the gap junctions between odontoblasts to facilitate the synapse or synaptic transmission.

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Hydrodynamic theory:

o Proposed by Brannstrom.o Dentinal tubules contain dentinal fluid, odontoblastic

process, and nerve fibers.o This theory states that fluid in the dentinal tubules can be

affected by various stimuli such as mechanical, chemical and osmotic.

o Movement of dentinal fluids within the tubules in either direction stimulates nerves in the dentin or pulp which results in the painful response.

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Mechanical, chemical or

osmotic stimulus

Movement of dentinal fluid

within the dentin tubules

Stimulation of nerves in the

dentin or pulp

Painful responseHypersensitivity.

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Currently most investigators accept that dentin sensitivity is due to the hydrodynamic fluid shift

Occurs across exposed dentin with open tubules.

Rapid fluid movement in turn activates the mechanoreceptor nerves of A group in the pulp.

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• Mathews et al noted thatStimuli such as cold causes fluid flow away from the pulp.Produces more rapid and greater pulp nerve response than those such as heat, which causes an inward flow.

• Dehydration of dentin by air blasts or absorbent paper causes outward fluid movement and stimulates the mechanoreceptor of the odontoblast causing pain.

• Prolonged air blast causes formation of protein plug into the dentinal tubules, reducing the fluid movement and thus decreasing pain

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• The pain produced when sugar or salt solutions are placed in contact with exposed dentin can also be explained by dentinal fluid movement.

• Dentinal fluid is of relatively low osmolarity, which have tendency to flow outwards solution of higher osmolarity i.e., salt or sugar solution.

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Dentin hypersensitivity 173/11/2015


Incidence and distribution

• Most sufferers range from 20-40 years of age and a peak occurrence is found at the end of the third decade.

• In general slight higher incidence is reported in females than in males.

• Reduced incidence in older individuals reflect: Age changes in dentin and pulp.

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Intra-oral distribution:• Most commonly noted on buccal cervical zones of

permanent teeth, canines and premolars in either jaw are the most frequently involved.

• In right handed tooth brushers, dentin hypersensitivity is greater on the left sided teeth compared with the equivalent contra-lateral teeth.

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Etiology and predisposing factors:

• The primary underlying cause for dentin hypersensitivity is exposed dentinal tubules.

• Dentin may become exposed to by 2 processes Loss of covering periodontal structures Loss of enamel.

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causes

Enamel loss

Cemental loss others

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Causes of enamel loss

Attrition by exaggerated occlusal functions like bruxism

Abrasion from dietary components or improper brushing technique

Erosion associated with environmental or dietary components particularly acids

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Cemental loss

• Root planing• Periodontal diseases• Periodontal surgeries• Recession of the

gingiva.

Other causes

• Changes in temperature

• The careless use of scalers

• Action of caries and wasting diseases

• Action of cracks/ fracture of the enamel

• Action of salts, sweets and acidic substances.

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Aggressive or poor oral hygiene

Extrinsic acidsIntrinsic acids

Gingival recession Erosion

Dentin exposure through either enamel or gingival

recession

Opening of tubules dentinal

Disturbed flow=sensitivity Stimulates A delta fibers

DENTIN HYPERSENSITIVITY3/11/2015


• The most common cause for exposed dentinal tubules is gingival recession.

• Various factors that cause recession are Inadequate attached gingiva Prominent roots Tooth brush abrasion Oral habits resulting in gingival laceration Excessive tooth cleaning Excessive flossing Gingival recession secondary to specific Diseases NUG, Periodotitis. Crown preparation

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• The recession may or may not be associated with bone loss. • If bone loss occurs, more dentinal tubules get exposed.• When gingival recession occurs the outer protective layer of

root dentin, i.e cementum gets abraded or eroded away.• This leaves the exposed underlying dentin• These cells contain nerve endings and when disturbed,

nerves depolarizes and this is interpreted as pain.

