ASSESSMENT OF PULP

VITALITY

Presented by:-

Anjali Miglani

(P.G Student)

Department of Conservative

Dentistry & Endodontics

INTRODUCTION

The assessment of pulp vitality is a crucial diagnostic

procedure in the practice of dentistry-Noblett 1996

Most methods rely on stimulation of A-fibers gives no

indication of blood flow within the pulp

THE MOST COMMON SYSTEM ASSOCIATED WITH

SYMPTOMATIC PULP IN THE PAIN

PATHOPHYSIOLOGY OF PAIN

- An unpleasant sensory and emotional experience associated with

actual or potential tissue damage defines the physiologic and the

physiologic components.

- The pain process begins in the periphery, where specialized nerve

fibers receive a painful stimulus. These nerve fibers transmit this

information to the spinal cord and ultimately to the brain where

information is interpreted and recognized as PAIN.

DETECTION OF PAIN

Odontogenic pain transmission is mediated primary by peripheral sensory

nerves of the trigeminal nerve.

A fibers nerve – innervate the dentin (Fibers) – Unmyelinated fibers

innervate the body of these pulp and its blood vessels

A – DELTA FIBERS

Pulpodentinal complex – The circumpulpal nerve sends free nerve

ending onto and though the odontoblastic cell layer extending upto 200 um

into the dentinal tubules while also conducting the odontoblastic cell

processes. This intimate association of A Delta fibers with the odonto

blastic cell layer and dentin is referred to as the pulpodentinal complex.

Disturbances of the pulpodentinal complex in a vital tooth initially

affect the low threshold a delta fibers.

Drying, probing drying with air and application of hyper osmotic solution

to exposed dentin will cause pain.

- Movement of fluid in dentinal tubules known as the hydrodynamic

theory of dentin sensitivity stimulation the A –delta fibers.

- Vital pulp responds immediately with symptoms of dentinal pain.

- Through a Delta fibers pain is perceived as quick, Sharp, Momentary

Pain.

- Dessipates quickly upon removal of the stimulus such as drinking

cold liquids a probing exposed dentin.

- The clinical symptoms of a delta fiber pain signify that the

pulpodentinal complex is intact and capable of responding to a

external disturbance.

NERVE FIBERS

- Small,

- Unmyelinated nerves

- High Threshold fibers subadjacent to the A-delta fibers.

- Pain associated with C fibers dull, poorly localized

C fibers activated by intense heating or cooling of the tooth crown or

mechanical stimulation of the pulp.

C fiber pain associated with tissue injury and is modulated by inflammatory

mediations. Vascular changes in blood volume blood flow decrease in

tissue pressure

CLINICAL SIGNIFICANCE

- When inflammation leads to pulp necrosis, periradicular lesions may

develops

- Radiograph shows lesion

- Vital testing – response is seen

- Instrumentation of necrotic pulp may also cause pain

REASON

C fibers more resistant that A fibers to compromised blood flow and

hypoxic conditions

Pain associated with a necrotic pulp in due to

C fiber stimulation.

CLINICAL FEATURES OF PULPAL PATHOLOGIES

Clinical classification of pulpal disease is based on

INFLAMMATION OF THE PULP OR PULPITIS

May be

Acute on chronic partial or total infected or sterile

Can be

Determined can not be determined

Chronic inflammation of exposed pulp

Due to caries or trauma chronic hyperplasic pulpitis.

Acute form runs

- a short, painful cause

Chronic form runs

- Symptoms or slightly painful and of longer duration.

- Clinical class

- Baume found no direct correlation between clinical symptoms and

histologic findings.

Based on clinical symptoms, he divided disease of pulp into 4 categories

1) The symptom less, vital pulp which has been injured or involved by

deep caries, for which pulp capping may be done.

2) Pulps with a history of pain amenable to pharmacotherapy.

3) Pulps indicated for extirpation and immediately root filling.

4) Necrosed pulp accessible to root canal therapy.

Garfunkel and associated found a direct correlation between clinical

diagnosis and histologic examination in 49% of pulps examined.

HISTOLOGICAL FEATURES

Nature – Direct and immune mechanisms

- Release of chemical mediators

- Increase in vascular permeability of vessels

- Benkoryfe around dilated vessels

An interesting phenomenon

Mast cells (inhabitant of loose fibrous connective tissue)

Rarely seen in heath pulps appears in inflammation.

Immune and inflammatory reactions may destroy normal cellular and

extracellular components.

A. REVERSIBLE PULPITIS

Clinical Features

- Mild to moderate inflammatory condition

- Pulp is capable of returning to the uninflamed state following

removed of stimuli.

- Pain of brief duration subsides as soon as stimulus is removed

Histopathology

- Reparative dentin

- Disruption of the Odontoblastic layer

- Dilated blood vessels

- Extravasation of edema fluid

- Pressure of immunologically competent cells.

B. IRREVERSIBLE PULPITIS

It is a persistent inflammatory condition of the pulp, symptomatic or

asymptomatic, caused by a noxious stimulus.

Acute irreversible pulpitis exhibits pain usually caused by hot or cold

stimulus or pain that occurs spontaneously.

- Pains persists for several minutes to hours, lingering after removal of

the thermal stimulus.

- Nerves may occur quickly or the process may require years.

- Pulp death occur slowly and without dramatic symptoms.

- Microabssecesses of the pulp begin as tiny zones of necrosis within

dense inflammatory all infiltrates comprised principally of acute

inflammatory cells.

.

Symptoms

- Sudden temperature changes causes pain.

- Pressure from packing food into a cavity or suction exerted by tongue

or cheek.

- Recumbency which results in congestion of the blood vessels of the

pulp.

- Pain – Sharp, piercing or shooting may be intermittent or continuous.

- Changes of position, bend over or lying down excerts pains.

- In late stage, pain is more severe ,growing throbbing.

