Caries diagnosis

caries diagnosis with all recent advancements

1. CARIES DIAGNOSIS
Presented by
Nadeem Aashiq
MDS 1
st
year
Batch 2020

2. INTRODUCTION
Cariesisaninfectiousmicrobiologicdiseasethatresultsin
thelocalizeddissolutionofthecalcifiedtissuesofthe
teethanddestructionoftheorganicpart.
Theprimaryobjectivesofcariesdiagnosisaretoidentify
•patientswithlesionsthatrequirenonsurgicaltreatment,
•patientswhoareathighriskfordevelopingcarious
lesions.
Knowingwhichpatientsareathighriskfordeveloping
cariesprovidesanopportunitytoimplementspecific
preventivestrategiesthatmaypreventcaries.

3. Idealrequirementsofdiagnostictests:(Pitts1997)
1.Accurate.
2.Sensitive.
3.Specific.
4.Reproducible.
5.Reliable.
6.NottransferS.Mutansorotherbacteriafromaffected
areatounaffectedareas.
7.Costeffective.

5. TRADITIONAL METHODS
Patient’s Complaint:
mayprovideahintaboutthepresenceofcaries.
Thepatientmaycomplainofsensitivitytothermalchanges,
mildtomoderatetoothache,etc.
Patient History:

6. Clinical Examination:

7. NutritionalAnalyses:
•exposuretosucroseincreasesthelikelihoodofplaque
developmentbythemorecariogenicMSorganisms.
Salivary Analyses:
•may provideimportantinformationabout
appropriatenessofsecretionratesandbufferingcapacity
andnumbersofMSandlactobacilli.
•ThecorrelationbetweensalivaryMScountsandthe
numberofMS-colonizedtoothsurfacesisrelativelygood
(Lindquistetal,1989)

8. Caries activity tests
Cariesactivity:
•Referstotheincrementofactivelesions(newand
recurrentlesions)overastatedperiodoftime.
•Measureofthespeedofprogressionofacariouslesion.
•Cariesactivitytestsmeasurethedegreetowhichthe
localenvironmentchallengefavorstheprobabilityof
cariouslesions.
Cariessusceptibility:
•Referstotheinherenttendencyofthehostandthetarget
tissue(tooth)tobeaffectedbythecariousprocess.

9. LACTOBACILLUS COLONY COUNT TEST
(Dentocult LB)
IntroducedbyHadleyin1933
Principle:estimates the number of acidogenic and aciduric bacteria in
patient’s saliva by counting the number of colonies appearing on
tomato agar plates (pH 5.0) after inoculation.
Paraffin stimulated saliva 0.4 ml of 1:100 dilution

Spread on agar plate (20 ml cooled liquefied agar: Rogasa’a SL agar plate)

Incubated for 3-4 days at 37C

Colonies counted using light and magnifying glass
Number of lactobacilli per ml saliva is calculated by multiplying the
number of colonies on the agar plate by the dilution factor.

10. Salivary lactobacilli counts

11. STREPTOCOCCUS MUTANS LEVEL IN SALIVA
Principle:measuresthenumberofS.mutansCFUperunitvolumeof
saliva.IncubationisdoneonMitisSalivariusAgar.
Samples of organisms obtained by tongue blades

Pressed against MSB agar

Incubated at 37C for 4 hrs in 95% and 5% CO
2
gas mixture
Interpretation:
LevelsofSM>10
5
/mlofsaliva------unacceptable
Colonization of a new surface does not occur readily unless SM levels
reaches 4.5 X 10
4
/ ml for smooth surfaces and 10
3
/ ml for occlusal
surfaces.

12. DIP SLIDE METHOD FOR S. MUTANS COUNT
•describedbyJensenandBratthall(1989)
Undiluted paraffin stimulated saliva poured on plastic slide coated with
MSA containing 20% sucrose.

Agar is thoroughly moistened and excess is drained

2 discs of 5 mg bacitracin placed on agar 20 mm apart.