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Gingival

recession

Removal of cemental layer

Exposure of dentin and thus dentinal tubules

Depolarization of nerve endings of odontoblast

Pain

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• Poor plaque control• Excess oral acids (soda, fruit juice)

• Tooth brush abrasion• Cervical decay

• Tartar control tooth paste

Reasons for continued dentinal tubular exposure

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Clinical features:

o Pain is the primary symptomo The patient usually experiences a short, sharp pain in

response to heat, cold, tactile stimuli, sweets or sour foods.o Intensity of pain is usually mild to moderate.o The clinical symptoms of hypersensitive dentin are similar

to those of acute reversible pulpitis.o Tooth hypersensitivity differs from dentinal or pulpal pain. In

case of dentin hypersensitivity, patient’s ability to locate the source of pain is very good where as in pulpal pain, it is very poor. The pulpal pain is explosive, intermittent and throbbing and can be affected by hot or cold.

o The character of pain does not outlast the stimulus.

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Diagnosis

• A careful history together with a thorough clinical and radiographic examination is necessary before arriving at a definitive diagnosis of dentin hypersensitivity.

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Careful case history: The history and nature of pain The intensity of pain The stimuli which initiate the sensitivity The frequency and duration of sensitivity History of restorative procedures, periodontal procedures

and other related dental procedures.

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Clinical examination:

Clinical observations:o Percussion sensitivityo Sensitivity or pain on tactile examinationo Evidence of dentin exposure (gingival recession, loss of

enamel)o Pain lingering after stimulus is removed.o Signs of fractured, leaky or poor restorative margins.Diagnostic test:o Vitality test to rule out the pulpal involvemento Radiographic examination, to detect caries, pulpal

involvement, or periodontal involvement.

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Differential diagnosis

Dentin hypersensitivity is perhaps a symptom complex rather than a true disease and results from stimulus transmission across exposed dentin.• A number of dental conditions are associated with dentin

exposure and may produce same symptoms. • They are Chipped tooth Fractured restoration Restorative treatments Dental caries Cracked tooth syndrome Other enamel invaginations.

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Treatment strategies

• Hypersensitivity can resolve without the treatment or may require several weeks of desensitizing agents before improvement is seen.

• Treatment of dentin hypersensitivity is challenging for both patient and the clinician mainly of 2 reasons.

1) Difficult to measure or compare pain among different patients

2) Difficult for patient to change the habits that initially caused the problem.

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Management

It is well known that hypersensitivity often resolves without treatment.

This is probably related to the fact that dentin permeability decreases spontaneously because of occurrence of natural processes in the oral cavity.

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Natural process contributing to desensitization

Formation of reparative dentin by the pulp

Obturation of tubules by the formation of mineral deposits. (Dental sclerosis)

Calculus formation on the surface of the dentin.

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• Treatment options for managing dentin hypersensitivity should be based on the extent and severity of the problem.

Sl no Condition Treatment

1 Localized hypersensitivity Try application of varnishes, dentin adhesive restoration.

2 Generalized hypersensitivity Prescribe desensitizing toothpastes and restorations.

3 Severe hypersensitivity Consider endodontic therapy

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• 2 principal treatment options:

Plug the dentinal tubules preventing the fluid flow.

Desensitize the nerve, making it less responsive to stimulation. All the current modalities address these 2 options.

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Management

Restorative methods

Non-restorative methods

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Sl no Condition Treatment

1 Wasting diseases GIC or composites with proper pulp protection if required.

2 Dental caries Metallic or nonmetallic restorations

3 Dentin expose Resin impregnation technique, dentin bonding agents.

4 Root cementum expose Application of Ca(OH)2

5 Faulty restoration Replace with suitable restoration

6 Cracked tooth syndrome Full crowns

Restorative methods:• When hypersensitivity is associated with significant

loss of tooth structure then restorative methods are employed.

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Non-restorative methods:

• If the loss of tooth structure is insignificant and generalized, then the non-restorative methods are indicated.

1. Lasers2. Desiccation3. Iontophoresis4. Chemical agents5. Dentin bonding agents6. Medicated tooth pastes7. Topical fluoride applications8. Resin impregnation techniques9. Application of calcium hydroxide.

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Treatment of dentin hypersensitivity can be divided into:

1. Home care with dentifrices2. In office treatment procedures3. Patient education

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Home care with dentifrices:

• Dentifrice: a substance used with a toothbrush to aid in cleaning the accessible surfaces of the teeth.