- Pain increased by heat and sometimes relieved by cold.

C. CHRONIC HYPERPLASTIC PULPITIS

- Pulp Polyp.

Due to extensive carious exposure of young pulp.

Rising out of the carious shell of the crown in mushrooms of pulp tissue

that is often firm and insensitive to touch.

- Low grade, long standing irritation

Histopathology

- covered by Stratified squamous epithelium

- Granulation tissue

Symptoms

- Symptoms except during mastication.

D. INTERNAL RESORPTON

- Is idiopathic slow or fast progressive resorptive process in the dentin of

the pulp.

HISTOPATHOLOGY

- Results of osteoclastic activity.

- Pressure of granulation tissue accounts for profuse bleeding when

pulps is removed

- Multinucleated giants cells are present

Symptoms

- Asymptomatic

- Manifested as reddish area pink spot.

E. NECROSIS

- Death of the pulp.

Partial total

Can be due to traumatic injury, sequel to inflammation.

Lack of collateral circulation and unyielding walls of dentin

Insufficient drainage

Necrosis

Coagulation necrosis liquefaction necrosis

Symptoms

- No painful stimulus.

- Dull or opaque appearance of the crown due to back of normal

transluscency

Teeth with partial necrosis can respond to thermal changes owing to

presence of vital nerve fibers.

Clinical Classification of Pulpal and Periapical Disease according to Cohen

Clinical classification system was developed. This system was based on the

patient’s symptoms and the results of clinical tests. It was developed to

provide basic terms and phrases that clinicians could use to describe the

extent of pulpal and periapical disease before selecting a method of

treatment. A clinical classification of this sort is not meant to list every

possible variation of inflammation, ulceration, proliferation, calcification

degeneration of the pulp, or attachment apparatus. Rather its purposes are to

suggest in the broadest possible interpretation whether the pulp is either

healthy or unhealthy and to help the clinical experience.

Pulpal Disease

Within Normal Limits – A normal pulp is asymptomatic and produces a

mild to moderate transient response to thermal and electrical stimuli. When

the stimulus is removed the response subsides almost immediately. The

tooth and its attachment apparatus do not cause a painful response when per

cussed or palpated radiographs reveal a clearly delineated canal that taper

smoothly toward the apex. There is no evidence of root resportion, and the

lamina dura is intact.

Reversible Pulpitis

The pulp is uninflamed to the extent that thermal stimuli – usually cold

cause a quick sharp hypersensitive response that subsides as soon as the

stimulus is removed. Otherwise the pulp remains asymptomatic. Any

irritant that can affect the pulp may cause reversible pulpitis including early

caries, periodontal scaling root planning microleakage and unbased

restorations.

Reversible pulpitis is not a disease it is a symptom. If the irritant is

removed and further insult is prevented by sealing the dentinal tubules

communication with the inflamed pulp the pulp will revert to an

asymptomatic uninflamed state. Conversely if the irritant remains the

symptoms may persist indefinitely or may become more widespread leading

to irreversible pulpitis. Reversible pulpitis can be distinguished from a

symptomatic irreversible can be distinguished from a symptomatic

irreversible pulpitis in two ways.

1. Reversible pulpitis causes a momentary painful response to thermal

change that subsides as soon as the stimulus is removes. However

symptomatic irreversible pulpits causes a painful response to thermal

change the lingers after the stimulus is removed.

2. Reversible pulpitis does not involve a complaint of spontaneous

(unprovoked) pain. Symptomatic irreversible pulpitis commonly

includes a complaint of spontaneous pain. Therefore the key

difference is that reversible pulpitis is reactive it produces a response

albeit exaggerated only when stimulated.

Irreversible Pupitis

Irrreversible pulpitis may be acute subacute or chronic it may be partial it

be partial or total infected or sterile. Clinically the acutely inflamed pulp is

symptomatic whereas the acutely inflamed pulp is symptomatic whereas the

chronically inflamed pulp is asymptomatic in most cases. The apical extent

of irreversible pulpitis cannot be determined clinically until the periodontal

ligament is affected by the cascade of inflammatory mediators and the tooth

becomes sensitive to percussion.3,58 Dynamic changes in the irreversibly

inflamed pulp are continual the pulp may move from quiescent chronicity to

acute pain within hours.

Asymptomatic Irreversible Pulpitis

Although uncommon asymptomatic irreversible pulpitis may be the

conversion of symptomatic irreversible pulpits to a quiescent state. Caries

and trauma are the most common causes of this condition which can be

information gathered from the patient’s dental history and properly exposed

radiographs.

Hyperplastic Pulpits

A reddish cauliflower like growth of pulp tissue through and around a

carious exposure is one variation of asymptomatic irreversible pulpitis. The

proliferative active nature of this pulpal reaction sometimes known as a

“pulp polyp,” is attributed to a low grade chronic irritation of the pulp and

the generous vascularity characteristically found in young people.”

Occasionally this condition may cause mild transient pain during

mastication.

Internal Resorption

Internal resorption is a painless condition resulting from the recruitment of

blood-borne clastic cells often stimulated by trauma which produces dentin

routine radiographic examination. If undetected internal resorption will

eventually perforate the root. Before perforation of the crown the resorption

can be detected as a pink spot on the site. Only prompt endodontic therapy

to eliminate these elastic cells will prevent tooth destruction.

Symptomatic Irreversible Pulpitis Symptomatic irreversible pulpitis is

characterized by spontaneous )i.e.), intermittent or continous paroxysms of

pain. Sudden temperature changes (usually cold) elicit prolonged episodes

of pain )i.e., pain that lingers after the thermal stimulus is removed). This

pain may be relived in some patients by the application of heat or could.

Occasionally patients may report that a postural change (lying down or

bending over) induces pain resulting in fitful sleep. Even with the use of

several pillows to stabilize themselves at a comfortable postural lives

patients ,may continue the experience pain.

