ADVANCED DIAGNOSTIC TECHNIQUES LIMITATIONS OF CONVENTIONAL
PERIODONTAL DIAGNOSIS Periodontal diseases are prevalent human
diseases defined by the signs and symptoms of gingival inflammation
and periodontal tissue destruction. These diseases are
conventionally diagnosed by clinical evaluation of the signs of
inflammation in the gingiva without periodontal tissue destruction
(gingivitis) or by the presence of both inflammation and tissue
destruction (periodontitis). The traditional clinical diagnosis is
made by measuring either the loss of connective tissue attachment
to the root surface (clinical attachment loss) or the loss of
alveolar bone (radiographic bone loss). However, this evaluation
cannot reliably identify sites with ongoing periodontal destruction
and does not provide any information on the cause of the condition,
on the patients susceptibility to disease, whether the disease is
progressing, whether it is in remission, or whether the response to
therapy will be positive or negative. The current view of the
natural history of destructive periodontal disease is that disease
susceptibility is related to the whole person rather than the local
site. This means that a persons susceptibility and host defense
mechanisms are generalized. However, the disease process itself is
considered to be site specific and has a multifactorial origin in
which periodontal pathogens, host response, and genetic, systemic,
and behavioral risk factors interplay to develop the disease
process. In light of this information, consideration should be
given to including microbiologic, immunologic, systemic, genetic,
and behavioral factors, in addition to the traditional clinical and
radiographic parameters, when assessing patient status. This topic
systematically reviews the advances made in the use of these
parameters. Advances in clinical diagnosis Gingival temperature
Periodontal probing Dental endoscope Advances in microbiologic
analysis Bacterial culturing Direct microscopy Immunodiagnostic
methods Enzymatic methods of bacterial identification
Deoxyribonucleic acid probe technology[DNA probe] Restriction
Endonuclease analysis Polymerase chain reaction[PCR]
Advances in characterizing host response Source of samples
Inflammatory mediators and products Host derived enzymes Tissue
breakdown products Assessment of susceptible host for markers in
peripheral blood. Advances in radiographic assessment Digital
radiography Substraction radiography Computer assisted
densitometric analysis Computed tomography Magnetic resonance
imaging Nuclear medicine scans SUBGINGIVAL BLEEDING Clinical
evaluation of the degree of gingival inflammation includes
assessment of the redness and swelling of the gingival along with
assessment of gingival bleeding. Gingival bleeding is related to
the persistent presence of plaque on the teeth and is regarded as a
sign of the associated inflammatory response. The use of gingival
bleeding as an indicator of inflammation has the clinical advantage
of being more objective, because color changes require a subjective
estimation. It has also been shown that gingival bleeding is a good
indicator of the presence of an inflammatory lesion in the
connective tissue at the base of the sulcus and that the severity
of bleeding increases with an increase in size of the inflammatory
infiltrate. Therefore, clinicians tend to evaluate gingivitis by
gingival bleeding alone, with the use of a periodontal probe or
signs of both inflammation and bleeding.
Limitations-Lang et al. demonstrated that any force greater than
0.25 N may evokebleeding in healthy sites with an intact
periodontium. Although bleeding on probing may have a limited
predictive value for disease progression, its absence indicates
periodontal stability with high probability. SUBGINGIVAL
TEMPERATURE Local physical changes such as temperature elevation
can be used for prediction of metabolic events occurring in
periodontal tissues. Early studies by Kung et al 1990 linked
subgingival temperature with periodontal pocketing. Maxillary
periodontal sites are hotter than mandibular periodontal sites and
posterior sites are hotter than anterior sites [Haffajee et al
1992]. There is a positive correlation between elevated subgingival
temperature and
-Severity of disease -Degree of gingival inflammation -Presence
of putative pathogens. Subgingival temperature, like other signs of
inflammation has good specificity but poor sensitivity when
considered alone as a marker for progressive periodontitis.
