Dental Caries diagnosis /certified fixed orthodontic courses by Indian dental academy

CARIES
DIAGNOSIS
INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education

www.indiandentalacademy.com

CONTENTS
 INTRODUCTION
 DEFINITION
 ASSESSMENT TOOLS
 CONVENTIONAL METHODS OF DIAGNOSIS
 RECENT METHODS OF CARIES DETECTION
 CARIES RISK ASSESSMENT
MODERN CONCEPTS OF CARIES
MEASUREMENT
POTENTIAL NEW DIAGNOSTIC MODALITIES
 CONCLUSION

INTRODUCTION

Thirty two white horses on a red hill,
Champing, stamping, they never stand still!
- What am I?


What is diagnosis?
Diagnosis is an art and science that results from the
synthesis of scientific knowledge, clinical experience,
intuition & common sense
Caries diagnosis implies deciding whether a lesion is
active, progressing rapidly or slowly or whether is
already arrested
Signs: Clinical examination
Supplemental test
Symptoms: Anamnestic information
↓
Diagnosis
↓
Treatment planning


ASSESSMENT TOOLS
Stepwise progression toward diagnosis &
treatment planning depends on thorough
assessment of the following
 Patient History

 Clinical examination

 Nutritional analysis

 Salivary analysis

 Radiographic assessment


HIGH RISK LOW RISK
Social History
Socially deprived Middle class
High caries in siblings Low caries in sibling
Low knowledge of caries High dental aspirations
Medical History
Medically compromised No such problem
Xerostomia
Long-term cariogenic
medicine
Dietary habits
Sugar intake: frequent Infrequent


HIGH RISK LOW RISK
Use of fluoride
Non-fluoridated area Fluoridated area
No fluoride supplements Fluoride supplements used

Plaque control
Poor oral hygiene Good oral hygiene
maintenance maintenance
Saliva
Low flow rate& buffering Normal flow rate& buffering
capacity capacity
↑ S.mutans & lactobacillus ↓ S.mutans & lactobacillus
counts counts

HIGH RISK LOW RISK
Clinical evidence
New lesions No new lesions
Premature extractions No extraction for caries
Anterior caries restorations Sound anterior teeth
Multiple/repeated No/few restorations
restorations
No fissure sealants Fissure sealed
Multi-band orthodontics No appliances


CONVENTIONAL METHODS OF
CARIES DETECTION
 VISUAL-TACTILE METHOD
 RADIOGRAPHY
 CARIES DETECTING DYES
 FIBEROPTIC TRANSILLUMINATION
 ELECTRONIC CARIES MONITOR

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VISUAL-TACTILE METHODS
Visual methods:
 Detection of white spot, discoloration / frank cavitations
 Without aids, unreliable
 Magnification loupes- Head worn prism loupes (X 4.5) or
surgical microscopes(X 16) may be used
comfort, relatively inexpensive, available in various
magnification
 Use of temporary elective tooth separation

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G.J. Mount classification
Classified caries according to the site and size of the
lesion and it is represented in the form of two digits.

Site of caries
SITE 1 ----- PIT AND FISSURES
SITE 2 ----- APPROXIMAL SURFACE
SITE 3 ----- CERVICAL AREAS

Size of caries
SIZE 0 ----- Small and early enough to be remineralized
or the lesion has been remineralized and there is just
residual stain. ‘Zero’ means no restoration needed.
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SIZE 1 ---- Minimal dentinal spread that can
be remineralized.
SIZE 2 ----Moderate involvement of dentine.
SIZE 3 ----Enlarged, with weakened cusps or incisal
edges that needs protection.

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Tactile methods:
 Explorers are widely used for the detection of carious
tooth structure
- Right angled probe- no.6
- Back action probe- no.17
- Shepherd's crook- no. 23
- Cowhorn with curved ends- no.2
 Dental floss

History of use of explorers
1942- G.V Black:
passing the explorer into pits, noting whether or not
there is any softening & whether the instrument catches
or enters any point
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1956- Simon:
recognize marginal changes around a previously
placed restoration, accomplished with a mirror & explorer
1982- Gilmore:
susceptible site can be entered by use of a small
sharp explorer
1985- Marzouk:
Sharp explorer- pressing the tip into pits & fissures
will cause it to penetrate the enamel &/ or dentinal caries
cone, making a definitive diagnosis
1985- Sturdevant:
defects are best detected when an explorer provides
a tug back / resistance on removal
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Use of explorer is not advocated
because;
 Sharp tips physically damage small
lesions with intact surfaces
 Probing can cause fracture & cavitation of
incipient lesion. It may spread the
organism in the mouth
 Mechanical binding may be due to non-
carious reasons
Shape of fissure
Sharpness of explorer
Force of application
Path of explorer placement
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Use of explorer
• Explorer is useful to remove plaque
and debris and check the surface
characteristics of suspected carious
lesions.
• gentle pressure just required to blanch
a fingernail without causing any pain
or damage
• All surfaces of a tooth are cleaned of
debris and plaque, using an air
syringe and examined visually.
Suspicious areas are explored to
check for the surface texture.