Generally pain from symptomatic irreversible pulpitis is moderate to severe

it can be sharp or dull localized or referred. In most cases radiographs are

not useful in diagnosing symptomatic irreversible pulpitis because the

inflammation remains confined to the pulp. However radiographs can be

helpful in identifying offending teeth (i.e., teeth with deep caries extensive

restorations pins evidence of previous pulp capping calicific

metamorphosis)2. In the advanced stage of symptomatic irreversible pulpitis

thickening of the apical portion of the periodontal ligament may become

evident on the radiographs. Symptomatic irreversible pulpitis can be

diagnosed through synthesis of the information provided a thorough dental

history a complete visual examination properly exposed radiographs and

carefully conducted thermal tests. If radiating or referred pain is involved

the application of 0.2 ml of intraligamentary anesthesia in the distal sulcus

of the correctly identified tooth will immediately stop the pain. EPT is of

little value in the diagnosis of symptomatic irreversible pulpitis because the

pulp though inflamed is still reversible pulpitis because the pulp though

inflamed is still responsive to electrical stimulation.

There inflammatory process of symptomatic irreversible pulpitis may

become so severe that it will lead to necrosis of the pulp. In the

degenerative transition from pulpitis to necrosis the usual symptoms of

symptomatic irreversible pulpitis may subside as necrosis occurs.

Necrosis

Necrosis the death of the pulp actually refers to a histologic condition

resulting from an untreated irreversible pulpitis a traumatic injury or any

event that causes long –term interruption of the blood supply to the pulp.

Pulp may become liquefied or coagulated. Total necrosis is asymptomatic

before it affects the periodontal ligament because the pulpal nerves are

nonfunctional. For this reason there is no response to thermal or EPT. Some

crown discoloration may accompany pulp necrosis in anterior teeth but this

diagnostic sign is not reliable.27,48 Partial necrosis may be difficult to

diagnose because it can produce may be difficult to diagnose because it can

produce some of the symptoms associated with irreversible pulpitis. For

example a tooth with two or more toot canals could have an inflamed pulp

in one canal and a necrotic pulp in the other.

The bacterial toxins (and sometimes bacteria) that produced the

necrosis in the pulp follow the pulp tissue through the apical foramen to the

periodontal ligament resulting in an inflammatory reaction in the

periodontium. This inflammation will lead to thickening of the periodontal

ligament and manifest itself as tenderness to percussion and chewing.3.58

As these irritants cascade out of the root canal system often periapical

disease will occur.5

The difficulty with the use of the term “necrosis” is that pulp vitality testing

has been limited to electrical and thermal stimulation of pulpal nerves. In

the case of teeth that have been traumatized9 teeth in a segment of bone that

has been surgically repositioned,1 teeth with immature apices, 17,18,31 or

teeth that have calcified with age,8 nerve function can be diminished or

cease altogether while the pulp retains an intact vasculature. Thus reliance

upon EPT and thermal pulp testing can result in the unnecessary removal of

healthy denervated pulps. Perhaps the use of more sophisticated testing

techniques, such as laser Doppler flowmetry or pulse oximetry will

overcome this limitation and provide a clinical test

Laser doppler measurements augement clinical observations providing

an improved basis for dental treatment plan

Assessments of pulpal status in by various AIDS

Correction of various methods pulp vitality in different pulpal

conditions,

VARIOUS AIDS IN DETECTING THE VITALITY OF THE

PULP

Assessment of pulp vitality should be based on blood supply of the

pulp. Unfortunately, assessment of the pulpal blood supply remains

complicated and there is no practical clinical test to determine this basis

aspect of the tooth’s biology.

The clinical condition of the pulp can be evaluated by various

methods.

1. History of the patient

2. Thermal test

3. Percussion

4. Palpation

5. Electric pulp test

6. Transillumination

7. Liquid crystal testing.

8. Hughes probeye camera.

9. Occlusal pressure test

10.Anaesthetic test

11.Test cavity

12.Pulse oximetry.

13.Dual Wavelengths spectrophotometry

14.Laser Doppler flowmetry

15.Use of tooth temperature

16.MRI.

1. HISTORY OR THE PATIENT

To know the status of the pulp, patients is chief complaint plays an

important role includes symptoms that occur following specific events

(eg chewing drinking cold liquids)

- Whether pain is of short duration of long duration we can judge

condition to be

Acute chronic

It patient presents with so symptoms, but gives a part history of pain then

we can suspect necrosis of the pulp history should be corroborated with

other clinical tools and radiographs.

2. PALPATION

- Uses digital pressure to check tenderness in the cavity covering suspected

tooth.

Sensitivity indicates inflammation in the periodontal ligaments surrounding

affected tooth.

We can suspect that inflammation through caries lesion has gone to the

PDL if tenderness to palpation occur.

Thermal Pulp Tests:- One of the most common

symptoms associated with the symptomatic inflamed pulp is pain elicited

by thermal stimulation. Although some patients suffer pain when cold is

applied to the tooth but are comfortable with warm substances and others

require frequent applications of cold liquid to keep their pain bearable there

is no particular response to either heat or cold that is unique to a specific

pulpal pathologic state56.

The only conclusion the clinician may draw when a pulp responds

abnormally to thermal stimulation either in an exaggerated manner or not at

all is that is not in a state of good health.

The rationale for innervation of any bodily structure is to provide a warning

of damage that is occurring pain with the application of thermal stimuli is

normal and a vital part of the patient’s protective defense mechanism.

The pain is proportionate to the stimulation consequently even teeth with

intact enamel will react to extreme cold such a in ice or carbon dioxide

snow. When teeth begin to react to stimuli that do not normally produce

pain such as tap water the probability is that dentin has been exposed by

caries that the tooth structure is fractured or that faulty restoration abrasion

or attachment loss caused by periodontal disease exists. Additionally an

exaggerated response to thermal stimuli can indicate a lowered threshold to

stimulus because of pulpal inflammation (e.g immediately after placement

of a restoration).

