caries diagnosis

Caries diagnosis &Caries risk assessment

Dr.G.ThiruvenkadamPost Graduate

Department of Pediatric Dentistry

Presentation outline

• Introduction• Need for diagnosis• Diagnostic methods• Traditional methods• Newer technologies• Implications of newer technologies• Caries risk assessment• Caries activity tests• Conclusion• References

Introduction

• Merriam – Webster , 2003– Diagnosis, art or act of identifying a disease from its signs and symptoms

• Signs and symptoms of caries form a whole continuum of changes ranging from barely discernible at the ultra structural level to overt caries

• This raises the question of which lower threshold to use to distinguish between caries and no caries

• So far, this lower threshold has predominantly been determined by the limits of detection of the traditional diagnostic methods, i.e. what we are able to detect based on the visual-tactile examination or in bitewing radiographs

• Now this threshold is further lowered by newer diagnostic methods

Diagnostic threshold{Pitts & Longbottom,1995}

Early diagnosis and prompt treatment

• During the early stages of the disease the process is reversible and can be arrested– Non invasive intervention can convert a lesion from an active to an

inactive state[Featherstone,2008]

• Clinician needs to be able to– Monitor the outcome of non-invasive measures – Cases where there is evidence of lesion progression, make a timely

decision to intervene, using minimally invasive techniques – Restoring damaged tooth structure without weakening the tooth

• This modern, conservative approach to clinical management of dental caries has necessitated a critical appraisal of methods used today for clinical detection of carious lesions

Why do we diagnose?

• Knottnerus and Van Weel, 2001– Medical perspective

• Detecting and excluding disease• Assessing prognosis• Contributing to the decision-making process with regard to further

diagnostic and therapeutic management• Informing the patient• Monitoring the clinical course of the disease

• Dental perspective• To achieve the best health outcome for the patient by classifying caries

lesions corresponding to the best management options for each lesion type• To inform the patient• To monitor the clinical course of the disease

Diagnostic methods

Diagnostic methods

Traditional

1. Visual 2. Visual – Tactile

3. X-Ray – Bitewing

Advanced methods

Diagnostic methods

Visible light1. FOTI

2. DIFOTI3. QLF

X-rays1.Digital

subtraction2. Digital

image enhancemen

t

Laser 1.

DiagnoDent

Electrical current1.ECM

2. CarieScan

Ultrasound1. Ultrasonic

caries detector

Other methods

1.Midwest Caries I.D.

2. Polarization

sensitive OCT

Advanced methods

Visual method

• Most commonly used method• Easy technique that is routinely performed in practice• Has high specificity

– Proportion of sound sites correctly identified

• Has very low sensitivity– Proportion of carious sites correctly identified

• Has low reproducibility– Because of its subjective nature

• Use of detailed visual indices may improve sensitivity and reproducibility

Visual – Tactile method

Should be in a systemic manner

After isolation with cotton rolls and a suction device to prevent saliva from wetting the teeth

Begin with upper right molars upper left molars lower left molars lower right molars

No teeth or surfaces are missed

Visual-Tactile method

• Good lighting and clean, dry teeth• An initial non-cavitated enamel lesion is more easily disclosed

when tooth is dry, since the difference in the refractive index between carious and sound enamel is greater when water is removed from the porous tissue

• No standardized drying time, as the humidity and salivary flow differ from site to site and from person to person

Sensible use of probe

• If the teeth are heavily covered by plaque , it may be necessary to clean

• Presence of plaque covering a lesion may be of diagnostic value– Sticky adhering plaque covering a chalky/opaque enamel lesion is

strongly indicative of active caries

• Probe serves two purposes– To remove the biofilm to check for signs of demineralization and

surface break– To feel the surface texture of a lesion, as sensed through minute

vibrations of the instrument

• Probe tip 20-40˚ to the surface

Sensible use of probe

• Ekstrand et al 1987 one should definitely abstain from poking vigorously, there by running the risk of causing irreversible damage to the surface of the incipient lesion

• Lussi, 1993 histological evaluation has shown that gentle probing does not disrupt surface integrity of non-cavitated lesion

How to use the 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.

