Efficacy of Diagnostic Treatments Flashcards
(28 cards)
What are the current diagnostic methods used for periodontal diseases?
Periodontal disease is currently diagnosed almost entirely on the basis of its clinical manifestations
- sign of gingival inflammation: redness and swelling
- periodontal probing: PD, BOP, CAL
- tooth mobility
- furcation involvement
- radiographs: bone changes - amount of bone loss
**(periodontal examination and radiographs are traditionally used diagnostic procedures for people over the age of 50)
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What are some diagnostic techniques and methods for periodontal diseases that are not routinely used in clinical practice?
- Microbiologic testing
- Assessment of the Host response
- genetic analysis (only for research)
How is microbiologic testing used as a diagnostic technique for periodontal diseases?
These are expensive and require well-trained personnel to conduct these tests (obtain saliva and plaque for testing)
- bacterial culturing
- direct microscopy
- immunodiagnostic methods
- enzymatic methods
- molecular biology techniques
How do you assess the host response to diagnose periodontal diseases?
- this is an biochemical analysis of host as part of periodontal diagnosis:
- some sources of samples to test are are GCF (most commonly used), saliva, and serum (Blood)
How can genetic analysis be be used to diagnose periodontal disease?
- there is a genetic susceptiloitilty to periodontitis
- gene polymorphism is a risk marker for periodontitis
What are some limitations of using probe penetration as a diagnostic method?
- lack of sensitivity and reproducibility
- probing depth depends on : gingival inflammation, insertion force, placement and angulation, size, probing technique, probe calibration, presence of sub gingival calculus, overhand restorations
what are some limitation of using CAL as a diagnostic method?
- poor reliability and reproducibility
- limited practical value
what are some limitation of using radiograph examination as a diagnostic method?
- limited sensitivity in small bone change
- changes in bone can be identified by eye only after 30% to 50% of the bone mineral has been lost (subtraction radiography: detect bone density change as low as 5%)
- no value in evaluating disease activity or progression
What is a ultrasonic periodontal probing?
ultrasonic periodontal probe uses a hollow tapered tip that is filled with water for coupling of the ultrasonic beam into the tissues (non-invasive)
What is cone-beam computed tomography?
- conventional radiographs (PA; Pano) are very specific, but lack sensitivity
- recently, CBCT has been introduced in periodontology for the detection of periodontal defects in in vivo settings
- CBCT is promising for periodontal applications, especially for intrabony defects, dihiscence and fenestration defects, periodontal cysts, furcation defects and thickness of palatal masticatory mucosa
what is bacteria culturing for diagnostic testing?
- is the gold standard (reference) method for microbe testing
- assess for antibiotic susceptibility of microbes
- can only grow live bacteria; strict sampling and transport conditions are essential
- some putative pathogens are fastidious and difficult to culture
- sensitivity is low: detection limits for selective and nonselective media average 10^4 to 10^ 5 bacteria
- sophisticated equipment and experienced personnel required; relatively time- consuming and expensive
What’s direct microscopy for diagnostic testing?
- alternative to bacterial culture methods
- dark-field or phase-contrast microscopy
- see the morphology and motility of bacteria in a plaque sample
- most of the main putative perio pathogens are non-motile (so its is difficult to identify)
what are some immunodiagnostic methods for diagnostic testing?
use Ab that targets specific bacteria Ag
- direct and indirect immunofluorescent microscopic assay (IFA)
- able to identify pathogens using a plaque smear
- used mainly to detect Aa and Pg
- comparable to bacterial culture
- does not require viable bacterial cells
- cytoflurorography (flow cytometry)
- complexity and cost prevent its wide use
- enzyme-linked immunosorbent assay (ELISA)
- used primarily to detect serum antibodies to periodontal pathogens
- membrane immunoassay (Evalusite): chairside use to detect Aa, Pg, and Pi (detection limit of 10^5 for Aa and 10^6 for Pg)
- latex agglutination:
- based on the binding of protein to latex: latex beads are coated with species-specific antibody
- currently these assays only for research purposes
what are some enzymatic methods for diagnostic testing?
- several putative periodontal pathogens such as Pg, Tf, and Aa possess in common have a trypsin-like enzyme that hydrolyzes a subtract N-benzoyl-DL-arginine-2- naphthylamide (BANA)
- chair-side kit (Perioscan) was available in the 1990’s
- inability to distinguish between individual bacteria
- it may be positive at clinically healthy sites
- negative result doesn’t rule out the presence of other important periodontal pathogens
What are some molecule biology techniques for diagnostic testing?