PERIODONTAL PROBING -Widely used diagnostic tool for measurement of
CAL loss. -Increased pocket depth and loss of clinical attachment
level is pathogneumonic sign for periodontitis. -Clinical pocket
depth does not coincide with the histologic pocket depth.-because
probe penetrates the coronal level of the junctional epithelium -If
the tissues are also inflamed then the tissue offer's less
resistance to probe penetration false reading is obtained. The
difference in measurements depends upon the Probing technique
Probing force Size of the probe Angle of insertion of the probe
Precision of the probe calibration Forces up to 30 gm the tip of
the probe seems to be in the junctional epithelium Forces up to 50
gm - necessary to diagnose periodontal osseous defects Various
generations of probe development: Generation I: conventional
probes. Generation II: Pressure sensitive. Generation III:
Computerized. Generation IV & V probes is currently under
development. Generation IV probes aim at recording sequential
probing positions along the gingival sulcus. Generation V: would
have an ultrasonic device attached to the fourth generation probe
for identifying attachment level without penetrating it. Probing
measurements can be affected by incorrect angulation /interference
with the calculus/presence of overhanging restorations Measurements
can also be affected by force applied. Can be overcome by using
automated probes.
Currently used automated probes Florida probes( GIBBS et al)
Features Constant probing force Precise electronic measurement
Computer storage of data Precise early detection of disease Clear
graphic charting Components Probe hand pieces Digital read out 3-
Pedal foot switch Computer interface FEATURES OF HAND PIECE Probe
tips are manufactured by micro polishing technique Constant force
measurements in 0.2 mm Probe tips are 0.4 millimeter in diameter
made of implant grade titanium Can be steam sterilized in a
standard autoclave
Three Pedal foot switch Solo operator may enter all data
Eliminates error in visual reading Less contamination
Computer interface Pocket depth & bleeding sites called out
automatically using sound effects from computer Color coded digital
read outs Educates and motivates patient
Two models Stent model Has 1 millimeter metal collar that rests
on a prepared ledge on a prefabricated vaccuoform stent. Disk model
Has 1 millimeter disk which rests on the occlusal surface/ incisal
edge of tooth. The disk is placed on the occlusal/incisal surface
while measuring the probing a pocket.
Jeffcoat probes [Foster Miller probes] Automatically extends
& retracts under controlled force Rapid change in acceleration
when C-E Junction is crossed Working end of probe has Michigan O
probe markings Internal moving tip Teflon coated stainless steel
wire Circular in cross section & 0.15 millimeter in diameter
Probe motion provided by custom low friction pneumatic cylinder
Toronto probes Uses occlusal incisal surface as reference Sulcus
probed with 0.5 millimeter nickel - titanium wire under air
pressure Mercury tilt sensor limits angulation within 30o
INTER PROBE ( Goodson & Kondon 1988 ) Electronic probe using
an optical encoder transduction element BIREK PROBE Works under
constant air pressure Uses occlusal surface as reference THE DENTAL
ENDOSCOPE A dental endoscope has been introduced recently for use
subgingivally in the diagnosis and treatment of periodontal
disease. Produced by Dental View, Inc.- called as Perioscopy
system. It consists of 0.99mm diameter reusable fibroptic endoscope
over which is fitted a disposable, sterile sheath. The fibroptic
endoscope fits on to the periodontal probes and ultrasonic
instruments that have been designed to accept it. The sheath
delivers water irrigation that flushes the pocket while the
endoscope is in use and keeps the field clear. The fibroptic
endoscope attaches to a Medical grade Charged Coupled Device [CCD],
Video camera and Light source that produces a image on a flat panel
video monitor for viewing during subgingival exploration and
instrumentation. Magnification ranges from 24X to 46X, enabling
visualization of even minute deposits of plaque and calculus.
Uses: Allows clear visualization of deep subgingival pockets and
furcations. Enables operator to detect the presence and location of
subgingival deposits and guides the operator in their removal.
Using this device it is possible to achieve levels of root
debridement and cleanliness that are much more difficult to produce
without it. Can also be used to evaluate subgingivally For caries,
Defective restorations, Root fractures and Resorption. These are
diamond abrasive files. These are just two of the special
instruments used to remove calculus that is adherent to the root
surface. This is another example of a special root planing
instrument. It is a slotted file. The end of the instrument is
about 1.5 mm in diameter. It reaches areas of the root surface that
conventional root planing instruments can not reach.