Caries predilection sites

• In every dentition there are sites that are at increased risk of lesion development

• Sites reflect the stagnation areas for dental plaque– Along the gingival margin– Occlusal fissures– Margins of restorations

Caries predilection sites

• Caries predilection sites vary distinctly according to age• Distal surface of first primary molar• Mesial surface of second primary molar

Preschool children

• Erupting first and second permanent , particularly occlusal surface

• Relatively long eruption period [ Carvalho et al., 1989]School years

• Distal surfaces of second premolars• Mesial surfaces of second molars [Mejare et al., 1999]Teenagers

• With gingival recession, root caries is more predominantElders

Some diagnostic systems…

• JACKSON,1950


• WHO,1987

• WHO,1997


• Pitts & Fyffe,1988


• Fejerskov et al, 1991 Root surface cariesCategory Description

1 Inactive lesion without surface destruction

2 Inactive lesion with cavity formation

3 Active lesion without definitive surface destruction

4 Active lesion with surface destruction, but not exceed 1 mm visually

5 Active lesion with cavity depth exceeding 1 mm, but not involving the pulp

6 Lesion expected to penetrate in to the pulp

7 Filling confined to root surface or extending from a coronal surface

8 Filling with an active secondary lesion along the margin

9 Filling with an inactive secondary lesion confined to the margin


• Pitts et al, 1997

• Ekstrand et al,1997


• Nyvad et al, 1998

Some other methods

• Tooth separation– Difficult to diagnose the cavity on contacting proximal surfaces– Orthodontic elastic separators are applied for 2 – 3 days– Separation increases the access to inspection and probing is improved– Disadvantages:

• Accessibility for inspection after tooth separation is not always improved• May create discomfort, especially in established dentitions • Requires an extra visit• Not recommended for routine use in dental practice

• Magnification– Magnification loupes- Head worn prism loupes (X 4.5) or surgical

microscopes(X 16) may be used– comfort, relatively inexpensive, available in various magnification

Finally…

• Caries activity assessment put forth by Nyvad et al is the best choice for performing a caries diagnosis– They reflect current evidence based management options for different

stages of caries lesion management– They have predictive value for lesion activity– Applied for all entities of caries, including root surface caries and

recurrent caries– In general, visual-tactile examination is quick and easy to perform

Bitewing radiography

• Introduced by Raper in 1925• Grondhal,1994 – when radiography is applied in the clinic for

caries detection, the recommended technique is bitewing projection

• For optimal image quality, a bitewing examination should– Involve an aiming device– Exposure to be kept “as low as reasonably achievable”

Radiographic scores (Mejare et al.,1985)

• R0 = No radiolucency• R1 = Radiolucency confined to outer half of enamel• R2 = Radiolucency in inner half of enamel + extending upto

but not beyond DEJ.• R3 = Radiolucency in dentin, broken DEJ, but with no obvious

spread in dentin• R3 = Radiolucency with obvious spread in outer half of

dentin.• R4 = Radiolucency with obvious spread in inner half of dentin

(> half way through to the pulp)

Disadvantages of bitewing

• Overlapping of approximal contact• Two dimensional representation• Cervical burnout may mimic cervical caries• False diagnosis of lesion depth{underestimates the depth)• Early stages of enamel lesion cannot be detected{30-40%

mineral loss}

Advantages of bitewing…

• Surfaces that are inaccessible to visual-tactile inspection• Depth of approximal lesion can be assessed and the relation to

the pulp can be estimated• Non invasive method

Key ages (Mejare.,2005)

•Undetected approximal lesions in primary molars

•Useful to exclude children with negligible risk of approximal caries

Age 5

•First permanent molar is in tight contact with second primary molar for about 2 years

•If found to be caries free, these children run a comparatively small risk of developing new approximal lesions for next 2-3 years

Age 8 - 9

•Fully erupted premolars and second molar

•Children judged as having negligible caries risk [good oral hygiene, dietary habits and no previous caries experience] excluded from bitewing examination

•This age is also useful for risk assessment

Age 12 - 14

•First 3 – 4 years after tooth eruption and establishment of approximal contacts

•A caries free 15 – 16 year old runs a very small risk of developing new lesions during the next three years

Age 15 - 16

Interval between bitewing examinations

• Based on individual risk assessment• Annual examinations should be considered in the following

situations

Age 5 – 7

• One or more approximal dentin lesion

• Several approximal enamel lesions in primary molars

Age 7 – 12

• A permanent first molar with approximal enamel caries

• Several approximal lesions in primary molars

Age 12 - 13

• One or more approximal dentin lesion

• Three or more approximal enamel lesions

• Recently restored approximal lesion

Digital radiography

• A digital radiograph is comprised of a number of pixels• Each pixel carries a value between 0 and 256, i.e ., 0 being

black and 256 being white• The values in between represents the shades of grey• Digital images with a potential of 256 grey levels has

significantly lower resolution than a conventional radiograph that contain millions of grey levels