Slide is screwed and incubated at 37C for 48 hrs in a sealed candle jar

13. S. mutans colonies

14. GlucosyltransferaseasaMarkerforCariesActivity
•provenvirulencefactorsincariesetiologyidentifiedfrom
Streptococcusmutans[DeStoppelaaretal.,1971;Hamadaetal.,1984;
Tanzeretal.,1985;Yamashitaetal.,1993].
LevelsofactiveGtfinsalivacorrelatewithsalivarypopulationsofS.
mutans
[R611aetal.,1983;Scheieetal.,1987;Vacca-Smithetal.,1996].
The enzyme(s) is used as a marker(s) for caries detection.
BOWEN,WILLIAMH.etal(2004-06)attempted:
•TodeterminethequantitiesofGtfB,GtfC,andGtfDofS.mutansin
thesubjects'salivausingmonoclonalantibodiesinanenzyme-linked
immunosorbentassay.
•TocorrelatetheassayedactivityofGtfwiththeconcentrationsofGtf
B,GtfCandGtfDofS.mutans.
•TodeterminethecorrelationbetweenboththeconcentrationsofGtf
B,GtfC,andGtfD,andtheoverallassayedGtfactivityinsaliva,with
thecurrentlevelsofclinicalcariesofthesubjects

15. COLORIMETRICSNYDERTEST(Snyderin1951)
Principle:measurestheabilityofsalivarymicroorganismstoformorganic
acidsfromacarbohydratemedium.
Bromocresolgreen:changescolorformgreentoyellowintherangeof
pH5.4to3.8.
0.2 ml paraffin stimulated saliva + 10 ml melted agar containing medium

Cooled to 50C; allowed to solidify; incubated at 37C

Amount of acid produced is detected by pH indicator, and compared with
uninoculated control tube after 24, 48, 72 hrs.

16. SWAB TEST(Graingar in 1965)
Principle:basedonthesameprincipleasSnyder’stest.
Theoralfloraissampledbyswabbingthebuccalsurfacesof
theteethwithacottonapplicatorandincubated.
Change in pH is read on the pH meter after 48 hrs of
incubation.

17. ALBANS TEST
AsimplifiedsubstituteforSnydertest.
60 gms of Snyder test agar + 1 liter water
boiled over flame
When melted, agar distributed (5 ml per tube)

Tubes autoclaved for 15 minutes, allowed to cool and stored
in refrigerator

2 tubes taken, Patient asked to expectorate saliva into tubes

Labeled and incubated at 37C for 4 days and observed daily

18. Finalreadingstakenafter72or96hrsofincubation.
Interpretation:
•Readingsnegativefortheentireincubationperiodarelabeled
“negative”.
•Allotherreadingsarelabeled“positive”.
•Slowerchangeorlesscolorchangeislabeled“improved”.
•Fastercolorchangeormorepronouncedcolorchangeis
labeled“worse”.
•Whenconsecutivereadingsarenearlyidentical,theyare
labeled“nochange.

19. SALIVARY BUFFER CAPACITY TEST
Principle:measuresthenumberofmillilitersofacidrequiredtolowerthe
pHofsalivathroughanarbitrarypHinterval,suchasfrompH7.0to
6.0.
Evaluation:
Thereisaninverserelationshipbetweenbufferingcapacityofsalivaand
cariesactivity.

20. SALIVARY REDUCTASE TEST
Principle:measurestheactivityofreductaseenzymepresent
insalivarybacteria.
Tradename:Treatex
Collected saliva is mixed with dye (Diazo-resorsinol)

Color changes observed after 15 minutes

21. ENAMEL SOLUBILITY TEST
Principle:whenglucoseisaddedtothesalivacontainingpowdered
enamel,organicacidsareformed.Theseinturndecalcifytheenamel,
resultinginanincreaseintheamountofcalciuminSaliva-Glucose-
Enamelmixture.
The extent of increased calcium is supposedly a direct measure of the
degree of caries susceptibility.
FOSDICK CALCIUM DISSOLUTION TEST
Principle:measuresthemgsofpowderedenameldissolvedin4hrsby
acidformedwhenpatient’ssalivaismixedwithglucoseand
powderedenamel.
DEWAR TEST
Principle:similar to Fosdick calcium dissolution test. The final pH after 4
hrs is measured instead of amount of calcium dissolved.

