Diagnosis of Dental caries / dental implant courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
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Introduction
Dental caries is a microbial disease of the calcified
tissues of the teeth characterized by
demineralization of the inorganic portion and
destruction of the organic substance of the tooth.
The carious process can be viewed as a complex,
multifactorial interaction between the tooth, oral
microorganisms and fermentable carbohydrates,
with factors like saliva and fluoride playing key
roles in this dynamic interplay.

According to WHO system:
Shape and depth of caries region can be scored
on four point scale (D1 to D4)
D1: Clinically detectable enamel lesion with intact
surfaces
D2: Clinically detectable cavities limited to enamel
D3: Clinically detectable lesions in dentin with or
without cavitations of dentin
D4: Lesion into pulp

The process of caries diagnosis involves assessing the
caries risk of an individual and applying different
diagnostic methods.
Each method uses one or all of the following:
1. Assessment of environmental conditions such as
pH, salivary flow and salivary buffering.
2. Determination of bacterial activity.
3. Identification of subsurface demineralization.

Caries risk assessment: involves assessment of
environmental conditions, bacterial activity, age,
gender, fluoride exposure, general health of the pt
and his ability to maintain a good oral hygiene.
Subsurface demineralization: can be identified
by various diagnostic methods, of which most
commonly used are visual examination, tactile
examination and radiographic examination.

Various diagnostic aids used for dental
caries:
 Visual method
 Visual tactile method with light, mirror , and gentle probing
 Meticulous clinical visual method involving floss
 Visual method with temporary elective tooth separation with /
without impression of approximal lesion.
 Caries activity test
 Radiographic methods
 Electrical conductance method
 Fiber-optic transilluminition (FOTI) method
 Quantitative laser fluorescence method
 Ultraviolet illumination
 The endoscopic filtered fluorescence method
 Ultrasonic detection
 Dye penetration method

Visual Method (European method)
Commonly used method
Teeth are cleaned and dried with compressed
air and illuminated with adequate light source.
It includes looking for cavitation, surface
roughness opacification and discoloration.
Problem using this method – discolored pits and
fissures, which is a universal finding in normal
adult teeth, may be mistaken for caries.

Radiographic MethodsConventional Radiography
Xero-Radiography
Digital Imaging
Subtraction Radiography
Computer image analysis
Radiographic examination has great value in detection
and determination of those carious lesions which are not
readily determined by clinical examination.
Examination for dental caries can not be considered
adequate without properly conducted radiographic
examination.

Limitations of Radiograph:
Two dimensional image of three dimensional objects, so sometimes
interpretation becomes difficult.
Does not disclose earliest stages of caries development (30-40%
demineralization is required to be detected).
Occlusal lesion, many a times becomes impossible because of solid
buccal and lingual cusps.
To some degree, radiographs underestimate the extent of carious
lesion, but overestimation may also occur as result of projection
errors.
Fracture at the cusp may appear as the approximal cavity.
Radiographic diagnosis is subjective and the interpretation of
radiographic findings is subject to inter observer and intra observer
variations.
Difficult to diagnose occlusal, facial, lingual decay and non cavited
carious lesions on the root surfaces.
It cannot distinguish between an arrested (demineralized scar) or
active lesion. Only a second R/G taken at a later time can reveal
whether the lesion is active.

Advantages of Radiographic carries assessments:
Discloses sites inaccessible to other diagnostic
procedures.
Depth of the lesion can be evaluated.
Provides permanent records and helps in
accessing progression of lesion in recall
appointment.
Non-invasive procedure.

Conventional Radiography
Involves intra oral periapical radiographs and
conventional bitewing radiographs.
Periapical radiographs obtained with paralleling
technique – are useful for detecting the changes about
the roots and in between the teeth.
Conventional bitewing radiographs are used for diagnosis
of incipient lesions at the contact points, and recurrent
caries at the cervical margins of restorations, since
central ray is directed along the direction of cervical
areas.
Bitewing radiographs is useful in monitoring and
evaluating the progress or arrest of caries.
Care should be taken to standardize positioning,
exposure and processing conditions.

Bitewing Radiograph IOPA Radiograph

Radiographic appearance of caries:
Occlusal caries:
Occlusal lesion when confined to enamel, surrounding enamel often
obscures the lesion- so visual or tactile detection is considered best.
As caries progresses, a radiolucent line extends along the DEJ.
As dentine is involved- the classic appearance can be seen as – broad
based, radiolucent zone, often beneath a fissure, with little or no
apparent changes in the enamel.
D/D- superimposition of the image of the buccal pit, with or without a
carious lesion – simulate an occlusal caries.
- mach band effect- this is an optical illusion seen as a more R/L
region immediately adjacent to the enamel, due to the sharply defined
density difference between enamel and dentine.
- internal resorption.
Advanced occlusal caries in dentine – will show a band of increased
opacity between the caries and the pulp chamber. This white band
represents calcification within the primary dentine (not evident in
buccal caries).