• Its components includes Abrasive Surfactant Humectant Thickener Flavoring agent sweetener Coloring agent Water

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

o The habit of tooth brushing with a dentifrice for cosmetic reasons is well established in the population, thus compliance with this regimen can be easily made.

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• 10% strontium chloride desensitizing dentifrice found to be effective in relieving the pain of tooth hypersensitivity.

Strontium chloride

dentifrices

• 5% potassium nitrate dentifrice found to alleviate pain related to tooth hypersensitivity.

Potassium nitrate

dentifrices

• 0.7% Sodium monofluorophosphates dentifrices are the effective mode of treating tooth hypersensitivity.

Fluoride dentifrices

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In office treatment proceduresRationale of therapy:o According to hydrodynamic theory of hypersensitivity, a

rapid movement of fluid in the dentinal tubules is capable of activating intra-dental sensory nerves.

o Therefore treatment of hypersensitive teeth should be directed towards reducing the anatomical diameter of the tubules, obliteration of the tubules or to surgically cover the exposed dentinal tubules so as to limit fluid movement.

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Criteria for selecting desensitizing agent:

Provides immediately and lasting relief from

pain

Well tolerated by patients

Does not stain the tooth

Easy to apply

Not injurious to the pulp

Relatively inexpensive

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Treatment options to reduce the diameter of dentinal tubules can be:

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

Application of agents that form insoluble precipitates within the tubules

Impregnation of tubules with plastic resins Application of dental bonding agents to seal off the tubules. Covering the exposed dentinal tubules by surgical means.

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• Prior to treating sensitive root surfaces, hard/soft deposits should be removed from the teeth.

• Root planning on sensitive dentin may cause considerable discomfort, in this case teeth should be anesthetized prior to treatment and the teeth should be isolated and dried with warm air.

• Varnishes: open tubules can be covered with a thin film of varnish, providing a temporary relief.

Varnish such as copalite can be used for this purpose. For more sustained relief a fluoride containing varnish Duraflor can be applied.

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Corticosteroids: • Containing 1% prednisolone in combination with 25% para-

chlorophenol, 25% methacresyl acetate and 50% gum camphor was found to be effective in preventing postoperative thermal sensitivity.

• The use of corticosteroids is based on the assumption that hypersensitivity is linked to pulpal inflammation; hence more information is needed regarding the relationship between these 2 conditions.

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Partial obliteration of dentinal tubules.

• Burnishing of dentin:Burnishing of dentin with a toothpick or orange wood stick results in the formation of a smear layer.This layer partially occludes the dentinal tubules which help in reducing the hypersensitivity.

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Formation of insoluble precipitates to block tubules: Certain soluble salts react with ions in tooth structure to

form crystals on the surface of dentin. To be effective, crystallization should occur in 1-2 mts and

the crystals should be small enough to enter the tubules and must also be large enough to partially obturate the tubules.

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Chemical agents are:Potassium oxalateFerric oxalatePotassium oxalateCalcium chlorideStrontium chlorideCalcium phosphate

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Oxalates:• Relatively inexpensive• Easy to apply• Well tolerated by patients.• Eg: Potassium oxalate and ferric oxalate solution• They make available oxalate ions that can react with

calcium ions in the dentin fluid to form insoluble calcium oxalate crystals that are deposited in the apertures of the dentinal tubules.

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Application of potassium oxalate on

dentinal tubules

Formation of calcium oxalate in tubules

Blockage of dentinal tubules

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• Silver nitrate has ability to precipitate protein constituents of odontoblast processes, thereby partially blocking the tubules.

• Zinc chloride- potassium ferrocyanide. When applied forms precipitate, which is highly crystalline and covers the dentin surface.

• Formalin 40% is topically applied by means of cotton pellets or orangewood sticks on teeth.

• Strontium chloride: Topical application of concentrated sodium chloride on an abraded dentin surface produces a deposit of strontium that penetrates dentin to a depth of approximately 10-20 micro m and extend into dentinal tubules

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• Calcium compounds have been popular agent for many years for the treatment of hypersensitivity.

• The exact mechanism of action is unknown but evidence suggests that:

* It may block dentinal tubules * May promote peritubular dentin formation. * On increasing the concentration of calcium ions around nerve fibers, may result in decreased nerve excitability. So calcium hydroxide might be capable of suppressing nerve activity.

