Periodontology

1. 1

2. ADVANCES IN
DIAGNOSTIC AIDS
SEMINAR
2

3.  INTRODUCTION
 COMPLEXITIES IN DIAGNOSIS
 ADVANCES IN PERIODONTAL DIAGNOSIS
 ADVANCES IN ASSESMENT OF GINGIVAL INFLAMMATION
 ADVANCES IN ASSESMENT OF PERIODONTAL ATTACHMENT
3

4.  ADVANCES IN RADIOGRAPHIC DIAGNOSIS
 ADVANCES IN MICROBIOLOGICAL ANALYSIS
 ADVANCES IN IMMUNODIAGNOSTIC TECHNIQUES
 ADVANCES IN ASSAYS BASED ON MOLECULAR BIOLOGY TECHNIQUES
 ADVANCES IN IDENTIFYING BIOMARKERS
 CHAIRSIDE DIAGNOSTIC TESTS
 ADVANCES IN IMPLANTOLOGY
4

5. INTRODUCTION
DIAGNOSIS is defined as; correct determination;
discriminative estimation and logical appraisal of
conditions found during examination as evidenced
by distinctive marks, signs & characteristics of
diseases.
5

6. COMPLEXITIES IN DIAGNOSIS OF
PERIODONTAL DISEASES
 Microbes- Primary etiology of periodontal diseases; insufficient to cause disease themselves
alone.
 Microbiological investigations- shown that both, the disease causing and non-disease
causing bacteria are present in both in healthy individuals and periodontitis patient.
 Presence of specific putative microorganisms in plaque can not be considered to establish
periodontal diagnosis
 Individual host response- equally important factor-pathogenesis of periodontal diseases
 Systemic conditions like Diabetes & environmental factors- stress/smoking – Risk factors for
Periodontal diseases
Constitute a complex situation where establishing a diagnosis becomes difficult.
6

7. ADVANCES IN PERIODONTAL DIAGNOSIS
Assessment of
gingival
inflammation
Assessment of loss
of periodontal
attachment
Microbiological
analysis
Immunodiagnostic
techniques
Molecular biology
techniques
Biomarkers for
periodontal disease
activity
Genetic testing
7

8. Microbiological
Analysis
Bacterial Culturing Chromatography
Microscopic
Identification
Light Microscopy
Dark-Field/phase
contrast
microscopy
Fluorescence
microscopy
8

9. Immunodiagnostic
Techniques
Immunofluoresc
ence Assay
Radio-
Immunoassay
(RIA)
ELISA Flow Cytometry
Latex
Agglutination
Assay
9

10. Based
On
Molecular
Biology
techniques
Nucleic Acid
hybridization
Nucleic Acid
Amplification
Nucleic Acid sequencing
Enzymatic digestion of
nucleic acids
10

11. ADVANCES IN THE ASSESMENT OF
GINGIVAL INFLAMMATION
 Haffajee et al. (1992) used a periodontal temperature probe
(Periotemp,ABIODENT, Inc, Danvers,MA, USA)- to assess subgingival
temperature.
This probe can detect temperature differences of 0.1ºC from a referenced
subgingival temperature.
Has two light emitting diodes: Red emitting diode ( indicates higher temp.) & green
emitting diode ( lower temp., indicating lower risk)
 Haffajee et al. (1992) demonstrated increase in subgingival temperature in
inflamed sites.
12

12. Areas with increased temperature
A.actinomycetcomitans P.Gingivalis
Tannerella Forsythia
Peptostreptococcus
Micros
13

13. ADVANCES IN THE ASSESMENT OF LOSS
OF PERIODONTAL ATTACHMENT
 The conventional periodontal probes have been used to calculate the attachment loss, but may not give
accurate results.
 Measurement of accurate CAL may be challenging.
 Periodontal probes generally stops coronal to the apical extent of the junctional epithelium, which is at the
CEJ
 During gingival inflammation- there is less resistance to probe penetration & the periodontal probe
generally passes apical to the level of CT attachment. This results in overestimation of pocket depth in the
inflamed gingival sites.
 Many other factor influence calculation by a periodontal probe, including diameter of the probe tip,
insertion force & angulation of the probe.
14

