au14_-_periodontology_exam_1_20141210195103 Flashcards
What are 2 other names for the periodontium?
- attachment apparatus- supporting tissues of the tooth
What are the 2 functions of the periodontium?
- attach the tooth to bony tissue of the jaw- maintain integrity of masticatory mucosa
Development of the periodontia occurs early in the ___ phase along with ___ development.
- embryonic phase- tooth development
During periodontia development, cells originate from the ___ and migrate into the ___. These cells form ___ beneath the stomadeal epithelium. The stomadeal epithelium releases factors which initiate ___.
- neural crest- first branchial arch- ectomesenchyme- epithelial-ectomesenchymal interactions
The dental lamina forms what 3 stages?
- bud stage- cap stage- bell stage
During embryogenesis, ectomesenchyme condenses around ___ to form the ___ and the ___.
- dental organ- dental papilla- dental follicle
What does the dental papilla give rise to? What does the dental follicle give rise to?
- gives rise to dentin and pulp- gives rise to periodontium
What does the dental papilla determine?
shape and form of the tooth
During embryogenesis, what part of the tooth forms first?
crown
During embryogenesis, the outer and inner enamel epithelium proliferate apically to form ___. Odontoblasts form ___. Inner cells secrete ___. The root sheath fenestrates so that ___ cells contact the root surface. ___ induces differentiation of these cells into cementoblast. Cemtnoid forms. Fibers of the cementoid intermingle with immature dentinal fibers.
- Hertwig’s Epithelial Root Sheath- dentin- enamel-related proteins (amelogenins)- ectomesenchymal cells- amelogenin
Periodontal ligament is formed by ___ that are differentiated from the dental follicle lateral to the cementum.
fibroblasts
Osteoblasts differentiate from ___.
dental follicle ectomesenchymal cells
True or false: Ectomesenchymal cells remain in mature periodontium and participate in turnover.
true
What is the definition of gingiva?
part of the masticatory mucosa which covers the alveolar process and surrounds the cervical portion of the teeth
What are the 3 parts of the gingiva?
- free gingiva- attached gingiva- interdental papilla
What are other names for free gingiva? It extends from ___ to ___. Is it keratinized?
- gingival sulcus, marginal gingiva, sulcus depth- from free gingival margin to free gingival groove- yes, it is keratinized
Where is the free gingival margin located?
on the coronal end of the gingiva, 1.5-2.0 mm coronal to the CEJ
What is the free gingival groove? How prevalent is it?
- junction between free and attached gingiva; corresponds to CEJ- only found in 30-40% of adults
The oral epithelium faces ___. The oral sulcular epithelium faces ___. The junctional epithelium provides contact between ___ and ___.
- oral cavity- tooth surface without contacting it- gingiva and the tooth
What are the macroscopic limits of the free (marginal) gingiva? What are the microscopic limits? Why does it matter?
- extends from FGM to FGG- extends from FGM to JE- because how these landmarks change from health to disease will determine the accuracy of your probe readings
Describe the texture, color, and mobility of attached gingiva. How often is stippling present?
- firm texture- coral pink- immobile- 40% of adults present stippling
How does the width vary in attached gingiva?
- increases with age (passive eruption)- widest in incisors, narrowest in premolars- mandibular lingual: narrowest in incisors, widest in molars
What is the definition of the mucogingival junction? Where is the mucogingival junction not present?
- junction between attached gingiva and alveolar mucosa- not in the palate
True or false: The absence of stippling in the gingiva indicates disease.
FALSE: the presence of stippling is an indication of health, but its absence does not mean anything
attached gingiva + marginal gingiva = ___
keratinized gingiva
keratinized gingiva - sulcus = ___
attached gingiva
What 3 things does the interdental papilla depend upon?
- the contact relationships between adjacent teeth- width of approximal tooth surfaces- course of CEJ
What is the definition of the col? Is it keratinized?
- concavity seen in contact areas of premolar/molar region- non-keratinized epithelium (similar to JE)
The bottom of the gingival sulcus in a healthy mouth is positioned apical to the CEJ. When is this condition most likely to occur?a. prenatallyb. at 10-20 years of agec. before the roots of primary teeth are resorbedd. at 40-60 years of agee. just after a permanent tooth has erupted
e. just after a permanent tooth has erupted
Describe the cells of the oral epithelium. Is it keratinized?
keratinized, stratified, squamous epithelium (keratinocytes)
What are the 4 layers of the oral epithelium?