22. AccordingtotheWorldHealthOrganization(WHO)system,theshape
andthedepthofthecariouslesioncanbescoredonafour-point
scale(D1toD4):
•D1:clinicallydetectableenamellesionswithintact(noncavitated)
surfaces
•D2:clinicallydetectable"cavities"limitedtotheenamel
•D3:clinicallydetectablelesionsindentin(withandwithoutcavitation
ofdentin)
•D4:lesionsintopulp
•Intact tooth (43)
•Primary enamel caries (42)
•Primary dentin caries with cavitation (41)
•Secondary caries with cavitation (31)
•Advanced secondary caries (32)
•Complete destruction of the crown (33)

23. Meticulousclinicalexamination(VisualExamination):
undercleananddryconditionsusinggoodillumination
nBrownishdiscolorationofpitsandfissures
nOpacitybeneathpitsandfissuresormarginalridges
nFrankcavitationofthetoothsurface.
Problem:discoloration of the pits & fissures may be mistaken
for the presence of caries.
Magnifying lens:enhances Visual examination

24. TactileEvidenceofCaries:Exploreranddentalfloss
curved explorers are used for examination of occlusal pits and fissures
interproximal explorers are used to detect proximal caries.
Tactile findings suggestive of caries:
•Softness at the base of a pit or fissure and discontinuity of enamel
surface
•Binding or catch of the explorer tip
•Cavitation at the base of pit or fissure.

25. Disadvantages:
1.Maytransmitcariogenicbacteriafromonesitetoanother.
2.Mayproduceirreversibletraumaticdefectsinpotentially
remineralizableenamel.
3.Maynotbeabletoaddanyinformationtothevisualexamination.
4.Mechanicalbindingofanexplorertipinafissuremaynotbebecause
ofcariesbutbecauseofothercauseslike:
a. Shapeofthefissure.
b. Sharpnessofanexplorer.
c. Forceofapplication.

26. DentalFloss:whensawedthroughthecontactareas
betweenteeth,ifitfraysorshredsthenitisasignfor
proximalcaries.
overhangingrestorationsontheproximalsidealsogive
thesamefeatures.
Toothseparation
can be achieved using wedges or mechanical separator.
Once the proximal surface is accessible, visual examination
and gentle probing may help in diagnosis of the carious
lesion.

27. ConventionalRadiographs:
presentsa2-Dpictureofa3-Dobject.
netminerallossmustexceedatleast20%-30%inordertobe
radiographicallyvisible.
•intraoralperiapical
•bitewingradiographs
(bitewingradiographshavemorediagnosticvalue)
Advantages:
•Non-invasivemethod
•Disclosesitesinaccessibletootherdiagnosticmethods
•Permanentrecordformonitoringprogressorarrestofthe
cariouslesion.

28. Recurrent caries

29. Problemsencounteredwithradiographicmethodsare:
1.Overlappingofapproximalcontacts.
2.Falsediagnosisduetooverestimationoflesiondepth,dueto
changeinangulations.
3.Radiolucencymaybebecauseofcariesorresorptionoranyother
defecti.e.wear,etc.
4.Asuperficialdemineralizationinthebuccal&lingualsurfacesmay
beimagedontheradiographasanapproximalcariouslesion.
5.Fractureofonelingualcuspmayappearasradiolucentapproximal
cavity.
6.Tiltofmaxillarylateralincisorsappearsascariesonthemesialside
oflateralincisors.
7.Cervicalburnoutmaymimiccervicalcaries.

30. CariesDiagnosisforRootSurfaces
exposedRootsurfacesareatriskforcariesandshouldbeexamined
visuallyandtactilely.
Discolorationiscommonandisassociatedwithremineralization.
darkerthediscoloration,thegreatertheremineralization.

31. DyePenetrationMethod
nqualitativeassessment:toobserveforcolorordifferentiatecolored
objectsfromthenon-coloredones.
nquantitativeassessment:intensityofcoloristobedetermined.
TheIntensityofcolorcanbedeterminedbyabsorptionorfluorescence.
n Absorption:byquantitatingthedecreaseoflightintensityata
particularwavelength
nFluorescence:byquantitatingtheincreaseoflightintensityata
particularweavelength.
Criteriafordyeselection:
•shouldbeabsolutelysafeforintraoraluse
•shouldbespecificandstainonlythetissuesitisintendedtostain
•shouldbeeasilyremovedandnotleadtopermanentstaining.

32. Dyesfordetectionofcariousenamel
n'Procion‘:stainenamellesions,stainingbecomes
irreversiblebecausethedyereactswithnitrogenand
hydroxylgroupsofenamelandactsasafixative.
n 'Calcein‘:makesacomplexwithcalciumandremains
boundtothelesion.
n 'Fluorescentdye‘:likeZygloZL22ismadevisibleby
ultravioletillumination.
notsuitableinvivo
n'Brilliantblue‘:toenhancethediagnosticqualityof
fiberoptictransillumination.