Advances in microbiologic analysisMICROBIOLOGIC ANALYSIS Since
subgingival oral bacteria are the main initiating agents in the
development of periodontal disease, it makes sense to look for
specific bacteria in the patients with periodontal disease. Several
methods have been employed for the detection of putative
periodontal pathogens in subgingival samples. Some of these methods
are used strictly for research purposes while other methods are
adapted for clinical use. All these methods require subgingival
plaque as sample. The essential element in periodontal microbiology
is: Selection of proper sample site. Collecting adequate sample
size. Collection of these samples become difficult in patients
infected with organisms that are unevenly distributed. Mombelli et
al reported that four individual subgingival specimens each from
the deepest periodontal pocket from each quadrant should be pooled
to detect Porphyromonas gingivalis. Uses include: These tests have
the potential To support the diagnosis of various forms of
periodontal diseases. To serve as indicators of disease initiation
and progression [i.e., disease activity] To determine which
periodontal sites are at higher risk for active destruction.
To monitor periodontal therapy directed at periodontopathogenic
microorganisms.
the suppression or eradication of
Predictive treatment model [1989] By Kornman and Newman. A
method has been proposed that uses a combination of clinical and
microbiologic parameters to predictably recommend specific therapy
-This is termed as Predictive treatment model. They used this model
in the treatment of refractory periodontitis patients. DIRECT
MICROSCOPY Dark field / Phase contrast microscopy: It is an
alternative for culture methods on the basis of its ability to
directly or rapidly assess the morphology and motility of bacteria
in a plaque sample. Uses: Used to indicate periodontal disease
status and to structure maintenance programs. Demerits: Most of the
putative periodontopathogenic organisms like
A.actinomycetamcomitans, P.gingivalis, B.forsythus,E.corrodens and
Eubacterium species are non motile. Hence this technique is unable
to identify these species. Unable to differentiate among various
species of Treponema. Hence dark field microscopy seems to be
unlikely candidate as a diagnostic test of destructive periodontal
disease.
BACTERIAL CULTURING Considered as the reference method/gold
standard when determing the performance of new microbial diagnostic
methods. Historically has been used widely and aimed at
characterizing the composition of the subgingival microflora.
Generally, plaque samples are cultivated anaerobically and by using
selective media, together with several biochemical and physical
tests the different putative organisms can be identified.
ADVANTAGES: We can obtain relative and absolute counts of cultured
species. Moreover it is the only invitro assessment for antibiotic
susceptibility of the microbes SHORT COMINGS Culture methods can
grow only live bacteria, therefore strict sampling and transport
condition are essential. Some of the putative periodontopathogens
such as Treponemas sps and Bacteroides forsythus are fastidious and
are difficult to culture. The sensitivity is very low, since the
detection limits for selective and non selective media average 103
to 104 bacteria leading to undetection of low numbers of specific
pathogens in a pocket. Most importantly culture require
sophisticated equipment and experienced personnel Time consuming
and expensive. IMMUNO DIAGNOSTIC METHODS Immunologic assays employ
antibiotics that recognize specific bacterial antigens to detect
target microorganisms. This reaction can be revealed using
different procedures like: Direct and indirect immunoflouresent
microscopy assays Flow cytometry Enzyme linked immunosorbent assay
Membrane assay Latex agglutination. IMMUNOFLOURESCENT MICROSCOPY
Direct: Employs both monoclonal and polyclonal antibodies
conjugated to a fluorescein marker that binds with bacterial
antigen to form a fluorescent immune complex, which is detectable
under a microscope. Indirect: Employs a secondary -fluorescein
conjugated antibody that reacts with the primary antigen antibody
complex. Both these are able to detect the pathogens and quantify
the percentage of the pathogens directly from a plaque smear. Has
been widely used to detect A.a, P.gingivalis.
This technique is comparable to bacterial culture in its ability
to identify these pathogens in subgingival dental plaque
samples[Zambon et al ]. It does not require viable bacterial cells
like bacterial culturing. Sensitivity of these assays 82%-100% for
detection of A.a; 91-100% P.gingivalis. Specificity 88-92% for A.a;
87-89% for P.gingivalis. CYTOFLUOROGRAPHY Flow cytometry. This
involves rapid identification of oral bacteria. This method
involves labeling bacterial cells from a patient plaque sample with
both species specific antibody and a second fluorescein conjugated
antibody. Then, this suspension is then introduced into the flow
cytometer, which separates the bacterial cells into an almost
single cell suspension by means of a laminar flow through a narrow
tube. After incubation the cells are passed through a focused laser
beam. The cells scatter the light at low and wide angles, and the
fluorescent emission can be measured by appropriate detectors.