Interproximal caries:
Since the proximal surfaces of the posterior teeth are broad, the loss
of small amount of mineral (incipient caries) becomes difficult to
detect.
Early caries may appear as – notch, dot, band or a thin line. As it
progresses, a classic triangle with its broad base at the tooth surface
can be seen.
As it reaches the DEJ, it spreads along the junction, frequently
forming the base of a second triangle (wider than the enamel) with
the apex directed towards the pulp chamber.
More irregular shapes of decalcification can be seen.
D/D- cervical burnout- seen on the mesial and distal aspect of the
teeth in the cervical regions between edge of enamel cap and crest of
alveolar ridge. Whereas, caries susceptible zone is a broad area of 1-
1.5mm between the contact point and the free gingival margin.
- hypoplastic pits and concavities produced by wear.

Buccal and lingual carious lesions:
Occur in enamel pits and fissures and are initially round and as they
enlarge become elliptical or semilunar.
Demonstrate sharp well defined borders – representing parallel non-
carious enamel rods surrounding the buccal or lingual lesions.
Cannot differentiate between a buccal or lingual lesion.
D/D – occlusal caries- these are more extensive and outlines are not
well defined.
Root caries / cemental caries / senile caries:
These are associated with gingival recession, involving cementum and
dentine.
Observed within 2mm area of CEJ, as an ill-defined saucer like
appearance.
Can be easily detected clinically, except the proximal root surface
lesions.
D/D – cervical burnout- root caries cad be detected by the absence of
intact root edge image and diffuse rounded inner border where the
tooth substance has been lost.www.indiandentalacademy.com

Secondary and residual caries:
Carious lesions developing at the margins of an existing
restoration are termed secondary or recurrent caries,
whereas the caries that remains if the original lesion is not
completely removed is the residual caries.
Initial lesions or lesions next to the restorations are best
detected clinically, and should be differentiated from the
discolorations due to extrinsic stains and corrosion
products.
Recurrent lesions at the mesiogingival and distogingival
margins are detected R/G.
D/D – radiolucent restorative materials – eg. Calcium
hydroxide without barium, lead, zinc, composite, plastic &
silicate restorations.
R/G they can be differentiated from caries by their well-
defined and smooth outline reflecting the preparation.

Xero-Radiography
It simulates photocopying machine.
Image is recorded on aluminum plate coated with a layer of selenium
particles.
Ability to have both positive and negative prints together.
It has the Edge Enhancement property i.e.differentiating areas of
different densities especially at the margins or the edges.
Xeroradiography is twice as sensitive as D speed films and
comparable with speed E film of conventional radiography.
Disadvantages:
Electric charge over the film causes discomfort to the patient as
the oral cavity is humid which cats as a medium for the flow of the
current.
Exposure time varies as manufacturers do not indicate the exact
thickness of plate.
The process of development can not be delayed and is to
completed within 15 min.

Digital Imaging
An image formed and represented by spatially distributed
set of discrete sensors and pixels.
Two types of non film receptors to record digital images:
Digital Image receptor (DIR) collects X-Rays directly (Direct
Digital Imaging)
Video Camera for forming digital images of a radiograph
(Indirect Digital Imaging)
Direct imaging receptor (DIR) works on charged couple
device.

CCD is sensitive to both X-rays and visible light.
It is helpful in detecting lesions in dentin.
Digital radiographic system commercially available are:
(Image Receptor Size)
Radio Visio Graphy (RVG) 19 X 28 mm
(Trophy – Japan)
Flash Dent (Villa – Italy) 20 X 24 mm
Sens –A- Ray (Regam - Sweden) 17 X 26 mm
Vixa (Gendex – Italy) 18 X 24 mm
Studies have shown that the diagnostic accuracy for
detecting caries is similar for conventional and digital
images.

Advantages of Digital Imaging:
Darkroom not required, instant image is viewed.
Quality of image is consistent.
Density and contrast upto 70% can be enhanced.
Greater exposure latitude.
Signal to noise ratio is high.
Elimination of need of film development.
Radiation does is decreased.
Capability for tele-transmission.
Disadvantages:
High cost of system.
The life expectancy of CCD is not fixed.

Subtraction Radiography
It is a technique by which structured noise is reduced in
order to increase the detectability of changes in the
radiographic pattern.
Structured noises are images which are not of diagnostic
values and interfere in routine interpretation of
radiograph.
Presently, Digital subtraction radiography (DSR) is used.
Digitization is achieved by taking a picture of the
radiograph using a high quality video camera and fed to
the computer imaging device, termed digitizer.