33. Dyesfordetectionofcariousdentin
nHistopathologically,cariousdentinisdividedintotwolayers;
outerlayerofdecalcification,whichissoftandcannotbe
remineralizedandtheinnerdecalcifiedlayer,whichishardand
canberemineralized.
n 0.3%BasicFuchsininpropyleneglycolhasbeentriedto
differentiatebetweenthentwozonesofdentincaries
n Demineralizeddentininwhichthecollagenhasbeen
denaturedisstainedwhiletheinneroneremainsunstained.
nrecommendedasaclinicalguideforcompleteremovalofthe
outercariouszone
nconsideredtobecarcinogenic
Others:
acidredandmethyleneblue.
Methylene blue is slightly toxic so acid red is preferred.

34. Amodifieddyepenetrationmethod
n'TheIodinepenetrationmethod'formeasuring
enamelporosityoftheincipientcariouslesions
wasdevelopedbyBakhosetal.(1977).
nPotassiumiodideappliedforaspecificperiodof
timetoawell-definedareaoftheenameland
thereaftertheexcessisremoved.
The iodine, which remains in the micropores, is
estimated and that indicates the permeability of
enamel.

35. UltravioletIllumination
nhasbeenusedtoincreasetheopticalcontrastbetween
thecariousregionandthesurroundingsoundtissue.
nNaturalfluorescenceoftoothenamel,asseenunderUV
lightilluminationisdecreasedinareasoflessmineral
contentsuchasincariouslesions,artificial
demineralizationordevelopmentaldefects.
nCariouslesionappearsadarkspotagainstafluorescent
background.
Advantages
moresensitivemethodthanthevisualtactilemethod.
Disadvantage
specificityisaproblembetweenthecariouslesionand
thedevelopmentaldefect.

36. FiberOpticTransIllumination(FOTI)
Principle:acariouslesionhasaloweredindexoflight
transmission,anareaofcariesappearsasadarkened
shadowthatfollowsthespreadofdecaythroughthe
dentine.
nconsistsofahalogenlampandarheostattoproducea
lightofvariableintensity.
n Twoattachmentsareused;aplanemouthmirror
mountedonasteelcuffandafiberopticprobeof0.5mm
diametersothatitcanbeplacedintheembrasureregion.
nItproducesanarrowbeamoflightfortransillumination.

37. Advantages
Nohazardsofradiations.
Non-invasivemethod
Simpleandcomfortableforthepatients.
Lesions,notdiagnosedradiographically,canbediagnosedbythis
method.
Usefulinpatientswithposteriorcrowding
Nottimeconsuming.
Disadvantages
 Permanentrecordsaredifficulttomaintainascanbekeptin
radiographs.
ItissubjectedtoIntraandInterobservervariations.
•Difficulttolocatetheprobeincertainareas.

38. RECENTMETHODSOFCARIESDIAGNOSIS
VISUAL EXAMINATION
MagnificationAids
•Loupes:providelargerimagesizeforimprovedvisual
acuity,whileallowingproperuprightposture.
Magnificationsusedare2X,3X,4.5X
Highermagnificationsystemsareheavier,expensiveand
requiremorelightthanlowerpowersystems.
Average working distance (focal length)13-14 inches.
•Dental microscopesallow the clinician to view intraoral
structures at a higher level of magnification.
Areas 1m in size can also be viewed to identify minute
decay.

39. DigitalFOTI
nResultantchangesinlightdistributionaslighttraversesthetoothare
recordedasanimageforanalysis.
nReducesshortcomingsofFOTI-combinesFOTI&digitalCCDcamera.
Images captured by the camera sent to a computer for analysis, which
produces digital images that can be viewed.
DIFOTItoconventionalradiographs
DIFOTItwicesensitiveindetectingapproximallesions&3timesas
sensitiveindetectingocclusallesionswithadifferenceoflessthan
10%inspecificity.
Buccal-linguallesions:sensitivity10timesthatofconventional
radiographs,againwitha10%lossofspecificity.
Detectincipientorrecurringcariesbeforetheyarevisibleon
radiographs.

40. EARLY DECAY LEAKING FILLING LATE DECAY
DIGITAL FIBEROPTIC TRANSILLUMINATION

41. Advantages:
•Instantaneousimageprojection
•Imagequalityiseasytocontrol
•Candetectincipientandrecurrentcariesveryearly
•Non-invasive
Disadvantages:
•Doesnotmeasurethedepthofthelesion
•Difficult to distinguish between deep fissure, stain and
dental caries.

