Pulp vitality assessment/prosthodontic courses

ASSESSMENTASSESSMENT
ofof
PULP VITALITYPULP VITALITY
AA
Critical AppraisalCritical Appraisal
ofof
Various TechniquesVarious Techniques
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.comwww.indiandentalacademy.com

AnAn ‘ Accurate’‘ Accurate’ diagnosis is a prelude………….diagnosis is a prelude………….
diagnosisdiagnosis

Vitality assesment…crucial…Vitality assesment…crucial…
Assessment aidsAssessment aids
Patient historyPatient history
Clinical examinationClinical examination
* inspection* inspection
* palpation* palpation
* percussion* percussion
* mobility – depressibility* mobility – depressibility
Traditional diagnostic aidsTraditional diagnostic aids
New generation diagnostic aidsNew generation diagnostic aids

PATIENT HIS – STORYPATIENT HIS – STORY
Information gathered throughInformation gathered through
‘‘pertinent leadingpertinent leading questionsquestions’…..’…..
…… Onset of painOnset of pain
...Type of pain...Type of pain
…Duration & frequency…Duration & frequency
…Factors provoking / relieving...…Factors provoking / relieving...
……Tender on biting ??Tender on biting ??
…Type and nature of past dental…Type and nature of past dental
treatment.treatment.
……………………….enable to reach a……………………….enable to reach a
‘‘provisional diagnosis’.provisional diagnosis’.

CLINICAL EXAMINATION
1.Visual & tactile inspection
2.Palpation
3.Percussion
4.Mobility – depressibility
Visual & Tactile Inspection

Visual inspection of teeth -dry conditionsVisual inspection of teeth -dry conditions
Inspect the 3Inspect the 3 CCss

Palpation,Percussion and Depressibility – Mobility test evaluatePalpation,Percussion and Depressibility – Mobility test evaluate
the status of periodontal apparatus.the status of periodontal apparatus.
Does not give any definite answers on the vitality of tooth.Does not give any definite answers on the vitality of tooth.
So used in conjunction with other vitality tests.So used in conjunction with other vitality tests.

TRADITIONAL DIAGNOSTIC AIDSTRADITIONAL DIAGNOSTIC AIDS
THERMAL TESTSTHERMAL TESTS
ELECTRIC PULP TESTING (EPT)ELECTRIC PULP TESTING (EPT)
TEST CAVITYTEST CAVITY
ANESTHETIC TESTANESTHETIC TEST
RADIOGRAPHSRADIOGRAPHS

Thermal TestsThermal Tests
Heat testHeat test
Cold testCold test
How ?How ?
By applying heat /cold stimuli to the tooth.By applying heat /cold stimuli to the tooth.
Normal response ?Normal response ?
Patient ‘Patient ‘feelsfeels’ a sensation,that disappears on removal.’ a sensation,that disappears on removal.
Abnormal responses ?Abnormal responses ?
* no response .* no response .
* sudden excruciating pain.* sudden excruciating pain.
* lingers/intensifies after removal of stimulus.* lingers/intensifies after removal of stimulus.

PrinciplePrinciple
Response to thermal stimuli is based onResponse to thermal stimuli is based on
hydrodynamic theory of sensitivityhydrodynamic theory of sensitivity of dentin because pulpof dentin because pulp
has no thermal sensory nerve endings.has no thermal sensory nerve endings.
On application of thermal stimuli,there isOn application of thermal stimuli,there is
stimulation of fluid movement with in the dentinal tubulesstimulation of fluid movement with in the dentinal tubules
that stimulates the odontoblasts and its associated fastthat stimulates the odontoblasts and its associated fast
conductingconducting A –deltaA –delta nerve fibers,which interprets thenerve fibers,which interprets the
response asresponse as painpain..
Terminals of A-delta are located principally at theTerminals of A-delta are located principally at the
PDJ.From there free nerve endings penetrate into thePDJ.From there free nerve endings penetrate into the
dentinal tubules for a distance of 150 -200 µm.dentinal tubules for a distance of 150 -200 µm.

Therefore a sensation of pain requires the existence ofTherefore a sensation of pain requires the existence of
atleast some intact pulp tissue,including odontoblasts,for theatleast some intact pulp tissue,including odontoblasts,for the
hydrodynamic mechanism to function.hydrodynamic mechanism to function.
HEAT TESTHEAT TEST
A basic sensitivity test.A basic sensitivity test.
IndicationIndication
when patient complains of pain upon contact with hot food/ drink.when patient complains of pain upon contact with hot food/ drink.
difficult to localise pain.difficult to localise pain.www.indiandentalacademy.comwww.indiandentalacademy.com

How ?How ?
* isolate and dry the tooth.* isolate and dry the tooth.
* warm air.* warm air.
* hot GP stick, blade of wax instrument or hot* hot GP stick, blade of wax instrument or hot
water bath under rubber dam isolation.water bath under rubber dam isolation.
* rubber cups.* rubber cups.
Where ?Where ?
*on the middle third of the facial surface.*on the middle third of the facial surface.
*on the middle of the remaining intact surface.*on the middle of the remaining intact surface.
*for FMC –directly on the surface ???*for FMC –directly on the surface ???
*for PFM –on the exposed metal suface/hot*for PFM –on the exposed metal suface/hot
water bath under rubber dam isolation.water bath under rubber dam isolation.