• So digital radiographs have lower diagnostic yield than that of conventional radiographs

Digital image enhancement

• Digital radiographs offer the potential of image enhancement by applying number of algorithms

• When these enhanced radiographs are assessed their diagnostic performance is at least as good as conventional radiographs

• After image enhancement sensitivity and specificity increases to 0.95 and 0.83 respectively

Digital subtraction radiography

• One of the most promising technologies in digital radiography is the radiographic subtraction, which has been extensively evaluated for– Detection of caries– Assessment of bone loss in periodontal diseases

• Basic principle of subtraction radiology is that two radiographs of the same object can be compared using their pixel values

• The value of pixels from the first object are subtracted form the second image

• If zero, there is no change• Any value other than 0 must be attributable to either the onset

or progression of demineralization, or regression

Digital subtraction radiography

• Radiographs should be aligned perfectly or as close to perfect as possible

• Recent advances in software have enabled two images with moderate alignment to be correctly aligned and then subtracted

Physical properties

• Optical caries detection methods are based on observation of the interaction of energy which is applied to the tooth, or the observation of energy which is emitted from the tooth [Hall & Girkin,2004]

• Optical caries detection methods use light in the visible and near infra red range.

Physical properties

• Caries process leads to distinct optical changes that can be measured and quantified with advanced detection methods based on light that shines on and interacts with the tooth

Optical properties [Hall&Girkin,2004]

Fiber Optic Trans Illumination [FOTI]

• Fact : carious enamel has lower index of light transmission than sound enamel

• Light absorption is more when the demineralisation process disrupts the crystalline structure of enamel and dentin

• Uses bright light source• Has fiber optic illuminator, which is readily available at the

hand piece coupler • Used for detection of approximal and occlusal caries

Fiber Optic Trans Illumination [FOTI]

Carious tissue

Porosity

Illuminated by light

Scatters the light

Enamel

Darkened areas

Dentin

Dark, shadow

FOTI….

• Disadvantages– Only useful for approximal and occlusal surfaces– Not able to detect very early lesions– Not quantitative, and hence not useful as a caries monitor over time

Digital Imaging FOTI (DIFOTI)

• Digitized and computed version of FOTI• Used for detection of both incipient and frank caries in all

tooth surfaces• Also used to detect fractures, cracks, and secondary caries

around restoration

How this works?..

• Principle: carious tooth tissue scatters and absorbs more light than surrounding healthy tissue

• Uses white light to transilluminate the tooth• A single fiber-optics illuminator in the mouth piece delivers

the light• As this light travels through the layers of enamel and dentin, it

scatters in all directions toward the nonilluminated surface• The light is then directed through the mouth piece to a

miniature electronic charge coupled device camera in the handpiece

• The camera digitally images the light emerging from the tooth

Quantitative Light Fluorescence (QLF)

• Introduced in 1995• Uses natural fluorescence of teeth to discriminate between

caries and surrounding sound enamel• Auto fluorescence decreases with demineralization• QLF measures the percentage fluorescence change in

demineralised enamel with respect to surrounding sound enamel• Demineralised tissue limits the penetration of light due to

excessive scattering of photons• Light scattering of sound enamel is 10 times lesser than the

carious one• So, carious lesion is observed as dark spot surrounded by highly

luminescent sound enamel

QLF….

QLF….

• QLF system comprises of– Arc lamp which emits white light based on xenon technology– Special intra oral camera with CCD sensor connected to a computer– QLF software installed in the computer– Filters

• Blue – violet light with wavelength of 370nm is passed to the tooth through arc lamp

• A dental mirror is used to provide uniform illumination to the tooth surface

• The camera with CCD sensor has a yellow – transmitting filter (≥ 520 nm), which captures the fluorescent image of the tooth

• Captured image is then available for quantitative analysis using QLF software in computer

QLF…

• Decrease in percentage was determined by calculating the percentage of difference between the actual and reconstructed fluorescence

• Any area with a drop in fluorescence radiance of more than 5% - lesion

• Advantages– Uses ordinary white light source– Increased contrast between carious and sound enamel makes earlier and

faster detection of lesion– No danger to examiner or patient

• Disadvantages– High sensitivity, but low specificity– It cannot distinguish between caries, stains on tooth surface and white spots

due to developmental anomalies

DIAGNOdent

• This is a laser fluorescence system that detects changes in the tooth structure due to demineralization.