42. Endoscope/Videoscope
PittsandLongbottom(1987)exploredtheuseofEFF
(Endoscopicfilteredfluorescence)methodfortheclinical
diagnosisofcariouslesions.
Principle:when a tooth is illuminated with blue light in the
wavelength range of 400-500 nm, sound enamel and
carious enamel demonstrate different fluorescence.
•Whenthisisviewedthroughaspecificbroadbandgelatin
filter,whitespotlesionsappeardarkerthansound
enamel.
•awhitelightsourcecanbeconnectedtoanendoscopeby
afiberopticcablesothattheteethcanbeviewedwithout
afilter-whitelightendoscopy.

43. Theintegrationofthecamerawithendoscopeiscalledavideoscope.
vAminiaturecolorvideocameraismountedinacustom-mademetal
mirrorholder.
vimageofthesurfaceofenamelcanbevieweddirectlyovera
televisionscreen.
Advantages
Itprovidesamagnifiedimage
Earlydiagnosisofincipientenamelcaries
Moreaccuratethanradiographs
Clinicallyfeasible.
Disadvantages
Requiresmeticulousdryingandisolationofteeth.
Timeconsuming
•Verycostly

44. Ultrasonicimaging
Principle:Theinteractionofultrasounddependsonthe
acousticpropertiesofthetissue,suchastheattenuation,
absorptionandscatteringimpedanceandvelocity.
Acousticparametersdependonthefrequencyof
ultrasoundaswellasotherparameterssuchas
temperature.
Thedemineralizationofenamelisassessedbyultrasound
pulseechotechnique.
thereisadefinitecorrelationbetweenthemineral
contentofthebodyofthelesionandtherelativeecho
amplitudechanges.
Ultrasound in ultrasonography is a sound wave with a
frequency ranging from 1.6 to about 10 MHZ.

45. Theultrasonicprobesendslongitudinalwavestothesurface
ofthetoothandalsoreceivesthewaves.
Normalenamelproducesnoechoes
•initialwhitespotlesionsproduceweaksurfaceechoes
•areaswithcavitationproduceechoesofhighamplitude.
Thismethodmaybemoresensitivethanvisual,tactileor
radiographicmethodsfordetectingearlycaries.

46. AIR-ABRASIVETECHNOLOGY
developedin1940s.TheS.SWhiteCompanyintroducedtheAirdentair-
abrasiveunitin1951.
Principle:uses a pressurized stream of microscopic non-toxic abrasive
powder, and rapidly removes enamel, dentine, decay and previous
restorations.
The scouring action can clean out both stains and organic debris and can
open areas of early caries for replacement with resin restorative
materials.

47. stained pits and fissures
Revealed hidden vein of decay
3-mm depth of the lesion

48. Advantages:
•minimizesheat,vibrationandbone-conductednoise.
•Patientstreatedwiththeair-abrasionsystemrarelyrequire
anesthesia.
•advantageinexaminingdarkenedareasinthebottomofpitsand
grooves.
•roughensthetoothsurface,leavingitsuitablefordirectbonding
techniqueswithoutacidetching.
Disadvantage:
•Notwell-suitedforremovingalldecay.Moistandresilientdecayed
dentincannotbeabradedeffectivelywiththeair-abrasionunit.
•cut dentin more readily than enamel, which allows overhanging
enamel to develop.

49. ElectricalresistanceorElectricalconductanceMeasurements
1878-Magitot:Soundtoothenamelisagoodelectricalinsulator
duetoitshighinorganiccontent.
Principle:
Cariousenamelhasameasurableconductivity,whichincreases
withthedegreeofdemineralization.
Caries/enameldemineralizationresultsinincreasedporosity.
Salivafillstheseporesandformsconductivepathwaysfor
electriccurrent.
Theelectricconductivityisdirectlyproportionaltotheamount
ofdemineralizationthathasoccurred.
Electricalresistanceismeasuringtheelectricalconductivity
throughthesepores.

50. 2instruments(1980s):
1.Vanguardelectroniccariesdetector.
2.CariesMeterL.
Measureelectricalconductancebetweentipofprobeplaced
inafissure&aconnectorattachedtoanareaofhigh
conductance.(Gingivaorskin)
scale:0to9forVanguardsystem.
4coloredlightsforCariesmeter:
nGreen-nocaries
nYellow-enamelcaries.
nOrange-dentincaries.
nRed-pulpalinvolvement.
To prevent polarization, both systems used a low frequency
alternating voltage, 25Hz and 400 Hz, respectively.