Ideal temperature ?Ideal temperature ?
65.5ºC /150ºF65.5ºC /150ºF
Heat test may produce temperature as high as 150ºC at theHeat test may produce temperature as high as 150ºC at the
surface of the tooth.surface of the tooth.
Response ?Response ?
Normal –mild to moderate,transient,should not evokeNormal –mild to moderate,transient,should not evoke
pain.pain.
No response –pulp is non vital/vital giving a false( – )No response –pulp is non vital/vital giving a false( – )
test.test.
Painful,but relieved on removal of stimuli – Rev.pulpitis.Painful,but relieved on removal of stimuli – Rev.pulpitis.
Pain,Pain,spontaneousspontaneous andand excruciatingexcruciating//intensifyingintensifying//lingelinge
ringring even after removal of stimuli-even after removal of stimuli- Irrev.pulpitisIrrev.pulpitiswww.indiandentalacademy.comwww.indiandentalacademy.com

How does heat test work ?How does heat test work ?
Heat application has a ‘biphasic effect’- ie,initial heatHeat application has a ‘biphasic effect’- ie,initial heat
stimuli produces a pain due to rapid fluid movement insidestimuli produces a pain due to rapid fluid movement inside
DTs and then subsides.This is due to stimulation ofDTs and then subsides.This is due to stimulation of A-deltaA-delta
fibers.fibers.
If the heat application is continued,there is a brief painIf the heat application is continued,there is a brief pain
cessation followed by more intense pain with greatercessation followed by more intense pain with greater
frequency.This is because continuous application of heatfrequency.This is because continuous application of heat
results in vasodilatation and increase in intrapulpalresults in vasodilatation and increase in intrapulpal
pressure,which inturn stimulate thepressure,which inturn stimulate the C-fibersC-fibers
What does a (+) heat test tell ?What does a (+) heat test tell ?
** localises pain by indirect stimulation of mesencephaliclocalises pain by indirect stimulation of mesencephalic
nucleus through the proprioceptive fibers.nucleus through the proprioceptive fibers.
** irreversible pulpitis,could be managed by RCT.irreversible pulpitis,could be managed by RCT.

COLD TESTCOLD TEST
Another basic sensitivity test.Another basic sensitivity test.
1º test for endodontists today.1º test for endodontists today.
To be more reliable,now a days it is used in conjunction with EPT.To be more reliable,now a days it is used in conjunction with EPT.
IndicationsIndications
in younger permanent tooth with less developed apices.in younger permanent tooth with less developed apices.
recently traumatised tooth ???recently traumatised tooth ???
tooth with PJCs and FMCs.tooth with PJCs and FMCs.

How ?How ?
* isolate and dry the tooth.* isolate and dry the tooth.
* stream of cold air.* stream of cold air.
* ice sticks* ice sticks
* cold water bath under RD isolation.* cold water bath under RD isolation.
* dry ice.* dry ice.
* refrigerant spray.* refrigerant spray.

MMethod of application ?
Always start from the posterior tooth.
Stream of cold air can be directed against the crown.
Isolate,EC sray at - 50°.
Isolate,cotton pellet saturated with EC is placed over
the tooth.(pref by Cohen)
Merits & demerits ?
Icesticks,cold water,airblast – affects the adjacent teeth.
Dry ice – does’ nt affect adjacent teeth,produces an intense
,reproducible response;most efficient method for testing
multiple teeth with out moving away from the mouth.

dry ice is expensive;marketed in pressurised cans,has safetydry ice is expensive;marketed in pressurised cans,has safety
concerns;dry ice at -78°C can be injurious to toothconcerns;dry ice at -78°C can be injurious to tooth (but at(but at
clinically used -56°C,upto 2 min application do not damageclinically used -56°C,upto 2 min application do not damage
the tooth)the tooth)
EC sprayEC spray –– direct spaying is not advisable as EC is andirect spaying is not advisable as EC is an
inflammable liquid and aninflammable liquid and an anestheticanesthetic.Cotton soaked in EC is.Cotton soaked in EC is
used;this can be used on FMCs also.used;this can be used on FMCs also.
Refrigerant spray(1,1,1,2 TFE) –Refrigerant spray(1,1,1,2 TFE) – low liquid temp of –low liquid temp of –
26.2°C,safe,zero O26.2°C,safe,zero O 3 depletion potential,more intense and
rapid response,effective equally on restored and unrestored
teeth,less expensive and convenient to use.
TFE dissipates from satrurated cotton
,resaturation is time consuming.www.indiandentalacademy.comwww.indiandentalacademy.com

