Advanced Diagnostic Aids in Periodontology and Oral Surgery; Probes, Bacterial Culture, Phase Contrast Microscopy, DNA-DNA hbridization Technique, Latest Radiographic Techniques

1. Introduction
 Periodontal diseases are prevalence human diseases
defined by signs and symptoms of gingival inflammation
and/or periodontal tissue destruction.
 These diseases are conventionally diagnosed by clinical
evaluation of the signs of inflammation in the gingiva
without tissue destruction in case of gingivitis
 Or by presence of both inflammation and tissue
destruction in case of periodontitis
 Routinely used clinical and radiographic evaluation can
provide evidence of past periodontal destruction and its
extent and severity
 But they do not provide any information on the cause of
the condition, on the patients susceptibility to disease or
whether the disease is progressing or in remission
 Periodontitis is a multifactorial disease and is caused by
the interplay of several factors such as periodontal
pathogens, host response, genetic, systemic and
behavioral risk factors
 Considering this in addition to clinical and radiographic
parameters several advances have been made that aid in
the diagnosis of PDL diseases
Diagnosis

2.  A periodontal diagnosis is an important label that
clinicians place of a patient’s periodontal condition or
disease
 It is derived from information obtained from the patients
medical and dental histories combined with findings
from a thorough oral examination
 Under the best of circumstances a periodontal diagnosis
is a clinicians best guess as to what condition or disease
the patient has
 When a diagnosis is given it is implicated that the
patient has ruled out other possible diseases
 But because there is always some uncertainty, clinicians
routinely provide a differential diagnosis that provides
the clinician with other diagnostic. Options, the initial
diagnosis is wrong
Components
 A basic periodontal examination should consist of
a. History and chief complaint
b. The initial periodontal examination
c. Occlusal relationships are inspected that consists of
recognition of gingival inflammation
 The four most common signs of gingival inflammation
that are routinely observed are
a. Redness
b. Swelling

3. c. Bleeding on probing
d. Purulent exudate
 Detection of departures from normal anatomy, shape and
form such as aberrant frenal attachments, reduced width
of keratinized gingiva
 Assessment of etiologic and predisposing facial such as
local factors, close roots, palato gingival grows furcation
anatomy, cervical enamel projection etc.,
 Assessment of periodontal damage
 This should include measurement of PPD – gingival
margin to the base of the pocket recorded at 6 sites for
all teeth
 Clinical attachment loss from CEJ to base of pocket
 RAC from apical margin of a restoration or from incisal
edge of the tooth
 Gingival recession – CEJ to gingival margin
 Furcation involvement
a. I – Incipient
b. II – Cul-de-sac
c. III – through and through
 Mobility
 Inspection of teeth for caries, restoration problems,
occlusal discrepancies etc.,
 Despite our increased understanding of the etiology and
pathogenesis of periodontal infections, the diagnosis and

4. classification of these diseases are still based on
traditional diagnostic methods.
 Most important among which are
a. Periodontal probing that measures PPD, CAL &
bleeding
b. Mobility
c. Detection and assessment of local factors
Evaluation of a diagnostic test / aid
 The validity of a diagnostic / prognostic test can be
estimated
 This involves the use of a two-by-two contingency table
or decision matrix
 A diagnostic aid / test is intended to detect the presence
of a specified disease from a single examination
 To evaluate a test, data is collected using cross-sectional
sampling
 The validity of any diagnostic test or aid can be
estimated by several measures namely
a. Sensitivity
b. Specificity
c. Positive predictive value
d. Negative predictive value
Sensitivity – it refers to the probability of the test being
positive when the disease is truly present

5.  A perfect test should be able to detect the disease in all
cases without registering a false negative
 The sensitivity of such a perfect test would be 1.00.
 Specificity – this refers to the probability of the test
being negative when the disease is not present
 A perfect test would be able to correctly identify all
instances in that the disease was absence without
registering a false positive
 The specificity of such a perfect test would be 1.00.
 However, a perfect diagnostic test does not exist,
therefore a test sensitivity and specificity will always be
less than 1.00.
 But it is reasonable to expect that a clinically useful
diagnostic test for periodontal disease should have high
values for both sensitivity and specificity
 Sensitivity and Specificity are calculated in disease or
healthy individuals and not in mixed population
 On the other hand predictive values are calculated in
mixed populations
 Positive predictive value – of a test refers to the
probability that the disease is present when the test is
positive.
 Negative predictive value refers to the probability that
the disease is absent when the test is negative.
Sensitivity = A / A + B