Solution is to address the cause of the dentin sensitivity by occluding the

dentinal tubules by placing a temporary sedative restoration such as

intermediate restorative material (IRM).In the case of the new restoration

the clinician should simply wait to see whether the acute inflammation

subsides in a short.

When the chief complaint is pain to a thermal stimulus (usually cold)

the clinician must distinguish between thermal testing to isolate the

offending tooth by reproducing the patient’s symptoms and attempting to

determine whether a suspected tooth has a vital or nonvital pulp. In the

former case the patient is complaining of painful pulpal response cold

therefore pulpal vitality is not at issue.

A graduated method of applying the stimulus is required to avoid causing

the triple syringe followed by isolation the tooth under a rubber dam and

bathing it with cold water should elicit the patient’s symptoms and quickly

indicate the offending tooth. In contrast when there is no complaint of cold

sensitivity the following methods for using cold to determine pulpal vitality

are appropriate.

Cold Test: Various methods have been used to apply cold to the teeth for

testing. The most commonly used method are ice sticks, various

compressed gasses and carbon dioxide snow.

Freezing water in the plastic covers from hypodermic needles one is

removed from the freezer and held tightly in the clinician’s hand for a few

minutes. This melts the outside of the stick so that it can be removed from

the plastic and held in a 2” x 2” gauze for use. The ice stick applied

immediately to the middle third of the facial surface of the crown of the

tooth or on any exposed metal surface of crowns and kept in contact for 5

seconds of until the patient begins to feel pain.

Ethyl chloride is available as a compressed spray, commonly used in

medicine as a skin refrigerant. Its use in pulp testing is no longer

recommended because it has been found to be less effective than carbon

dioxide snow or dichlorodifluoromethane which is the refrigerant R-12

commercially packaged as a compressed spray (Endo-Ice). It has been

replaced by the manufacturer with 1,1,1,2 Tetrafluoroethane, which is the

nonchlorofluo-rocarbon refrigerant R-134a, available as Green Endo-Ice.

No studies are yet available on the efficacy of this replacement compared

with other testing methods. However it also has a low boiling point (-

15.10F). The material is sprayed liberally onto a cotton pellet or swab,

which is then applied immediately to the middle third of the facial surface

of the crown of the tooth. The pellet is kept in the contact with the crown

for 5 seconds of until the patient begins to feel pain.

Carbon dioxide snow formed into sticks is extremely cold. It is the

most effective method of eliciting a response in vital teeth. No detrimental

effects occurred in vital pulpal tissue and no cracks or surface irregularities

were produced in the enamel of tested teeth.26,43,47 The carbon dioxide is

released into a special syringe in which it forms the “snow”. It is compacted

with a plunger and the pellet is expressed onto a 2” x 2” gauze. It is applied

immediately to the middle third of the facial surface of the crown of the

tooth and kept in contact with the crown for 2 second or until the patient

begins to feel pain. Although less convenient than the isolating the teeth

individually with a rubber dam and bathing each tooth with ice water from a

syringe for 5 secs simultaneously cools all surfaces of the teeth.

Heat Test : As with cold testing many methods for heat testing teeth have

been suggested. Although all transfer heat to the tooth the methods most

commonly used are warm sticks of temporary stopping used are warm

sticks of temporary stopping and the hot water bath. Warm sticks of

temporary stopping and the hot water bath. Warm sticks of temporary

stopping are the most convenient for the clinician but the hot water bath

will yield the most accurate patient response.

Temporary stopping consists of gutta-percha in 3-inch sticks. To use

this technique the teeth to be tested are first protected with a light coating of

petrolatum to prevent the warm temporary stopping from sticking to them.

The stopping is warmed over a flame until it becomes soft and just begins

to glisten (Grossman’s method)23 but not so that it slumps and becomes too

limp to use. Application to the middle third of the facial surface of the

crown usually results in a response in less than 2 seconds. A 5- second

application has been found to increase the temperature at the pulpodentinal

junction less then 20 C there fore it is unlikely that damage will occur to the

pulp47.

The tooth is bathed in very warm water from a plastic syringe for 5 seconds

or until the patient begins to feel pain. Since the patient’s chief complaint is

pain in response to heat the temperature is gradually increased if no

response is obtained rather than producing unnecessary’s pain by beginning

with excessively hot liquid.

Although the cold and hot water bath methods of thermal testing are time

consuming they are clearly superior in their accuracy compared to very

warm temporary stopping or ice pencils. The use of water allows allows the

entire crown to be immersed not just one section of one surface of the tooth.

Even when the tooth has been restored with a full crown (metal or

porcelain) sufficient contact is made to allow cooling or warming of the

pulp. In addition the cold ant hot water bath methods prevent damage to the

tooth caused by excessive temperature change.

Responses to Thermal test: The sensory fibers of the pulp transmit only

pain whether the pulp has been cooled or heated. There are four possible

responses to thermal stimulation:

1. No response

2. mild- to – moderate degree of awareness of slight pain that subsides

within 1 to 2 seconds after the stimulus has been removed

3. Strong momentary painful response that subsides within 1 to 2

seconds after the stimulus has been removed

4. Moderate –to strong painful response that lingers for several seconds

or longer after the stimulus has been removed

If there is no response to thermal testing a nonvital pulp is often the cause.

However no response to thermal testing can also indicate a false negative

response because of excessive calcification an immature apex recent trauma

or patient premedication. A momentary mild-to-moderate response to

thermal change is generally considered within normal limits. A somewhat

exaggerated response that subsides quickly is characteristic of reversible

pulpitis. A painful response that linger for several minutes after the stimulus

is removed that lingers for several minutes after the stimulus is removed is

characteristic of irreversible pulpitis.