14. Advances in Assessment of loss of
Periodontal Attachment
First Generation
• Conventional
• Manual Probes
Second
Generation
• Pressure sensitive probes
Third Generation
• Pressure sensitive probes with computer capturing of data
Fourth Generation
• Periodontal probe utilizing 3D technology
Fifth generation
• Periodontal probes utilizing 3D technology & ultrasound
15

15. 16

16. ADVANCES IN RADIOGRAPHIC
DIAGNOSIS
Digital radiography
Computed
Tomography
Computer
assisted
densitometric
Image Analysis
17

17. DIGITAL
RADIOGRAPHY
18

18.  X-Rays – discovered – W C Rontgen – 1895 ( Noble Prize-1901)
 1st digital dental radiographic image- RVG (Radiographic Imaging system)-
Trophy-1897
 1991-Gendex Dental Systems- introduced new direct digital system
The advantage of digital images is that
they can be manipulated on the
computer screen to aid in diagnosis by
changing density, contrast &
magnification.
19

19. Physical Properties of Digital Radiography
 Conventional film-based radiography- film serves as both detector & storage
medium
 Digital detectors-used only to generate digital image- stored on digital medium
Energy absorbed by
detector
Transformed into
electrical charges
Recorded Digitized
Quantified into gray
scale
Represents the
amount of X ray
energy deposited
Software- processes
information
Converts raw data
Forms meaningful
image
• The final digital image is stored in a digitized
storage archive which contains the demographic
information of the patient.
• Provides freedom to manipulate the image-
panning, zooming, inverting the gray scale & in
measuring distance & angle.
20

20. DIGITAL RADIOGRAPHY
Direct
Converts X-rays into
electrical charges by
means of a direct
process
Indirect
Uses storage-phosphor
image plates with a
separate image readout
process
21

21. Direct Digital Radiography Technology
 Uses an X-ray generator & a solid-state image receptor, referred as SENSOR
 A sensor- made up of a SILICON CHIP – sensitive to light & has scintillator layer-
converts X-rays to light.
 Quality of an image produced by a solid state detector- depends on
chip pixel dimensions,
type & configuration of scintillator layer,
Solid-State sensor
technologies
CCD (Charge-coupled
device)
CMOS
(Complementary
oxide semiconductor)
22

22. CCD (Charge-Coupled Device)
 Metal oxide semiconductor (MOS) device.
 Base-constructed of a material – good conductor under certain conditions
 Base layer- topped with a layer of metal oxide.
 Usually silicon is used as the coating
 Final, top layer- also made of silicon-polysilicon
 CCD Chip- consists of array of small cells/pixels. Inside cells- photosensitive devices.
Charge
generation
Charge
Collection
Charge
transfer
Charge
measurement
23

23. CMOS (Complementary metal oxide
semiconductor)
 Both CMOS & CCD – share common principles of physics
 CMOS chip- more of the electronic components controlling the conversion of
photon energy into the electronic signal are incorporated into the chip itself.
 This simplifies manufacturing process & thus, reduces the cost of production.
 Quality of image produced by CCD & CMOS systems is comparable.
24

24. Indirect Digital Radiography Technology
 Uses image plates having a detective layer of Photostimulable crystals- contain different
halogenides such as Bromide, Chlorine, or, Iodine.
 Phosphor crystals usually cast into plates & then into resin material in an unstructured way
(Unstructured scintillators).
 When X-rays are exposed on these photostimulable crystals, they absorb their energy by
bringing their electrons to higher energy level for several hours depending on their
specific physical properties of the phosphor crystals.
The next step involves the scanning of the image plate with
LASER beam.
This converts the energy stored in the photostimulable
into light.
25

