Chapter 41.Ppt Hypersensitivity

7/27/2019 Chapter 41.Ppt Hypersensitivity

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Chapter 43Dentin Hypersensitivity


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Hypersensitivity General considerations

Sensitive to dental treatment

Cold water, air, scaling

Definition

Stimulus causes pain but is alleviated upon removal

Can be difficult to diagnose, rule out other causes


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Stimuli That Elicit

Pain Reaction

Tactile or mechanical Toothbrush, instrument, clasps

Thermal Hot and cold, beverages, food, air

Evaporative - suction Osmotic

Pressure in dentinal tubules

Chemical citrus, spices, wines, soda


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Characteristics of Pain from

Hypersensitivity

Pain at onset

Sharp, short, transient pain, rapid onset

Cessation upon removal of stimulus

Chronic condition with acute episodes

Response to nonnoxious stimulus

No dental defect or pathology


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Etiology

Anatomy of tooth structures

Mechanisms of dentin exposure

Hydrodynamic theory Neural theory


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Review

Which of the following factors contributes to loss of enamel and

cementum and contributes to sensitivity?

A) Enamel and cementum overlap at the CEJ

B) Attrition and abrasion

C) Erosion from high pH drinks

D) Brushing with baking sodaE) Rinsing with bicarbonate of soda after getting sick


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Answer

B) Attrition and abrasion

Loss of tooth structure is multifactorial. Wear can occur if the

enamel and cementum do not meet at the CEJ, not if they

overlap. Low, not high, pH drinks would cause erosion.

Brushing with baking soda would not increase erosion as it is

not abrasive. Rinsing with bicarbonate of soda would help

erase the acidic environment that enhances erosion.


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Anatomy of Tooth Structures

Dentin

Pulp

Nerves


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Dentin

Portion of the tooth covered by enamel on the

crown and cementum on the root.

Composed of fluid-filled dentinal tubules that

narrow and branch as they extend from the

pulp to the dentinoenamel junction.


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Dentin

The only portion of the dentinal tubules that

are innervated with nerve fiber endings from

the pulp chamber are those closest to the

pulp. Tubules in sensitive areas are wider and

more numerous


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Pulp Highly innervated with nerve cell fiber endings

that extend just beyond the dentinopulpal

interface of the dentinal tubules. Body portion of odontoblasts (dentin-producing

cells) located adjacent to the pulp extend their

processes from the dentinopulpal junction ashort way into each dentinal tubule.


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Nerves Nerve fiber endings extend just beyond the

dentinopulpal junction and wind around the

odontoblastic processes as shown in the nextslide. Nerves react via the same neural

depolarization mechanism (sodium potassium

pump), which characterizes the response of anynerve to a stimulus.


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Mechanisms of

Dentin Exposure

General considerations Gingival recession and root exposure

Loss of enamel and cementum

Once exposed, demineralization of the root surfacewill occur more rapidly than of the enamel because of

the higher mineral content of enamel and the lower

critical pH to initiate demineralization.


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Mechanisms of

Dentin Exposure

Acute hypersensitivity may occur with sudden dentin

exposure since gradual exposure allows for the

development of natural desensitization mechanisms

such as smear layer or sclerosis. After many years,secondary or reparative dentin may have formed, which

also protects the pulp.


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Factors Contributing to Gingival

Recession and Root Exposure

Improper oral hygiene self-care Medium/hard toothbrush

Aggressive brushing

Anatomy and physiology of area Narrow zone of attached gingiva

More susceptible

Facial orientation

High frenum attachment


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Recession and Root Exposure

Subgingival instrumentation

After scaling and root planing

Tissues will shrink

Excessive scaling in shallow sulci

Periodontal disease processes

NUG

Junctional epithelium migrates apically in response toinflammatory factors

Connective tissue breaks down, loss of attachment


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Surgical procedures Reducing pocket depth

Removes gingival coverage of root

Restorative procedures Crown preparation

Can abrade gingival tissues

Factors Contributing to GingivalRecession and Root Exposure


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Recession and Root Exposure Orthodontic procedures

During toothmovement

Oral habits or piercings Metal repeatedly traumatizes the adjacent facial

or lingual gingival tissue and may lead to gingival

recession and bone loss around the involved

teeth.


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Factors Contributing to Loss ofEnamel and Cementum

Anatomy of cervical area

Cementum

Thin, easily abrades

Enamel and cementum do not meet at the CEJ in 10% of

teeth, leaving exposed area of dentin


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Factors Contributing to Loss of Enamel

and Cementum

Attrition and abrasion

From mastication, and improper oral hygiene

practices.

Erosion

Dietary acids, such as citrus fruits/juices, wine, and

carbonated drinks.


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and Cementum

Erosion

Brushing with a dentifrice immediately after

consumption of acidic foods and beverages further

abrades the already demineralizing tooth surface.