A response to cold test indicates vitap pulp,whether it isA response to cold test indicates vitap pulp,whether it is
vital /non-vital.vital /non-vital.
Summary on thermal tests.Summary on thermal tests.
Both heat and cold tests are basically sensitivity tests.Both heat and cold tests are basically sensitivity tests.
Cold test is a test of vitality where as heat test helpsCold test is a test of vitality where as heat test helps
differentiate between reversible and irreversible pulpitis.differentiate between reversible and irreversible pulpitis.
Emerging thermal sensitivity is a sign of pulpal pathosis.Emerging thermal sensitivity is a sign of pulpal pathosis.
As a rule cold sensitivity comes first.Continuing pulpalAs a rule cold sensitivity comes first.Continuing pulpal
deterioration leads to a change to hot sensitivity,where asdeterioration leads to a change to hot sensitivity,where as
cold sensitivity disappearscold sensitivity disappears,(Howard Selden –JOE 2006),(Howard Selden –JOE 2006)

Selden recommends a combination heat and cold test toSelden recommends a combination heat and cold test to
assess the status of tooth .assess the status of tooth .
Thermal tests give superior pain reaction whenThermal tests give superior pain reaction when
extremeextreme differencedifference in temperature is applied to the crownin temperature is applied to the crown
of the tooth.The fluid with in the dentinal fluids shouldof the tooth.The fluid with in the dentinal fluids should
move faster and stronger to deform the cell membrane tomove faster and stronger to deform the cell membrane to
excite the A-delta nerves.Gradual temperature changesexcite the A-delta nerves.Gradual temperature changes
cause no immediate response as there is no fluid movement.cause no immediate response as there is no fluid movement.
Thermal tests are veryThermal tests are very subjectivesubjective,as it is totally,as it is totally
dependent on the patient response.Best results aredependent on the patient response.Best results are
obtained in mature ,emotionally stable patients.obtained in mature ,emotionally stable patients.

Sensitivity & Specificity of Thermal testsSensitivity & Specificity of Thermal tests
Sensitivity is defined as the ability of aSensitivity is defined as the ability of a
test to identify the teeth that are diseasedtest to identify the teeth that are diseased..
Cold test -0.83(means Ct could identify 83 % of teethCold test -0.83(means Ct could identify 83 % of teeth
with necrotic pulp).with necrotic pulp).
Heat test -0.86Heat test -0.86
EPT – 0.72EPT – 0.72
InferenceInference
Comparatively heat test is better equippedComparatively heat test is better equipped
to point out necrotic pulp.to point out necrotic pulp.

Specificity is related to the ability of aSpecificity is related to the ability of a
test to identify teeth without diseasetest to identify teeth without disease..
Cold test and EPT performed better inCold test and EPT performed better in
identifying healthy pulp.identifying healthy pulp.
Studies show that the accuracy wasStudies show that the accuracy was
CT – 86 %CT – 86 %
EPT – 81 %EPT – 81 %
HT – 76 %HT – 76 %

Electric pulp testerElectric pulp tester
Employs a gradually increasing cuurrent to test the neural status ofEmploys a gradually increasing cuurrent to test the neural status of
a tooth.a tooth.
Modern EPTs are battery powered,self contained devices with anModern EPTs are battery powered,self contained devices with an
extended electrode.extended electrode.
HowHow ??
Tooth to be tested is isolated and dried.Tooth to be tested is isolated and dried.
Critical readings are taken under RD isolation and mylarCritical readings are taken under RD isolation and mylar
strips are used to insulate teeth from each other.strips are used to insulate teeth from each other.
Electrode is coated with tooth paste.Electrode is coated with tooth paste.www.indiandentalacademy.comwww.indiandentalacademy.com

The circuit is completed with the other ungloved hand.The circuit is completed with the other ungloved hand.
The contralateral/adjacent normal teeth tested first.The contralateral/adjacent normal teeth tested first.
Response ?Response ?
Normal – tingling/unusual feeling.Normal – tingling/unusual feeling.
At a lower level – indicates an inflammed pulp.At a lower level – indicates an inflammed pulp.
At a higher level – undergoing necrosis.At a higher level – undergoing necrosis.