25. ADVANTAGES OF DIGITAL RADIOGRAPHY
Reduced exposure to X-radiation
Superior gray scale resolution
Colorization & enlargement of the images
Provides freedom of manipulation of contrast, sharpness,
image orientation & pseudocolor alterations
26

26. ADVANTAGES OF DIGITAL RADIOGRAPHY
Decreased processing time
Storage of radiographs into the small hard drive of the
computer- great space saver
Can be easily transmitted to other dental offices
Environment-friendly because there are no disposal hazards
of processing chemicals.
27

27. SUBTRACTION RADIOGRAPHY
 Originally described by Ziedses des Plantes (1934)
 Involves detection of areas of changes in bone density &/volume on two serially obtained radiographs of
a particular site, detected as lighter areas (bone gain)/ darker areas (bone loss).
 Quantitative changes in comparison to baseline images can be detected using an algorithm for grey
scale levels. Accomplished by means of a computer.
 Radiographs taken with identical exposure geometry can be scanned using microphotometer that
determines a gray level value for each picture point.
 After superimposition of 2 subsequent radiographs, this technique can show differences in relative
densities.
28

28. Limitations of Subtraction Radiography
 For successful subtraction radiography, reproducible exposure geometry, &
identical contrast & density of the serial radiographs, are essential
prerequisites, & long experience shows that this technique is very sensitive to
any physical noise occurring between the radiographs.
 Hence, the projection geometry & contrast & density should be standardized.
29

29. DIGITAL SUBTRACTION RADIOGRAPHY
(DSR)
 Allows the detection of small changes in alveolar bone.
 Webber et al. (1982) & Grondhal et al. (1983)- introduced digital
subtraction & dental radiography.
 Technique – involves subtraction of pixels of one image from another
with the same projection geometry where radiographs are taken at a
specified time apart.
30

30. 31
ORTHOPANTOMAGRAM

31.  Panoramic Imaging is also called as Pantomography
 Produces a single tomographic image of facial structures that includes both the
maxillary & mandibular dental arches & their supporting structures.
 This is curvilinear variant of conventional tomography.
32

32. PRINICPLE of ORTHOPANTOMAGRAM
 Accomplished by rotating a narrow beam of radiation in a horizontal plane
around an invisible rotational axis that is positioned intraorally.
 Vertical narrow beam is used compared to larger circular/rectangular x-ray
beams used in conventional intraoral radiography.
 In panoramic radiography the image confirms to the shape of the dental arches.
33

33. COMPUTER ASSISTED DENSITOMETRIC
IMAGE ANALYSIS (CADIA)
 Evaluation of bone density- Important part of treatment planning
Bone
quality
&
volume
can
be
analyzed
Intra-oral
Panoramic
Cone Beam
Micro-computed
tomography
DEXA
Ultrasound/ Laser doppler
flowmetry
MRI
34

34. COMPUTER ASSISTED DENSITOMETRIC
IMAGE ANALYSIS (CADIA)
 DEXA- considered as gold standard for analysis of bone density; widely
used for the analysis of bone density in osteoporosis. (because of high
cost, not available in dental clinics)
 Most widely used densitometric method in Implantology is CADIA
 CADIA- one form of subtraction radiography; allows investigator to
quantify the changes by comparing the radiographic density in a
predetermined region of interest between baseline & follow-up
radiograph.
35

35. COMPUTER ASSISTED DENSITOMETRIC
IMAGE ANALYSIS (CADIA)
Video camera
(measures)
Light transmitted
through radiographs
Signals from
camera(converted
into)
Gray scale image
Camera Interfaced with
Image processor
+computer
Bragger et al (1988)- compared the ability of CADIA to detect
alveolar bone changes on radiographs with the interpretation of
digital subtraction images & conventional radiographic
interpretation in areas where osteoplasty/ostectomy was done.
They found 72.7% negative change by digital subtraction images,
50.9% negative change by conventional interpretation & 81.8%
density change by CADIA.
36