Gastric acids from conditions such as gastric reflux,

morning sickness, or self-induced vomiting (bulimia)

repeatedly expose teeth to a highly acidicenvironment.


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Abfraction

Cervical lesion caused by occlusal stressed ortooth flexure from bruxing

Microscopic portions of the enamel rods chip

away from the cervical area of the tooth

resulting in loss of tooth structure. Lesion

appears as a wedge- or V-shaped cervical

notch.

Factors Contributing to Loss ofEnamel and Cementum


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and Cementum

Restorative procedures procedures that remove enamel or cementum can

expose dentin at the cervical area.

Periodontal instrumentation

SR&P

Improper stain removal techniques

Abrasive materials

Root surface caries


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Hydrodynamic Theory Transmission of stimuli

Fluid movement within tubules

Hydrodynamic Theory

Fluid movement creates pressure on the nerve

endings=stimulation=pain

Pain impulse

Widened dentin tubules

Seen in sensitive teeth, not present in non-sensitve teeth


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Neural Activity Pain registered by the depolarization/neural

discharge mechanism that characterizes all

nerve activity

Sodium-potassium pump is responsible for

depolarizing the nerve as potassium leaves the

nerve cell and sodium enters it


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Review

The hydrodynamic theory states that a stimulus at the outer aspect of dentin

causes fluid movement within the dentinal tubules. Developed by Brannstrom

in 1960, the hydrodynamic theory is the currently accepted explanation fortransmission of stimuli from the outer surface of dentin and pulp.

A) Both statements are true

B) Both statements are false

C) The first statement is true and the second statement is false

D) The first statement is false and the second statement is true


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Answer

A) Both statements are true

This is the most currently accepted explanation

for sensitivity.


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Open dentinal tubules. (centered tubule is partially occluded)


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Natural Desensitization

Sclerosis of dentin occurs by mineral deposition within tubules as a result of

traumatic stimuli

such as attrition or dental caries.

Creates a thicker, highly mineralized layer ofperitubulardentin (deposited within the periphery of the tubules).

Results in a smaller-diameter tubule that is less able to transmitstimuli through the dentinal fluid to the nerve fibers at thedentinopulpal interface.


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Secondary dentin

deposited gradually on the floor and roof of the pulp

chamber after teeth are fully developed.

Secreted more slowly than primary dentin that

formed prior to tooth eruption; both types of dentin

are created by odontoblasts.


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Creates a walling off effect between the dentinal

tubules and the pulp

Insulates the pulp from dentin fluid disturbances caused by

a stimulus such as dental caries.

As aging occurs, secondary dentin accumulates

Results in a smaller pulp chamber with fewer nerve endings and

less sensitivity.


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Smear layer consists of organic and inorganic debris that cover the

dentinal surface and the tubules.

Accumulates following

scaling and root instrumentation

use of toothpaste (abrasive particles),

cutting with a bur

attrition, or abrasion (burnishing with a toothbrush or

toothpick, or other device).


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Smear Layer (cont)

Occludes the dentinal tubule orifices, forming asmear plug or a natural bandage that blocksstimuli.

The nature of the smear layer changes constantlysince it is subject to effects such as mechanicaldisruption from ultrasonic debridement, ordissolution from acid exposure. Smear layer mayhave a positive or negative effect. It protects fromhypersensitivity, but may interfere withreattachment of periodontal tissues.


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Calculus

provides a protective coating to shield exposeddentin from stimuli. Postdebridement sensitivity can

occur after removal of heavy calculus deposits;

dentinal tubules may become exposed as calculus is

removed.


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Patients and Their Pain

Pain profile

Usually reported at 20-40 yrs of age

Prevalence of hypersensitivity

Teeth affected

Pain experience

Pain perception Impact of pain


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Differential Diagnosis

Differentiation of pain table 43-1

Data collection by interview

Use open-ended questions

Location and degree of pain

Source of stimulus

Record in patient record


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Differential Diagnosis

Diagnostic techniques and tests Bite on a stick pain = fracture

Nasal congestion/sinus = pain

Check occlusion for contacts high Radiographs check for caries

Transillumination to check for cracks

Pulp tests to check vitality


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Hypersensitivity Management

Assessment components

Evaluate OH self-care procedures

Parafunctional habits bruxism, grinding

Educational consideration


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Hypersensitivity Management

Treatment hierarchy there are two basic treatment goals

pain relief

modification or elimination of contributing factors Address mild to moderate pain with conservative

activities or agents

More severe pain requires an aggressive approach.


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Sequence treatment approaches From the most conservative and least invasive measures to

more aggressive modalities.

Prognosis of pain resolution is difficult to predict

A trial-and-error approach may be necessary until a particular

treatment option is found to be most effective. Treatment

options that include both self-care measures and professional

interventions have synergistic effects with the same objective

of reducing hypersensitivity.