6. Specificity = D / C + D
Positive predictive value = A / A + C
Negative predictive value = D / B + D
Advantages in traditional diagnostic methods
Gingival temperature
 Normal subgingival temperature falls between a range of
33.9 ± 0.40
C
 Instruments that measure the temperature in the gingival
tissues have been developed
 Kung et al claim that thermal probes are sensitive
diagnostic devices for measuring early inflammatory
changes in the gingival tissues
 Studies have shown that active periodontitis lesions can
create measurable elevations in sulcular temperatures
 One of the commercially available system is the
periotemp probe (Abiodent, Inc, Danvers Mass)
 It detects pocket temperature changes of 0.10
C from a
referenced subgingival temperature
 A naturally occurring temperature gradient exists
between maxillary and mandibular teeth and between
posterior and anterior teeth
 Haffajee et al have shown that maxillary periodontal
sites exhibit higher temperature than mandibular sites

7. with those expected for each tooth and higher
temperature pockets are signaled with a red emitting
diode
 Haffajee et al used this probe to asses its predictability
in identifying loss of attachment concluding that sites
with a red temperature indication had more than twice
the risk for future attachment loss than did those with a
green indication
 However the influence of pocket depth on temperature is
still not clear and so the ability and accuracy of this
device need further studies
Periodontal probing
 The periodontal probe is the most widely used diagnostic
tool for the clinical assessment of connective tissue
destruction in periodontitis
 Increased probing depth and loss of clinical attachment
are pathogenic for periodotitis
 Pocket probing is a crucial procedure not only for
diagnosing periodontitis but also to evaluate the outcome
of periodontal therapy
 However use of periodontal probes present problems in
terms of sensitivity and reproducibility of the
measurements
 Clinical pocket depth readings do not normally coincide
with the histologic pocket depth, since the probe

8. normally penetrates the coronal level of the junctional
epithelium.
 Also the precise location of the probe depends on the
degree of inflammation of the underlying connective
tissues
 If tissue is inflamed it offers less resistances to probe
penetration and the probe tip either coincides with or is
apical to the coronal level of the connective tissue
attachment
 On the other hand healed gingival following therapy
shows increased resistance to probing
 Also the probing technique, probing force, size of the
probe, angle of insertion of the probe and precision of
the probe calibration
 All these factors contributes to the large standard
deviations (00.5 to 1.3mm) in clinical probing results
that makes detection of small changes difficult
 One of the main problems in reproducibility has been the
variation in probing force
 Therefore pressure – sensitive probes with standardized
controlled insertion pressure have been developed
 Mombelli et al – studies have shown that penetration of
the probe positively correlated with probing force
 These studies have shown that with forces up to 30g, the
tip of the probe seems to remain within the junctional

9. epithelium and forces of up to 50g are necessary to
diagnose periodontal osseous defects
 Standardization of probe tips and use of registration
stents to maintain reproducible probing angulation have
also been used to overcome sources of error
 But again fabrication of stents is time consuming and is
impractical for clinical diagnosis
 Also current techniques for data readont and storage are
inaccurate and time consuming
 New probing systems have been developed
 Currently computers are routinely used in many dental
offices only for billing and accounting
 But there is enormous potential for the use of computers
in data collections
 One such use is the development of antomated probes
 They fulfill the 9 criteria of the NIDCK by having a
a. Precision – 0.1mm
b. Range – 10mm
c. Probing force – constant and standardized
d. Applicability – non invasive, light out, easy to use
e. Reach – easy to access any location
f. Angulation – guidance system to ensure probes
angulation
g. Security
- Complete sterilization of all portions entering
the mouth

10. - No biohazard from material / electric shock
h. Read out – digital electronic read out
i. Recorded – digital output
 After a National Institute of Craniofacial Research
(NIDCR) workshop on the quantitative evaluation of
periodontal diseases by physical measurement techniques
there was a proposal to develop and clinically evaluate
an improved periodontal pocket depth – attachment level
measurement system that would meet the 9 criteria of
conventional
a. Precision – 1mm
b. Range – 12mm
c. Probing force – not standardized
d. Applicability – non invasive and easy to use
e. Reach – easy to access any location
f. Angulation – subjective
g. Security – simple stain steel instrument easily
sterilizable
h. Read out – on voice read out
i. Recorded – in writing
 Gene I – conventional probe
 Gene II – pressure sensitive probe
 Gene III – computerized
 Gene IV – probes that aim at recording sequential
probing positions along the gingival sulcus