36. COMPUTED TOMOGRAPHY
 “Tomography” – Greek word: ‘tomos’ means slice & ‘graphein’ means to write.
 So, Tomography literally means ‘writing slices’
 It is a technique of reconstructing a cross-sectional image of the body from a ‘virtual pile of X-
ray photographs’.
 In this scan, the patient remains stationary on the examination table while the X-ray tube
rotates in a circular orbit around the patient in a plane perpendicular to the length-axis of the
patient.
 A fan-shaped/cone-shaped X-ray beam passes through the body of the patient, which is
received by the receptors on the opposite side of the X-ray source.
 Presently – we are using 3rd/4th generation CT-Scans
37

37. ADVANCES IN THE
MICROBIOLOGICAL
ANALYSIS
38

38.  Socransky & Haffajee (1998) showed that many bacterial
species contribute to the development of periodontitis.
 In a systematic review, Mombelli et al. (2002) found that the
presence or absence of certain identified periodontal
pathogens could not distinguish cases of chronic
from the cases of aggressive periodontitis.
39

39. • Various microorganisms can be identified based on their phenotypic/genotypic
composition.
• Phenotypic criteria of bacterial identification are based on observable physical/ metabolic
characteristics of bacteria.
• Most of the phenotypic characterizations used in diagnostic bacteriology are based on
tests that establish a bacterial isolate’s morphology & metabolic capabilities.
Principles of Microbial Identification
Microscopic morphology
&
Staining characteristics
Macroscopic (colony)
morphology
Environmental
requirements for growth
Resistance or
susceptibility to
antimicrobial agents
Nutritional requirements
& metabolic capabilities
40
Most commonly used phenotypic criteria:

40.  The genotypic identification methods involve characterization of some portion of a
bacterium’s genome using molecular techniques for DNA or RNA analysis.
 The genotypic approach is highly specific & often very sensitive because it
identifies presence of a specific gene or a particular nucleic acid sequence which is
specific for a particular microorganisms.
41

41. Properties of an Ideal diagnostic test
Highly specific
Highly sensitive
Reproducible
Quantitative
Simple to perform
Rapid
Amenable to chairside
use
One-stage or a two-
stage procedure
Non-Invasive
Versatile in terms of
sample handling,
storage, & transport
Economical , &
Dependent on simple
& robust
instrumentation
42

42. Bacterial Culturing
 Most common bacterial identification method – conventional bacterial
cultivation; involves growing bacteria in either aerobic / anaerobic conditions on
different media & performing tests to identify & quantify specific species.
 Helps in bacterial identification
 Helps in determination of antibiotic susceptibility
MULTIPLE DRAWBACKS
• Time-consuming procedures
• Expensive
• Can only grow live bacteria
• Many putative pathogens such as Treponema species & Bcateroides cannot be
cultured
• Outcome of analysis- can be affected by method of sample collection
43

43. Microscopic Identification
 Since the introduction of the light microscope, many
advances have taken place in microscopy.
 Light Microscopy- limited capability in regards to the
size of a particle that can be examined
 Electron Microscopy- provides additional resolution that
allows for the examination of subcellular structures and
even molecules
44

44. Dark Field Microscopy
 Works on principle of creating a contrast between the object & the surrounding
field, such that the background is dark & the object is bright.
 Can be used to assess directly & rapidly the morphology & the motility of
bacteria in a plaque sample.
 Inexpensive means of smearing a microbial sample for major morphotypes.
DRAWBACKS
• Inability to identify certain species & to distinguish individual bacterial species
• Absence of species identification & the lack of guidance concerning the choice of an
appropriate antibiotic.
Listgarten & Hellden (1978)- systematically evaluated dark field characteristics of
subgingival microflora
45