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SMOOTH SURFACE CARIES
Non- cavitated:
 No signs of cavitation after visual or
tactile examination.
 Location: where dental plaque
accumulates (gingival margin).
 Surface characteristics: Matted (not
glossy) when a tooth is dried.

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 Areas of demineralization
not in close proximity to the gingival
margin
not covered by plaque
smooth and glossy
are non-cavitated
not active non-cavitated carious lesions.
 Visual enamel opacity under sound
marginal ridge indicate undermined enamel
due to dental caries
non-cavitated carious lesion in dentin
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Non-cavitated carious lesion
ENAMEL DENTIN

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Cavitated Lesions:
 Where there is visual breakdown of a tooth
surface, it is classified as cavitated carious
lesion. An active cavity on a smooth surface
has soft walls or floors shown below:

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Questionable Area:
 All stained smooth coronal tooth surfaces that do not
have the characteristics of non-cavitated or cavitated
lesions are classified as questionable shown below

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Non-Carious Enamel Opacities

Opacity not fluorosis Moderate Fluorosis

Mild Fluorosis Severe Fluorosis
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Caries in Pit or Fissure Surfaces

 All discolored areas should be explored using gentle
pressure.
 There is no need to penetrate a suspected lesion with an explorer.
 If a discolored and non-cavitated area is soft when
explored, it is recorded as non-cavitated carious pit or fissure.
 A cavity is detected when there is an actual hole in the
tooth in which an explorer could easily enter the space.
 An active cavity has soft walls or floors (detected using
gentle exploring).

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 If there is visual enamel opacity under an ostensibly
sound or stained pit or fissure, then the enamel is
undermined because of dental caries and the tooth
surface is classified with a non-cavitated carious lesion in
dentin.

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Pit and Fissure Caries
Non-cavitated carious lesion

Enamel Enamel

Enamel www.indiandentalacademy Dentin
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Cavitated Carious lesion

 If a discolored area is hard when gently explored
then it should be marked as questionable.

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Root Caries
• Root surface caries comprises of a continuum of
changes ranging from minute discolored areas
to cavitation that may extend into the pulp
For diagnostic purpose; they may be:
 Active root surface lesion:
• well-defined area showing yellowish or light brown
discoloration
• covered by visible plaque
• presence of softening/ leathery consistency on
probing with moderate pressure

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 Inactive root surface lesion (arrested):
• well-defined dark brown/ black discoloration
• smooth and shiny
• hard on probing with moderate pressure
Active lesion

Questionable

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Arrested Caries
 Arrested (remineralized) lesions can
be observed clinically as intact, but
discolored, usually brown or black
spots.
 The change in color is presumably
due to trapped organic debris and
metallic ions within the enamel.
 These discolored, remineralized
lesions are intact and are highly
resistant to subsequent caries .
The arrested caries need not be
removed.

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Recurrent caries
 It is diagnosed whenever there is softness due
to caries at a defective margin, and when the tip
of a periodontal probe (WHO probe) can enter
the defect without any resistance.
 A restoration with a discolored margin or a small
marginal ditch (<0.5 mm or the head of the WHO
or PSR probe) is recorded as an early recurrent
carious area. A larger defect should be
classified as advanced recurrent carious area

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 There are two valid indicators of recurrent
(secondary) caries:
• softness at the margin of a filling that is detected
using an explorer or
• presence of a large defect (a minimum diameter of
0.4 mm) at a margin of a filling with softness in the
area.
 Large defects are associated with a high level of
colonization with cariogenic bacteria. Marginal
discoloration by itself is not a valid sign for
dental caries.