Disadvantages: Expensive Time consuming ELISA Enzyme linked
immunosorbent assay Is similar in principle to other
radioimmunoassays but it is enzymatically derived in place of radio
isotope. ELISA detects either antigens or antibodies. Antigens are
incubated in wells in a plastic plate to allow absorption and
binding of the material. After washing to remove the unbound
antigens, samples containing suspected antigen is incubated with
known antibodies to bind to the antigen on the surface of the well
After washing, antisera to the immunoglobulin conjugated to either
alkaline phosphatase or horse shoe peroxidase are incubated in the
wells. A positive reaction is visualized as solution changes from
colorless to colored The intensity of color depends on the
concentration of the antigens and is usually read photometrically
for optimal quantification.
Uses: Used primarily to detect serum antibodies to
periodontopathogens. It is used in research studies to quantify
specific pathogens in subgingival samples using specific monoclonal
antibodies. Commercially available as, Evalusite[Kodak] using
antibodies to detect antigens for P.gingivalis, P.intermedia A.a,
Simple chair side kit. LATEX AGGLUTINATION It is a simple
immunological assay based on the binding of protein to latex. Latex
beads are coated with species specific antibody and when these
beads come in contact with the microbial cell surface antigens or
antigen extracts cross linking occurs. Agglutination or clumping is
visible in 2-5 minutes. Two types: Direct Inhibition Direct assay:
It is a common latex agglutination test for bacteria. The antibody
is bound to latex, when a suspension of plaque sample is mixed with
sensitized latex and gently agitated for 3-5 minutes resulting in
agglutination or clumpingInhibition assay: Based on the principle
that inhibiting the expected agglutination reaction between known
antigen and known antibody as a result of competition. Advantages:
Simplicity and rapidity. Used as chair side detection of
periodontal pathogens. Particle concentration fluorescence immuno
assays[PCIFA] Uses bacterial cells as a solid phase together with
LPS specific monoclonal antibodies. The resulting assays exhibits
97%-100% of sensitivity and 57% to 97% specificity. Selection
limits of 104 cells. Disadvantages of immunological assays:
Although used extensively, lack clinical validation since most of
them are not available commercially. Cross reactivity leading to
detection of false positives- major problem -when polyclonal
antibodies are used. False negatives occur when using monoclonal
antibodies when compared with culture.
Can identify dead target cells, thus not requiring stringent
sampling and transport methodology. Most of these, Cannot be used
to determine antibiotic susceptibility Provide only quantitative or
semi quantitative estimate of target organisms. Show poorer
detection limits than nucleic acid probes/PCR assays. ENZYMATIC
METHODS OF BACTERIAL IDENTIFICATION:BANA TEST Based on the activity
of trypsin like enzyme with N benzoyl dl arginine 2 napthylamide.
The activity of this enzyme can be measured with the hydrolysis of
the colorless substrate BANA. When hydrolysis takes place, it
releases the chromophore, beta napthylamide, which turns orange red
when a drop of fast garnet is added to the solution.
B.forsythus,P.gingivalis,T.denticola,Capnocyto-phaga sp.,- all
share a common enzymatic profile, since all have an common trypsin
like enzyme. Diagnostic kits are available PERIOSCAN. Loesche et al
: Studied the reaction of BANA with subgingival plaque samples in
shallow pockets and deep pockets to detect presence of these
pathogens and thus serve as marker of disease activity Using pocket
depth as measure of periodontal morbitity he showed that Shallow
pockets less than or equal to 5mm exihibited only 10% of positive
BANA reactions. Deep pockets greater than or equal to 7 mm
exhibited 80 90 % of positive BANA reactions. Beck et al: Used BANA
test as an indicator for periodontal attachment loss. Taken
collectively , positive BANA findings are a
T.denticola/P.gingivalis or both are present at sample sites.
good
indication
that
Difficulties: It may be positive at clinically healthy sites and
remains to be proven whether it can detect sites undergoing
periodontal destruction. It only detects a very limited number of
pathogens, its negative result does not rule out the presence of
other periodontal pathogens. DEOXYRIBONUCLEIC ACID PROBE TECHNOLOGY
NUCLEIC ACID PROBES: DNA probes consists of single stranded nucleic
acid, labeled with an enzyme or radio isotope that can locate and
bind to their complimentary nucleic acid sequences with cross
reactivity to non target microorganisms. DNA probe may target whole
genomic DNA or individual genes.