Factors affecting the response ?Factors affecting the response ?
* enamel thickness.* enamel thickness.
* dentin calcification.* dentin calcification.
* patient’s anxiety.* patient’s anxiety.
* patient’s medication.* patient’s medication.
* restorative materials.* restorative materials.
* probe placement.* probe placement.
* crosssectional area of probe tip.* crosssectional area of probe tip.
Mechanism ?Mechanism ?
A pulsating DC.A pulsating DC.
Impulses of negative polarity is preferred.Impulses of negative polarity is preferred.
Most of analog PT works on – 15 to - 300 volts.Most of analog PT works on – 15 to - 300 volts.
Current of upto 1050µ amps.Current of upto 1050µ amps.

For each degree, 1 burst of 10 pulses of negative polarity isFor each degree, 1 burst of 10 pulses of negative polarity is
applied,followed by a pause to minimise the patientapplied,followed by a pause to minimise the patient
discomfort.discomfort.
The slower the increase in output voltage,the less theThe slower the increase in output voltage,the less the
discomfort for the patient.At the same time,the stimulationdiscomfort for the patient.At the same time,the stimulation
is more effective if the current rise is faster.is more effective if the current rise is faster.
Analog PT is reccomended as it always start at 0.Analog PT is reccomended as it always start at 0.
Each tooth is tested 2 to 3 times and the readingsEach tooth is tested 2 to 3 times and the readings
averaged.averaged.
OHM’s LawOHM’s Law
E=RE=R хІхІ wherewhere
E –electromotive force ;R –resistance;I –current flow.E –electromotive force ;R –resistance;I –current flow.

This applies to EPT also,but the response to EPT is likely toThis applies to EPT also,but the response to EPT is likely to
be a combination of impedance and resistance.be a combination of impedance and resistance.
Pulp tester operate at a relatively high pd,but atPulp tester operate at a relatively high pd,but at
a very low current (mA).a very low current (mA).
Enamel and dentin offer high resistance to electric currentEnamel and dentin offer high resistance to electric current
through the tooth.Enamel has the highest resistance.Inthrough the tooth.Enamel has the highest resistance.In
dentin the lowest resistance occur parallel to the tubules.dentin the lowest resistance occur parallel to the tubules.
The product of E and I(ie EMF and Impedance)The product of E and I(ie EMF and Impedance)
results in neural response.this energy is absorbed by theresults in neural response.this energy is absorbed by the
hard tissues of the tooth,leaving too little stimulation forhard tissues of the tooth,leaving too little stimulation for
the pulpal nerves.Therefore the electrode must be appliedthe pulpal nerves.Therefore the electrode must be applied
at the same location,and under the same condition for eachat the same location,and under the same condition for each
recording.recording. www.indiandentalacademy.comwww.indiandentalacademy.com

EPT causes pain respose due toEPT causes pain respose due to ionic movementionic movement.Electric.Electric
conductivity causes an ionic imbalance across the neuralconductivity causes an ionic imbalance across the neural
membrane,inducing an action potential with a rapid saltatorymembrane,inducing an action potential with a rapid saltatory
or hopping action.or hopping action.
Pricking pain produced by most EPTs is due toPricking pain produced by most EPTs is due to
stimulation of A-delta fibers.stimulation of A-delta fibers.
C-fibers need a stronger electric current than the onesC-fibers need a stronger electric current than the ones
used in conventional EPTs.used in conventional EPTs.
AdvantagesAdvantages
Easy to use as it is very compact.Easy to use as it is very compact.
A quantitative reading is obtained,unlike thermal tests.A quantitative reading is obtained,unlike thermal tests.

DisadvantagesDisadvantages
Checks the neural status only.Checks the neural status only.
False positive/false negative.False positive/false negative.
Difficult to measure the threshold for each tooth,so if theDifficult to measure the threshold for each tooth,so if the
intensity of EPT keeps increasing,a great amount of stress isintensity of EPT keeps increasing,a great amount of stress is
generated.this induces sympathetic nerve stimulation,thereby increasinggenerated.this induces sympathetic nerve stimulation,thereby increasing
the arterial BP and steroid hormone levels.the arterial BP and steroid hormone levels.
Special indicationsSpecial indications
In heavily calcified tooth.In heavily calcified tooth.
To monitor traumatic injuries to tooth.An increase in stimulation fromTo monitor traumatic injuries to tooth.An increase in stimulation from
time to time often suggest increased hard tissue formation in the pulptime to time often suggest increased hard tissue formation in the pulp
space.space.
Used along with thermal and periodontal tests to differentiate amongUsed along with thermal and periodontal tests to differentiate among
radiographic signs of pulpal,periodontal and non-odontogenic etiologies.radiographic signs of pulpal,periodontal and non-odontogenic etiologies.