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Advanced Recurrent Carious lesions

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Nursing bottle caries Vs Rampant caries
Specific form of rampant caries Acute, widespread caries with
early pulpal involvement of
teeth that are usually immune to
decay
Primary dentition affected Both dentitions affected

C/F: specific pattern- maxillary Rapid appearance of new lesions
incisor →molars Mandibular incisors also
Mandibular incisors not affected affected

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RADIOGRAPHY
 Carious lesions are detectable radiographically
when there has been enough demineralization to
allow it to be differentiate from normal
 They are valuable in detecting proximal caries
which may go undetected during clinical
examination.
 On average they have around 50% to 70%
sensitivity in detecting carious lesions.
 40% demineralization is required for definitive
decision on caries


 Radiographic examinations include;
Bitewing radiographs
IOPA radiographs using paralleling technique
Dental panoramic tomograph

 The two important decisions related to
radiographic examination are (1) when to take a
radiograph and (2) how to evaluate a radiograph
for presence of signs of dental caries.


PIT & FISSURE CARIES
Incipient occlusal lesions:
Not very effective.
Caries starts on the walls of
the pits & fissures and tends
to spread perpendicular to the
DEJ
Only detectable change is a
fine gray shadow at the DEJ.
A similar, but a narrower
shadow is seen below the
occlusal enamel – Mach
Band

Moderate occlusal lesions:
First to induce specific changes
helping in a definitive diagnosis
Broad based, thin radiolucent
zone in dentin with minimal or
no changes in enamel
Presence of a band of increased
opacity between the lesion and
the pulp chamber due to
calcification within primary
dentin
This feature is not seen in
buccal caries


Severe occlusal lesions:
Readily observed both
clinically and
radiographically
Appear as large cavities in
the crowns of the teeth
However pulp exposure
cannot be determined


PROXIMAL CARIES
Density along the proximal surface is high
which does not permit the detection of loss of
small amounts of mineral content
Incipient lesions:
Commonly seen in the caries-
susceptible zone
Presents as a notch on the outer
surface not involving more than half
of enamel
Diagnosis can be missed, best
viewed under a magnifying glass.

Moderate proximal lesions:
Involve more than outer half of
enamel but do not extend into
DEJ
May have one of type of
appearance:
67% - triangle with broad base
towards outer
surface
16% - a diffuse radiolucent
image
17% - combination of both

Advanced proximal lesions:
Radiolucent triangular cone
invading into the dentin
In addition, it spreads along
the DEJ and subsequently into
dentin
This forms a 2nd cone with base
at DEJ
Does not involve more than
half of dentin
In some cases, lesions
penetrated into dentin may
appear not to have penetrated
enamel

Severe proximal lesions:
Penetrating more than half
of dentin
Narrow path through
enamel, an expanded
radiolucency at DEJ, with a
progress towards pulp
Lesions may or may not
appear to involve pulp
Undermined enamel
fractures under masticatory
load leaving a large cavity

Facial & Lingual Caries
 They start as round lesions and
enlarge to become elliptical or
semilunar
 Presence of well defined non-
carious enamel around
radiolucency
 When superimposed on DEJ,
they may mimic occlusal caries
 Clinical examination helps in
definitive diagnosis


ROOT SURFACE CARIES

 Also called cemental caries
with an incidence of 40%- 70%
of the aged population
 Buccal, lingual, proximal
 Usually it is a lesion of dentin
associated with recession
 Ill-defined, saucer-like
radiolucency


RECURRENT CARIES
 Occurs immediately next to
restorations
 Results from microleakage or
residual caries
 Incidence- 16%
Radiolucency depends on amount of demineralization
& extent of restoration
Mesio/disto-gingival & occlusal margins- clearly seen
Under facial/ lingual restorations-difficult to detect
Materials like Ca(OH),composite & silicate cements


OTHER RADIOGRAPHIC SHADOWS
 Radiolucent Cervical Burn out:
- Evident at the neck of tooth
well demarcated above by
enamel cap& below by alveolar
bone level
- It is triangular in shape
being less apparent at the center
of tooth
-good alveolar bone height
will enhance cervical burn-out
 Radiopaque zone beneath amalgam restorations

Tin & zinc ions are released into underlying
dentin

Pitfalls Of Radiography
 2 dimensional view of 3 dimensional object
 Radiographic depth of a lesion is often less than
actual depth
 Overlapping of proximal surfaces on a
radiograph
 Occlusal (incipient) caries of enamel difficult to
detect
 Dental anomalies like hypoplastic pits mimic
proximal caries
 Cervical burnout often confused with root caries


XERORADIOGRAPHY
 It is similar to photocopy machine
 Consists of Aluminum plate coated with selenium which
provides a uniform electrostatic charge
 X- rays → selective discharge of particles → Latent
image
 Processing unit: Latent image → positive image
 Very good Edge enhancement i.e., differentiating areas
with different densities
 Twice more sensitive than D speed film, but equivalent
to E speed film
 Disadvantages:
Electrostatic charge may cause patient discomfort
Processing to be completed by 15 minutes