- basal layer: stratum basale or stratum germinativum- prickle cell layer: stratum spinosum- granular cell layer: stratum granulosum- keratinized cell layer: stratum corneum
What is the difference between orthokeratinized and parakeratinized?
- orthokeratinized: no nucleus- parakeratinized: nuclear remnants
From the basal layer to the granular layer, do the cytoplasmic tonofilaments increase or decrease? The number of desmosomes? The number of organelles?
- cytoplastmic tonofilaments: increase- desmosomes: increase- organelles: decrease
What are the types of cells in the oral epithelium? What percentage of the cells does each make up?
- keratinocytes (90%)- clear cells: melanocytes, Langerhans cells, Merkel’s cells (10%)
What is the purpose of each of the clear cells in the oral epithelium?
- melanocytes: synthesize melanin pigment- Langerhans cells: defense cells- Merkel’s cells: sensory
Where is the basement membrane? What molecules does it contain?
- present between the basal layer of the oral epithelium and CT; 1-2 micrometers wide- rich in glycoproteins; contains protein-polysaccharide complexes
What are the 2 layers of the basement membrane that are distinguished by electron microscopy? Where is each located?
- lamina lucida: adjacent to basal cells- lamina densa: adjacent to connective tissue; achoring fibers project from LD into CT
What are hemidesmosomes? Desmosomes?
- hemidesmosomes: dense plaques that attach epithelium to the basement membrane- desmosomes: pairs of hemidesmosomes
Describe how stippling is created microscopically.
- at the boundary between the oral epithelium and underlying connective tissue, CT projects into the epithelium papillae- epithelial ridges or rete pegs intervene- when rete pegs fuse and there is no CT support in that area, it is seen as stippling- rete pegs are missing at the JE site
During tooth eruption, the junctional epithelium is derived from ___.
reduced dental epithelium
Where is the junctional epithelium the widest?
widest in coronal portion (15-20 cell layers) and thin toward the CEJ (3-4 cell layers)
Which has a faster turnover rate: junctional epithelium or oral epithelium?
junctional epithelium
Junctional epithelium or oral epithelium?- larger cell size?- larger size of intercellular space?- larger number of desmosomes?- keratinization?
- larger cell size: junctional epithelium- larger size of intercellular space: junctional epithelium- larger number of desmosomes: oral epithelium- JE has potential to keratinize
Where is the JE in comparission to the CEJ in a child? In a healthy adult? In a diseased adult?
- child: JE above CEJ- healthy adult: JE at CEJ- diseased adult: JE below CEJ
Periodontitis occurs when the junctional epithelium ___.
migrates apically down the root surface
True or false: Viable junctional epithelium is not necessary for pocket formation.
FALSE. It is necessary for pocket formation.
Describe Necrotizing Ulcerative Periodontitis (NUP).
junctional epithelium cells die so no pocketing! bone is exposed
What are the cells (6) of the lamina propria and describe what each does?
- fibroblasts: synthesize matrix and fibers- mast cells: vasoactive substances- macrophages: phagocytosis and synthesis- neutrophilic granulocytes- lymphocytes- plasma cells
What are the fibers (4) of the lamina propria and describe each (where they are found, etc.)?
- collagen: characteristic cross-banding; produced by fibroblasts, cementoblasts, and osteoclasts; most abundant- reticulin: numerous adjacent to basement membrane; around blood vessels- oxytalan: mostly in PDL; run parallel to long axis of tooth- elastic: around blood vessels
What are the 3 purposes of the gingival fibers?
- reinforce the gingiva- provide resilience and tone- maintain architectural form and integrity
What are the 4 gingival fibers and where does each run?
- circular fibers: encircle tooth like a cuff- dentogingival fibers: fan out from supra-crestal cementum into free gingiva- dentoperiosteal fibers: run from supracrestal cementum into attached gingiva- trasseptal fibers: run from tooth to tooth (embedded in cementum)
True or false: The periodontal ligament is richly vascular.
true
What two structures does the periodontal ligament join?
joins cementum and alveolar bone
What are the 2 functions of the periodontal ligament?
- permits forces to be distributed- essential for the tooth mobility
What are the 4 fibers of the periodontal ligament?
- alveolar crest fibers- horizontal fibers- oblique fibers- apical fibers
What are the 6 cells of the periodontal ligament?
- fibroblasts: aligned along principal fibers- osteoblasts: line bone surface- cementoblasts: line cemental surface- osteoclasts: multinucleated; create ruffled surface of bone- epithelial cells- nerve fibers- epithelial cell rests of Mallassez: remnants of the Hertwig’s epithelial root sheath
What is the cementum?
mineralized tissue covering root surface and, occassionally, small portions of the crown of the teeth
How is cementum similar to bone? How is it different?