45. Fluorescence Microscopy
 Fluorochrome- excited by UV light- resulting in visible fluorescence- bright image, in
dark background is seen.
 Fluorescence emission- is always a longer wavelength (less energy) than the
absorption (or excitation) – results in bright illumination of the specimen.
 Used extensively to study the intercellular distribution, dynamics & molecular
mechanisms of a large variety of macromolecules & metabolites.
 Commonly used to visualize the distribution of certain proteins in a cell or to make
visible the specific organelles, filaments, & biochemically distinct membrane regions.
46

46. Chromatography
Used to separate & characterize substances based on their size, ionic charge, or their solubility in
particular solvents.
Involves two phases: the mobile phase ( Gas/liquid)- contains & carries the sample to be analyzed
through/across the stationary phase.
Gas-Liquid chromatography: refers to a chromatography method that uses gas as the mobile phase &
liquid as the stationary phase.
Procedure involves mixing the sample with mobile phase- which carries the sample through a column
containing the stationary phase.
Depending on the nature of the solid phase, different analytes within the sample will be retained within
the column based on the size, ionic charge; or analyte solubility in the mobile phase.
As the mobile phase continues to ,move through the column, analytes with different characteristics will
have different retention times & thus will come out from the column at different times.
Eluted analytes – pass through detector – generates a signal – translated into an electronic signal-
recorded & used to produce chromatogram.
47

47. High performance liquid chromatography
 Type of liquid chromatography used to separate & quantify compounds that have
been used to separate & quantify compounds that have been dissolved in a solution.
 HPLC – accomplished by injection of a small amount of liquid sample into moving
stream of liquid (called the mobile phase) – passes through a column packed with
particles of stationary phase.
 Different compounds are separated from each other as they move through the
column.
 HPLC- multiple application in research for identification of various molecules &
bacterial cell wall components, especially in the antibiotic resistant bacteria.
48

48. 49

49.  Immunodiagnostics is a diagnostic methodology that uses an antigen-
antibody reaction to detect target organisms.
 Various immunodiagnostic techniques including immunofluorescent
assays, radioimmunoassay, enzyme-linked immunosorbent assays, flow-
cytometry & latex-agglutination tests, have been used widely to detect
various target microorganisms.
 Radioimmunoassay & ELISA – predominant techniques during the initial
era of immunodiagnostics.
 ELISA- Gold standard of clinical immunodiagnostics.
50

50. IMMUNOFLUORESCENCE ASSAYS
 Utilizes fluorescent-labelled antibodies to detect specific target antigens.
 Antibodies are chemically conjugated to fluorescent dyes such as fluorescein
isothiocyanate (FITC)/tetramethyrhodamine isothiocyanate (TRITC).
 These labelled antibodies bind (directly/indirectly) to the antigen of interest
which allows for antigen detection through fluorescence techniques.
 The fluorescence can be quantified using a flow cytometer, array
scanner/automated imaging instrument, or visualized using fluorescence or
confocal microscopy.
51

51. Immunofluorescence Assays
DIRECT
Single antibody is used
which is directed against
the target of interest
(Primary Antibody)
INDIRECT
Two antibodies are used.
Primary antibody is
unconjugated
Fluorophore-conjugated
secondary antibody directed
against the primary antibody is
used for detection
52

52.  Use antibodies to detect & quantitate the amount of antigen(analyte) in a sample.
 These assays are typically very sensitive & specific.
 RIA-has been the 1st immunoassay technique developed to analyze nanomolar &
picomolar concentrations of hormones in biological fluids.
 Any biological substance for which a specific antibody exists can be measured, even
in minute concentrations.
53

53. ENZYME-LINKED IMMUNOSORBENT ASSAY
(ELISA)
• Plate-based immunoassays designed for detecting & quantifying substances such as peptides, proteins,
antibodies, & hormones.
• ELISA- primarily used to detect serum antibodies to periodontopathogens
• This test is performed by first incubating a specific antigen in the wells of a plastic microtiter plate (96-wells
or 384-well polystyrene plate).
• Antigen-binds to the surface of wells, the excess antigen is removed, & the sample suspected to contain
antibodies against this antigen is applied to the antigens in the wells.
• After a wash to remove any unbound sample antibodies, a secondary antibody specific to the antibody
being investigated, is applied.
54