DIGITAL IMAGING
 A digital image is an image formed & represented by a
spatially distributed set of discrete sensors & pixels
 2 types of non- film receptors
Direct digital imaging – digital image receptor
Indirect digital imaging – video camera for forming
digital images of a radiograph
 Two types of detectors are used in Direct digital imaging
Photostimulable phosphor ( PSP) –barium
fluorohalide
Charged couple device (CCD) – silicon
 Image is stored on a computer


DIGITAL IMAGING

Schick System Digora System Trophy System


Manipulation of images
1. Magnification
2.Variable contrast
3. variable density
4. Labeling important information
5. Highlighting and colorization
Advantages:
1.Images are available in seconds
2. Exposure is reduced 50-90%
3. Image size, contrast and density can be manipulated to
improve interpretation
4. Record keeping is vastly improved. All films are labeled,
filed and retrieved easily. Duplicate hard copies are the
same as originals and simple to make
5. Provision of teletransmission

SUBTRACTION RADIOGRAPHY
 Structured noise is reduced in order to increase the
detectablity of changes in the radiograph
 Structured noise refers to the information on the
radiograph which have not diagnostic value
 It requires 2 identical images. The subtracted image is a
composite these two, representing a difference in their
densities
 Sensitive enough to detect changes of 0.12 mm
 90% accurate in detecting mineral loss of 5%
 Black end of gray scale suitable for proximal & recurrent
caries
 Contrast can be enhanced with color aid.


COMPUTER IMAGE ANALYSIS
 Softwares have been developed for automated
procedures which are able to overcome the short coming
of human eye
 Software supports an operation whereby a threshold is
set up by the examiner which determines the program’s
display of lesion probability
 Tuned Aperture Computed Tomography (TACT) involve
the tomosynthesis of structures in 3D thereby increasing
the accurate detection of caries
 Useful for monitoring carious lesion
 Increased sensitivity but decreased specificity


DYES FOR CARIES DETECTION
 They selectively complex with carious tooth structure
which is later disclosed with the help of fluorescence
 Aids in both quantitative & qualitative analysis of the
lesion
DYES FOR ENAMEL CARIES:
Procion: N2 & (OH) groups irreversibly complex
with caries
Acts as a fixative
Calcein: complexes with calcium & remains bound
to the tooth
Zyglo ZL-22: fluorescent tracer dye, not used in vivo
Brilliant blue: 10% aqueous Brilliant Blue, not used in
vivo

DYES FOR DENTIN CARIES:
 1% acid red 52 in propylene glycol complexes specifically
with denatured collagen, hence used to differentiate
infected and affected dentin
 Iodine penetration method (Pot iodide) for evaluating
enamel permeability

DISADVANTAGES
• Dye staining and bacterial penetration are independent
phenomena, hence no actual quantification
• They also stain food debris, enamel pellicle, other organic
matter
• Dye aided carious removal- laborious
• Stains DEJ


FIBEROPTIC TRANSILLUMINATION
 Different index of light transmission for
decayed & sound tooth. Decayed tooth
structure has decreased index &
appears dark
 The tooth is illuminated using
fiberoptics
 Have a high level intra & inter-examiner
variability
 Digital imaging FOTI introduced,
images captured by a CCD camera &
fed into the computer for image analysis
 DIFOTI can detect caries on all types of
teeth & also detect incipient & recurrent
caries before their visibility on
radiographs

ELECTRIC MEASUREMENTS FOR CARIES
 First proposed by Magitot in 1878
 Tooth demineralization due to caries
process causes increased porosity of
tooth structure. This porosity contains
fluid containing ions. This leads
increased electrical conductivity,
conversely, leads to decreased
electrical resistance or impedance
 ECM device uses a fixed-frequency
(23 Hz)alternating current which
measures ‘bulk resistance’ of tooth


 Two systems
Vangaurd system – 25 Hz – ordinal scale of 0 –9
Caries meter L – 400 Hz – 4 colored lights
green –no caries yellow – enamel caries
orange – dentin caries red –pulp involvement

 ECM limited to occlusal sites.ECM to H/P- 97%
accuracy
 Cannot be used where amalgam filling is present
 Materials have different responses at different
frequencies. Electrical Impedance Spectroscopy
(EIS) operates over different frequencies & thus
determine more accurately these differences. EIS can
be used on both occlusal & proximal surfaces

Factors affecting electrical measurements
1. Porosity
2. Surface area
3. Thickness of the tissues
4. Hydration of enamel
5. Temperature
6. Concentrations of ions in the dental tissue
fluids