ELECTRIC PULP TESTS: The electric pulp tester (EPT) uses

electric excitation to stimulate the A sensory fibers within the pulp.

A positive response to electric pulp testing does not provide any

information about the health or integrity of the pulp it simply indicates that

there are vital sensory fibers present within the pulp.58 Often irreversibly

inflamed pulp is responsive to EPT because it still contains vital function

nerve fibers that can produce a toothache. The EPT provides only a

responsive or nonresponsive result that correlates in many cases with vital

or nonvital pulpal status. Therefore attempting to interpret the numerical

values produced by the EPT is not recommended. The electric pulp test fails

to provide any information about the vascular supply to the pulp which is

the true determinant of pulp vitality. As a result teeth that temporarily or

permanently lose their sensory function (e.g., teeth damaged by trauma or

teeth that have undergone orthognathic surgery) will be nonresponsive to

EPT. However they will have intact vasculature.9

Seltzer et al reported that 28% of teeth necrotic pulps tested positive

to EPT, and more that half of those with [partially necrotic pulps were

responsive.

When a patients reports sensation in a tooth with a necrotic pulp, it is

termed a false positive response. Circumstances that can cause false

positive response to electric pulp testing include patients anxiety, saliva

conducting the stimulus to the gingiva, metallic restorations conducting the

stimulus to the adjacent teeth, and liquefactive necrosis conducting the

stimulus to the attachment apparatus.

A false negative response means that although the pulp is vital, the patient

dose not indicate that any sensation is felt in the tooth. This situation can be

produced by premedication with drug or alcohol, immature teeth, trauma,

poor contact with the tooth, inadequate media, partial necrosis with vital

pulp remaining in the apical portion of the root, and individual patients with

atrophied pulps or high pain thresholds. Therefore, it is essential that

multiple tests be performed before a final diagnosis is made.

EPT is an imperfect, though useful, way to determine the pulpal status of a

tooth. In the case of a periapical radiolucency, EPT will help the clinician

determine whether the pulp is vital. When used thermal and periodontal

testing the EPT can help differentiate pulpal disease from periodontal

disease or nonodontogenic causes.

LASER DOPPLER FLOWMETRY. EPT uses electric current to

stimulate the A nociceptors in the pulp. When these fibers are intact

stimulation results in a painful sensation and the pulp is said to be vital.

However, intact nerve functioning is not essential for pulp vitality. Teeth

that have experienced recent trauma or are in a portion of jaw that has under

gone orthognathic surgery can lose sensibility while retaining an intact

blood supply and vital pulp. Investigators found that 21% of teeth in

patients that tested nonresponsive to electrical stimulation after having

undergone Le Fort operations had intact blood supplied when tested with

laser Doppler flowmetry. With EPT only, the pulps would have been

considered necrotic, and endodontic therapy would have been needlessly

undertaken.

Laser Doppler flowmetry uses a laser beam of known wavelength that is

directed through the crown of the tooth to the blood vessels within the pulp .

Moving red blood cells cause the frequency of the laser beam to be

Doppler shifted ands some of the light to the back scattered out of the

tooth. This reflected light is detected by a photocells on the tooth surface,

the output of which is proportional to the number and velocity of the

blood cells.

Laser Doppler flowmetry is complicated by the fact that the laser beam

must interact with moving cells within the pulpal vasculature. To avoid

artifactual responses, a custom fabricated. Jig (i.e., mouth guard) is needed

to hold the sensor motionless and maintain its contact with the tooth. The

position on the crown of the tooth and the location of the pulp within the

tooth cause variations in pulpal blood flow measurements. Additionally

differences in sensor output and inadequate calibrations by the

manufacturer may mandate the use of multiple probes for accurate

assessment and antihypertensive medications and nicotine may affect blood

flow to the pulp, producing inaccurate results. Finally, the equipment still is

too expensive for the average dental office.

Current limitations aside, laser Doppler flowmetry promises an objective

measurements of pulpal vitality and health.

When equipment costs decrease and clinical applications improves, this

technology could be used for patients who cannot communicate effectively

or whose responses may not be reliable (e.g. young children). Because this

testing modality produces no noxious stimuli, apprehensive or distressed

patients may accept it more readily than current methods.

PULSE OXIMETRY –

Another optical diagnostic method currently under investigation is the

adaption of pulse oximetry to the diagnosis of pulpal vitality. Pulse

oximetry is a widely used technique for recording blood oxygen saturation

levels during the administration of intravenous anesthesia. Increased acidity

and metabolic rate produced by inflammation cause deoxygenation of

hemoglobin and change the oxygen saturation of the blood. A pulse

oximeter uses a probe for oxygen saturation of the blood. A pulse oximeter

uses a probe containing a diode that emits light in two wavelengths (1) red

light of approximately 660 mm and (2) infrared light or approximately 850

nm. This light is received by a photodetector diode, connected to a

microprocessor. The device compares the ratio of the amplitude of the

transmitted infrared with red light. It uses this information together with

known absorption curves for oxygenated and deoxygenated hemoglobin, to

determine the oxygen saturation levels.

By monitoring changes in oxygen saturation, pulse oximetry may be able to

detect pulpal inflammation or partial necrosis in teeth that are still vital.

Several investigators have successfully used modified finger probes or

adapted the instruments to teeth to demonstrate the reliability of the system

in the diagnosis of pulp vitality. Other investigators indicate that the use of

reflected light may be preferable to transmitted light and that different or

multiple wavelengths may be required to improve the sensitivity of the

technique.