Two standardized radiographs with identical exposure
geometry are used.
The first one is ‘Reference Image’. Subsequent images
are for comparison.
The reference image is displayed on the screen. Then
the subsequent images are superimposed. The
difference between the reference image & the
subsequent images will show as dark bright areas, which
can be interpreted readily.
Approximal carious lesions are clearly visible by digital
subtraction solution.
DSR are also useful in detecting the progress of
remineralization and demineralization patterns of dentinal
caries. ( Halse et al , 1990)

Computer image analysis
 Softwares have been developed for automated interpretation of
digital R/G in order to standardize image assessment.
 These programs are based on the “expert system” which contains
facts about the pathologic conditions.
 The clinician enters the pts data and the programme compares
the pts data with the basic knowledge of the pathology and tells
about the possible diagnosis and other ailments.
 Advantages: Automated analysis may provide sensitive and
objective observation of smaller lesions which may not be
perceptible to naked eyes. Possible to monitor the lesion
 Disadvantage: there is always need for standardization of
exposure geometry. It is time consuming and less economical.

Fiber-optic Transilluminition (FOTI) Method
It woks under the principle that since the carious lesion
has lowered index of light transmission, an area of caries
appears as a darken shadow that follows the spread of
decay through the dentin.
It is regularly used to for diagnosis for proximal caries in
incisors and premolars.
Recent study, (Vaarkamp et al, 1997) showed that use of
FOTI allowed quantitative diagnosis of early enamel
caries.
Study (Verdonschot et al, 1991) have shown that FOTI
was more useful than bitewing radiograph for
detection of enamel lesions.

Transilluminated view of small proximal carious lesion

Advantages :
No radiation hazards
Simple and
comfortable for patient
Lesion Can not be
diagnosed radio
graphically.
Less time consuming
Disadvantages:
Permanent records are
difficult to maintain.
It is subjected to Intra
and inter observer
variation
Difficult to locate probe
in certain areas

Digital Fiber Optic Transilluminition
Irivington, NewYork
This technique uses digital imaging fiberoptic
tranillumination whereby the transient light image is
recorded by a Charge-Couple Device (CCD) digital
camera.
The resultant changes in the light distribution captured by
the camera are send to computer for analysis.
Advantages : more accurate in assessing shadow of
caries and more sensitive in detecting early lesions when
compared to R/G.

Digital imaging fiber-optic
transillumination device

Electrical Conductance Method
Magitot 1987
Principle: sound tooth enamel is a good electrical
insulator, due to its high inorganic content. Caries /
enamel demineralization results in increased porosity.
Saliva fills these pores and forms conductive pathways for
electric current. Thus electric conductivity is directly
proportional to the amount of demineralization.
Two instruments have been designed- Van Guard
Electronic caries detector and Caries Meter L.
Both instruments measure electrical conductance
between the tip of a probe placed in the fissure and a
connector attached to an area of high conductivity
(gingiva or skin).

The electrical conductivity is expressed in numerical scale
of 0-9 for the Van Guard system and four colored lights
for the caries meter (green=no caries, yellow= enamel
caries, orange= dentine caries and red= pulpal
involvement).
Moisture and saliva shd be removed by air stream
(minimum 7.5L/min) in Van Guard system and Caries
Meter required the pits and fissures to be moistened with
saline to ensure good electrical contact and minimize the
effect saliva.
Show high sensitivity & specificity (than fissure
discoloration and FOTI) for early, non-cavitated occlusal
enamel lesions.

The Electronic Caries Monitor

Advantages:
Very effective in detecting early pit and fissure caries
Monitor the progress of caries
Disadvantages:
It can only recognize demineralization and not caries
specifically
Presence of enamel cracks may leads to false positive
diagnosis.
Time consuming.
Newly erupted teeth of less than 18 months exposure
will give false positive result.

Quantitative Laser Auto Fluorescence
(QLAF) Method
Visible light has been used as the light source
for detection of smooth surface & fissure caries
at an early stage. ( Bjelkagen et al, 1982)
Tooth is illuminated with broad beam of blue
green light of 488 nm wavelength from an Argon
ion laser.
This fluorescence of enamel in yellow region
(540nm) is observed through a yellow high pass
filter to exclude the tooth scattered blue light
De-mineralized area appears dark in this region.

De-mineralized tissue absorb dyes like fluorol TGA,
sodium fluorescein etc & fluoresce strongly. This is
referred to as dye enhanced laser fluorescence.
Advances include – a technique which involves micro
camera to capture real images and display on the
computer screen.
Recently Diagnodent (kavo) a laser fluorescence device
is introduced which contains diode laser.(655nm)
It helps in analysis of non cavitated enamel & dentinal
lesions on buccal, lingual & occlusal surface.
- Lussi et al, 1999
Study (Shixq, Welander U, Angmar- Mansson B., 2000
Showed that accuracy of DIAGNO dent was
significantly better than that of radiography for occlusal
lesions.