RECENT ADVANCES IN CARIES
DETECTION
 Research in the past two decades has lead to the
development of new technologies that asses changes in
fluorescence of enamel & dentin due to loss of mineral
 Benedict- 1929, normal teeth fluorescence
 Optical methods used are
Quantitative light- induced fluorescence- QLF™
Infrared laser fluorescence - DIAGNOdent


ORIGIN OF FLUORESCENCE
SOUND ENAMEL:
 Baseline fluorescence is a result of inorganic matter &
organic molecules
 Whiter teeth < darker teeth

 Fluorescence is a result of absorption ie, electrons move
to higher states following absorption & fall back to their
original states , emitting energy in form of light
 False positives:

Calculus
Composite restoration
Remnants of polishing paste
Stains


CARIOUS ENAMEL:
 Light scattering in lesion- light path shorter than that in
enamel
 Light scattering acts as a barrier for the excitation light
penetrating dentin
 Besides scattering of light, bacteria & their metabolites
can contribute to fluorescence
 Proved by agar diffusion test

 Bacterial metabolites like protoporphyrins &meso-
porphyrins produce intense fluorescence in red spectral
region


Quantitative Light-induced Fluorescence
 Detection of carious lesion & quantifying mineral loss
Argon ion laser(488nm) / Xenon arc lamp
Blue light transmitting filter
↓
Fluorescence of enamel- demineralized areas appear as
dark spots
↓
Passes thro’ high pass filter
↓
Captured on CCD
↓
Transferred to computer thro’ a frame grabber

• Hardware consists of:
measurement probe – transmits monochromatic light
Control unit – illumination device & imaging
electronics
Computer fitted
with frame grabber – digitalize image from CCD
• Qlf software for quantitative image analysis
Lesion Area in mm2
Lesion depth in percentual loss of
fluorescence (DF%)
Lesion volume in nm3 (DQ)
• Good reliability & reproducibility


 acquiration of measurement results
with high precision and
repeatability; easy use, reliable
software measurement cycles
 The contrast between
demineralised enamel and sound
enamel has almost increased by a
factor ten
 other things can be detected and
quantified also, like dental plaque,
calculus, and staining


Applications:
 Quantify in situ effects of fluoride treatments on
demineralization of enamel lesion
 Monitor caries activity in orthodontic patient

 Evaluative caries preventive measures in caries
prone patients
 Longitudinal quantification of incipient caries lesion
on smooth surface
 QLF technology must be combined with visual
examination in order to detect hypocalcified area
due to development defects, fluorosis


DIAGNODENT - KAVO
 Spectral investigation of carious
teeth revealed that good contrast
between sound and carious
enamel
 Fluorescence: carious teeth >
sound teeth
 Intensity of fluorescence: 655nm <
488nm (QLF)
 But contrast between sound &
carious tooth is better in 655nm
 Infra-red rays are less absorbed by
enamel , hence penetrate deeper
into dentin & fluoresce carious
dentin

Component parts:
 Laser diode – 655nm, modulated at 1mW peak power
- excitation light source
- modulated to eliminate long λ ambient
light also passing thro’ the filter
 Photodiode + long pass filter
- detector
- transmission >680nm
long pass filter – absorbs back scattering
 Optical fiber – transmit excitation light
- bundle of 9 fibers arranged concentrically
around the optical fiber
 Digital display – quantitatively analyze fluorescence


Procedure.
1. Clean tooth surfaces preferably with an air polishing
device (e.g. PROPHYflex) to completely remove
plaque, stains and calculus from fissure areas.
2. Dry the tooth.
3. Perform clinical examination
4. Diagnose and evaluate quantitative measurement of
DIAGNOdent


Use of DIAGNOdent:
 Baseline value: record fluorescence of sound spot
on the smooth surface of tooth. This value is the
subtracted electronically from the fluorescence on
the site to be measured
 Occlusal tip & smooth surface tip
 Maximum fluorescence value is indicated by rising
tone
 Decision making for operative intervention

set peak value at 30, ↓sensitivity but ↑specificity
safety fraction for stained fissures/ calculus


Interpretation of values:
Display Therapy:
value:

0 - 14 No special measures.

15 - 20 Usual prophylactic measures.

21 - 30 More intensive prophylaxis or
restoration: indication is dependent
on
•caries activity.
•caries risk.
•recall interval, etc.

from 30 Restoration and more intensive
prophylaxis.