When cold test is not possible on tooth with PJC/FMC.When cold test is not possible on tooth with PJC/FMC.
ContraindicationsContraindications
In patients with indwelling cardiac pacemaker.In patients with indwelling cardiac pacemaker.
In recently traumatised tooth.In recently traumatised tooth.
False Positive / False NegativeFalse Positive / False Negative
False positive means pulp is necrotic,but patientFalse positive means pulp is necrotic,but patient
gives a positive response.gives a positive response.
False negative means pulp is vital,but patient isFalse negative means pulp is vital,but patient is
unresponsive to EPT.unresponsive to EPT.
Both these occur fairly frequently.Both these occur fairly frequently.www.indiandentalacademy.comwww.indiandentalacademy.com

False +False + False -False -
Failure to isolate and dryFailure to isolate and dry
the tooththe tooth
Recently erupted toothRecently erupted tooth
with immature apex.with immature apex.
Multirooted tooth.Multirooted tooth. Recently traumatisedRecently traumatised
tooth.tooth.
Tooth with heavyTooth with heavy
liquifaction necrosis.liquifaction necrosis.
Increased calcification inIncreased calcification in
canal.canal.
Tooth with metalTooth with metal
restorationrestoration
High levels ofHigh levels of
alcohol/analgesics.alcohol/analgesics.
AnxietyAnxiety Inadequate contact withInadequate contact with
tooth.tooth.
Dead batteries/forgettingDead batteries/forgetting
to turn the EPT on.to turn the EPT on.

RadiographsRadiographs
Status of pulpal health /necrosis cannot be determined.Status of pulpal health /necrosis cannot be determined.
Gives clues on the degenerative changes in the pulp,as well asGives clues on the degenerative changes in the pulp,as well as
sequelae of pulp necrosis.sequelae of pulp necrosis.
Not of much value in the assesment of pulp vitality.Not of much value in the assesment of pulp vitality.
Helps in identifying deep carious lesions,extensiveHelps in identifying deep carious lesions,extensive
restorations,pulp caps,pulpotomies,pulp stones,canalrestorations,pulp caps,pulpotomies,pulp stones,canal
calcification,root resorptions,blockages,perforations,calcification,root resorptions,blockages,perforations,
periodontal problems and periapical pathologies.periodontal problems and periapical pathologies.

LimitationsLimitations
Radiograph is a 2-D representation of a 3-D object,andRadiograph is a 2-D representation of a 3-D object,and
being a shadow,it has all the elusive qualities of shadows.being a shadow,it has all the elusive qualities of shadows.
Usefulness of radiographs is dependent on itsUsefulness of radiographs is dependent on its
interpretation,which is relative.interpretation,which is relative.
Even with all its limitation radiographs help inEven with all its limitation radiographs help in
* diagnosis* diagnosis
* case selection* case selection
* treatment* treatment
* evaluation of healing* evaluation of healing

Anaesthetic TestAnaesthetic Test
IndicationIndication
Cases of diffuse pain of vague origin,when other testsCases of diffuse pain of vague origin,when other tests
are inconclusive.are inconclusive.
Conduction,selective infiltration or intraligamentaryConduction,selective infiltration or intraligamentary
anesthesia is used.anesthesia is used.
Based on the fact that pulpal pain even when referred isBased on the fact that pulpal pain even when referred is
invariably unilateral and could stem from only one of the twoinvariably unilateral and could stem from only one of the two
branches of the trigeminal nerve.branches of the trigeminal nerve.
IL injection used to be the choice.IL injection used to be the choice.
Has an advantage over test cavity where there is possibilityHas an advantage over test cavity where there is possibility
of iatrogenic damage.of iatrogenic damage.

Test CavityTest Cavity
The ‘last resort’.The ‘last resort’.
Carried out without anesthesia.Carried out without anesthesia.
Test cavity is made deep into dentin/or on crownedTest cavity is made deep into dentin/or on crowned
tooth.tooth.
Enamel or crown is penetrated with bur in aEnamel or crown is penetrated with bur in a
h.s.handpiece,once the dentin is reached,a round bur ish.s.handpiece,once the dentin is reached,a round bur is
used in a l.s.handpiece.used in a l.s.handpiece.
If the pulp is vital,patient will respond before the pulpIf the pulp is vital,patient will respond before the pulp
chamber is reached.chamber is reached.
The test cavity is prepared on surface,that can be easilyThe test cavity is prepared on surface,that can be easily
repaired.repaired.