54. FLOW CYTOMETRY
Basic principle: measuring physical & chemical
characteristics of particles in fluid stream as they pass
through one/ more lasers.
The properties measured include particle’s relative size,
relative granularity or internal complexity, & relative
fluorescence intensity.
Basic components: Fluidics, Optics & Electronics
Fluidic system transports particles in a stream of the
laser beam
Optical system- illuminates the particles for detection
of resultant light signals into electronic signals that can
be processed by the computer.
55

55. LATEX AGGUTINATION ASSAYS
• Common immunological tests done in clinical laboratories.
• In latex agglutination procedures- an antibody (or antigen) coats the surface of latex particles.
• When sample containing specific antigen is mixed with the milky-appearing sensitized latex, it causes
visible agglutination.
• Degree of agglutination plotted as a function of agglutinant concentration follows a bell-shaped curve.
• Latex particles are used to magnify the antigen-antibody complex & make it visible.
Latex
Agglutination
Assays
Indirect Assays
Commonly used to detect
various bacteria in plaque
samples
Inhibition Assay
Fixed quantity of antibody
is mixed with dilution of
the test sample
the ligand of interest.
56

56. Immunoblotting (Western Blotting)
 Typically used to determine the amount (dot blot) & molecular weight (western blot) of an
antigen present in complex mixture.
 Technique uses antibodies (or other specific ligands in related techniques) to identify target
proteins among a number of unrelated protein species.
 The process involves the separation of proteins by electrophoresis & then transferred them onto
membranes (usually nitrocellulose).
 Membrane is usually overlaid with a primary antibody for a specific target & then with a
secondary antibody labeled, for example, with enzymes or radioisotopes.
57

57. 58

58. 59

59.  DNA probe uses a segment of single stranded DNA, labeled with a enzyme of a
radio isotope, that is able to hybridize to a complimentary nuclei strand, & thus
detect presence of target microorganisms.
60
DNA PROBE
Whole Genomic
Targets the whole DNA
strand rather than specific
sequence/gene
Oligonucleotide Probe
Target variable region of
16sRNA or a specific
sequence in the DNA
strand

60. Advances in assays based on molecular
biology techniques
 The recent advances in microbiology are in field of molecular analysis.
 Conventional methods- Mainstay of diagnostic bacteriology
 Limitations- associated with the use of phenotypic methods
Limitations
• Inability to grow certain fastidious pathogens
• Inability to maintain the viability of certain pathogens in specimens during transport
to the laboratory.
• Extensive delay in the cultivation & identification of slowly growing pathogens.
• Lack of reliable methods to identify certain microorganisms grown in vitro.
• Use of considerable time & resources in the establishment.
61

61. Nucleic Acid Hybridization
 Hybridization methods are based on the ability of two nucleic acid strands that have
complementary base sequences to a specifically make a bond with each other & form a
double-stranded molecule, or duplex or hybrid.
 Hybridization assays require that one nucleic acid strand (the probe) originates from an
organism to be detected or identified.
 Positive hybridization identifies the unknown organism as being the same as the probe-
source organism.
 With negative hybridization test, the organism remains undetected/unidentified.
 Positive hybridization- identified by labeling the probe with radioactive molecules,
62

62. Checkerboard DNA-DNA Hybridization
 Socransky et al. (1994) developed this technique for the detection & levels of 40
bacterial species often found in the oral cavity.
 This technique is rapid, sensitive, & relatively inexpensive.
 Offers the ability to include more potential periodontal pathogens in large-scale
studies with a single analysis which is usually not possible with cultural analysis.
 These new probe-target format permits to enumerate large numbers of species in
very large number of samples.
 Method requires sophisticated laboratory equipment & is highly specific, & thus this
assay has not been generalized for diagnostic purposes.
63