DIFFERENT:- no blood vessels- no lymph vessels- no innervation- no physiology resorption/remodelingSIMILAR:- continuing deposition throughout life- collagen fibers embedded in organic matrix- high mineral content (65%), mainly HA
What is the difference between intrinsic and extrinsic cemental fibers?
- intrinsic: produced by cementoblasts; composed of fibers oriented parallel to root- extrinsic: Sharpey’s fibers; produced by PDL fibroblasts
What are the 3 different forms of cemental fibers? Where are each located?
- acellular extrinsic fiber cementum: coronal or middle portion of root- cellular mixed stratified cementum: apical 1/3 of root and in the furcation- cellular intrinsic fiber cementum: resorption lacunae
True or false: Cementum thickness increases by gradual apposition throughout life.
true
What is the cementum thickness in the cervical portion of the root? What is the cementum thickness in the apical portion of the root?
- cervical portion: 20-50 micrometers- apical portion: 150-250 micrometers
The alveolar bone consists of ___ bone and ___ bone formed by cells from ___ and ___.
- cancellous- cortical- from the dental follicle- independent of tooth development
What cells/structures are in the bone marrow?
adipocytes, vascular structures, and undifferentiated mesenchymal cells
Alveolar bone remodels in response to ___ and ___.
- forces- tooth movement
In the alveolar bone, ___ produce bone matrix (osteoid) consisting of ___, ___, and ___. Osteoid undergoes mineralization by the deposition of minerals like ___.
- osteoblasts- collagen fibers- glycoproteins- proteoglycans- calcium and phosphate
The dental tissue that most closely resembles bone is:a. dentinb. pulpc. cementumd. enamel
c. cementum
The supraperiosteal vessels (blood supply to gingiva) are terminal branches of what 7 arteries?
- sublingual artery- buccal artery- mental artery- facial artery- greater palatine artery- infraorbital artery- posterior superior dental artery
What are the 4 arteries that make up the blood supply of the periodontal tissues?
- dental artery- superior/inferior alveolar arteries- intra-septal artery- rami perforantes artery (terminal branch of intra-septal; penetrates alveolar bone all through the socket)
What are the 4 relevant lymph nodes to the periodontia?
- submental lymph nodes- deep cervical lymph nodes- submandibular lymph nodes- jugulodigastric lymph nodes
What are the 7 nerve branches that supply the periodontia?
- infraorbital nerve- sublingual nerve- posterior superior dental nerve- mental nerve- greater palatal nerve- buccal nerve- long sphenopalatine nerve
In health, the periodontal probe penetrates to ___. In disease, the probe penetrates ___.
- free gingival groove- past junctional epithelium into connective tissue
True or false: Diagnosis of periodontitis is based on probe depths.
FALSE. It is based on attachment loss, not probe depths.
True or false: The position and dimensions of the contact area determine probe angulations in posterior teeth.
true
What is the proper probe angulation and position when charting probe depths?
- find interproximal contact- use contact as guide to insert probe- open angulation by 10 degrees
What was the initial thinking of why gingival recession occurred?
- width of keratinized tissue <2 mm predisposes to recession- narrow gingiva cannot protect from friction and cannot buffer against muscle pull- facilitates subgingival plaque formation since mobile tissue causes pocket to open, facilitates food impaction, and impedes oral hygiene
What is the current thinking of how gingival health is related to the width of the gingiva?
- gingival health can be maintained independent of its dimensions- narrow gingiva has same resistance to attachment loss as wide gingiva
The thin phenotype has:___ (inc/dec) recession___ (more/less) vulnerable to trauma___ (more/less) inflammation___ (more/less) favorable treatment outcome (root coverage, GTR, etc.)
- increased recession- more vulnerable- more inflammation- less favorable
When would you recommend gingival grafts?
- when recession causes symptoms (caries, esthetic concerns, progressive recession, sensitivity)- subgingival restoration margins on thin biotype- pre-orthodontic therapy (final tooth position will be buccal)
Are the characteristics of the gingiva determined by genetics or by functional adaptation to environmental stimuli?
genetics
The initial thought was that gingiva will become keratinized in response to friction, but now we think ___.
connective tissue determines epithelial characteristics
Early grafting procedures involved ___ and ___ with the rationale that ___.
- free gingival grafts- coronally advanced flaps- keratinized epithelium converted to firm attached gingiva
What type of gingival graft is now used? With what rationale?