Conventional diagnostic methods rely on theConventional diagnostic methods rely on the subjectivesubjective
perception of peripheral nerve stimulation.perception of peripheral nerve stimulation.These tests areThese tests are
unreliable at times,as they are subject to false +/false –unreliable at times,as they are subject to false +/false –
results.results.
Eg a recently traumatised tooth may give a false – result.Eg a recently traumatised tooth may give a false – result.
a multirooted tooth with a partially necrotised pulp gives aa multirooted tooth with a partially necrotised pulp gives a
false + result.false + result.
A non invasive method to assess theA non invasive method to assess the vascularity of thevascularity of the
dental pulpdental pulp seem to be a better indicator of toothseem to be a better indicator of tooth
vitality.This is reliable as blood supply aids the reparativevitality.This is reliable as blood supply aids the reparative
potential of the pulpal tissue.potential of the pulpal tissue.
A whole series of new techniques was introduced,most of themA whole series of new techniques was introduced,most of them
looks theoretically feasible,but as of now onlylooks theoretically feasible,but as of now only LaserDopplerLaserDoppler
Flowmetry(LDF)Flowmetry(LDF) andand Pulse OximetryPulse Oximetry looks promising.looks promising.

NEW GENERATION DIAGNOSTIC AIDSNEW GENERATION DIAGNOSTIC AIDS
1.1. LASER DOPPLER FLOWMETRYLASER DOPPLER FLOWMETRY
2. PULSE OXIMETRY2. PULSE OXIMETRY
3. LIQUID CRYSTAL TESTING3. LIQUID CRYSTAL TESTING
4. HUGHES PROBEYE CAMERA4. HUGHES PROBEYE CAMERA
5. TRANSILLUMINATION with FIBROPTIC LIGHT5. TRANSILLUMINATION with FIBROPTIC LIGHT
6. XENON -1336. XENON -133
7. SPECTROPHOTOMETRY7. SPECTROPHOTOMETRY
8. DETECTION OF INTERLEUKIN- 18. DETECTION OF INTERLEUKIN- 1 ββ
9. DIGITAL SUBTRACTION RADIOGRAPHY9. DIGITAL SUBTRACTION RADIOGRAPHY
10. PLETHYSMOGRAPHY10. PLETHYSMOGRAPHY
11. GAS SATURATION11. GAS SATURATION
12.12. ELECTROMAGNETIC FLOWMETRYELECTROMAGNETIC FLOWMETRY
13. RADIOLABELLED MICROSPHERES13. RADIOLABELLED MICROSPHERES

14.14. TOMOGRAPHYTOMOGRAPHY
15. DIRECT DIGITAL RADIOGRAPHY15. DIRECT DIGITAL RADIOGRAPHY
Laser Doppler FlowmetryLaser Doppler Flowmetry
CombinesCombines LASERLASER && Doppler effectDoppler effect..
Have been used to assess microcirculation.Have been used to assess microcirculation.
Tenland &Holloway introduced it into medicine in theTenland &Holloway introduced it into medicine in the
1980s.1980s.
First application in dentistry by Gazelius et al in 1986.First application in dentistry by Gazelius et al in 1986.
Smith et al (1988) concluded that LDF could assess PBF.Smith et al (1988) concluded that LDF could assess PBF.
ApparatusApparatus
Monochromatic light from a Laser source(He – Ne atMonochromatic light from a Laser source(He – Ne at
632.8),working at low power level –1 or 2 mW is transmitted632.8),working at low power level –1 or 2 mW is transmitted

by optic fibers through the crown of the tooth.A probeby optic fibers through the crown of the tooth.A probe
attached to the optic fiber helps in this transmission.attached to the optic fiber helps in this transmission.
The probe is placed 2 – 3 mm coronal to the freeThe probe is placed 2 – 3 mm coronal to the free
gingival margin,then three more additional readings aregingival margin,then three more additional readings are
taken by turning the probe by 90ºeach time.taken by turning the probe by 90ºeach time.
The transparency of enamel and tubular nature ofThe transparency of enamel and tubular nature of
dentin fecilitate the transfer of light through the tooth.dentin fecilitate the transfer of light through the tooth.
MechanismMechanism
•A beam of laser light is used to illuminate a small
area of tissue
•The incident light is scattered by the tissue and is
detected by the receiver

•The Doppler shifted light causes fluctuation in the detector
signal
•The moving blood cells in the capillaries cause a Doppler shift
to the incident light
•The power spectrum of the detector signal gives the strength
of signal fluctuations
Interpretation

