ADVANCED PERIODONTAL DIAGNOSTIC TECHNIQUES
Dr MIDHUN KISHOR S
I
DIAGNOSIS
Diagnosis is defined as; correct determination, discriminative estimation and logical appraisal of conditions found during examination by distinctive marks, signs and characteristics of diseases
Diagnosis can be defined as the art of identifying a condition or disease and differentiating it from other entities
Text book of Carranza's clinical periodontology, Second south Asia Edition
Diagnosis is defined as an utilisation of scientific knowledge for identifying a disease process and to differentiate it from other diseased process
Types of diagnosis
Provisional Therapeutic Differential Comprehensive Emergency
DIAGNOSTIC AIDS IN PERIODONTICS
CONVENTIONAL
ADVANCED
Current conventional techniques
Clinical diagnosis is made by measuring either
clinical attachment loss (CAL) or radiographicallyby loss of alveolar bone
This kind of evaluation identify and quantify
current clinical signs of inflammation
Provides historical evidence of damage with
its extent and severity
STATUS of current conventional methods
POSITIVES
They can be performed swiftly with minimum equipment and effort and are
in expensive
Epidemiologic surveys can be carried out easily and the results are usually a true representation
of the periodontal status of population
Diagnostic techniques in periodontology: a historical review STEVENI. GOLD Periodontology 2000, Vol. 7, 1995, 9-21
NEGATIVES
• Does not provide cause of the condition, EXACT etiology cannot bedetermined
• No info. on patient’s susceptibility to the disease
• Cannot identify sites with ongoing periodontal destruction or sites inremission
• No reliable markers of current diseases activity
• Difficult to determine the prognosis accurately and to perform anappropriate treatment
Diagnostic techniques in periodontology: a historical review STEVENI GOLD Periodontology 2000, Vol. 7, 1995, 9-21
Advanced periodontal diagnostic techniques
Text book of Carranza's clinical periodontology, Second south Asia Edition
Advances in clinical diagnosis
GINGIVAL BLEEDING
• Indicator of inflammatory lesion
• Relation to disease activity is unclear.
• Normal probing force is 0.25N
• Presence is not an indicator but absence indicates health.
Gingival temperature
• Kung et al (1990) claim that thermal probes are sensitive diagnostic devices for measuring early inflammatory changes in gingival tissue.
• Subgingival temperature at diseased sites is increased as compared to normal healthy sites
• Commercially available system PerioTemp probe enables the calculation of temperature differential (with sensitivity of 0.10C) between the probed pocket and subgingival temperature
Kung RT, Ochs B, Goodson JM: Temperature as a periodontal diagnostic. J Clin Periodontol 1990; 17:557
• Possible explanation for increase temperature with increasing probing depth is an increase in cellular and molecular activity caused by increased periodontal inflammation
• Haffajee et al. (1992): found that elevated subgingival site temperature is related to attachment loss in shallow pockets and elevated proportions of Pg, Pi, Tf, Aa
• Smokers have differences in sub gingival temperature and sublingual temperature
Periodontal probing
• Most widely used diagnostic tool
• Probing depth is measured from the free gingival margin to the depth of the probeble crevice.
• Longitudinal measurement of CAL or probing depth is a ‘gold standard’ for recording changes in periodontal status
Limitation of conventional probing
Lack of sensitivity and reproducibility.
Disparity between
measurement depends on:
probing technique,
probing force, angle of
insertion of probe, size of
probe, precision of calibration,
presence of inflammation.
Readings of clinical pocket
depth measured with probe does
not coincide with the histologic pocket depth.
All these variable contribute to the
large standard deviations (0.5-
1.3 mm) in clinical probing results
Classification of periodontal probesdepending on generation
1.First generation probes: (conventional probes)
Conventional manual probes that do not control probing force or pressure and that are
not suited for automatic data collection.
Williams periodontal probe CPITN probe UNC-15 probe Goldman Fox probe
Comparison of a Conventional ProbeWith Electronic and Manual Pressure Regulated Probes. Dorothy A. Perry," Edward J. Taggart/ Angela Leung/ and Ernest Newbrurt J Periodontol 1994; 65:908-913
2.Second generation probes: (Constant force probes)
• Study done by Tupta et. Al ,Hunter (1994) has shown that
• force to probe pocket: 30g
• force to probe osseous defect: 50g
• Introduction of constant force or pressure sensitive probes allowed for improved standardization of probing.
e.g.: Pressure sensitive probe
Constant pressure probe
• Limitation: data readout and storage is inaccurate
• 3.Third generation probe:(Automated probes)
• Computer assisted direct data capture was an important step in reducing examiner bias and also allowed for generation of probe precision. (according to NIDCR criteria)
• Toronto probe
• Florida probe
• Inter probe
• Foster Miller probe.