Pulse oximeters measure the arterial oxygen saturation of

hemoglobin, the technology involved is complicated but there are two basic

physical principles, first the absorption of light at two different wavelengths

by

haemoglobin differs depending on the degree of oxygenation of

haemoglobin second the light signal following transmission through

the tissues has a pulsatile component ,resulting from the changing

volume of arterial blood with each pulse beat .this can be distinguished

by the microprocessor from the non-pulsatile component resulting

from venous ,capillary and tissue light absorption the function of a

pulse oximeters is affected by many variable ,including :ambient

light ,shivering

abnormal haemoglobin pulse rate and rhythm ;vasoconstriction and

cardiac function a pulse oximeter gives no indication of a patient ,

ventilation ,only of their oxygenation ,and thus can give a false sense

of security if supplemental oxygen is being given ,in addition ,there

may be a delay between the occurrence of a potentially hypoxic event

such as respiratory obstruction and a pulse oximeter detecting low

oxygen saturation however ,oximetry is a useful non-invasive monitor

of a patient ,s cardio-respiratory system which has undoubted

improved patient safety in many circumstances

Pulse Oximeters are now the standard part of

preoperative monitoring which give the Operator a non -

invasive indication of the patient ,s cardio –respiratory

status .having been successfully used in intensive care the

recovery room and during anaesthesia they have been

introduced in other areas of medicine such as general wards

apparently without staff undergoing

What dose a pulse oximeter measure ?

1 the oxygen saturation of haemoglobin in arterial blood –which is a

measure of the average amount of oxygen bound to each

haemoglobin molecule ,the percentage saturation is given as a digital

readout together with an audible signal varying in pitch

depending on the oxygen saturation

Principles of modern pulse oximetry

oxygen is carried in the bloodstream mainly bound to

haemoglobin .one molecule of haemoglobin can carry up to four

molecules of oxygen ,which is then 100%saturated with oxygen .the

average percentage saturation of a population of haemoglobin

molecules in a blood sample is the oxygen saturation of the blood ,In

addition ,a very small quantity of oxygen is carried dissolved in the

blood ,which can become important if the haemoglobin levels are

extremely low .the however ,is not measured by pulse oximetry

a pulse oximeter consist of a peripheral probe, together with a

microprocessor unit, displaying a wave from, the oxygen saturation and

the pulse rate. Most oximeters also have an audible pulse tone, the pitch

of which is proportional to the oxygen saturation – useful when one can

not see the oximeter display. The probe is placed on a peripheral part of

the body such as a digit, ear lobe or the nose. Within the probe are two

light emitting diodes (LED’s) one in the visible red spectrum (660nm)

and the other in the infrared spectrum (940nm). The beams of light pass

through the tissue to a photodetector. During passage through the tissue,

some light is absorbed by blood and soft tissue depending on the

concentration of haemoglobin. The amount of light absorption at each

light free frequency depends on the degree of oxygenation of

haemoglobin within the tissue.

The microprocessor can select out the absorbance of the pulsatile

fraction of blood, i.e. that due to arterial blood, from consists absorbance

due to non pulsatile venous or capillary blood and other tissue pigment.

Several recent advances in microprocessor technology have reduced the

effect of interference on pulse oximeter function. Time division

multiplexing, whereby the LED’s are cycled, red on then infrared on,

then both off many times per second, helps to eliminate background

noise. Quadrate division multiplexing is a further then recombined in

phase later. In this way, an artifact due to motion or electromagnetic

interference may be phase later. In this way, an artifact due to motion or

electromagnetic interference may be eliminated since in will not be in

the same phase of the two LED signal once they are recombined.

Saturation values are averaged out over 5 to 20 second. The pulse rate is

also calculated from the number of LED cycles between successive

pulsatile signals and averages out over a similar variable period of time,

depending on the particular monitor.

From the proportions of light absorbed at each light frequency, the

microprocessor calculates the ratio of two. Within the oximeter memory

is a series of oxygen saturation values obtained from experiments

performed in which human volunteers were given increasingly hypoxic

mixtures of gases to breath. The microprocessor compares the ratio of

absorption at the two light wavelengths measured with these stored

values, and then display the oxygen saturation digitally as a percentages

and audibly as a tone of varying pitch.

Practical tips to the successful use of pulse oximetry.

Plug the pulse oximeter in to an electrical socket, if available to recharge the batteries.

Turn the pulse oximeter on the wait for it to go through its calibration and check tests. ]

Selects the probe you require with particular attention to correct sizing where it is going to go. The light should be clean (remove nail varnish).

Position the probe on the chosen digit, avoiding excess force. Allow several seconds for the pulse oximeter to detect the pulse and

calculate the oxygen saturation. Look for a displayed waveform. Without this, any reading is

meaningless. Read off the displayed oxygen saturation and pulse rate.

Be cautious interpreting figures where there has been an instantaneous change in saturation – for example 99% falling suddenly to 85%. This is physiologically not possible.

Is in doubt, rely on your clinically judgement, rather than the value the machine gives.

Pulse oximetery is a simple non invasive method of monitoring the

percentage of haemoglogin (Hb) which is saturated with oxygen. The pulse

oximeter consists of a probe attached to the patient finger or ear lobe which

is linked to a computerized unit. The unit displays the percentage of Hb

saturated with oxygen together with an audible single for each pulse beat, a

calculated hart rate and in some models, a graphical display of the blood

flow past the probe. A audible alarms which can be programmed by the

user are provided.

How does an oximeter work? A source of light originates from the probe

at two wavelengths (650nm and 805nm). The light is partly absorbed by

haemoglobin, by amounts which differ depending on whether it is saturated

or desaturated with oxygen. By calculating the absorption at the two

wavelengths the processor can compute the proportion of haemoglobin

which is oxygenated. The oximeter is dependent on a pulsatile flow and

produce a graph of the quality of flow.

The computer within the oximeter is capable of distinguishing pulsatile

flow from other more static signals (such as tissue or venous signals) to

display only the arterial flow.

Calibration and Performance. Oximeters are calibrated during

manufacture and automatically check their internal circuits when they are

turned on. They are accurate in the range of oxygen saturations of 70 to

100% (/-2%), but less accurate under 70%. The pitch of the audible pulse

signal falls with reducing values of saturation.