Reassessment


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Oral Hygiene Care and Treatment

Interventions Mechanisms of desensitization

Behavioral changes

Desensitizing agents and mode of action

Self-applied measures

Dental professional measures

Additional considerations


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Behavioral Changes Dietary modifications

Dental biofilm control

Toothbrush type and technique

Burnishing

Eliminate parafunctional habits


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Burnishing sensitive root surface. A small amount of a fluoride agent or fluoride dentifrice

can be burnished into the sensitive area with a toothpick or wooden point. Moderate

pressure with a rubbing or circular stroke is applied. A toothpick holder facilitates

effective use of a toothpick to burnish an exposed root surface

Desensitizing Agents and Theorized


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Potassium salts Formulations containing

potassium chloride

potassium nitrate

potassium citrate, or potassium oxalate Reduce depolarization of the nerve cell

membrane and transmission of the nerveimpulse. Potassium nitrate dentifrices

containing fluoride are widely used and readilyavailable over the counter.


Mode of Action



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Mode of Action

Fluorides

Precipitate calcium fluoride (CaF2) crystals

within the dentinal tubule to decrease thelumen diameter

Create a barrier by precipitating CaF2 at theexposed dentin surface to block open dental

tubules.


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Dentifrices 5% potassium nitrate and fluorides separately or in

combination are the active desensitizing agents inOTC sensitivity-reducing dentifrices.

Studies have suggested that some of thedesensitizing effects of dentifrices may be due to theblocking action of the abrasive particles. Tartarcontrol dentifrices may contribute to increased toothsensitivity for some individuals, although themechanism is unclear.

Self-Applied Measures


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Dentifrices Prescription-strength dentifrices are available

containing highly concentrated fluoride (5,000 ppm

fluoride) combined with an abrasive to facilitate

extrinsic stain control. This formulation is alsoavailable with the addition of potassium nitrate.



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Gels

5,000 ppm fluoride gels (available by prescription)

are brushed on for generalized hypersensitivity or

can be burnished into localized areas of sensitivity. Contain no abrasive agents for biofilm and stain

control. Can be self-applied with custom or

commercially available fluoride trays.



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Dental Professional Measures

Fluoride agents Sodium or stannous fl with a tray delivery system

Fluoride varnish 5% sodium f

Glutaraldehydes

5% formulation can be applied to tooth surface

with microbrush

Isolate area with cotton roll first


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Oxalates

Oxalate salts such as potassium oxalate and ferric

oxalate precipitate calcium oxalate crystals to

decrease the lumen diameter Oxalate preparations are applied to a dried tooth

surface, or can be burnished.

Block open tubules

These provide immediate and short-term, rather

than long-term, relief.



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Calcium Phosphate Technology

Amorphous calcium phosphate (ACP)

Theorized to plug dentinal tubules with calcium

and phosphate

Enhances fluoride delivery in calcium and

phosphate-deficient saliva Remineralize acid erosion, abrasion, improves enamel

luster, reduce hypersensitivity

Calcium sodium phosphosilicate (CSP) (Nova

Min)

Contains sodium and silica in addition to calcium

and phosphorus


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Calcium sodium phosphosilicate (CSP) (Nova

Min)

Delivered in solid bioactive glass particles that

react in the presence of saliva and water to

release calcium and phosphate ions to create acalcium phosphate layer that crystallizes to

hydroxyapatite

Reacts with saliva; sodium buffers the acid, and

calcium and phosphate saturate saliva to fill

demineralized areas with the new hydroxyapatite


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Casein phosphopepetide-amorphous calcium

phosphate (CPP-ACP or Recaldent)

CCP is a milk-derived protein that stabilizes ACP

and allows it to be released during acidic

challenges Benefits are described as remineralization of acid

erosion and caries inhibition by promoting

fluoride uptake in plaque biofilm


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Arginine and Calcium Carbonate Technology

Occludes the dentinal tubules utilzing arginine

Naturally occurring amino acid, bicarbonate (pH) buffer,

and calcium carbonate

Marketed as a prophy paste to apply beforeinstrumentation


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Restorative materials Resins cover tubules, must etch first - may

need anesthesia

Dentin sealers obturation of the tubule Methylmethacrylate polymer

Composite/glass ionomers

Soft tissue grafts

Iontophoresis electric current Lasers



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Review

Which of the following desensitizing agents requires the use of

an acid etch step prior to application?

A) Dentin sealers

B) Unfilled resins

C) Oxalates

D) 5% glutaraldehyde

E) 5% potassium nitrate


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Answer

B) Unfilled resins

Unfilled resins cover patent dentinal tubules.

This requires an acid etch preparation and

drying of the tooth, which may necessitatelocal anesthetic use.


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Periodontal debridement

New developments Tooth-whitening-induced sensitivity

Additional Considerations


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Factors to Teach

the Patient

Etiology of gingival recession

Contributing factors to hypersensitivity Natural, self-care, and professional measures to

alleviate sensitivity

Oral hygiene and dietary relationship to

sensitivity

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Chapter 41.Ppt Hypersensitivity