- connective tissue graft- connective tissue determines epithelial prototype
What are the 2 parts of the soft tissue attachment to the tooth? How large is each? How does this relate to the biologic width?
- fibrous connective tissue (1.06-1.08 mm)- junctional epithelium (1.4 mm)- approx 1 mm of free gingiva which allows for a 3 mm total biologic width
The distance from the CEJ to the alveolar crest is ___. The distance from crown margins to alveolar crest has to be ___. If you don’t have this distance, then ___.
- 3 mm- 3 mm- crown lengthening
Describe the process of healing after a tooth extraction.
- clot formation- wound cleansing PMNs, monocytes, macrophages migrate into the wound- new vasculature, mesenchymal cells (from PDL) form granulation tissue- provisional connective tissue- immature bone forms- bundle bone (socket proper) is resorbed- wound filled with woven bone- bone maturation
True or false: Socket preservation is important for preserving bone morphology.
true
What is guided tissue regeneration? How is this clinically applied?
- epithelium grows faster than bone or connective tissue; epithelial exclusion will allow selective growth of these cells- use barrier membranes
How were studies on plaque formation conducted?
- adhesive tape samples from the tooth surface- plaque grown on epoxy resin crowns worn for different time periods- in vitro studies of attachment and aggregation between different bacterial species- experimental gingivitis models
Early studies of oral microbiology were based on: ___ and ___.
cultivation and microscopy
What is the great plate anomaly?
when you look under a microscope, you see 100 species, but on a plate, only 50 grows; not everything you see will grow
What is the “we know what we can grow” bias?
all studies focused on cultivable species, but there are so many more species in the mouth
What approaches to study oral microbiolgy revolutionized species identification?
molecular (DNA, RNA) approaches
How many distinct oral species are there? What % have never been cultured?
- more than 700 distinct oral species- +60% never have been cultured- includes exotics (ex. Archea) like termite guts and other extreme environments- fungi and viruses may also play a role in disease
What is the definition of a plaque biofilm?
organized cooperating community of organisms with specific inter-bacterial and host-bacterial interactions
What is atopic dermatitis?
“Purell disease”; children who are not exposed to bacteria when they are young begin making autoantibodies; 1st world problem (seriously!)
In the attachment stage of biofilm formation, planktonic bacteria adhere to ___ which is made up of ___ and ___. There is an alteration in ___ and ___.
- acquired pellicle- salivary glycoproteins- antibodies- surface charge- free energy
What is the difference between rapid attachers and slow attachers?
- rapid attachers: specific attachment structures (fimbrae, extracellular polymers, glycocalyx)- no specific mechanism
How do bacterial characteristics change following attachment?
- synthesis of new outer membrane proteins- active cellular growth
What is the difference between co-aggregation and co-adhesion during the growth phase of biofilm formation?
- co-aggregation: cell-to-cell recognition of genetically distinct cell types; mediatedby protein or glycoprotein receptors on one cell and carbohydrates on the other; all cells are suspended; “clumps” form which then attach to the pellicle- co-adhesion: interactions between suspended and already adhering microorganisms; influenced by temperature and lactose
What two factors affect co-adhesion?
- temperature: no co-adhesion at higher than 37 degrees- lactose: inc lactose, dec co-adhesion
What 3 things occur during biofilm maturation?
- increase in diversity- replication and matrix formation- ecological succession
What are the 3 categories of bacteria in ecological succession?
- tertiary colonizers: gram negative- secondary colonizers: bridge species- primary colonizers: gram positive and some negative
Which bacterial colonizers are usually beneficial? Which are usually pathogenic?
- beneficial: primary colonizers- pathogenic: tertiary colonizers
Name examples of tertiary, secondary, and primary colonizers.
- tertiary: Porphyromonas gingivalis, A. actinomycetemcomitans- secondary: F. nucleatum- primary: S. sanguis
S. sanguis is found in large numbers in deep, active periodontal pockets. Through scaling and root planing of a deep periodontal pocket will most likely result in increased numbers of A. actinomycetemcomitans.State whether each statement is true or false.
both are false
When a biofilm increases in thickness, what changes?
- difficulty in diffusion in and out of the biofilm- an oxygen gradient develops- completely anaerobic (no oxygen) conditions emerge in the deeper layers- reverse gradients of fermentation products develop as a result of bacterial metabolism
How does the nutrition in the biofilm differ between the supragingival plaque and subgingival plaque?