63. Checkerboard DNA-DNA Hybridization
 The technique includes the use of whole genomic DNA
probes & allows the identification & the quantification
of multiple microorganisms.
 Socransky et al. (1998) described the presence of five, &
subsequently six microbial groups within the
subgingival biofilm.
 A group of species denominated the red complex
consisted of three species: P gingivalis, T. Forsythia, & T.
Denticola.
64

64. Nucleic Acid Amplification
 Although hybridization methods are highly specific for organism detection
& identification, but they may give false negative results in case where an
insufficient target nucleic acid is present in the reaction.
 Therefore many hybridization methods require “Amplifying” target nucleic
acid by growing target organisms to greater numbers in culture. The three
strategies for molecular amplification are target nucleic acid amplification,
nucleic acid probe amplification, & amplification of the probe “signal”.
65

65. TARGET NUCLEIC ACID AMPLIFICATION
 Amplification of target nucleic acid- Polymerase chain reaction (PCR) is used.
 PCR- based on three-step process:
Denaturing double stranded
DNA into single strand
Annealing Primers to the
single stranded DNA
Enzymatically extending the
primers complementary to
the single stranded DNA
templates
66

66.  Taq Polymerase- is the enzyme commonly used for primer extension which
occurs at 72º C.
 Enzyme is used because of its ability to function efficiently at elevated
temperatures & withstand the denaturing temperature of 94ºC through several
cycles.
 After the primers are annealed to the denatured DNA, the single stranded DNA
segment becomes the template for the extension reaction.
 Various derivatives of PCR procedures are available today:
Multiplex PCR Nested PCR Quantitative PCR
Reverse
Transcription PCR
(RT-PCR)
Arbitrary Primed
PCR
Real-Time PCR
67

67. NUCLEIC ACID SEQUENCING
 The term DNA sequencing refers to the sequencing methods for determining the order of the
nucleotide bases- adenine, guanine, cytosine, & thymine- in a molecule of DNA.
 Nucleotide order determines the amino acid order, & by extension of amino acid order, the
protein structure & function (proteomics).
 By nucleotide sequence of a gene or gene fragment of an organism is identified.
 DNA nucleotide sequence of microorganism from the test sample can be identified &
compared with the known DNA sequences to determine the exact microorganism in the test
sample.
68

68. DNA FINGERPRINTING
The global population of different bacterial species consists of discrete clonal lines.
There are genetic variations in between different clonal lines, but these species are not comprised of
an infinite number of genetically different strains.
The degree of genetic diversity is different for each bacterial species.
With the help of enzyme restriction endonuclease, the bacterial chromosome can be cut in a unique
set of DNA fragments.
These unique DNA fragments of total genomic DNA from isolates of selected species provides a
useful method for fingerprinting individual stains.
Procedure involves isolation & cultivation of a particular bacterial species in the liquid or solid
medium.
69

69. ADANCES IN IDETIFYING
BIOMARKERS FOR
PERIODONTAL DISEASE ACTIVITY
70

70.  The biomarkers which can be used as diagnostic markers in periodontal diseases can
either be involved in some way in the disease process or released as a consequence of
tissue damage during disease progression.
 Most important source of these biomarkers is gingival crevicular fluid (GCF)
 GCF has been investigated for multiple periodontal disease biomarkers.
 The potential sources of these biomarkers can be derived from:
Subgingival bacteria &
their products
Inflammatory & Immune
Products
Proteolytic & hydrolytic
enzymes released from
inflammatory cells
Enzymes released from
dead cells
Connective tissue
degradation products
71

71. COMMERCIALLY AVAILABLE DIAGNOSTIC
KITS FOR BACTERIAL IDENTIFICATION
Evalusite
(Kodak)
Omnigene
(OmniGene,Inc)
BTD(Biotechnic
Diagnostics, Inc)
72