51. ELECTRICAL CARIES METER

52. Advantages
1.Veryeffectiveindetectingearlypitandfissurecaries.
2. Itcanmonitortheprogressofcariesduringcariescontrol
programme.
• Verdonschotetal:highsensitivity&specificityindiagnosing
occlusalcaries.(Comparedtoclinical,radiographic,FOTI)
•sensitivity-92%&specificity-82%.
Disadvantages
canonlyrecognizedemineralizationandnotcariesspecifically.The
hypomineralizationareasmaybeofdevelopmentaloriginorcarious
originwillgivesimilartypeofreadings.
Presenceofenamelcracksmayleadtofalsepositivediagnosis.A
sharpmetalexplorerisutilizedwhichispressedintothefissure
causingtraumaticdefects.
•Separate measurements are required for different sites making full
mouth examination quite time consuming.

53. 'ElectronicCariesMonitor'(Lodediagnostic,Groningen,the
Netherlands)
notonlydetectscariesatasinglepointontoothbutalsocan
screenwholeoftheocclusalsurfaceforcariesbycovering
thesurface
The sensitivity and specificity for ECM was 0.78 and 0.80 for
the diagnosis of occlusal dentinal caries and 0.65 and 0.73
for enamel lesions.
OtherUse:
Can be used to predict the probability that a sealant or a
sealant restoration will be required within 18-24 months.

54. RADIOGRAPHY
Xeroradiography:
nSimulatesthephotocopyingmachine.
nImageisrecordedonanaluminiumplatecoatedwitha
layerofseleniumparticles.
n Seleniumparticlesaregivenauniformelectrostatic
chargeandarestoredinaunitcalled“conditioner”.
nWhenX-raysarepassedontothefilm,itcausesselective
dischargeoftheparticles,whichformsalatentimage.
Thisisconvertedintoapositiveimageby“development”in
theprocessorunit.

55. Advantages:
TwiceassensitiveasconventionalD-speedfilmsandaphenomenon
of'EdgeEnhancement'ispossible.
Edgeenhancementmeansdifferentiatingareasofdifferentdensities
especiallyatthemarginsoredges.
Lessradiationexposure.
Nowetprocessing.
Bothpositiveandnegativeprintsarepossible.
Disadvantages:
Expensive
Theelectricchargemaycausediscomforttothepatientsincetheoral
cavityhasahumidenvironment,whichactsasamediumforflowof
current.
Theprocessofdevelopmentcan'tbedelayedandistobecompleted
within15minutes.

56. Digitalimaging
Adigitalimageisanimageformedandrepresentedbya
spatiallydistributedsetofdiscreteSensorsandPixels.
Whenviewedfromadistance,theimageappears
continuous,butcloserinspectionrevealsindividualpixels.
Digitalradiographscanbeobtainedby2methods:
•Video recording and digitization of conventional
radiograph.
•Direct digital radiograph.
Digital Image Receptor works on a charged couple device
(CCD), which is electronically connected, to a computer.

57. CCD
•asemiconductormadeupofmetaloxidessuchassilicon
thatiscoatedwithx-raysensitivephosphorous.
•sensitivebothtox-raysandvisiblelight.
•TheintraoralDIRisplacedinthemouthinsteadofthex-
rayfilm.
TheimageareaislimitedbythesizeoftheCCDpresentin
thedigitalimagereceptor.
Once the image is captured by the CCD, it can be can be
stored in the computer memory for image processing and
displayed for viewing.

58. RadioVisioGraphy(RVG):firstdirectdigitalradiographysystem
introducedin1989.(Trophy;Japan)
FlashDent(Villa;Italy)
SensARay(Regarn;Sweden)
Advantages:
1.Darkroomisnotrequired,instantimageisviewed.
2.Thequalityofimageisconsistent.
3.Eliminationofthehazardsoffilmdevelopment.
4.Radiationdoseisdecreased.
5.Capabilityforteletransmission
6.Imagecanbemagnified.Contrastanddensityofimagecanbe
enhanced.
Disadvantages
1.Highcostofsystem
2.ThelifeexpectancyofCCDisnotfixed.