Uses of DIAGNOdent:
 To measure both sensitivity & specificity of lesions
 Detection of occlusal & accessible smooth surface
caries
 Decision making for operative intervention
 Reproducible method for caries detection epsl at D2
& D3 levels
 Longitudinal monitoring of caries

Disadvantages:

• Measures false positives
• Not useful in approximal caries detection
• Lack of repositioning systems that may affect
reproducibility of results

CARIES RISK ASSESSMENT
 Clinical examination neither predicts caries activity
nor susceptibility
 Certain simple reliable lab tests can facilitate
this,which is important because;
- need & extent of personalized preventive measures
- index for therapeutic measures
- patient education
- manage progress of restorative procedures
- identify high risk groups / individuals

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Requisites of tests
 Correlation between predicted & actual caries
development
 Reliability & validity
 Simple to perform
 Quick results
 Measurement of mechanism involved in caries
process

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Caries activity Vs Caries susceptibility
 Caries activity refers to the increment of active
lesions
 Susceptibility refers to inherent propensity of the
host & target tissue affected by caries
 Most of the tests measures the former
 Caries activity tests measure either the quantity of
specific bacterial group or their ability to produce
acids. Hence this must be coupled with clinical
examination prior to treatment planning.

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Caries Activity Tests
Lactobacillus colony count test:
 Introduced by Hadley in 1933
 Stimulated saliva collected & diluted with distilled
water. Spread evenly on Rogasa’s SL agar plate.
Incubated at 37°C for 3-4 days. No.of colonies
developed counted
No.of org/ ml Degree of caries activity
0 – 1000 Little / none
1000 – 5000 Slight
5000 – 10,000 Moderate
> 10,000 marked
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Calorimetric Snyder test:
 Measures the ability of micro organisms to form
organic acids in carbohydrate
 0.2 ml of patient’s saliva is pipetted into melted
medium at 50°C. Incubated for 72 hrs. medium
contains bromocresol green which changes color
from green to yellow in the range of pH5.4 – 3.8

24 hrs → 48 hrs → 72 hrs
If yellow If yellow If yellow
Marked caries Definite caries Limited caries
activity activity activity
If green If green If green
Observe – 48hrs Observe –72hrs Caries inactive
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Swab Test:
 Developed by Grainger in 1965
 Based on the principle of Snyder test
 Swab is taken from the teeth & incubated in
medium
 pH change after 48 hrs is read on a pH meter

pH 4.1or less Marked caries activity

pH 4.2 – 4.4 Active

pH 4.5 – 4.6 Slightly active
pH 4.6 0r more Caries inactive
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Salivary buffer capacity:
 Tests the buffering capacity of bicarbonate ion in
saliva
 2 ml of stimulated saliva + 4 ml of distilled water
 Set up is placed under paraffin seal to prevent loss
of volatile bicarbonate ion
 Micro-burette & micro glass electrode are
introduced under the seal & the amount of 0.5 N
HCl required to bring saliva to pH 5 is measured
 Samples requiring less than 0.45 ml of HCl indicate
low buffering capacity & vice-versa

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Saliva-Check BUFFER:
 Checking pH level & salivary buffering capacity of
resting & stimulated saliva
 The kit consists of pH strips 5.0 – 8.0 & buffering
strips
 Resting salivary analysis is made by asking the
patient to expectorate any pooled saliva
 Stimulated saliva is obtained by asking the patient
to chew paraffin wax for 30 sec
 Samples collected are tested with the strips
available in the kit
 Buffer strips contain 3 rows test pads. Salivary
sample is pipetted onto each of these pads. Color
change noted after 5 min
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pH analysis: Results in 10 seconds

Color change pH range
Red 5.0 – 5.8
Yellow 6.0 – 6.6
Green 6.8 – 7.8

Buffering capacity analysis: Results 5 min
Color change on each of the test pad is noted &
points are assigned accordingly
Green – 4 pts Blue/ Red – 1 pt
Green/ blue – 3 pts Red – 0 pt
Blue – 2 pts .com

Interpreting results:

Combined total Buffering ability

0–5 Very low

6–9 Low
10 – 12 Normal/ high

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Alban test:
 Simplified substitute of Snyder test
 Alban test medium – 60 g Snyder test agar + 1 liter
water
 Patient to expectorate saliva in test tube containing
Alban test medium. Incubated at 37°C upto 4 days
 Tubes are observed daily for:
- change of colour from green to yellow
- depth in the medium to which change has
occurred

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Scale for scoring:
color change is noted After 72 hrs/ 96 hrs of
incubation
1. No color change
2. Beginning of color change = +
(from top to bottom)
3. One half color change = ++
4. ¾ color change = +++
5. Total color change = ++++