• These structural changes cause an increase in the fluorescence at specific excitation wavelengths.

• The intensity of the fluorescence depends upon the wavelength of the light as well as the structure and condition of hard dentinal tissues.

• DIAGNOdent with a laser diode that generates a pulsed 655 nm laser beam via a central fiber is transported to the tip of the device and into the tooth. .

DIAGNOdent

• When the incident light interacts with tooth substance, it stimulates fluorescent or luminescent light at longer wavelengths.

• The intensity of fluorescence is a function of the degree of demineralization or bacterial concentration in the probed region.

• The DIAGNOdent operates on the premise that a high level bacteria reading indicates a probability of having a decalcified enamel structure.

• This generated fluorescence light travels through the additional light fibers in to a microprocessor, which analyses and translates the signal in to an acoustic signal and shows a digital display of numerical values ranging from 0 – 99

DIAGNOdent

DIAGNOdent

• Hence, one weakness of this technology is that all bacteria, not only caries-related bacteria, produce fluorescence. A lot of organic and nonorganic materials such as stains, plaque and calculus, some prophy paste, food, and even the tooth itself can cause fluorescence.

• Advantages– Quantitative nature of its readings gives a basic guideline as to when to

intervene. – Decay in a patient can be followed longitudinally to monitor the extent

of the decay at every recall.

Electrical conductance - ECM

• This technology is based on the electrical conductivity differences between sound and carious dental tissues.

• ECM is based on the principle that electrical conductivity is a function of porosity.

• Demineralized enamel becomes more porous, fills with ion-containing fluid and minerals from saliva, and therefore exhibits increased electrical conductance (McComb & Tam, 2001).

ECM

• Since saliva is a better electrical conductor than enamel tissue, the conductivity increases with demineralization.

• On this basis, ECM measures the electrical resistance of a site on the tooth during controlled drying.

• By drying the tooth surface, the resistance is determined by the tooth structure, avoiding electrical conductance by surface liquid saliva

• High measurements indicate well-mineralized tissue while low values indicate demineralised tissue.

ECM

• The electrical conductivity of a tooth changes with demineralization even when the surface remains macroscopically intact.

• The entire occlusal surface is first covered with a conducting medium. Conductivity from the occlusal surface to a ground electrode is then measured with a probe

• Example of this device is the lode electronic caries monitor. • A major advantage of the ECM is to present objective

readings, which have the potential for monitoring lesion progression, arrest, or remineralisation

CarieScan

• Based on the technology of AC impedance spectroscopy and involves the passing of an insensitive level of electrical current through the teeth

• First diagnostic tool to use AC• Not affected by optical factors such as staining or

discolouration

CarieScan

• During measurement, it shows three different colours

• Green colour – sound tooth tissue• Red colour – deep caries requiring operative

treatment• Yellow colour – ranges from 1 – 99

– Depicts varying severity of caries, which requires preventive care

• Disadvantages:– Cannot be used to assess

• Secondary caries• Integrity of restoration• Dentinal root caries

Cone beam computed tomography

• Not been widely studied• Two systems are available

– NewTom 3G– 3DX Accuitomo

• NewTom 3G CBCT had lower diagnostic accuracy for detection of caries

• 3DX Accuitomo had higher sensitivity than intra oral systems• CBCT scanners are more accurate than dental periapical films

or panoramic X rays

Cone beam computed tomography

Mesio distal slicing Bucco lingual slicing

Ultrasound caries detector

• A novel ultrasonic detector of approximal caries (UCD) is based on the transmission of surface ultrasonic waves, discovered by Lord Rayleigh in 1885

• Principle: Sound waves can pass through gases, liquids and solids and the boundaries between them.

• The ultrasonic probe positioned at a specific angle relative to the inspected surface converts longitudinal waves to surface waves.

• The latter propagate uninterruptedly on smooth, flat, or curved surfaces. Sharp angles and interfaces present on the surface, distant to the area of contact with the ultrasonic probe, produce distinct echoes.