FLORIDA PROBE
• Tip is 0.4mm
• Sleeve- edge provides reference to make measurements
• Coil Spring; provides constant probing force
• Computer for data storage
Comparison of a Conventional Probe With Electronic and Manual Pressure RegulatedProbes. Dorothy A. Perry," Edward J. Taggart/ Angela Leung/ and Ernest Newbrurt J Periodontol 1994; 65:908-913.
FP Hand piece tip with constant force in use (tip at bottom of sulcus) and sleeve properly positioned at the top of thegingival margin allowing the computerto measure the difference (3.0 mm).
FP Handpiece tip as it enters the sulcus
• Clark and Yang (1992): trained operators and performing the ‘double pass’ method, the measurements taken with Florida probe system shows lower standard deviation than those obtained with conventional probing.
• Mean Standard Deviation for CAL of about 0.3mm, which is superior to an average of 0.82mm reported by Haffajee et al. For conventional probing.
Disadvantages of Florida probe.Lack of tactile sensitivityFixed probing forceUnderestimation of deep periodontal pockets
Description and clinical evaluation of a new computerized periodontal probe-the Florida Probe –journal of clinical periodontology Volume 15, Issue 2 February 1988 Pages 137–144
• 4.Fourth generation probes: (Three dimensional probes) (WATTS 2000)
• Currently under development, these are aimed at recording sequential probe positions along a gingival sulcus.
• An attempt to extend linear probing in a serial manner to take account of the continuous and three dimensional pocket that is being examined.
• 5.Fifth generation probe: (3D + Noninvasive)
• Basically these will add an ultrasound to a fourth generation probes.
• If the fourth generation can be made, it will aim in addition to identify the attachment level without penetrating it.
• e.g.: Ultra sono graphic probe.
Advances in Radiographic Assessment• Dental Radiographs are traditional method to assess destruction of alveolar bone.
• “Conventional radiographs are very specific but lack sensitivity”
• Primary criterion for bone loss is the distance from CEJ to the alveolar crest and distance more than 2 mm is considered as the bone loss.
• But variability affecting conventional radiographic technique are,
Variation in projection geometry
Variation in contrast and density
Masking by other anatomic structures.
Radiographic diagnosis in Periodontics MARJORIKE. JEFFCOAT, I.-CHUNGW ANG& MICHAELS. REDDY Periodontology 2000, Vol. 7, 1995, 54-68
Digital radiography
• Capturing radiographic image using a sensor
• The first direct digital imaging system, RadioVisioGraphy (RVG), was invented by Dr. Frances Mouyens.
• Advantages
Elimination of chemical processing
Increased efficiency and speed of viewing
Diagnostic information can be enhanced
Computerized storage of radiographs
Reduced exposure to the radiation
Fundamentals of periodontics- WILSON and KORMAN
Uses a Charge Couple Device (CCD) or CMOS sensor linked with fiber optic or other wires to computer system
CCD receptor is placed intra orally as traditional films ,images appear on a computer screen which can be printed or stored
Text book of Carranza's clinical periodontology, Second south Asia Edition
Subtraction radiography
• Subtraction radiography was introduced to dentistry in 1980 by Ruttimann, Webber et & Grondahl HG
• This is a technique by which images not of diagnostic value in a radiograph, are eliminated so that changes in the radiograph can be precisely detected
Fundamentals of periodontics- WILSON and KORMAN
• This technique requires a paralleling technique to obtain a standardize geometry and accurate super imposable radiographs
• This technique facilitates both quantitative and qualitative visualization of even minor density changes in the bone
• Bone gain appears as light areas and bone loss appears as dark areas
• Rethman et al.(1985): increased detectability of small osseous lesions by substraction method compared with conventional radiography
Recent image subtraction:“diagnostic
subtraction radiography” (DSR)
Modification
Use of a positioning device during film exposure
Image analysis software system applies an algorithm to correct
angular alignment discrepancies.
Ortmann (1994)- 5% of bone loss can be detected.