59. nDigitalmodecanenhancedensityandcontrastupto
70%.
Digital method is 50% more sensitive in detecting occlusal
caries as compared to conventional films.
The Digoraimage plate system
•alternative to the CCD systems
•Radiographic information is recorded on a phosphorous
storage screen called the image plate.
•outer dimensions of the scanning unit are 483 X 452 X 135
mm.
•After exposure to radiation, the image plate is placed in a
scanner, which uses a laser beam to scan image. This is
then digitized and displayed on the computer screen.

60. Digora image plate system

61. Advantages:
•Image plate takes less than 30 seconds for the image to appear on the
computer screen.
•Wide exposure range.
•Image brightness and contrast can be adjusted
•Edge enhancement and gray scale inversion possible
•Different measurements can be made
Wenzeletal-compared(CCDbasedunits):
nTrophyRVG
nSens-A-Ray
nVisualix
nPhosporstorageplate(PSP)basedunits
Detection of occlusal caries: performed almost equally well.
Radiography is of no value in detection of initial enamel lesions or for
detection of approximal dentinal lesions, especially for lesions
confined to enamel.

62. Magnetic Resonance Micro-Imaging
Principle:proton of hydrogen ion behaves as small spinning
magnet and when placed in magnetic field, they tend to
move parallel to the field.
If a coil is now wound around a volume of proton, the tube
can be arranged to turn the magnetization through 90
(90pulse).
The protons now process at 90around the magnetic field at
the same frequency and induce a minute current in the
coil (Free Induction Decay) and lasts for some seconds.
This energy is utilized in scanning procedures

63. Highintensitysignalfromwaterpenetratedintotheporous
decayedregionsoftoothiscontrastedwithlackofsignal
frommineralizedtoothtissue,andthisallowsfor
visualizationofthepresenceandextentofcaries.
The black areaof the image: corresponds to the mineralized
tooth tissue,
(Martin M. Tanasiewicz et al.)
Panoramicradiographicsensitivityforcariesis18%,but41%
whencombinedwithbite-wingradiographs.This
sensitivityislowwhencomparedwithafullmouthseries
withoverallsensitivityof70%.
The specificity of diagnosis of healthy surfaces varies from
98% to 99% from panoramic, bite-wing and full series
radiographs.

64. TACT: TUNED APERTURE COMPUTED TOMOGRAPHY
•local computed tomography (CT) for caries diagnosis
has been demonstrated.
•produces stacks of axial and vertical slices of teeth
•caries diagnosis on vertically reformatted CT slices
was significantly better than on conventional
radiographs.
(Van Daatselaar et al2003)
In local CT the size of the beam is just enough to cover a standard
dental
CCD detector (roughly 6 cm
2
).

65. TACT requires multiple images of the same
object of interest –called source, basis or component
images–obtained from different projection angles.
TACTuses presumably larger amount of information
contained in the multiple views of an object while a
single plain film or digital radiography image uses the
presumably smaller amount of information contained
in a single view of this object.

66. ComputerImageAnalysis
nbasedonthe"expertsystem"whichcontainsfactsabout
thepathologicconditions.
nclinicianentersthepatient'sdataandtheprogramme
comparesthepatient'sdatawiththebasicknowledgeof
thepathology.
nprovidesagraphicvisualizationofthesizeandprogression
ofcariouslesionsespeciallyproximallesions.
Example: Trophy 97 Systemwith an integrated software-
Logicon Caries Detector.

67. Advantages:
1.mayprovidesensitiveandobjectiveobservationofsmallerlesions
whichotherwisearenotperceptibletonakedeye.
2.Itispossibletomonitorthelesion.
Disadvantages:
1.needforstandardizationofexposuregeometry.
2.Sensitivityishigherbutspecificityislesser.
3.Timeconsumingandlesseconomical.

68. DigitalSubtractionRadiography
Principle:
•Structurednoiseisreducedinordertoincreasethedetectabilityof
changesintheradiographicpattern.
•Structured noises are the images, which are not of diagnostic value
and interfere in routine interpretation of radiographs.
Digitization:achievedbytakingapictureoftheradiographusinghigh
qualityvideocamera.
fedtocomputerimagingdevice,termedas“digitizer”.
Twostandardizedradiographsproducedwithidenticalexposure
geometry:a
firstoneisthe‘ReferenceImage’andthesubsequentimagesarefor
comparison.
The reference image is displayed on the screen over which the
subsequent images are superimposed.

