Efficacy of Diagnostic Techniques for Periodontal Diseases Flashcards
How is periodontal disease diagnosed?
Almost entirely on the basis of its clinical manifestations
- Signs of gingival inflammation
- Perio probing
- Tooth mobility
- Furcation involvement
- Radiographs
What are some diagnostic methods for periodontitis not routinely used in clinical practice?
Microbiologic Testing
Assessment of the Host Response
Genetic Analysis
Why isn’t Microbiologic testing frequently used for periodontal diagnosis?
It’s expensive and well-trained personnel is required
Assessment of the Host Response
Biochemical analysis as part of periodontal diagnosis
Source of samples: GCF, saliva, and blood serum
Genetic Analysis
There is a genetic susceptibility to periodontitis
Gene polymorphism can be used as a risk marker for periodontitis
What are the limitations of periodontal probing as a diagnostic tool?
Lack sensitivity and reproducibility
Probing depth can be altered by inflammation, insertion force, plaement/angulation, size, technique, probe calibration, presence of subgingival calculus, overhang restorations
What are the limitations of clinical attachment levels as a diagnostic tool for periodontitis?
Poor reliability and reproducibility
Limited practical value
What are the limitations of Radiographic examination as a diagnostic tool for periodontitis?
Limited sensitivity in small bone change
-Changes in bone can be identified by the eye only after 30-50% of bone mineral has been lost
No value in evaluating disease activity or progression
Ultrasonic Periodontal Probing
Ultrasonic periodontal probe that uses a hollow, tapered tip that is filled with water for coupling of the ultrasonic beam into tissues
Cone-beam Computed Tomography
Recently been introduced for the detection of periodontal defects in in vitro settings
A promising tool for periodontal applications, especially for intrabony defects, dehiscence and fenestration defects, periodontal cysts, furcation defects, periodontal cysts, furcation defects, and thickness of palatal masticatory mucosa
Sensitivity of a diagnostic tool
Refers to the probability the test being positive when diseases is truly present
sensitivty = true positive/(true positive + false negative)
Specificity of a diagnostic tool
Refers to the probability the test being negative when disease is truly negative
specificity = true negative/(true negative + false positive)
Bacterial Culturing
Gold standard method
Assess for antibiotic susceptibility of microbes
Sensitivity is low: detection limits for selective and nonselective media average 10^4 to 10^5 bacteria
Relatively time consuming and expensive
Direct Microscopy
Alternative to culture methods
Dark-field or phase-contrast microscopy
Morphology and motility of bacteria in a plaque sample
Most of the main putative perio pathogens are non-motile (so its difficult to identify)
Immunodiagnostic methods
Use Ab that targets specific bacterial antigens
What are the different Immunodiagnostic methods?
Direct and indirect immunofluorescent microscopic assay
Cytofluorography
Enzyme-linked immunosorbent assay
Latex agglutinaiton
Direct and indirect immunofluorescent microscopic assay
Able o identify pathogens using a plaque smear
Used to detect mainly Aa and Pg
Comarable to bacterial culture, but doesn’t require viable cells
Cytofluorography
Complexity and cost prevents this form being used
Enzyme-linked immunosorbant assay (ELISA)
Used primarily to detect serum antibodies to periodontal pathogens
Latex agglutination
Based on the binding of protein to latex
Latex beads are coated with a special antibody
Currently, these assays are only for research purposes
Enzymatic Methods
Several putative perio pathogens possess a common trypsin-like enzyme that hydrolyzes BANA - test for the hydrolysis
Test may be positive in healthy tissues
Negative results does not rule out presence
Molecular Biology Techniques
Analysis of DNA, RNA, and structure or function of proteins form target microorganisms Examples: -Nucleic acid probes -Checkerboard DNA-DNA hybridization -PCR -Real-time PCR
What are sources of samples for Assessment of the Host Response?
Saliva GCF Blood serum Blood cells Urine
What are the two types of Host-derived Enzymes?
Intracellular destruction enzymes
Extracellular destruction enzymes
Intracellular destruction enzymes
Possible markers of active periodontal destruction
Released from dead or dying neutrophils from periodontium
Aspartate amino-transferase
Released during tissues desctruciton
A marked elevation in AST levels in GCF from sites with severe gingival inflammation
Cannot discriminate between sites with or without attachment loss
What are examples of intracellular destruction enzymes?
Aspartate amino-transferase
Alkaline phosphataase
B-glucuronidase
Elastase
Alkaline phosphatase
A membrane-bound glycoprotein involved in maintenance of alveolar bone
Higher in diseased than healthy sites
B-glucuronidase
A lysozomal enzyme that degrades proteoglycans and ground substances
Higher in diseases sites
Elastase
A proteolytic enzyme found in lysozomal granules of neutrophils
Extracellular destruction enzymes
Associated with the activity of matrix metalloproteinases
Produced by inflammatory, epithelial, and connective tissue cells
Matrix Metalloproteinases
Extracellular destruction enzyme
Secreted by fibroblasts and macrophages
Responsible for remodeling and degrading ECM
High MMP levels are greater risk for progression of periodontitis - levels are reduced in response to treatment
What makes up the ECM of periodontium?
Collagen
Proteoglycans
Non-collagen proteins
What enzymes can be found in the GCF of periodontally diseased sites?
Hydroxyproline (breaks down collagen)
Glycosaminoglycans
Osteocalcin
Type I collagen
What are the “Inflammatory mediators”
Cytokines:
- TNF-a
- IL-1(a and B)
- IL-6
- IL-8
- PGE2
Bio-Plex Cytokine Assay
Incorporates novel technology using color-coded beads, permitting the simultaneous detection of up to 100 cytokines in a single well of a 96-well microplate
Designed to quantitate multiple cytokines in tissue fluid (including GCF)
Infra-red Spectroscopy
Measure the total contents of GCF
Can be used to characterize GCF from healthy, gingivitis, and periodontitis sites
Light is passed through and what wavelengths are absorbed can determine a molecular “fingerprint”
Near infra-red Spectroscopy
Measure of oxygen saturaiton in tissues
Wavelength region of 500-600 is dominated by the absorption from oxygenated hemoglobulin and deoxygenated hemoglobulin
Tissue oxidation at periodontitis sites is significantly lowered as compared to gingivitis or healthy gingiva
When can saliva analysis be useful in diagnosing periodontitis?
It can be a cost-effective approach to screening periodontal disease in large populations