The light reflected has an altered frequency .and thisThe light reflected has an altered frequency .and this
frequency shift is calculated asfrequency shift is calculated as
γγ11== γγ00 [1+(v/c)][1+(v/c)] wherewhere
γγ11 : frequency of reflected laser beam.: frequency of reflected laser beam.
γγ00 : frequency of emitted laser beam.: frequency of emitted laser beam.
V : velocity of flow.V : velocity of flow.
C : concentration of solute.C : concentration of solute.
This shift in frequency is considered a function ofThis shift in frequency is considered a function of velocityvelocity
of RBCsof RBCs..
Flow rateFlow rate ==Volume of cellVolume of cell ×× Average velocityAverage velocity..
This information is used as a measure of blood flow,andThis information is used as a measure of blood flow,and
the value is expressed as percentage of Full Scalethe value is expressed as percentage of Full Scalewww.indiandentalacademy.comwww.indiandentalacademy.com

* objective test.* objective test.
* non invasive / non painful.* non invasive / non painful.
* no problem in apprehensive patients.* no problem in apprehensive patients.
* accurate in traumatised / recently erupted tooth.* accurate in traumatised / recently erupted tooth.
DisadvantagesDisadvantages
* sensitive to movement.* sensitive to movement.
* sensitive to position of patient.* sensitive to position of patient.
* sensitive to position of the probe.* sensitive to position of the probe.
* influence of environment temperature* influence of environment temperature
* not accurate in patients on medications..* not accurate in patients on medications..
* periodontal / neighbouring tissues can contribute to* periodontal / neighbouring tissues can contribute to
the signal.the signal.
* change in ambient light intensity.* change in ambient light intensity.
* increase in 2ºdentin thickness affects PBF* increase in 2ºdentin thickness affects PBF
assesment.assesment. www.indiandentalacademy.comwww.indiandentalacademy.com

* not ideal for posterior tooth.* not ideal for posterior tooth.
* demands high technical skills.* demands high technical skills.
* expensive equipment.* expensive equipment.
Pulse OximetryPulse Oximetry
Pulse oximetry literally means measurement ofPulse oximetry literally means measurement of
percentage of Opercentage of O22 saturation of arterial blood.saturation of arterial blood.
Pulse oximetry = SpectrophotometryPulse oximetry = Spectrophotometry
++
Optical plethysmography.Optical plethysmography.
Carl Matthes – Father of oximetry(1935)Carl Matthes – Father of oximetry(1935)

Physics ?Physics ?
Detection of O2 saturation of Hb is based on the Beer –Detection of O2 saturation of Hb is based on the Beer –
Lambert law,which relates the the concentration of a soluteLambert law,which relates the the concentration of a solute
to the intensity of light transmitted through a solution.to the intensity of light transmitted through a solution.
ApparatusApparatus
Consists ofConsists of
* Probe* Probe
* photodetector* photodetector
* Microprocessor* Microprocessor
The probe is placed usually on the digit,earlobe orThe probe is placed usually on the digit,earlobe or
nose.This can be modified to be used on tooth.nose.This can be modified to be used on tooth.
The probe contains LEDs,which emit lights of twoThe probe contains LEDs,which emit lights of two
wavelengths.wavelengths.
The lights undergo preferential absorption.The lights undergo preferential absorption.
`` The ratio of wavelengths of light absorbed will corelateThe ratio of wavelengths of light absorbed will corelate
with Owith O saturation.saturation. www.indiandentalacademy.comwww.indiandentalacademy.com

* Non invasive* Non invasive
* Is objective* Is objective
LimitationsLimitations
* Thickness of enamel.* Thickness of enamel.
* Nail polish & coverings.* Nail polish & coverings.
* Scatter,reflection & absorbance of light by other* Scatter,reflection & absorbance of light by other
tissues and blood components.tissues and blood components.
* Dyshemoglobinemias.* Dyshemoglobinemias.
* Interference of ambient lighting.* Interference of ambient lighting.
* Poor peripheral pulsations.* Poor peripheral pulsations.
* Difficult to detect high O2 partial pressures.* Difficult to detect high O2 partial pressures.
* Sensor location .* Sensor location .
* electrical interference.* electrical interference.
* Motion artifacts.* Motion artifacts.www.indiandentalacademy.comwww.indiandentalacademy.com

Most important application of PO is in immediateMost important application of PO is in immediate
determination of vascular status of pulp,after trauma.determination of vascular status of pulp,after trauma.
Liquid Crystal TestingLiquid Crystal Testing
Substances that exhibit properties between those of aSubstances that exhibit properties between those of a
conventional liquid and solid crystals.conventional liquid and solid crystals.
Liquid crystals have different phases (in relation toLiquid crystals have different phases (in relation to
optical properties) which changes with temperature.Thisoptical properties) which changes with temperature.This
property has been exploited to show the temperatureproperty has been exploited to show the temperature
difference between vital and nonvital tooth.difference between vital and nonvital tooth.
Cholesteric liquid crystals are used for this purpose.Cholesteric liquid crystals are used for this purpose.

