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ADVANCED DIAGNOSTIC TECHNIQUES IN PERIODONTICS INTRODUCTION In light of advances in clinical and basic science research,our understanding of the initiation and progression of periodontal diseases and the pathogenic process involved has expanded enormously. CONVENTIONAL PERIODONTAL DIAGNOSIS - LIMITATIONS Conventional diagnosis of periodontal diseases include clinical evaluation of inflammation in gingivitis, clinical attachment loss with radiographic assessment of bone loss in periodontitis. This information provides only the evidence of past periodontal destruction and its extent & severity. This doesn't provide the information on cause of the condition, patients susceptibility to the disease, disease progression or remission & response to the therapy. Hence many advances are made to include; immunologic Microbiologic systemic genetic behavioral factors in addition to the traditional clinical & radiographic parameters. ADVANCES IN CLINICAL DIAGNOSIS 1.Gingival bleeding: It is the sensitive indicator of early gingival inflammation. The severity of bleeding increases with an increase in size of the inflammatory infiltrate. It can be evaluated using periodontal probe or a wooden interdental cleaner. A force greater than 0.25N may evoke bleeding in healthy sites with an intact periodontium. The sites that bled on probing at several visits has the higher probability of loosing attachment than those that bled at one visit or did not bleed. 2.Gingival temperature: • Active periodontitis can create measurable rise in sulcular temperature. • Thermal probes like Periotemp probe detects the temp differences of 0.1*c from a referenced sub gingival temperature. • Higher temperature are signaled with red indicator and has more than twice the risk for future attachment loss than did those of green indicator. 3.Periodontal probe: • The main disadvantage of traditional periodontal probing is its lack of sensitivity and reproducibility which is due to difference in Probing technique, Force of probe, Size of probe, Angle of insertion of the probe and Precision of the probe calibration. • This contributes to deviation of about 0.51.3mm making detection of small changes difficult. Classification of periodontal probes: Generation 1: conventional hand held probe. WHO Generation 2: pressure sensitive probe. Vivadent Generation 3: computerized probe. Florida, Foster Miller Generation 4: probes aimed at recording sequential probing along the sulcus. Generation 5: ultrasonic device attached to the fourth generation probe. NIDCR-National institute of cranio facial research Defined nine criteria for overcoming these limitations. They are: 1. 2. 3. 4. 5. 6. 7. 8. Precision Range Probing force Applicability Reach Angulations Security Readout - 0.1mm -10mm - constant and standardized - non-invasive, light weight &easy to use - easy to access - a guidance system for proper - complete sterilization and no biohazard - direct electronic reading and digital output. Following these criteria • Florida probe system was developedconsists of probe hand piece with coil springs, digital readout, footswitch and computer. * Advantage - constant probing force with precise electronic measurement and computer storage of data * Disadvantages – lack of tactile sensitivity and predetermined insertion point and angle producing inaccurate measurement and patient discomfort. PRESSURE SENSITIVE PROBE FLORIDA PROBE • Foster-Miller probe has coupling effect by determining the pocket depth and CE junction from which clinical attachment level is automatically detected. • Toronto automated probe: has 0.5mm nickel-titanium wire that is extended under air pressure with the mercury tilt sensor that limits the angulations to +_30* • The development of these probes will allow more sensitive assessments of disease progression. ADVANCES IN RADIOGRAPHIC ASSESSMENT • The substantial amount of bone loss(>30%)at alveolar crest must be there for a change in bone height should be recognized on a conventional radiograph. LIMITATIONS: • projection geometry, • film processing, voltage and exposure time, • masking of osseous changes by other anatomic structures. 1.DIGITAL RADIOGRAPHY: • It enables the use of computerized images that can be stored manipulated and corrected for under and over exposures. • There is important dose reduction obtained with technique( 1/3 to 1/2). • Based on the sensor, digital radiography can be divided as the direct and indirect methods. • Direct method-uses a charged coupled device(CCD)sensor linked with a fiber optic to the computer.The disadvantage being limited sensor rigidity making sterility and image projection using film holders is very difficult. CONTD:… • Indirect method(Digora system)-uses phosphor luminescence plate which is a flexible film like sensor placed intra-orally and exposed to conventional x-ray tube. large scanner reads the exposed plate and reveals the digital image. 