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Caries Susceptibility Test
Enamel solubility test:
 When glucose is added to saliva containing
powdered enamel, organic acids are formed. This will
decalcify enamel leading to an increase in soluble Ca
ions
 Amount of Ca obtained gives a direct measure of
caries susceptibility
Salivary reductase test:
 Measures the activity of reductase enzyme in salivary
bacteria
 Kit commercially available- Treatex
 Salivary sample mixed with Diazoresorcinol dye
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 Color changes are tabulated after 15 min

Color Caries conduciveness
Blue in 15 min Non- Conducive
Orchid in15 min Slightly Conducive
Red in 15 min Moderately Conducive
Red immediately on Highly Conducive
mixing
Colorless in 15 min Extremely Conducive

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CARIOGRAM
 Introduced by Bratthall to assess factors contributing
to development of caries
 Consists of a pie diagram divided into 5 sector
- Green – estimation of the chance to avoid caries
- Dark blue – Diet
- Red – bacteria- amt of plaque & S. mutans
- Light Blue – Susceptibility- combination of F
program Saliva secretion & buffering
capacity
- Yellow – Circumstances- past caries experience &
related disease

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MODERN CONCEPTS OF CARIES
MEASUREMENT
 Modern means accepted in dental research & practice
 Concepts of caries measurement must be seen as
theoretical frameworks based on both synthesized
evidence & contemporary practice
 Caries; to be seen as a continuum of disease states
ranging from subclinical, subsurface changes to more
advanced stages with microscopic & later macroscopic
cavitation & finally significant involvement of dentin
 Caries Measurement is how defined stages of caries
process are quantified, graded & recorded


This involves 7 linked steps:
1.Caries detection:
- essentially a yes / no decision
- result depends on: true state of tooth surface,
detection potential of method used
method’s accuracy & reliability
influence of detection threshold
2. Lesion measurement:
- Diagnostics threshold- What is diseased & what is
sound?
- this is given by the ‘Iceberg of dental caries’


Iceberg of dental caries with diagnostic threshold

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3. Lesion monitoring by repeated measures:
- used at a series of examinations when lesions are
less advanced than that which requires operative
intervention
- helps in decision making for preventive care aiming
at arrest or reversal of the lesion
4. Caries activity measurements:
- poorly developed as compared to other aspects
- ideally be able to measure dynamic activity of
individual lesion to differentiate its current behavior
from historical signs of past caries progression


5. Diagnosis, prognosis & clinical decision making:
- information from steps 1-4 are synthesized
- helps to derived stage of lesion & patient
circumstances which would translate into restorative
treatment decision
6. Interventions / Treatments:
-this is again given by ‘Iceberg of dental caries’ &
contemporary treatment need/ advice


7. Outcome of caries control / management:
- success in arresting & reversing initial lesion as
well as in preventing the development of cavitated
dentinal lesions


POTENTIAL NEW DIAGNOSTIC
MODALITIES
Light is a suitable tool for the study of teeth.
Disrupted surfaces scatter light passing into tooth.
In addition to scattering, changes may include
absorption & fluorescence
MULTI-PHOTON IMAGING
INFRARED THERMOGRAPHY
INFRARED FLUORESCENCE
OPTICAL COHERENCE TOMOGRAPHY
ULTRASOUND
TERAHERTZ IMAGING


MULTI-PHOTON IMAGING
 QLF uses single ‘blue’ photon to excite fluorescence
 MPI uses many infrared photons thus increasing the
chance of absorption of atleast two photons resulting in
fluorescence
 Ultra-short pulses (100fs) of 850nm laser light
generated at 200MHz results in two photon effect, which
is recorded in a particular focal plane
 Fluorescence for sound tooth > carious tooth
 Plane of focus can be moved thro’ the lesion & record
sectional images to form a 3D image
 Caries appears dark in a fluoresced tooth. Negative
images can be used to highlight the lesion

 MPI can measure lesion depths to 500 µ
 Gives a quantifiable measure of mineral loss in 3
dimensions
 Decreased laser power used in MPI ensure low risk of
photo-toxicity to pulp & increased depth of penetration
 Only in-vitro studies conducted. Requires future research
to develop laser equipment used for clinical practice


INFRARED THERMOGRAPHY
 Described by Kaneko et al in 1999. Measures lesion
activity not presence / absence of caries
 This measures the thermal changes when fluid is lost
from a lesion by evaporation. Thermal energy emitted by
sound tooth structure is measured with that emitted by
carious tooth structure
 Indium / antimony thermal sensors, detect temperature
changes close to 0.025°C
 Source to sensor distance – 20cm, & time taken to
capture an image – 2 min
 Not used intra-orally : variations of temp in mouth due to
respiration or fluid evaporation from tissues
 Detection of proximal caries - questionable