Study (Ross G., 1999)
Showed that the device could diagnose pit and fissure
lesions with 92% accuracy.
Study (Lussi A. Pitts N et al, Ionwinkelried, 1999)
Reported that DIAGNO dent has higher diagnostic
validity than ECM (Electronic Caries Monitor) for
occlusal caries and good in vitro reproducibility of
findings.
This all study suggest that laser devices could be
valuable tools for the longitudinal monitoring of caries and
for assessing the outcome of preventive interventions.

Advantages:
It is convenient & relatively fast method.
Carious lesion can be detected and mineral loss
measured.
Disadvantage:
Accuracy may be affected by preexisting restorations.
Cannot detect approximal and secondary caries.

Dye Penetration Method
Dyes are diagnostic aids for detecting caries in
questionable area i . e . Locating soft dentin that is
presumably infected.
Fusayama (1972) introduced a technique – use of basic
fuschin red stain to aid in differentiating layers of carious
dentin, but because of carinogeniety was replaced by
acid red, which show equal effectiveness.
Demineralised dentine in which the collagen has been
denatured is stained while the inner one remains
unstained.
Clinicians have good success with acid red 50, 51,54.
Some products contain red & blue disodium disclosing
solution. (e.g. Cari D-Tect, Gresco products, Stafford,
Texas)
These products stains infected caries dark blue to bluish
green.

Dyes for detecting carious enamel – procion, calcein, Zyglo
ZL - 22 and brilliant blue have been tried but are not
advisable for clinical use.
Yip & others (1994), confirmed lack of specificity of caries
detector dyes by correlating the location of dye stainable
dentin with tooth mineral density.
Modified Dye Penetration Method :[Bakhos et al (1977)]
Method for measuring enamel porosity of incipient carious
lesions.
Pottasium iodide is applied for a specific period of time to a
well defined area of enamel & thereafter excess is removed.
The iodine which remain in the micropores ,is estimated &
that indicates permeability of enamel.

Ultraviolet Illumination (UV)It has been used to increase the optical contrast between
the carious region & surrounding sound tissue.
Natural fluorescence of tooth enamel (as seen under UV
light illumination) is reduced in areas of less mineral
content appears dark spot against fluorescence
background.
Advantage :
More sensitive method than visual tactile.
Disadvantage:
Specificity is problem between the carious lesion and
development defect.

Endoscope / Videoscope
Based on observing the fluorescence that occurs when tooth is
illuminated with blue light in the wavelength range of 400-500 nm.
Difference seen in fluorescence of sound enamel & carious enamel.
When this fluoresced tooth is viewed through a specific broad band
gelatin filter,white spot lesions appears darker than enamel.
If white light source is connected to the endoscope by a fiberoptic
cable, there is no need of filter. This is “ White Light Endoscopy “
Additional camera can be used to store the image. The integration of
camera with the endoscope is known as Videoscope.
Advantages:
 Provides magnified image and also clinically feasible.
Disadvantage:
 Requires meticulous drying & isolation of teeth
 Time consuming and very costly
 Cannot be used in inaccessible areas.

Other techniques tried in in-vitro:
Ultrasonic imaging:
- Demineralization of enamel is assessed by ultrasound pulse
echo technique – as it is observed that there is definite
correlation between mineral content of lesion and echo
amplitude changes.
- Initial white spot lesions – no or weak echoes.
- Visible cavitation – echoes with higher amplitude.
Magnetic resonance micro-imagery: uses moderate
magnetic field. Accurate 3 dimensional reconstruction of
teeth and caries – in lab, not useful for clinical apllication.

Conclusion
Although current research and new technologies
have enabled early detection of caries, no current
diagnostic methods fulfill all the criteria for
optimal caries diagnosis.
Diagnosing caries if done at an early stage, can
prove to be extremely valuable in preventing its
progression and ensuring a healthy dentition,
which would last a lifetime emphasizing the need
to develop more accurate and reliable methods of
diagnosing dental caries.

References
A Text Book of Operative Dentistry” by Vimal
Sikri
Georg K Stookey, Richard D Jackson. Dental
caries diagnosis. Dental Clinics of North
America. October 1999;43:4:665-676
Staurt C White and Michale J Pharoah. Oral
Radiology Principles and Interpritation. 5th
Edition, Mosby, Missouri.
S.G. Damle. Textbook of Pediatric Dentistry. 3rd
Edition. Arya Publishing house, New Delhi.2006;
49-55.

Diagnosis of Dental caries / dental implant courses

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