11.  Gene V – have an ultrasonic device attached to the fourth
gene probe for identifying attachment level without
penetrating it
 The NIDCR criteria were met by Gibbes et al who
developed the Florida probe in 1988 system
 Components of this system include a probe hand piece,
digital read out, 3 pedal foot switch and computer
interface
 The hand piece probe tips are manufactured by micro
polishing techniques and are 0.4mm in diameter and
made of implant grade titanium
 Can be steam sterilized in a standard autoclave
 The 3 pedal foot switch helps a single operator enter data
and eliminates error in visual reading and reduces
contamination
 The computer interface has color coded digital read outs
and educates and motivates patients
 Two models available
 Stent model has a 1mm metal collar that rests on a
prepared ledge on a prefabricated vasccuoform sleit
 Disc model has a 1mm desk that rests on the occlusal or
incisal surface of tooth
 Jeffcoat probes (1986) automatically extend and retract
under controlled force. Probe motion provided by custom
low friction pneumatic cylinder
 It can detect the CEJ by a rapid change in acceleration

12.  Working end of probe has Michigan O probe markings
 Internal moving tip is Teflon coated stainless steel wire
 It is circular in cross section and 0.15mm in diameter
 Birek probe works under constant air pressure and
measures attachment level using occlusal surface as
reference
 Toronto probes use occusal incisal surfaces as reference
 Sulcus probes with 0.5mm Ni-Ti wire under air pressure
 Mercury tilt sensor limits angulation with in 300
.
 Interprobe (Goodson and Kondon, 1988) electronic probe
using an optical encoder transduction element
Merits
 Controlling insertion forces
 Automated entering of clinical information into a
computer
 Better resolution than manual probes, therefore detects
smaller changes in CAL
 Eliminates need for second operator
Demerits
 Tendency to underreslinate PD and CAL in untreated
patients
 Presence of subgingival calculus can interfere with probe
insertion

13.  To minimize this problem the ‘double – pass’ method is
used (measuring each site twice).
Mobility
 Periotest is a electronic device designed to perform
quantization measurements of the damping
characteristics of the periodontium, thereby establishing
a value for tooth mobility
 Mobility is measured as a function of the contact time of
a small plug containing an accelerometer that is used to
strike a tooth
 The possible range of values are from –8 to +50
Merits
 More reliable test of mobility
Demerits
 Lack of resolution
 Poor sensitivity
 Susceptibility to operator variables –08 to + 09  no
mobility; +10 to +19  just discernible monometer; +20
to +29  obvious movement (visible); +30 to +50 
mobile on pressure
Calculus detection

14.  Detector is a table top electronic devices to detect
calculus
 Consists of a micro processor based power unit,
electronic probe and foot pedal
 Dimensions of the probe tip similar to standard PDL
probe
 Probe tip emits light from a light emitting diode
 Reflected light is analyzed by the microprocessor
 When calculus is detected the system light up and a beep
is heard
Merits
 Light weight, well balanced, hand piece
 Audible beep makes it easy to detect
 Autoclavable probes
Demerits
 Expensive
 Low sensitivity and specific
Advances in radiographic assessment
 Dental radiographs are routinely used to assess
destruction of alveolar bone associated with periodontitis
 They cannot accurately reflect bone morphology buccally
and lingually
 But they provide useful information on interproximal
bone levels

15.  They also provide useful information regarding the
periodontium such as
a. Root length
b. Root proximity
c. Presence of periapical lesions
d. Estimates of remaining alveolar bone
 For bone loss to be detected in radiographs a substantial
volume of bone must be lost
 Approximately more than 30%
 Therefore conventional radiographs are very specific but
lack sensitivity
 This low degree of sensitivity is mainly due to inherent
sources of variability in radiographic technique such as
a. Variations in projection geometry
b. Variations in contrast and density due to differences
in film processing, voltage and exposure time
c. Masking of osseous changes by other anatomic
structure
 Variations in projection geometry can be minimized by
using the paralleling cone techniques
Digital radiography
 Digital radiography uses computerized images that can
be stored, manipulated and corrected for under and over
exposure

16.  Two digital radiography systems are available that rely
on a sensor
 Direct and indirect methods
 Direct method uses a charge coupled device (CCD)
sensor linked with a fiber optic or other wire to the
computer system
 This direct method obtains real – time imaging, offering
both clinician and patient improved visualization
 The indirect method (Digera system) makes use of a
phosphor luminescence plate that is a flexible film like
radiations energy sensor placed intraorally and exposed
to conventional x-ray tubes
 A laser scanner reads the exposed plates offline and
reveals digital image data that can be enhanced, stored
and compared with previous images
Advantages
 Images can be stored, manipulated and corrected for
under and over exposures
 Very important dose reduction obtained with this
technique (1/3 to 1/3 of dose)
 Real time images obtained
 With the indirect method these plate size and increase
flexibility that is sinutar to conventional x-rays. So a
paralleling cone techniques can be used with film holders
 Patient can also see images patient education component