Diagnostic subtraction radiography (DSR) can be used
for enhanced detection of crestalor periapical bone density
changes and to evaluate caries progression
Computer Assisted Densitometric Image Analysis (CADIA)
• Video camera measures the light transmitted through radiograph and the signals form the camera is converted to gray scale image.
• Camera is interfaced with an image processor
• Advantage
• Measures quantitative changes in bone density longitudinally.
• Higher sensitivity, reproducibility and accuracy as compared to DSR.
Computed tomography (CT)
• In 1972, Godfrey Hounsfield announced the invention of a revolutionary imaging
technique, which he referred to as “computerized axial transverse scanning”
• Fan shaped X-ray source is used
• The computed tomographic image is reconstructed by computer, which
mathematically manipulates data obtained from multiple projections.
• Computed tomography is a specialized radiographic technique that allows
visualization of planes or slices of interest
Textbook Of Dental & Maxillofacial Radiology 2nd Edition by Karjodkar
Advantages over conventional radiography
• eliminates the super imposition of images of structures superficial or deep to the area of interest.
• Because of inherent high contrast resolution, differences may be distinguished between tissues that differ in physical density by less than 1%.
• multiple scans of a patient may be viewed as images in the axial, coronal, or sagittal planes depending on the diagnostic task, referred to as multi planar imaging.
Application of CT• Used when accurate information regarding the topography of osseous
structure is needed
• Soft tissue contour and dimension
• To check continuity and density of the cortical plates
• vertical height of the residual alveolar ridges
• density of the medullary space and basilar bone
• when determining how much space is available above the mandibular canal or amount of bone below maxillary sinus to receive a dental implant or whether there is a space occupying lesion in the maxillofacial region.
Textbook Of Dental & Maxillofacial Radiology 2nd Edition by Karjodkar
Disadvantages of Computed Tomography
• specialized equipment and setting.
• Radiologists and Technicians need to be knowledgeable of the anatomy, anatomic variants and pathology of the jaws
• higher radiation
• Metallic Restorations can cause ring artifacts that impair the diagnostic quality of the image
HELICAL CT
Introduced in 1989
The gantry containing x ray tube and detectors continuously revolve around the patient ,where as patients table advances through the gantry.
Result is acquisition of a continuous helix of data.
Cone-beam Computed Tomography
• Routine use of CT in dentistry is not accepted due to its cost, excessive radiation, and general practicality.
• In recent years, a new technology of cone-beam CT (CBCT) for acquiring 3D images of oral structures is now available to the dental clinics and hospitals.
• It is cheaper than CT, less bulky and generates low dosages of X-radiations.
• The innovative CBCT machine designed for head and neck imaging are comparable in size with an ortho pantomogram.
Textbook Of Dental & Maxillofacial Radiology 2nd Edition by Karjodkar
ADVANTAGES
• It gives complete 3D reconstruction
• CBCT units reconstruct the projection data to provide inter relational images in three orthogonal planes (axial, sagittal, and coronal).
• Its beam collimation enables limitation of X-radiation to the area of interest.
• Patient radiation dose is five times lower than normal CT, as the exposure time is approximately 18 seconds, that is, one-seventh the amount compared with the conventional medical CT.
• Reduced image artefacts
Indications of CBCT Evaluation of the jaw bones which
includes the following:
Bony and soft tissue lesions
Periodontal assessment
Soft tissue CBCT for the measurement of gingival tissue and the dimensions of the dentogingival unit
Alveolar bone density measurement
Temporomandibular joint evaluation
Implant placement and evaluation
Whenever there is need for 3D reconstructions
INTERFACE CONE-BEAM CT MANAGEMENT SOFTWARE
CT vs CBCT
Conventional CT scanners make use of a fan-beam and Provides a set of consecutive slices of image
Conventional CT makes use of a lie-down machine with a large gantry.
Greater contrast resolution &More discrimination between different tissue types (i.e. bone, teeth, and soft tissue)
Utilize a cone beam, which radiates from the x-ray source in a cone shape, encompassing a large volume with a single rotation.
a sitting-up machine of smaller dimensions
Commonly used for hard tissueEase of operationDedicated to dentalBoth jaws can be imaged at the same time
Lower radiation burden
OTHER NEWER TECHNIQUES
• Micro Computed Tomography
• Denta scan -pre-operative planning of endosseous dental implants and subperiosteal implants
• SIMPLANTS-Computer program for assessing oral implant site
• TACT-tuned aperture CT
• BONE SCANNING or RADIONUCLIDE IMAGING-technique assesses biochemical alteration in body , It Is a nuclear scanning test that identifies new areas of bone growth or breakdown.