Ultrasound caries detector

• Because the amplitudes of the reflected ultrasonic surface waves are substantially greater than those of the background level, analysis of the wave profiles is relatively simple.

• UCD does not need to be applied directly to the area of interest on the tooth surface– Useful for detecting carious lesions

in areas such as the approximal site, which is inaccessible to ultrasonic devices

UCD, consisting of a PC-controlled ultrasonic pulse receiver and a probe attached to a handle. The signal appearing on the screen shows the acoustic reflection obtained from an approximal cavitated carious lesion.

Midwest Caries I.D

• Detects differences of optical behaviour inside the tooth related to change in the tooth structure

• Consists of infrared and red light emitting diodes and a fiber optic to distribute light

• A second fibre optic collects the light from the observed area to a photo detector that measures returned collected light

• This photodetector then• transmits the signal to a microprocessor

that compares signal• levels with defined parameters

Midwest Caries I.D

• If tooth is sound – green illumination• Carious teeth – red illumination• A buzzer also beeps with different frequencies to indicate the

intensity of demineralization• Detects 92% of occlusal and 80% of interproximal caries• Higher level of accuracy• Works in wet environment• Visual and Audible signals to indicate presence and location of

caries

Polarization sensitive OCT

• Demonstrated in 1991• Creates 2 D map of the tissue micro structure by illuminating

the tissue with low power near infra red light, collecting the back scattered light and analysing the intensity

• It produces image of tissue microstructure of the caries lesion over time

• Has the ability to quantitatively and qualitatively detect and monitor incipient enamel and root surface caries as early as 24 hrs in its development

• Staining , plaque, lighting, saliva will not influence the optical coherence tomography imaging

Polarization sensitive OCT

X-ray microtomography(in vitro)

• X-ray microtomography is a miniaturized version of computerized axial tomography

• In the biomedical field, it is particularly useful in the study of hard tissue because of its ability to accurately measure the linear attenuation coefficient.

• Microcomputed tomography allows for images of internal features to be constructed entirely upon their X-ray attenuation coefficients and enables the investigation of small samples at a resolution of a few micrometers.

• Nowadays, XMT has emerged as one of the non-destructive 3D analytical techniques in hard tissue research and has been used in various fields of dentistry including caries research

X-ray microtomography(in vitro)

In vitro methods

• Transverse micro radiography (TMR)• Longitudinal micro radiography (LMR)• Terahertz pulse imaging (TPI)

• Used to assess demineralisation and remineralisation in hard tissues

Caries detection dyes

• They selectively complex with carious tooth structure which is later disclosed with the help of fluorescence

• Aids in both quantitative & qualitative analysis of the lesionDYES 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

Caries detection dyes

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

Caries risk assessment

• An individualized risk assessment of an infant or toddler will help both health care providers and parents/caregivers identify and understand the factors associated with caries, so that a cooperative and proactive preventive care plan can be developed.

• Systematic assessment of caries risk guides the dentist in the decision-making process to establish treatment and preventive protocols for children with oral disease and for those deemed to be at risk

• Caries risk assessment and subsequent management of the disease in children is crucial due to the known fact that caries in primary dentition is a strong predictor of caries in the permanent dentition

Why CRA is important?

Gives an understanding of the disease factors for a specific patient and

aids in individualizing preventive discussions

Individualizes, selects, and determines

frequency of preventive and

restorative treatment for a patient

Anticipates caries progression or

stabilization

Fosters the treatment of the disease process instead of treating the

outcome of the disease

Caries balance concept

• The progression or reversal of dental caries is determined by the balance between pathological factors and protective factors

Pathological factors Protective factors

Antibacterials: Chlorhexidine, xylitol and others

Fluoride: Remineralisation with calcium and phosphate

Saliva flow and components

Frequent eating / drinking of fermentable carbohydrates

Acid producing bacteria

Subnormal salivary flow and function

CARIES NO CARIES

Caries risk assessment form

• It provides an easy way to compile and keep a record of the information that will aid the dentist in determining the infants caries risk

• Contains three major categories

Caries risk

Protective factors

Biological factors

Disease indicators

Biological factors

• Obtained from the caretaker interview

• Includes biological or life style factors that contribute to the development or progression of caries

Protective factors

• These are therapeutic factors, measures, and behaviours that, when used consistently, could reduce a child’s risk for ECC

Disease indicators

• These are findings , obtained during the clinical examination of the child, that are proven to have a strong correlation to the presence of disease

Risk category

• A risk assessment categorization of low, moderate, or high is based on a preponderance of factors circled on the caries risk assessment form

Risk category

Caries risk assessment form (0 – 5 years old)

Caries risk assessment form (˃ 6 years old)

Caries activity tests

• Measure the degree to which the local environment challenge (e.g. dietary effect on microbial growth and metabolism) favours the probability of occurrence of carious lesions

Some terms…

• Caries activity– Refers to the increment of active lesion (new and recurrent lesions)

over a stated period of time– Caries activity is a measure of speed of progression of a carious lesion.