The size of the pulse wave (related to flow) is displayed graphically.

APPLICATIONS

Tooth pulp vitality Testing

Tubules within the dentin act as light guides and direct light incident on the

tooth surface into the pulp. This in highly vascular tissue and because of its

position within a rigid structure, the vessel compliance is vary limited.

Cardiac cycle blood pulsation in the supplying artery are transmitted to the

pulp capillaries as pulsations in blood velocity. These pulsation are apparent

on Doppler monitor traces of vital teeth and are absent from non vital teeth.

The mean blood flux level in healthy teeth is much higher than for non vital

teeth. However in vital teeth with impaired blood supply the flux level can

be low and the presence of pulsation is the only indication of vitality.

RADIOGRAPHIC INTERPRETATION

Only films of the highest quality should be accepted; any time or

money saved by not taking questionable films would be forfeited by one

misdiagnosis. Clinicians should strive to limit their patients exposure to

radiation and maximize their skills and the skills of staff members to

achieve this end. However because the benefits or radiographs outweigh the

risks, diagnostic quality radiographs should be obtained even at the expense

of repeated image

Once high quality radiographs are obtained, the next step is to view them

properly.

They found that a diagnosis based on the continuity and shape of the lamina

dura and the width and shape of the periodontal ligament space was the

most accurate in identifying teeth with nonvital pulps.

In addition to inspecting the lamina dura and periodontal ligament space,

the clinician should consider whether the bony architecture is within normal

limits or whether there is evidence of demineralization. The clinician should

be also consider whether the root canal system is within normal limits,

whether it appears to be resorbing or calcifying and what anatomic

landmarks could be expected in the area. A sound, correct examination

protocol includes a careful investigation of each of these considerations.

In addition to periapical films in the posterior region, it is helpful to prepare

bite wing films. Early caries, the depth of existing restorations, pulp caps,

and pulpotomies or dens invaginatus can be identified in bite wing films.

Deep caries or extensive restorations increase the likelihood of pulpal

involvement.

A necrotic pulp will not cause radiographic changes until the enzymes

produced by the inflammatory process have begun to demineralize the

cortical plate. For this reason, significant medullary bone destruction may

occur before any radiographic sings begin to appear. Toxins and other

irritants may exit through a lateral canal, causing periradicular (rather than

periapical) demineralization. Conversely, a lateral canal in a tooth affected

by periodontal disease can become a portal of entry for harmful toxins.

Pulp stones and canal calcifications do not necessarily have pathologic

origin; they can be the result of normal aging of the pulp.

These calcification were not correlated with the severity of periodontal

disease, did not produce higher EPT responses and were not related to age.

In traumatized teeth with pulp obliteration studied between 7 and 22 years

posttrauma, 51% had a normal response to EPT. Another 40% did not

respond but were clinically and radiographically normal. The investigations

calculated the average rate of pulp survival for 20 years at 84%.

Consequently, in the pulp stones or canal calcification should not be

interpreted as a pulpal disorder that requires endodontic therapy.

However, internal resorption (occasionally seen after trauma) is an

indication for endodontic therapy. The inflamed pulp recruits clastic cells,

which asymptomatically resorb the radicular dentin from the blood vascular

system. In this case the pulp must be removed as soon as possible to

eliminate these cells and avoid a pathologic perforation of the root.

Recognizing the presence of immature apices allows the clinician to

anticipate erroneous responses to thermal and electric pulp tests.

If the canal appears blurred when compared with the irregular

demineralized radiolucency surrounding the root, lingual development

grooves would be suggested.

In a few cases root fractures may cause pulp degeneration. Only a

horizontal root fracture will be identifiable in the early stage and then only

if the fracture line is within 15 degree of the central radiographic beam. In

the case of a suggested horizontal fracture, two additional radiographs

should be produced from angles 30 degrees. Vertical and oblique root

fractures will eventually cause demineralization and a resultant diffuse

radiolucency adjacent to the fracture.

SPECIAL TESTS

Crown Removal – Many times a patient will describe symptoms of

irreversible pulpitis, but the suspected tooth is completely hidden from view

clinically and radiographically by a prosthetic crown. Although thermal and

EPT may be possible, if there are intact nerve fibers in the pulp, the results

may be difficult to differentiate from normal. In this case it is often

necessary to complete the examination by carefully removing the crown to

inspect the tooth underneath. Many times leakage from sub gingival

margins that were impossible to adequately explore clinically has resulted

in a carious exposure of the pulp.

Removal of the prosthetic crown not only conforms the diagnosis it also

allows the clinician to assess the restorability of the tooth.

SELECTIVE ANESTHESIA TEST

Test Cavity – Occasionally the clinical will encounter a tooth that exhibits

mixed responses to pulp testing (e.g. it fails to respond to cold, but it does

respond to EPT). Is this an example of a false positive response to EPT

caused by gingival conduction.

The most accurate technique to discover whether a pulp is vital is to begin

to make a preparations in a concealed area of the tooth without

anesthetizing the patient, who has been adequately approved of what to

expect and how to respond if discomfort is felt, when the dentinoenamel

junction (DEJ) is passed, or as the pulp is approached the patient should

feel pain if the pulp is vital. Once a vital response is elicited, the cavity

preparation should caesed and the tooth should be restored. If no response is

evoked access preparation may continue and endodontic therapy completed.

Although the damage can be repaired, this not a reversible procedure.

Therefore, it should be reserved for cases when it is impossible to arrive at a

pulpal diagnosis in another way.

Technical Details

The technique requires probe stability relative to the tooth. A dental putty

splint with a small hole drilled at the tooth position of interest, provides

mechanical stability for the probe. This technique has the advantage of

enabling reproducibility of prove position at successive visit for chronic

monitoring. 2) The splint also prevents backscattered light scattering off

other tissue and eliminates contamination of the laser Doppler signal by

these source.