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A paste of calcium hydroxide and sterile distilled water applied on exposed root surface and allowed to remain for 3-5mts, can give immediate relief in 75% of cases.

Dibasic calcium phosphate when burnished with round toothpick forms mineral deposits near the surface of the tubules and found to be effective in 93% of patients.

• Recaldent: CPP-ACP: complex of casein phosphopeptides and amorphous calcium phosphate.CPPs are a group of peptides derived from casein. Casein is the part of protein which naturally occurs in milk.CPP is responsible for high availability of calcium ions from milk.

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• CPP keeps calcium and phosphorus in ionic form.• In this state calcium and phosphate ions can enter the

tooth enamel and thus promote remineralization of the tooth.

Fluoride compounds:o Lukomsky was the first to propose sodium fluoride as

desensitizing agent.o Application of NaF leads to precipitation of calcium fluoride

crystals, thus reducing the functional radius of the dentinal tubules.

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•10% solution forms dense layer of tin and fluoride containing globular particles blocking the dentinal tubules.

Stannous fluoride

•Silicic acid forms a gel with the calcium of the tooth and produces an insulating barrier.

Sodium silico-fluoride

•Concentration of fluoride in dentin treated with acidulated sodium fluoride is found to be higher than dentin treated with sodium fluoride.

Acidulated sodium fluoride

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Iontophoresis:

• It is the transfer of ions under electrical pressure through electrodes having opposite charge.

• 1-2% sodium chloride or solution containing potassium, zinc ions etc are applied.

• These ions are forced into the tubules by applying electrical force through electrodes.

• Fluoride ions react with calcium get precipitated in the tubules and thereby blocks the tubules.

• It is an expensive procedure.

.

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Dental resins and adhesive:• Objective: seal the dentinal tubules to prevent pain

producing stimuli from reaching pulp.• GLUMA is a dentin bonding agent that includes

glutaraldehyde primer and 35% HEMA.• It provides an attachment to dentin that is immediately

strong.• GLUMA is found to be highly effective when other methods

of treatment failed to provide relief.

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LASERS:

• Kimura Y et al reviewed treatment of dentin hypersensitivity by Lasers.

• 2 groups 1) low output power: Helium –neon and gallium/ aluminium / arsenide lasers. 2) middle output power: Nd:YAG and CO2 lasers.• Action Effects of sealing of dentinal tubules: durable Nerve analgesia Placebo effect.

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Patient education:

Dietary counselling:

Dietary acids are capable of causing erosive loss of tooth structure

removing cementum

Opening of dentinal tubules

• Dietary counselling should focus on the quantity and frequency of acid intake and intake occurring in relation to tooth brushing.

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• Any treatment may fail if these factors are not controlled.• A written diet history should be obtained.• Loss of dentin is greatly increased when brushing is

performed immediately after exposure of the tooth surface to dietary acids.

• Patients should be cautioned against brushing their teeth soon after ingestion of citrus food.

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Tooth brushing technique:• Incorrect brushing appears to be an etiologic factor in

dentin hypersensitivity, instruction about proper brushing techniques can prevent further loss of dentin and the hypersensitivity.

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Plaque control:• Saliva contain calcium and phosphate ions and is therefore

able to contribute to the formation of mineral deposits within the exposed dentinal tubules.

• Presence of plaque may interfere with this process, by producing acid by bacteria, are capable of dissolving any mineral precipitates that form thus opening tubules.

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Conclusion Professional interest in the cause and treatment of dentinal hypersensitivity has been evident in the dental literature for approx. 150 years or more.It satisfies all the criteria to be classified as a true pain syndrome. Myelinated A fibers are seems to be responsible for the sensitivity of dentin.Management of this condition requires determination of etiologic factors and predisposing influences.Partial obturation of open tubules the most widely practiced in office treatment of dentinal hypersensitivity.

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References • Carranza’s clinical periodontology 9th edition• Textbook of operative dentistry 2nd edition- Nisha garg• Essentials of periodontology - sahitya reddy.

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Thank you…3/11/2015

Health & Medicine

dentin hypersensitivity