Advances In Microbiologic Analysis
Uses of microbiologic analysis
1. support diagnosis of various Periodontal disease
2. Can tell about initiation & progression
3. To determine which periodontal sites are at high risk for active destruction
4. Can also be used to monitor Periodontal therapy
Diagnosis of periodontal disease based on analysis of the host Response B. LAMSTER & JOHN T. GRBIC Periodontology 2000, Vol. 7, 1995, 83-99C
Advances In Microbiologic Analysis includes:1. Immunohistodiagnostic methods
2. Enzymatic methods
3. Molecular biology techniques
• Nucleic acid probes
• Checkerboard DNA-DNA hybridization
• PCR
Sample collection
• It is a common need of all the microbiologic analysis to collect an
appropriate subgingival plaque sample
• Mombelli et al. (2002) have shown that four individual subgingival
specimens, each from the deepest periodontal pocket in each quadrant,
should be pooled to be able to detect the highest amount of pathogens.
• Transport the specimen in an anaerobic environment
IMMUNODIAGNOSTIC METHODS
• Immunological assays use fluorescent conjugated antibodies that recognizespecific bacterial antigens, and the identification of these specific antigen-antibody reactions allows the detection of target microorganisms.
• This reaction can be visualized using a variety of techniques and reactions:
1. Direct (DFA) and indirect (IFA) immunofluorescent assays
2. Flow cytometry
3. Enzyme-linked immunosorbent assay (ELISA)
4. Latex agglutination
Page RC: Host response tests for diagnosing periodontal diseases. J Periodontol 1992; 63:356.
Immunofluorescent assays
• Direct IFA: AB conjugated with Fluorescein marker + Bacteria ( Antigen) =
Immuno complex
• Indirect IFA: Primary AB + Bacteria= Immune Complex+ Secondary Fl
conjugated AB
Flow cytometry
• Rapid identification
• Laser or impedence type
• Principle is labelling bacterial cells with both species-specific antibody and a
second fluorescein-conjugated antibody
• This suspension is introduced into flowcytometer, which separates bacterial
cells into an almost single cell suspension
• Limitation is sophistication and cost involved with this procedure
Text book of Carranza's clinical periodontology, Second south Asia Edition
ELISA= Enzyme Linked Immunosorbent Assay
ELISA has been used primarily to detect serum antibodies to periodontal
pathogens.
In research studies to quantify specific
pathogens in subgingival samples
A novel chair side ELISA commercially known as “Evalusite” has been marketed
in Europe and Canada for the chair side detection of 3 periodontal pathogens. Aa,
Pg and Pi
Latex agglutination
Test +ve
MERITS
Quantitative estimate of target species
Not requiring stringent sampling and transport methodology
Higher sensitivity and specificity
DEMERITS
Limited to number of antibodies tested
Not amenable for antibiotic susceptibility
Enzymatic Methods
• Bacteria release specific enzymes. Certain group of species share common enzymatic profile.
• e.g. Tf, PG, Td, and Capnocytophagea species release trypsin like enzyme
Trypsin like enzyme BANA hydrolysis
β-naphthylamide(chromophore)
PERIOSCAN uses this reaction for the identification of this bacterial profile in plaque
isolates
Loesh et al. (1986) detection of these periodontal pathogens by BANA reaction
serves as a marker of disease activity
He also showed that shallow pockets exhibited 10% positive BANA reaction, whereas deep
pockets (7mm) exhibited 80%-90% +ve BANA reaction
Beck et al. (1995) used BANA
test as a risk indicator for periodontal attachment loss
ADVANTAGES
• May be positive in clinically healthy site
• Can not detect sites undergoing periodontal destruction
• Limited organisms detected
• So that, negative results does not rule out the presence of other important periodontal pathogens.
Molecular Biology Techniques
• The principles of molecular biology technique reside in the analysis of DNA, RNA and the structure and function of proteins
• Diagnostic assays require specific DNA fragment that recognize complementary-specific DNA sequences from target microorganisms
• This technology requires bacterial DNA extracted from the plaque sample and amplification of the specific DNA sequence of the target pathogen
Socransky SS, Haffajee AD, Smith C, Martin L, Haffajee JA, Uzel NG, Goodson JM. Use of checkerboard DNA-DNA hybridization to study complex microbial ecosystems. Oral Microbiol Immunol 2004;19:352-362
1. Nucleic acid probes
• A probe is a known, single stranded nucleic acid molecule (DNA or RNA) from a specific pathogen synthesized and labelled with an enzyme of a radio isotope
• Hybridization: Pairing of complimentary strands of DNA to produce a double stranded DNA.