Laser Doppler sampling should be atleast 10 samples per second (10Hz)

and the integrated time should be set at 0.1 sec so that the cardiac pulse

wave can be observed. A record duration of at least 30 seconds is

recommended so that vasomotion features of vitality can also be assessed.

Comparison of a flux trace measured from the contra-lateral healthy tooth

often aids diagnosis of vitality. Signal processing technique now enable

diagnosis with a sensitivity and specificity better than 90%. that reliably

indicates pulpal necrosis

MAGNETIC RESONANCE IMAGING

Recently MRI has been tried out a diagnostic tool in endodontics Magnetic

fields and radiographic waves are used to generate high quality cross-

sectional images of the body. It works on electro magnetic energy (X-rays

involves ionization). It can distinguish blood vessel and nerves from

surrounding tissues.

However this needs large equipment. This high electromagnetic

waves which are needed have not been approved off for use in scanners. In

future MRI offers evaluation of odontogenic problems.

CONTRAINDICATIED in patients with cardiac pace makers metallic

restorations orthodontic appliances and aneurysms.

It can be divided into few simple stages-

1. The patient is placed in a magnetic field and essentially becomes a

magnet.

2. A radio wave is sent in

3. The radiowave is turned off.

4. The patient emits signal

5. The signal is received and used for reconstruction of the picture.

Application

MRI tried as for diagnosing pulp vitality By use of contrast medium

VITAL TEETH shows dye contrast

NONVITAL TEETH shows no dye contrast.

HUGHES PROBEYE CAMERA

It is used to assess the vitality of the pulp. It measure temperature changes

as small as 0.10C

TRANS ILLUMINATION WITH FIBER OPTIC LIGHT

Light is passed through a finely drawn glass or plastic fibres across the

tooth by a process known as Total Internal Reflection.

A pulp less tooth is not noticeably discolored may show a gross difference

in translucency when a shadow produced on a mirror is compared to that of

adjacent vital tooth

XENON -133

This was introduced by Ronni. It was used to check the status of pulpal

blood circulation. It is a radioactive substance and pulpal circulating is

checked by wash out of Xenon-133.

DUAL WAVELENGTH SPECTROPHOTOMETRY

This was developed by ‘Chance’. This technique measures the

oxygenation change of blood. This identifies the teeth with pulp chamber

that are either empty filled with fixed pulp tissue or filled with oxygenated

blood.

Wavelength of 760 nm and 850 nm were used.

– independent of a pulsatile circulation

– presence of arterioles rather than arteries in the pulp and

rigid encapsulation make it difficult to detect pulse in the

pulp space.

– PRINCIPLE :-

This method measures oxygenation changes in capillary bed rather

than in supply vessels hence does not depend on pulsatile blood flow.

• In young children ,in cases of avulsed and replanted teeth with

open apices the blood supply is regained within first 20 days after

replantation but nerve supply lags behind

• Spectrophotometric readings taken at start of replantation and

continuing up to 40 days revealed an increase in blood

oxygenation levels

indicating healing process

LIQUID CRYSTAL TESTING

Cholesterol liquid crystals are used to show temperature difference between

teeth. Vital pulp may be hotter or show a higher temperature than the

necrotic pulp (cooler)

IL-1 (A lymphocyte activating factor) is responsible for osteoclast

activation which results in bone resorption which is often a feature of

inflammatory response.

The presence of IL-1 is examined by an ELISA (Enzyme linked

Immunosorbent Assay)

PLETHEYSMOGRAPHY

It is a method in assessing the changes in volume and has been

applied to the investigation of arterial disease because the volume of the

limb or organ exhibits transient changes over the cardiac cycle.

Plethysmography in limb or organ exhibits transient changes over the

cardiac cycle. Plethyusmography in limb or digit can be performed using air

filled cuffs or mercury in rubber strain gauges.

As the pressure pulse passed through the limb segment, a wave form is

recorded which related closely to that obtained by intra–arterial

cannulation. The same principle can be used to assess the vitality of the

pulp. Presence or absence of a wave form can indicate the statue of the

tooth pulp.

Of all the diagnostic aids - Radiovisiography has gained popularity

and also Laser Doppler flowmetry, which has come into clinical use, but its

usage is limited due to the cost factor.

As we near the end of this discussion. We hope that it is possible in

the near future to have a host of tests, which will enable an endodontist to

assess the blood flow of the pulp and to make an accurate diagnosis, which

will help in devising proper treatment plan and increase the long-term

success of endodontic treatment.

An evaluation of the use of tooth temperature to assess human pulp

vitality

Thermographic imaging (TI) has also been used to measure tooth surface

temperature (Egg et al 1975. Pogrel et al 1989 kells et al. 2000 a,b)

The work of Pogrel el at (1989) supported the finding so Fanlbunda

(1986b) that. after cooling vital teeth would rewarm more quickly than

nonvital teeth. They also noted a disruptive effect of mouth air Currents.

and advocated the isolation of the teeth by rubber dam to exclude this

effect.

Kells et al. (2000a,b) isolated the eight. most anterior upper teeth in'

human subjects with heavy black rubber, dam and measured tooth surface

temperature using TI. They established that following isolation it took

about 15 min for tooth temperature to stabilize. Despite isolation from

respiratory air currents from both the mouth and the nose they noted a

significant cooling effect by room air currents.

Thermographic imaging is accurate allows comparison of different areas of

a tooth. and is entirely noninvasive. However it requires, considerable

technical expertise and demands rigorous standardization of the

experimental environment. Similarly 1n LDF it is valuable, as an

experimental tool but has limited prospect of becoming a common clinical

investigation in the near future.

CONCLUSION

Status of the pulp should always be collaborated with two or more test .no

one test should be considered final.