Hughes Probeye CameraHughes Probeye Camera
Is a thermographic / infrared camera.Is a thermographic / infrared camera.
Uses IR radiation of wavelength 14,000 nm.Uses IR radiation of wavelength 14,000 nm.
All objects emit certain amount of ‘black bodyAll objects emit certain amount of ‘black body
radiation’as a function of their temperature.Higher theradiation’as a function of their temperature.Higher the
object’s temperature,the more the IR,it emits.object’s temperature,the more the IR,it emits.
HPC can detect this radiation.HPC can detect this radiation.
Can be used to assess the pulp vitality as it can measureCan be used to assess the pulp vitality as it can measure
temperature changes as small as 0.1temperature changes as small as 0.1°°C.C.
Transillumination with Fiber Optic LightTransillumination with Fiber Optic Light
Optic fibers works on the principle of ‘ TotalOptic fibers works on the principle of ‘ Total
Internal Reflection’.Internal Reflection’.
With the help of OFs,light is transmitted throughWith the help of OFs,light is transmitted through
the tooth,and a non vital tooth may show a gross difference inthe tooth,and a non vital tooth may show a gross difference in
translucency when the shadow produced on a mirror istranslucency when the shadow produced on a mirror iswww.indiandentalacademy.comwww.indiandentalacademy.com

Xenon-133Xenon-133
Radioactive Xenon 133 is used.Radioactive Xenon 133 is used.
Based on the principle of radioactive decay.Based on the principle of radioactive decay.
Checks the status of pulpal blood circulation byChecks the status of pulpal blood circulation by
measuring the wash out of xenon 133.measuring the wash out of xenon 133.
SpectrophotometrySpectrophotometry
A spectrophotometer is used to measure the amount ofA spectrophotometer is used to measure the amount of
light absorbed by a medium.light absorbed by a medium.
It operates by passing light of wavelength 760 – 850 nmIt operates by passing light of wavelength 760 – 850 nm
through a tooth.through a tooth.
When the photon encounters the blood vessels in pulp,itWhen the photon encounters the blood vessels in pulp,it
gets absorbed and scattered.The scattered radiation isgets absorbed and scattered.The scattered radiation is
collected by the detector.collected by the detector.
As a result of this absorption, the intensity of theAs a result of this absorption, the intensity of the
emitted light falls.This change in intensity is a function ofemitted light falls.This change in intensity is a function of
oxygenation of blood.oxygenation of blood.

Interleukin-1ßInterleukin-1ß
Detection of IL – 1 by ELISA.Detection of IL – 1 by ELISA.
Inflammatory periapical lesions show high levels of IL-1.Inflammatory periapical lesions show high levels of IL-1.
So higher levels of IL-1 in assay indicates necrotic pulp.So higher levels of IL-1 in assay indicates necrotic pulp.
Digital Subtraction RadiographyDigital Subtraction Radiography
Identifies the osseous changes associated with a nonIdentifies the osseous changes associated with a non
vital tooth.vital tooth.
PlethysmographyPlethysmography
Measures pulsatile changes in arterial blood volume atMeasures pulsatile changes in arterial blood volume at
the sensor site.the sensor site.
Non vitality is associated with absence of pulsations.Non vitality is associated with absence of pulsations.
So the presence or absence of wave forms as detectedSo the presence or absence of wave forms as detected
by plethysmograph indicate the status of the tooth.by plethysmograph indicate the status of the tooth.

TomographyTomography
It is imaging by sections / sectioning.It is imaging by sections / sectioning.
A sectional imaging is taken by movimg the x-rayA sectional imaging is taken by movimg the x-ray
source and film in the opposite direction.source and film in the opposite direction.
Direct Digital RadiographyDirect Digital Radiography
Filmless xray.Filmless xray.
Direct images are acquired.Direct images are acquired.
It uses a detector system containing aIt uses a detector system containing a
scintillator that converts radiation into light by an array ofscintillator that converts radiation into light by an array of
charge couple devices(CCD).charge couple devices(CCD).
Low xray dose levels.Low xray dose levels.

CONCLUSIONCONCLUSION
Assessment of vitality has been consideredAssessment of vitality has been considered
both an art and science.It remains a challenging partboth an art and science.It remains a challenging part
of endodontics.Research in this field looks veryof endodontics.Research in this field looks very
promising,that a practical and sensitive diagnosticpromising,that a practical and sensitive diagnostic
tool that can efficiently provide stimulation with atool that can efficiently provide stimulation with a
definitive and measurable response and ampledefinitive and measurable response and ample
characterisation of the expected result,may becharacterisation of the expected result,may be
available in the near future.available in the near future.

Pulp vitality assessment/prosthodontic courses

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