Whole genomic probes are more likely to cross react with non
target microorganisms due to the presence of homologous sequences
between different bacterial species. However, specific genes, such
a 16s RNA genes, contain signature sequences limited to organisms
of same species. These oligonucleotides probes display limited or
no cross reactivity with non target microbes. How it is prepared?
To prepare the probe, specific pathogens used as marker organisms
are lysed to remove their DNA. Their double helix is denatured,
creating single strands that are individually labeled with a
radioactive isotope. Subsequently when a plaque sample is sent for
analysis, it undergoes lysis and denaturation. Single strands are
chemically treated, attached to a special filter paper and then
exposed to DNA library. If the complimentary base pairs hybridize
[cross link], the radio labeled strands will also be fixed to the
filter paper. After the filter is washed to remove any unhybridized
strands, it is covered with a radiographic plate. The radioactive
labels create spots on the film, which are read with a
densitometer. The darkness and size of the spots indicate the
concentration of the organism present in the given plaque samples.
Advantages : Assay can rapidly test for multiple bacteria, like
A.a., P.gingivalis, B.intermedius, C.rectus, E.corrodens,
Fusobacterium nucleatum and T.denticola. Can detect as few as 102
104 bacteria. Sensitivity and specificity are not affected by the
presence of untreated bacteria in mixed culture samples.
Commercially available kits: -DMDX TEST KIT -OMNIGENE
-BTD[Biotechnica Diagnostics., Inc] RESTRICTION ENDONUCLEASE
ANALYSIS Restriction endonucleases recognize the double stranded
DNA at specific base pair sequences. The DNA fragments thus
obtained, are separated by electrophoresis, Then stained with
ethidium bromide and visualized with ultraviolet light. The genetic
heterogenicity and homogenecity of strains can be evaluated by
comparing the number and size [electrophoretic pattern]of the DNA
fragments obtained. These DNA fragments patterns constitute a
specific finger print to characterize each strain. Uses:
REA is thus powerful tool for determining the distribution of a
specific pathogenic strain through out a population. Also used in
molecular genetic analysis of diverse oral bacteria like A.a.,
P.g.,P.i., E.c.,F.n.,T.d., Has been very useful in studying the
transmission patterns of putative periodontal pathogens among
family members. POLYMERASE CHAIN REACTION PCR involves a reiterate
amplification of a region of DNA flanked by selected primer
specific for the target species. The presence of specific
amplification product indicates the presence of target
microorganisms. Different bacterial species may be detected
simultaneously by multiplex PCR in which several distinct primer
pairs each specific for a given target microorganisms are employed
in a given single tube amplification. Advantages: Demonstrates best
detection limits,as few as five to ten cells. Shows no cross
reactivity under optimized amplification conditions Easy to
perform. Drawbacks: Most PCR assays use relatively small aliquots
for amplification process. If this small quantity of plaque sample
does not contain the targeted microorganisms the assay will not
detect it. Moreover, subgingival plaque, contain many enzymes that
can alter the amplification process. Recently, Fijise et al
developed a quantitative PCR method. ADVANCES IN CHARACTERIZING THE
HOST RESPONSE ADVANCES IN CHARACTERIZING THE HOST RESPONSE
Assessment of host response refers to study of mediators by
immunologic or biochemical methods, that are recognized as part of
the individuals response to the periodontal infection. These
mediators are either specifically identified with the infection or
like local release of inflammatory mediators, host derived enzymes
or tissue breakdown products. Diagnostic tests based on these
systems are usually non invasive. Source of samples: Saliva GCF
Blood serum Blood cells Urine
Most of the tests are based on components of GCF and to a lesser
extent, saliva and blood. ANALYSIS OF URINE Shows little promise
Except for its use in differential diagnosis of tooth loss related
to hypophosphatasia in young children. Here presence of
phosphoethanolamine in the urine is diagnostic of the disease.