17. Disadvantages
 With direct method the sensory area is limited therefore
only one or two teeth can be depicted at a time
 Also sensor rigidity that is attached to a wire makes
ideal image projection with film holders difficult
 Also sterilization poses a problem
Subtraction radiography
 This technique relies on the conversion of serial
radiographs into digital images
 These serially obtained digital images can then be
superimposed and the resultant composite can be viewed
on a video screen
 Changes in the density or volume of bone can be
detected as lighter areas that indicate bone gain or dark
areas that indicate bone loss
 Quantitative changes in comparison with the baseline
images can be detected using an algorithm for gray scale
levels
 This is achieved by using a computer and is called
computer assisted subtraction radiography
 This technique requires a parallelization technique to
obtain a standardized geometry and accurate super-
imposable radiographs

18.  Radiographs taken with identical exposure geometry can
then be scanned and superimposition of radiographs can
show differences in relative densities
Advantages
 High degree of correlation between alveolar bone
changes and attachment level changes
 Increase detects ability of small osseous lesions.
Grondahl et al showed a nearly perfect accuracy at a
lesion depth corresponding to 0.49mm of compact bone
but for conventional radiographs the lesion must be 3
times larger than that.
 High degree of sensitivity it can detect a change in bone
mass as little as 5%
 Facilitates both qualitatives and quantitative
visualization of even minor density changes in bone by
removing unchanged anatomic structures from the image.
This shows bone structures with true density change
Disadvantages
 Identical projection geometry for the sequential
radiographs
 Makes method very impractical in a clinical setting
 Recently diagnostic subtraction radiography (DSR) has
been introduced that corrects for the effects of angular
alignment discrepancies

19. CADIA
 It is a video based technique
 A video camera measures the light transmitted through a
radiograph and the signals from the camera are
connected into gray scale images
 The camera is interfaces an image processor and a
computer that allows storage and manipulation
Advantages
 It can follow density changes in alveolar bone over time
 It has higher sensitivity than DSR
 High degree of reproducibility and accuracy
Computed tomography
 Specialized radiographic technique that allows
visualization of planes or slices of interest
 Unlike conventional tomography that bluss all structure
not in the place of interest, computer tomo actually
removes the structures not in the plane of interest that
gives us an image with a clear visualization of the slice
through the organ under study
 A CT scanner is used for this purpose
Disadvantages
 CT equipment is expensive

20.  Procedure carries a relatively high radiation burden for
the patient
 Mostly used to assess sites planned to receive dental
implants
Nuclear medicine bone scan’s
 Nuclear medicine is the branch of radiology that uses
radiolabelled pharmacentraical that are specifically
intended to image particular organs or detect specific
disease processes
 The radiopharmacentrical is in effect, a magic bullet that
is taken up selectively by the tissue of interest
 Routinely used to image the brain, bone, kidneys, heart,
liver, lungs etc.,
 For the diagnosis of periodontal disease, bone scans have
been used to detect sites of active bone loss
 The radiopharmacentrical is a techniquim labeled
disphosphate called 99m – TC – methylene
disphosphonate
 The disphosphonate moiety is the bone seeker that is
adsorbed onto the forming front of bone that occurs
either during bone apposition or behind the bone
resorption
 Bone scans do not image the anatomy of the area of
interest but they detect changes in bone metabolism that
may occur prior to radiographically detectable changes

21. To perform a bone scan
 The radio pharma is infected I.V
 Following a period of 2 hours to allow for bony uptake
of the agent, uptake is alter imaged using a gamma
camera or measured using special detection
 Areas of active bone loss appear as hot spots in the
image
 It has a sensitivity and specificity of 90% in
prognosticating alveolar bone loss due to periodontitis
 Measurement of bone seeking radiopharmacentical
uptake (BSRU) would be indications of bone loss
occurring at the time of examination
 A miniature hand held BSRU detector was designed by
Kaplan et al
 It could measure the BSRU around individual teeth
 Jeffcoat et al showed that a tooth with a high BSRU at
time zero lost significant bone radiographically, whereas
a tooth with a low BSRU lost little bone.