Analysis of DNA, RNA, and structure or function of protein from target microorganisms
- Nucleotide acid probes
- synthesized and labeled DNA (20-30 nucleotides)
- genomic DNA probe (whole DNA strand); significantly decreased in sensitivity and specific due to cross-reactivity to non-target microorganism
- 16s rRNA - oligonucleotide probes (high sensitivity and specificity)
- checkerboard DNA-DNA hybridization
- whole genomic digoxigenin-labebled DNA
- up to 40 oral bacterial species in a single test
- not been generalized for diagnostic purpose
- PCR
- high sensitivity and specificity for the identification of target pathogens
- PCR lower detection limit: 25-100 cells (culture: 10^4-10^5 cells)
* unable to quantify pathogens accurately in clinical samples
- real-time PCR
* real-time PCR: good correlation between the fluorescent signal measured and the number of bacterial cells been used
* expensive and sophisticated technology in real-time PCR
How do you collect GCF?
- paper strips are placed within the crevice for 30 seconds
- fluid volume can be quantified by Periotron
- captured samples may not be present the entire periodontist
- selection of the teeth and sites is often difficult
What do you test when you obtain the GCF?
- over 1166 proteins are present in GCF - 65 of them. We are gong to check for their:
1) host-derived enzymes and their inhibitors
2) by products of tissue breakdown
3) inflammatory mediators and host-response modifiers
host-derived enzymes - what are intracellular destruction enzymes?
- possible markers of active periodontal destruction
- released from dead or dying PMN/neutrophils from periodontium
- aspartate amino-transferase: released during tissue destruction (cell death)
- alkaline phosphatase: a membrane-bound glycoprotein involved in maintenance of alveolar bone
- beta-glucuronidase: a lysosomal enzyme degrades proteoglycans and ground substance
- elastase: a proteolytic enzyme found in lysosomal granules of neutrophils
What are some intracellular destruction enzymes?
Aspartate aminotransferase (AST):
- periogard periodontal tissue monitors (chair side test kit)
- a marked elevation in AST levels in GCF from sites with severe gingival inflammation
- inability to discriminate between sites with sever inflammation with or without attachment loss
Alkaline phosphatase (ALP):
- ALP in GCF are higher in diseased then healthy sites
Beta-glucuronidase (betaG):
- elevated in betaG in GCF from sites with severe periodontal disease
- high sensitivity and specificity when related to occurrence of clinical attachment loss
- good predictor for future periodontal breakdown
Elastase:
- Periocheck (char side test kit)
- positive correlation of elastase in GCF with clinical attachment loss
host-derived enzymes - what are extracellular enzymes?
- associated with the activity of matrix metalloproteinases
- produced by inflammatory, epithelial and connective tissue cells
what is an extracellular destruction enzyme?
Matrix Metalloproteinases (MMPs):
- secreted by fibroblasts and macrophages
- responsible for remodeling and degradation of ECM components
- regulated by tissue inhibitors of MMPs (TIMPS)
- high MMP levels in GCF are at significantly greater risk for progression of periodontitis
- GCF MMPs level reduces in response to treatment
- MMP-2 (gelatinase A), MMP -9 (gelatinase B), MMP-8 (collagenase 2), MMP -13 (collagenous 3), and MMP-3 (Stromelysin-1) involve in the initial destruction of periodontal ECM
What are some tissue breakdown products from the destruction of collagen?
- the ECM of the periodontist is composed of collagen (predominant), proteoglycans (version, decorin, biglycan, syndecan) and non-collagen proteins (elastin, fibronectin, laminin, osteocalcin, and tenascin)
- elevated levels of hydroxyproline (breakdown from collage), glycosaminoglycans (From matrix degradation) and osteoclacin and type I collagen (from alveolar bone destruction) can be found note GCF from sites with periodontitis.
what are some inflammatory mediators from GCF?
Cytokines:
- TNFalpha
- IL-1alpha
- IL-1beta
- IL-6
- IL-8
- PGE2
1) traditional immunoassays analyze only a single cytokine at a time
2) Bio-plex cytokine Assay: multiplex bead-based assays designed to quantitative multiple cytokines
What’s optical spectroscopy - Infrared (IR) spectroscopy)?
- vibrating covalent bonds of organic molecules absorb a characteristic wavelength of IR light
- the wavelength of light absorbed depends on the nature of the covalent bond ( e.g., C=O and N-H), the type of vibration (e.g., bending and stretching), and the environment of the bond
- the spectrum of absorbed light can be used to establish a molecule fingerprint of a tissue or fluid