Socransky SS, Haffajee AD, Smith C, Martin L, Haffajee JA, Uzel NG, Goodson JM. Use of checkerboard DNA-DNA hybridization to study complex microbial ecosystems. Oral Microbiol Immunol 2004;19:352-362
Hybridization
Probe DNA
• DMDx and Omnigene are commercially available genomic probes for the detection of Aa, Pg, Pi and Td.
• Van Steenberghe et al. (1999) reported a sensitivity of 96% and specificity of 86% for Aa., and 60% and 82% respectively for Pg in pure lab isolates.
• In clinical specimens, both sensitivity and specificity were reduced significantly, suggestive of cross reactivity with non target bacteria in plaque sample because of the presence of homologues sequences between different bacterial species
Checkerboard DNA-DNA hybridization technology
• Developed by Socransky et.al in 1994
• 40 bacterial species can be detected using whole genomic digoxigenin-labeled DNA probes.
• Applicable for epidemiologic research and ecological studies
Socransky SS, Haffajee AD, Smith C, Martin L, Haffajee JA, Uzel NG, Goodson JM. Use of checkerboard DNA-DNA hybridization to study complex microbial ecosystems. Oral Microbiol Immunol 2004;19:352-362
Polymerase chain reaction (PCR)
• Repeated cycles of oligonucleotide (primer)–directed DNA synthesis of “target sequences” are carried out in vitro.
• The PCR method is considered the fastest and most sensitive method available for detecting the presence of bacterial DNA sequences
• A modification of the original PCR technology, "real-time" PCR, permits not only detection of specific microorganisms in plaque, but also its quantification.
• Advantages
• High detection limit. As less as 5- 10 cells can be amplified and detected.
• Less cross reactivity under optimal conditions
• Many species can be detected simultaneously
• Disadvantage
• Small quantity needed for reaction may not contain the necessary target DNA
• Plaque may contain enzymes which may inhibit these reactions.
Biochemical test kits
• Biochemical test kits used in periodontics analyze the gingival crevicularfluid (GCF).
• Since this fluid is derived from periodontal tissues, evaluating its constituents such as host-derived enzymes, inflammation mediators and extracellular matrix components may provide early signs of alterations.
CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
PERIO 2000
This test kit was released in the year
1993.
It detects elevated levels of MMPs in
the gingival crevicular fluid such
as the elastases.
The GCF is collected onto the
filter paper strip impregnated with a known amount
of buffered elastase substrate
labeled with a fluorescent indicator.
Elastase on the test strip cleaves
the substrate during the
reaction time of 4-6 minutes and
releases the indicator, visible
under fluorescent light.
Elastase is released from the lysosomes
of polymorphonuclear
leucocytes which accumulate at sites
of gingival inflammation.
The levels of these enzymes in
GCF have been noted to increase
with the development of gingivitis as well
as sites of established
periodontitis
CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
PERIOGARD
PerioGard is based on the detection of an enzyme called aspartate
aminotransferase(AST). AST is a soluble intracellular cytoplasmic
enzyme that is released from within the cell upon its death. Since cell
death is an important part of periodontal pathogenesis,
AST levels in GCF have great potential as markers of early periodontal tissue destruction. Elevated total AST levels
in a 30-second sample have been positively associated with disease-
active sites in contrast to inactive sites
CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
The test involves collection of GCF with the filter paper strip
which is then placed in trimethamine hydrochloride
buffer.
A substrate reaction mixture containing 1-aspartic and α-keto-
gluteric acid is added to the sample and allowed to react for ten
minutes. In the presence of AST, the Aspartate and α-keto-gluteric acid are catalyzed to oxaloacetate and
glutamate.
The addition of a dye such as fast red results in a colorproduct,the intensity of
which is proportional to the AST activity in the GCF
sample
POCKET WATCH
• The Pocket Watch was developed as a simple method of analyzing AST at the chairside .
• The principle of this test is that, in the presence of pyridoxal phosphate, AST catalyzes the transfer of an amino group of cysteine sulfuric acid by α- keto- glutericacid to yield β-sulfinylpyruvate.