72. COMMERCIALLY AVAILABLE DIAGNOSTIC KITS
FOR IDENTIFICATION OF BACTERIAL
PRODUCTS
Perioscan (Oral-B
Laboratories)
Omnigene
(OmniGene,Inc)
Toxicity
Prescreening
(TOPAS)
73

73. COMMERCIAL CHAIRSIDE DIAGNOSTIC KITS FOR
DETECTION OF PROTEOLYTIC & HYDROLYTIC
ENZYMES
Perio-check
Prognos-Stik
(Dentsply)
74

74. COMMERCIAL CHAIRSIDE DIAGNOSTIC KITS
FOR DETECTION OF LDH & AST ENZYME
PerioGard Pocket Watch
75

75. 76

76.  Periodontal disease- multi-factorial etiology
 Genetic Susceptibility- important factor contributing to the development &
progression of periodontitis.
 Various Genetic Syndromes- Grade C periodontitis as one of their components.
(For eg. Palmoplantar Dyskeratosis (Papillon-Lefevre syndrome- due to defective
on chromosome 11)
 Presently – Studies focused on IL-1 gene polymorphism have lead to the
development of the periodontitis susceptibility trait test.
 Kornman et al. found an association between the polymorphism in the genes
encoding for interleukin 1
77

77. • Originally introduced to dentistry in 1997
• 1st genetic test to identify an individual’s risk for
developing periodontal disease.
PST Genetic
susceptibility
test
• Interleukin Genetics Inc. introduced Periopredict in
2013
• It measures variations in the genes for Interliukin-1,
a key mediator of inflammation
PeroPredict
78

78. Oral Fluid Nano
Test(OFNASET)
Electronic Taste Chips
OraQuick
Integrated microfluidic
platform for oral
diagnostics (IMPOD)
79

79. When to Use Chairside diagnostic tests?
It is used before starting the periodontal therapy;
by doing this we can get the baseline values of
destructive activity going on in the periodontal pocket,
which can afterwards be compared with post-treatment
values
80

80.  The markers which have been selected as
indicators of periodontal disease activity have
been found to be increased in GCF & Saliva in
longitudinal studies. Hence, they can predict
the disease activity in the periodontal pocket.
 Simple to Use
 Can be read after a short time
 Can be used to educate the patient about the
condition of the disease.
 The choice of the most appropriate
biomarkers may still be difficult at present
because no biomarker has been proven to
be an exact indicator of disease activity.
 If a moiety is associated with inflammation
this may mask in association with
destructive disease.
 No account of biological control
mechanisms is taken in present tests.
 Costly as compared to conventional
diagnostic techniques.
ADVANTAGES DISADVANTAGES
81

81. 82

82. 83
Periotest is the instrument most
commonly used for measuring
osseointegration in dental implants.
The Periotest can be employed at all
stages of implantological treatment-
from primary stability testing
through the healing period, & right
up to the finished prosthetic.

83. 84

84. • Carranza’s Clinical Periodontology; A south Asia Edition
• Periobasics Textbook
• Armitage GC, Svanberg GK, Lde H: Microscopic evaluation of clinical measurements of connective tissue
attachment levels. J Clin Periodontol 1977;4:173
• Webber RL, Ruttimann UE, Grondahl HG. X ray image subtraction as a basis for assessment of
periodontal changes. J Periodontal Res 1982;17(5):509-11
• Savitt ED, Keville MW, Peros WJ. DNA probes in the diagnosis of periodontal microorganisms. Arch Oral
Biol. 1990;35 Suppl:153S-159S. doi: 10.1016/0003-9969(90)90147-3.
• Socransky SS, Smith C, Martin L., Paster BJ, Dewhirst FE, Levin AE.”Checkerboard” DNA-DNA
hybridization. Biotechniques 1994:17(4):788-92
85

85. 86