• Caries susceptibility– Refers to the inherent tendency of the host & target tissue, the tooth to

be affected by the carious process– This is the susceptibility (or resistance) of a tooth to a caries producing

environment

Requirements of caries activity tests

• Test should be reproducible & valid• There should be good correlation between the caries activity

scores & actual caries development• Should be simple• Results should be obtained rapidly, within hours or few days• Should have measurement of mechanisms involved in caries

process• Should be inexpensive, non-invasive & applicable to any

clinical setting

Lactobacillus colony count test

• Hadley, 1933• Principle:

– Estimates the no of acidogenic and aciduric bacteria in the patient’s saliva by counting the number of colonies appearing on agar plates

• Method:– Saliva is collected by chewing paraffin before breakfast– The specimen is vigorously shaken and after that 0.1 cc of sample is

withdrawn– Dilute and undiluted samples are then spread evenly over a agar plate

– The plate is incubated for 4 days & no. of lactobacillus colonies that

developed are counted.

No of organisms

1-1000

1000-5000

5000-10,000

More than 10,000

Symbolic designation

+

+ ++

+++/++++

Degree of caries activity suggested

Little or none

Slight

Moderate

Marked

Calorimetric caries activity test

• Snyder, 1951• This snyder’s test measures the ability of salivary

microorganisms to form organic acids from a carbohydrate medium.

• Snyder’s medium consists of:– Casein– Yeast extract– Dextrose– Agar– Bromocresol green

Snyder’s test

• Method– Saliva is collected by having the subject chew paraffin. – A tube of Snyder glucose agar is melted and then cooled at50°C.– 0.2ml of saliva is added to the agar tube. – The Snyder agar tube with saliva is incubated at37°C.– The colour change of indicator is observed after 24,48 and 72 hours

Snyder’s test

24 hrs 48 hrs 72hrs

Color : yellow yellow yellow

Caries activity: marked definite limited

Color : green green green

Caries activity: continue test continue test continue test

Ora test

• Rosenberg et al in 1989• Principle

– Rate of oxygen depletion by micro organisms in expectorated milk samples– In normal conditions the bacterial enzyme, aerobic dehydrogenase transfers

electrons to oxygen and oxygen get utilized– Once utilized , methylene blue acts as an electron acceptor and get reduced to

leuco methylene blue

• Method:– Mouth rinsed vigorously with 10 ml of sterile milk for 30 seconds and the

expectorate is collected– 3 ml of is transferred to a screw cap tube and 0.12 ml of 0.1 % methylene blue is

added– Tube is observed for colour change for every 10 min

• Inference:– Higher the infection , lesser was the time taken for the change in colour

Swab test

• Advantage is no collection of saliva is necessary• Valuable in evaluating caries activity in very young children• Principle is same as Snyder test• The oral flora is sampled by swabbing the buccal surface of

tooth with cotton.• The change in the pH following a 48 hour incubation period is

read on a pH meter

pH Caries activity

≤ 4.1 Marked caries activity

4.2 – 4.4 Active

4.5 – 4.6 Slightly active

˃ 4.6 Caries inactive

Dentocult

• Dentocult SM Strip mutans provides easy detection of mutans streptococci from a saliva sample and plaque.

• The method is based on the use of a selective culture broth and the adherence and growth of mutans streptococci on the test strip

Dentocult

• Saliva:– Let the patient chew a paraffin

pellet to stimulate the secretion of saliva and to transfer mutans streptococci from tooth surfaces into the saliva. Press the round-tipped test strip against the saliva on the patient’s tongue.

• Plaque: – Obtain a sample from an

interproximal site or a tooth surface and spread it on the square-tipped test strip.

Dentocult

• Place the strips, attached back to back to the cap, in the selective culture broth and recap the vial

• Incubate at 35-37°C for 48 hours with caps slightly open. Interpret the result.