69. Thedifferencebetweentheoriginalandthesubsequent
imageswillshowasdarkbrightareas,whichcanbe
interpretedreadily.
nDigitizationturnstheimageintoaform,whichcanbe
readbythecomputer.
90% accurate in detecting as little as 5% mineral loss of bone
compared to the 30-60% of the mineral content of the
bone that has to be lost before a radiographic lesion could
be seen on a conventional radiograph.

70. LASERAUTOFLUORESCENCE(LAF)
nLightscattering:measureofobservedwhitenessofa
cariouslesion–correlatedwithdegreeofmineralloss.
nbacterialmetaboliteswithincariesproducefluorescence
thatcanbeenhancedbyalaserlight.
QLF(QuantitativeLaserFluorescence)isameansbywhich
thelaser-inducedfluorescencecanbemeasuredto
quantifytoothdemineralization.
nvisiblelighthasbeenusedasthelightsourceforthe
detectionofsmoothsurfaceandfissurecariesatanearly
stage.
(Bjelkagen et al., 1982).

71. The Oral Health Research Institute (OHRI) of the Indiana University
School of Dentistry has used two fluorescent dyes, Pyrromethane 556
and Sodium fluorescein, in conjunction with laser fluorescence for
detection of carious lesions.
Advantages
•Itisconvenientandarelativelyfastmethod.
•Cariouslesionscanbedetectedandtheirminerallossmeasured.
•Lesionswithadiameteroflessthan1mmandadepthof5-10mm
havebeendetectedandmeasuredwiththistechnique.
•Preventivemeasurescanbeevaluated.
•developedforquantificationofenamelchanges.
Disadvantages
•Expensive
•Cannot differentiate between caries, hypoplasia, stains and calculus.
•Cannot differentiate between active or inactive lesions.

72. Carioustoothstructureproducesconsiderablefluorescence,whichis
revealedasadigitalnumericalreadout(0-99)onthedisplay.
•Numericdatabetween5and25indicatedinitiallesionsintheenamel
•Valuesgraterthanthisrangeindicatedearlydentinalcaries.
•Advanceddentinecariesissaidtoyieldvaluesgreaterthan35.
For detection of dentinal caries,
sensitivity values 0.19 to 1.0
Specificity values 0.52 to 1.0.
In comparison with visual assessment methods, the DD exhibited a
sensitivity value that was almost always higher and a specificity value
that was almost always lower.
(JAMES D. BADER, DAN A. SHUGARS, 2004)

73. OpticalCoherenceTomography:
Principle:Basedonprincipleofconfocalmicroscopyandlow
coherenceinterferometry.
Initially,OCTreferredtolongitudinalimagingonlyandno
quantitativeanalysisbeenprovidedwithOCT.

74. AlternatingCurrentImpedanceSpectroscopyTechnique
sophisticatedapproachtolesiondetectionandmeasurement
istocharacterizetheelectricalpropertiesofthetoothand
lesionbyusingACIST,whichscansmultiplefrequencies.
Has 100% sensitivity and specificity at the D1 and only a
marginal decrease in specificity at D3 level
(Longbottom et al 1996).

75. INFRAREDTHERMOGRAPHY
Principle:Whenfluidislostfromalesionbyevaporation,
somechangestakesplaceinthethermalenergy,which
canbecomparedwithsoundtoothstructure.
determineslesionactivityratherpresenceorabsenceofa
lesion.
Advantages:
•showtargetsandsurroundingsincompletedarknessand
throughsmoke
•improvedvisionthroughfog
•worksequallywelldayandnight

76. TERAHERTZ IMAGING
Principle:Thismethoduseswaveswithterahertzfrequency
(10
12
orawavelengthofapprox30m).
Thiswave-formisshortenoughtoprovidereasonable
resolutionbutlongenoughtopreventseriouslossof
signalduetoscattering.
Effectiveness:
•relativetransparencyofhumantissuestoterahertzrays
•lowpowersusedforimaging
•noalterationoftheelectricalchargesofthetissues
examined

77. TERAHERTZ TECHNOLOGY

78. CONCLUSION
Presently, we are at crossroads in caries detection
where along with the conventional methods, the
newer methods of early caries detection are still
being developed or are not yet widely
disseminated.
Although currently there is no single diagnostic
method on the horizon that can reliably detect
precavitated carious lesions on all the tooth
surfaces, the prospects look favorable that, with
continued research, newer methods will provide
the high degree of sensitivity and specificity
needed to detect early dental caries.

80. Thank you