INFRARED FLUORESCENCE
 Seldom reported. In theory, tooth is exposed to light with
a λ between 700 & 15,000nm. Barrier filters are used to
observe any fluorescence
 Longbottom suggested that this technique discriminates
bet sound & carious tooth structure (unpublished)
 Further studies are required to determine
- intensity of fluorescence signal
- heating effects on pulp due to↑ penetration & ↓
scattering
- sources that provide specific coherent irradiation
- infrared sensitive detector – CCDs / films


OPTICAL COHERENCE TOMOGGRAPHY
 This is used for imaging transparent & semi transparent
structures
 OCT uses light & measures scattering & hence depth of
penetration for imaging technique
 Based on interference of light
 Uses Super Luminescent Diodes as light source.
Spectral bandwidth of light source determines depth of
resolution
 Measure of scattering on single point on the tooth is
called an “ A-scan”. Several A-scans along a line gives a
tomogram called a “B-scan”


For an A-scan to be produced, light from source passes
thro’ a beam splitter
↓
two coherent beams produced- sample beam & reference
beam
↓
sample beam hits the tooth & gets scattered, part of it get
back scattered
↓
the reference beam hit a movable mirror & reflected back-
here it is combined with the back- scattered beam
↓
degree of interference is read by a photo detector


 By moving the beam thro’ 20µ on the sample results in a
tomographic scan / B- scan
 Wavelengths of 840 to 1310nm have been used resulting
in imaging depths of 0.6 to 2 mm
 Depth resolution varies from 10 - 17µ
 Development of intra-oral hand piece for OCT, underway
 OCT has also be used in analysis of restoration tooth
interface
 Has its’ implication in non-invasive diagnosis of
secondary caries


ULTRASOUND
• This has been used for the past 30 years & has
undergone tremendous change for the past 5 yrs
• Sound waves are pressure waves that have the ability to
travel thro’ gases, liquids & solid
• Ultrasound waves have frequency > 20,000 Hz that
undergo scattered, reflected, refracted & absorbed
• There is a difference in acoustic impedance between 2
surfaces at the interface which is interpreted by the
difference in the reflected sound waves
• The amount of reflected sound waves provide
information of the reflecting interface & time taken for
sound to be reflected provide info of the position of
reflecting surface under study

• Ultrasound waves are produced by AC applied to a
piezo-electric crystal. This travels thro’ a coupling
medium which delivers waves to the surface. Those
used in dentistry are water / glycerin
• Detection of DEJ / dentin-pulp interface – the waves are
delivered directly to the surface
• Detection of caries – waves travel along the interface of
air & enamel
• Flexible tips, wedge shaped for proximal areas
• Effective in detecting proximal caries that were missed
on radiograph
• Strength of reflected waves: cavitated lesion > non-
cavitated
• Also detects dentin involvement in intact surface enamel


TERAHERTZ IMAGING
 Uses waves of terahertz frequency – 1012 Hz & λ - 250µ
 Short enough to provide reasonable resolution but long
enough to prevent loss of information due to scattering
 Photo-conducive emitters / certain crystals like Zn
tellurite when exposed to short pulses of visible light/
infrared light, emit waves of terahertz frequency
 Reflected waves are detected with the help of photo-
conducive detectors like a CCD
 Adverse thermal effects thought to be unlikely
 Low signal : noise ratio facilitates clear imaging
 But long wavelength can reduce spatial resolution
 Terahertz waves are strongly absorbed in water, which
may complicate its use in the oral cavity

Conclusion
“ the complete divorcement of dental
practice from studies of pathology of dental
caries, that existed in the past, is an
anomaly in science that should not
continue. It has the apparent tendency
plainly to make dentists mechanics only”


References
 Art & science of operative dentistry – Sturdevant 4th
edition
 Understanding Dental Caries – Gordon Nikiforuk
 Textbook of Clinical Cariology – Thylstrup 2nd edition
 Operative Dentistry - Schwartz
 Principles of Radiology – White & Phoroah
 Essentials of radiology – Eric Whaites
 Journal of dental research – September 2004
 Caries Research Journal – 2000-04

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References
 DCNA- Cariology – Vol 43, Oct 1999
 Caries diagnosis, Risk assessment & management-
- School of dentistry, University of Michigan
 Textbook of paedodontics – Shoba Tandon
 Textbook of operative dentistry – Vimal Sikri
 Essentials of community dentistry – Soben Peter

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THANK YOU

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