• Glutamate β-sulfinyl pyruvate spontaneously and rapidly decomposes
• The sulphite ion instantaneously reacts with malachite green (MG), simultaneously causing MG to convert from a green dye to its colorless form, thereby allowing the pink–colored rhodamineB dye to show through.
• The rate of conversion of MG is directly proportional to AST concentration. However, components of the extracellular matrix and its dissolved products are present in GCF of destructive pockets, and they may release sulfide ions.
CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
• PST® genetic susceptibility test
• Periodontal susceptibility test (PST®) is the first and only genetic test that analyzes two interleukins (IL-1α and IL-1β) genes for variations.
• IL-1 genetic susceptibility may not initiate or cause the disease but rather may lead to earlier or more severe disease.
• The IL-1 genetic test can be used to differentiate certain IL-1 genotypes associated with varying inflammatory responses to identify individuals at risk for severe periodontal disease even before the age of 60.
CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
• Clinically, PST is used in
• New periodontal patients to assist in developing treatment plans.
• Patients requiring extensive periodontal and/or implant therapy to determine prognosis, improve patient acceptance and optimize treatment outcomes.
• Smoking patients as an additional incentive for smoking cessation.
• This discussion directly translates into improved periodontal therapy by offering the clinician, the radiographic & laboratory measure of periodontal infection as an adjunct to traditional clinical indices of periodontal disease.
• Future application of advanced diagnostic techniques will be of value in documenting disease activity and treatment options
• But, despite excellent progress in diagnostic methodology,conventionalefforts evaluating inflammation and past evidence of tissue breakdown remain the standard for disease evaluation
COMMON COMMERCIAL DIAGNOSTIC AIDS AND THEIR USES
PERIOTEMP - GINGIVAL TEMPERATURE
PERIOTEST - TOOTH AND IMPLANT MOBILITY
OSSTELL APPARATUS - IMPLANT MOBILITY
PERIOSCOPY - DETECTION OF CALCULUS
KEYLASER3 - DETECTION AND REMOVAL OF CALCULUS
PERIOSCAN - DETECTION OF BANA ORGANISMS
HALIMETER - HALITOSIS
DIGORA - DIGITAL RADIOGRAPHY
NEWTOM QR-DVT - CBCT
ULTRADENT - ULTRASONIC IMAGING
PERIOCHECK - NEUTRAL PROTEINASE
PROGNOSTIK ,BIOLISE - ELASTASE
PERIOGUARD - AST
POCKET WATCH - AST
TOPAS - BACTRIAL TOXINS AND PROTEASES
MICRODENT TEST - PCR for Pg,Aa,Tf,Td
My PERIO PATH - RT-PCR
My Perio ID - Genetic susceptibility test
OMNI GENE - NUCLEIC ACID PROBE
REFERENCES
• Socransky SS, Haffajee AD, Smith C, Martin L, Haffajee JA, Uzel NG, Goodson JM. Use of checkerboard DNA-DNA hybridization to study complex microbial ecosystems. Oral Microbiol Immunol 2004;19:352-362
• Periodontology 2000. Vol. 7, 1995
• CHAIRSIDE DIAGNOSTIC TEST KITS IN PERIODONTICS - A REVIEW by Sachin Malagi ,IAJD ,Vol 3
• Text book of Carranza's clinical periodontology, Second south Asia Edition
• Kung RT, Ochs B, Goodson JM: Temperature as a periodontal diagnostic. J Clin Periodontol 1990; 17:557
• Host response tests for diagnosing periodontal diseases. J Periodontol 1992; 63:356.
Host response tests for diagnosing periodontal diseases. J Periodontol 1992; 63:356.
Description and clinical evaluation of a new computerized periodontal probe-the Florida Probe –journal of clinical periodontology Volume 15, Issue 2 February 1988 Pages 137–144
Loesche WJ: The identification of bacteria associated with periodontal disease and dental caries by enzymatic methods. Oral Microbiol Immunol 1986; 1:65.
Comparison of a Conventional ProbeWith Electronic and Manual Pressure RegulatedProbes. Dorothy A. Perry," Edward J. Taggart/ Angela Leung/ and Ernest NewbrurtJ Periodontol 1994; 65:908-913
Fundamentals of periodontics- WILSON and KORMAN
Textbook Of Dental & Maxillofacial Radiology 2nd Edition by Karjodkar
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