ANALYSIS OF SALIVA: Easily collected Contain both locally and
systemically derived markers of periodontal disease. Collected from
parotid, submandibular and sublingual glands Whole saliva consists
of mixture of oral fluids, including secretions from Major/minor
salivary glands Constituents of non salivary origin GCF, bacteria,
bacterial products, desquamated cells, expectorated bronchial
secretions. Obtained with or without stimulation. Proposed
diagnostic markers in saliva include Proteins and enzymes of host
origin Phenotypic markers Host cells Hormones-cortisol Bacteria and
products Volatile compounds and ions. Biochemical markers in
saliva: Epithelial keratins in GCF: It has been suggested that
phenotypic markers for junctional, sulcular and oral epithelial
cells might eventually be used as indicators of periodontal
diseases. The keratin concentration in GCF was higher at sites
exhibiting signs of gingivitis and periodontitis compared with
healthy sites[Mchanghlin et al 1996] Hence keratin concentration
may serve as marker of gingival inflammation. Salivary ions:
Calcium is the ion that has been most widely studied as a potential
marker for periodontal disease in saliva. An elevated calcium
concentration in saliva was characteristic of patients[Sewon et al
1995]with periodontitis. Serum markers in saliva cortisol Recent
studies have suggested that emotional stress is a risk factor for
periodontitis.
One mechanism proposed - serum cortisol levels associated with
emotional stress exert a strong inhibitory effect on the
inflammatory process and immune response.[Genco et al 1998].
ANALYSIS OF GCF Most of the diagnostic tests in Periodontics have
the limitation that cannot differentiate between active and
inactive sites nor can identify susceptible individuals. To
overcome this difficulty, the components in GCF have been studied
over the years. More than 40 GCF components have been studied. They
can be divided into 3 main groups. Host derived enzymes Tissue
breakdown products Inflammatory mediators. Collection of GCF: Paper
strips Micro capillary tubes Micropipettes Micro syringes Plastic
strips Widely used paper strips. How is it collected? These strips
are placed in the gingival sulcus for standard period of time until
the filter paper is saturated. Fluid volume collected from the
strips are quantified by using Periotron This electronic device
measures the change in the capacitance across the wetted strip and
this change is converted to the volume of GCF. Periotron 8000
achieves the easiest and quickest measurement. Research on GCF has
focused on the search for biochemical markers for the disease
progression, many of which are discussed below: INFLAMMATORY
PRODUCTS AND MEDIATORS Cytokines are potent local mediators of
inflammation that are produced by variety of cells. The common
inflammatory mediators present in the GCF are investigated as
potential diagnostic markers: Prostoglandin E2 Tumor necrosis
factor Interleukin 1 and 1 Interleukin 6 and 8. Prostaglandin E2:
Product of cyclooxygenase pathway of the arachidonic acid
metabolism.
Potent mediator of inflammation and induces bone resorption. In
cases of untreated periodontitis, the concentration of
Prostaglandin E2 in GCF is increased during active phases of
periodontal destruction. Interleukin 1, 1, 6,8, TNF alpha: Produced
by macrophages at diseased sites. Potent immune regulatory
molecules with a variety of biologic effectsMatrix
metalloproteinase stimulation Bone resorption. Cross sectional
studies have shown good correlation with disease status and
severity but not disease progression. HOST DERIVED ENZYMES Various
enzymes are released from the host cells during the initiation and
progression of periodontal disease. These enzymes are released
from, dead and dying cells from periodontium PMN neutrophils
others, derived from inflammatory, epithelial and connective tissue
cells at the affected sites. The enzymes that received most
attention as periodontal destruction are: Aspartate
aminotransferase Alkaline phosphatase Beta glucronidase Elastase
Cathepsin Aspartate aminotransferase: Enzyme derived from variety
of cells through out the body including the heart and the liver
Elevated AST in GCF mainly from sites with severe gingival
inflammation and sites with recent history of progressive
attachment loss. Test involves, Collection GCF with filter paper
strip which is then placed in tromethamine hydrochloride buffer.
Substrate reaction mixture containing L-aspartate and -
ketogluterarate acids are added and allowed to react for 10
minutes. In the presence of AST, The aspartate and -glutarate are
catalysed to oxalo-acetate and glutamate. The addition of a dye
such as fast red results in a color product and the intensity is
proportional to the AST activity in GCF sample.