3.COMPUTER-ASSISTED DENSITOMETRIC IMAGE ANALYSIS SYSTEM (CADIA) • In this system video camera measures the light transmitted through a radiograph and the signals are converted into gray-scale images in a computer. • It has shown a higher sensitivity, high degree of reproducibility and accuracy. ADVANCES IN MICROBIOLOGIC ANALYSIS: Micobiologic analysis have the potential • To support the diagnosis, • To serve as indicator of disease activity • To determine the site at higher risk and • To monitor periodontal therapy. BACTERIAL CULTURING: They are still considered reference method (gold standard). Advantage: the relative and absolute count and antibiotic susceptibility of the microbes are obtained. Disadvantage: 1. media can grow only live bacteria needing strict sampling and transport, 2..sensitivity is rather low and 3..it requires sophisticated equipments,experienced personnel, is relatively time consuming and expensive. DIRECT MICROSCOPY: The morphology and motility of bacteria can be directly assessed, however the main putative organism are nonmotile. IMMUNODIAGNOSTIC METHODS: This employs antibodies that recognize specific bacteria to detect the target microorganism 1)Direct immunofluroscent microscopic assay : • This employs florescent marked antibody to form a complex with bacteria,which is detectable under microscope. • Studies shows 82% to 100% sensitivity for A.actinomycetemcomitans. 2) ELISA: {Enzyme linked immunosorbant assay}: • Here enzyme derived colour reaction is used as label. The intensity of the colour depends on the concentration of the antigen and is read photo metrically. • Used primarily to detect serum antibodies for periodontopathogens. ENZYMATIC METHODS OF BACTERIAL IDENTIFICATION: P.Gingivalis, Treponema denticola, B.forsythus have in common a trypsin like enzyme. The activity of this enzyme can be measured with the hydrolysis of BANA(N-benzoyl-l-arginine-2-naphthylamide) – releases chromophore –turns orange red with fast garnet. Perioscan- diagnostic kit. It is 80%-90% positive in 7mm deep pocket. Disadvantage: • It may be positive in healthy sites. • It detects limited no. of pathogens. PERIO SCAN: DEOXYRIBONUCLEIC ACID PROBE TECHNOLOGY: 1) NUCLEIC ACID PROBES: The probe is prepared by labeling the single strand DNA of specific organism with the radioisotope. The plaque sample is prepared by lyses and denaturation and single strand is attached to specific filter paper and exposed to DNA library. If complementary base pair hybridized isotope will be fixed to the filter paper and is read with a densitometer. The darkness and size indicate conc. of microorganism. It can rapidly test A.a, P.g, Fusobacterium nucleatum. DNA PROBE 2)RESTRICTION ENDONUCLEASE ANALYSIS: Restriction endonucleases recognize and cleaves the double stranded DNA to single stranded DNA,which is then separated by electrophoresis and stained & visualized with UV light. These fragment pattern constitute a specific finger print to each strain. Thus it is a powerful tool for determining specific pathogen. 3.POLYMERASE CHAIN REACTION: • It involves the amplification of a region of DNA by a selected primer of specific specious. the specific amplification product indicates its presence. • It has best detection limits, as few as 510 cells. • It has no cross reactivity. • Drawback- it uses small quantity of plaque sample hence negative results should be reconsidered. ADVANCES IN CHARACTERISING THE HOST RERSPONSE: This refers to the study of mediators like – antibodies which are specific to infection & - the less specific inflammatory mediators, host derived enzymes & tissue breakdown products. Sources of Sample: • saliva, • Gingival crevicular fluid, • blood serum & • urine. GCF SAMPLING: PERIO PAPER 1.Inflammatory mediators and products Research on GCF has focussed on search of potent mediators like • Cytokines- TNF, interleukins which produce metalloproteinase stimulation and bone resorption. • Prostoglandin E2-which induces bone resorption. Therefore they marks the disease progression. 2.Host-derived enzymes: • Aspartate amino transferase -released from dead cell. It is increased in GCF from sites with severe gingival inflammation and a progressive attachment loss. Chair side kit(Periogard)is available to detect this. • Alkaline phosphatase -found in osteoblast,fibroblast and neutrophils.It is significantly higher in diseased sites,showing the progression of periodontitis. •Beta glucorinidase, elastase are the enzymes found in neutrophils are elevated in periodontitis. •Elastase- is a protease stored in azurophilic granules of neutrophils.Periocheck is a chairside kit to detect neutral proteases in GCF. • Matrix metalloproteinases released from fibroblast and macrophages, increased in destructive periodontitis. 3.Tissue break down products: Periodontitis is the destruction of collagen and extracellular matrix, producing hydroxyproline and glycosaminoglycans respectively. Alveolar bone loss can be correlated with osteocalcin. • GCF from these sites shows elevated level of these products. • However no rapid chair side kit has been developed for clinical use. • CONCLUSION After all these years of intensive research, we still lack a proven diagnostic tests that has demonstrated high predictive value for disease progression, has a proven impact on disease incidence & prevalence and is simple & cost effective. THANK YOU