Other methods

• S.Mutans level in saliva test• Dip slide method for S.Mutans count• Salivary buffer capacity test• Salivary reductase test• Alban test• S,Mutans screening test• Fosdick calcium dissolution test

Cariostat

• Cariostat, was designed to measure the pH decrease caused by microorganisms in the plaque sample obtained from the buccal surfaces.

• Incubation was done on MS and MSB plates in an atmosphere of 95 percent N and 5 percent CO at 37 degrees C and for 48 hours

• As a calorimetric test, it determines the ability of the acid producing bacteria in dental plaque to change the colour of the supplied medium from dark blue to varying shades of blue, green and yellow

Cariostat

Colour pH inference

Blue (0) 6.1 +/- 0.3 Caries inactive

Green(1) 5.4 +/- 0.3 Slight caries activity

Yellow-green(2) 4.7 +/- 0.3 Moderate caries activity

Yellow(3) 4.0 +/- 0.3 Marked caries activity

Cariogram

• A new model for understanding the interactions of various factors leading to development of caries

• The computer version of the Cariogram presents a graphical picture that illustrates a possible overall caries risk scenario.

• The program contains an algorithm that presents a ‘weighted’ analysis of the input data, mainly biological factors.

• It expresses the extent to which different etiological factors of caries affect the caries risk for a particular individual and provides targeted strategies for those individuals.

• The Cariogram does not specify the particular number of cavities that will or will not occur in the future.

Caries related factors

Cariogram

• According to its built-in formula, the program presents a pie diagram where – ‘bacteria’ appears as a red sector– ‘diet’ as a dark blue sector – ‘susceptibility’ related factors as a

light blue sector– ‘circumstances’ are presented as a

yellow sector– ‘chance of avoiding caries’ as

green sector

Conclusion

Additional diagnostic methods, although some are quantitative , may used as an adjunct to visual inspection

To be used in practice, these methods must be better than clinical – visual and radiographic examination.

They must be convenient to use, not too expensive and the values must be reproducible

Of the methods we discussed today digital radiography and Diagnodent seem to be suitable for detection of caries in routine dental practice

However , the dentist should always remain responsible for the interpretation of the measurements and those measurements should be

considered and weighted against other relevant observations

References

• Essentials of preventive and community dentistry- Soben peter• Dental caries – ole Fejerskov and Edwina kidd• Fundamentals of pediatric dentistry by Richard.J.Mathewson• Pediatric dentistry:principles and practice by M.S Muthu and

N.Sivakumar• Cariology – Earnest Newburn• Clinical Diagnosis of Dental Caries: A Perspective - Nigel B Pitts • Shlomo Matalon. Detection of cavitated carious lesions in

approximal tooth surfaces by ultrasonic caries detector. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103:109-13

• A.I. Ismail. Visual and Visuo-tactile Detection of Dental Caries. J Dent Res 2004;83(Spec Iss C):C56-C66

References

• Gimenez T, Braga MM, Raggio DP, Deery C, Ricketts DN, et al. (2013) Fluorescence-Based Methods for Detecting Caries Lesions: Systematic Review,Meta-Analysis and Sources of Heterogeneity. PLoS ONE 8(4): e60421

• Iain A. Pretty. Caries detection and diagnosis: Novel technologies. j o u r n a l of de n t i s t ry 3 4 ( 2 0 0 6 ) 72 7 – 73 9

• Bennett T. Amaechi. Emerging technologies for diagnosis of dental caries: The road so far. JOURNAL OF APPLIED PHYSICS 105, 102047 2009

• Mariana M. Braga. Detection Activity Assessment and Diagnosis of Dental Caries Lesions. Dent Clin N Am 54 (2010) 479–493

References

• Guideline on Caries-risk Assessment and Management for Infants, Children, and Adolescents – AAPD

• Caries risk assessment, prevention, and management in pediatric dental care - Francisco Ramos-Gomez

• Dental Caries Detection and Caries Management by Risk Assessment - JOEL H. BERG

• N.B.Pitts. Modern Concepts of Caries Measurement. J DENT RES 2004 83: C43

• Wenzel. Bitewing and Digital Bitewing Radiography for Detection of Caries Lesions. J DENT RES 2004 83: C72

• Lussi. DIAGNOdent: An Optical Method for Caries Detection. J DENT RES 2004 83: C80

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