Disadvantage: Its inability to discriminate between sites with
severe inflammation but with no attachment loss from sites that are
losing attachment. Commercially available kits: PeriogardTM-
periodontal tissue monitor system [ Xytronyx Inc, San Diego,LA,
USA] Pocket watchTM [Steri Oss Inc., Yorba, Linda, CA, USA]
Alkaline phosphatase: Found in many cells of periodontium including
osteoblasts, fibroblasts and neutrophils. Cross sectional studies
show that higher levels are seen in GCF of diseased sites than from
healthy sites. Only one longitudinal study has associated whole
mouth alkaline phosphatase levels with the progression of
periodontitis but this study has not been reproduced[Binder et al
1987] Beta glucronidase: Found in primary [azrophilic] granules of
neutrophils. Cross sectional data show that elevated beta
glucronidase in diseased sites. Two longitudinal studies have shown
that concentration of this enzymes have predictive value in
identifying patients at higher risk for losing attachment[Lamster
et al 1988]. Commercial available kits: Is being developed by
ABBOTT laboratories, North Chicago, USA. Elastase: It is a serine
protease stored in the primary granules of neutrophils. Cross
sectional studies showed that higher levels of elastase are seen in
sites with periodontitis than with gingivitis/healthy sites.
Longitudinal studies has shown that some predictive value for
disease progression with elastase can be obtained in a short term
evaluation of an untreated population, but it remains if its
validity can be applied to a treated population in a maintenance
program. Commercially available kits: Periocheck: Measures presence
of nonspecific neutral protease activity. Prognostik[Dentsply, USA]
Presence of serine proteases, elastase in GCF. Cathepsin: These are
a group of acidic lysosomal enzymes that play an important role in
intra cellular protein degradation. Although they have been shown
correlation with disease severity and significant decrease after
periodontal therapy, they have not been evaluated longitudinally as
markers of disease progression.[Chen et al 1998]
Tissue breakdown products: One of the major feature of
periodontitis is the destruction of collagen and extracellular
matrices. Analysis shows that sites with periodontitis shows
elevated levels of Hydroxy proline from collagen breakdown
Gycosaminoglycans from matrix degradation. Osteocalcin and type I
collagen peptides These are bone and connective tissue proteins
that have been correlated with the progression of alveolar bone
loss induced in beagle dogs [Giannobile et al 1995]. Both markers
showed high predictive value and now need to be extended to
longitudinal studies in humans. Assessment of susceptible host
using markers in peripheral blood: The contents of circulating
blood can be used to diagnose periodontal disease has been
considered for several years. It will identify patients at risk
rather identify tooth/teeth sites that are with increased disease
activity.[Fine and Mandrel 1986,Johnson 1989]. Three constituents
of peripheral blood have been thoroughly pursued as assessment of
susceptibility: Polymorphonuclear leukocyte function Estimating
antibody levels to bacterial antigens Monocytes responsiveness to
bacterial LPS. Polymorphonuclear leukocyte [PMNS] Studies by Lavine
et al 1976 showed an essential role for the neutrophil in the
pathogenesis of periodontal disease. Defects in the neutrophil
functions such as chemotaxis, phagocytosis has been clearly
associated with localized and generalized aggressive periodontitis
and also with systemic conditions like Downs syndrome,
agranulocytosis, PLS,DM, etc., Genco et al in 1986 proposed that
transient neutrophil abnormalities in adults may lead to periods of
increased disease activity. It seems that measuring neutrophil
function should be used for screening individuals at high risk for
active periodontal disease progression. Since laboratory assessment
is very expensive and time consuming, this diagnostic test not yet
is applicable for everyday practice. Antibody titers: For many
years it has been suggested that circulating blood contains
antibody titers to periodontal pocket bacteria. Caton et al 1989
reported that elevation in serum antibody to plaque bacteria is
associated with increasing severity of periodontal disease.
Ebersole in 1987 in his study, though incomplete, suggested that
most patients with periodontal disease exhibit significant elevated
antibody responses to suspected periodontopathogens. Thus this
antibody measurement was reflection of host response to an
infection associated with episodes of active periodontal disease
progression. Monocytes responsiveness to LPS: Garrison and Nichols
in 1989 reported an interesting test on patient susceptibility or
resistance to periodontal disease based on possible altered host
response - monocyte responsiveness. They hypothesized that
susceptibility to periodontal destruction could be related to an
increased host response to gram-negative bacteria. Subsequently,
they compared susceptible patients with generalized severe adult
periodontitis to patients resistant to periodontitis. Patients who
were classified as susceptible demonstrated 2-3 fold greater
responsiveness of blood monocyte to LPS [i.e., as measured by PGE2
release] than did patients classified as resistant. Interestingly,
susceptible patients with severe disease had greater monocyte
responsiveness, regardless of their treatment stage. This test
needs further research, since susceptibility may also have a
genetic basis. Since these tests offer information at the patient
level, offering screening of risk patients but have a limitation in
relating information on status of particular sites within
patients.