- supragingival plaque: dietary products dissolved in saliva- subgingival plaque: periodontal tissues and blood (“clavicular fluid”); bacterial hydrolytic enzymes breakdown host macromolecules into peptides and amino acids
What makes up 15-20% of a biofilm? What makes up the remaining biofilm?
- microcolonies (15-20%)- interbacterial matrix
What are the 3 sources of the biofilm matrix?
- dead bacterial cells- saliva- gingival exudate
Are there voids/water channels in a bacterial biofilm? What makes up the backbone of the biofilm?
- yes- exopolysaccharides
Compare the lower layer, loose layer, and fluid layer of the biofilm.
- lower layer: dense microbes, polysaccharide matrix, tightly bound together, steep diffusion gradients- loose layer: irregular in appearance, extends into surrounding media- fluid layer: stationary sublayer, fluid layer in motion, nourishes the biofilm by molecular diffusion
Do shear forces determine the colony shape in supra or subgingival plaque? What do colonies with low shear force look like? With high shear force?
- supragingival plaque- low shear force: towers or mushrooms- high shear force: elongated colonies capable of oscillation (like seaweed)
Describe the difference between a gram-positive matrix and gram-negative matrix.
- gram-positive: very fibrillar, due to dextrans and levans- gram-negative: very regular; contains tri-laminar vesicles; filled with endotoxins and proteolytic enzymes; probably involved in adherence
Describe the structure of subgingival plaque.
- cuticle forms primary attachment- structure similar to supragingival plaque- bacterial layers near sulcular epithelium different from tooth-attached (no inter-bacterial matrix, more spirochetes and flagellated bacteria)
What are the 3 bacteria mentioned as an example of bacterial collaboration? How do they collaborate?
- Streptococcus cristatus: 1st colonizer; facultative species (can live with or without O2); uses up O2 when available- Fusobacterium nucleatum: 2nd colonizer; robust anaeriobe; binding to Strep improves survival when O2 is present- Porphyromonas gingivalis: 3rd colonizer; microaerophilic, obligate anaerobe; coagregation essential to survival when O2 is present
How did F. nucleatum and S. cristatus interact during the tissue culture experiment?
- F. nucleatum invades epithelial cells- S. cristatus does not invade cells- after coaggregation, S. cristatus is carried inside by F. nucleatum
What are the advantages to biofilm living?
- DEFENSE: presence of concentrated bacterial enzymes; inter-bacterial matrix- PROTECTION FROM EXTERNAL CHANGES: diffusion minimal in interior regions; antibiotic and antimicrobial resistance; protection from friction and shearing forces; attachment- TRANSFER OF INFORMATION AND GENETIC MATERIAL: signaling (quorum sensing); conjugation; transformation; plasmid transfer; trasposon transfer
What is the definition of quorum sensing?
regulation of expression of specific genes through accumulation of signaling compounds that mediate intercellular communication
Describe the process of quorum sensing between commensal and pathogenic bacteria.
- auto-inducer (AI) 1 or 2 turns on in response to cell density- commensal bacteria produce and respond to low levels of AI-2- pathogens produce AI-2 in high levels- Al-2 may determine the switch from commensal to pathogenic community
What are the 3 reasons why biofilm bacteria are more resistant to antibiotics?
- BIOFILM BACTERIA GROW MORE SLOWLY (antibiotics depend on cell turnover for efficacy; slow-growers express “non-specific defense mechanisms”; slow growers make more exo-polymers)- EXO-POLYMERS RETARD DIFFUSION (ion-exchange mechanism prevents highly charged molecules from reaching deeper zones; extracellular enzymes inactivate antibiotics)- BIOFILM BACTERIA EXPRESS DIFFERENT GENES (gene transfer; phenotypic expression of biofilm existence)
Why don’t oral pathogens fit the usual model of a pathogen?
- oral pathogens are normally present throughout life- damage requires presence in large numbers
The ecological concept of oral microbial diseases states…
- ecological shifts lead to changes in proportions- balance shifts in favor of “pathogens”/disease- periodontal disease is an example of “ecological catastrophe”
Which of the following is NOT a reason why growth of a microbe is different in nature compared to pure culture?a. limited nutrients in natural environmentb. poor nutrient distribution in natural environmentsc. not optimal temperature in natural environmentsd. lack of competition in natural environments
d. lack of competition in natural environments
What is the clinical significance (3) of biofilm formation?
- tooth-brushing has an effect on where the biofilm is located (interproximal, fissures, etc.) and non-contact brushing can remove towers and mushrooms by shear forces- antibiotic resistance- translocation and transmission of bacteria
What are the 2 targets of therapy in the prevention of biofilms?
- AI-2- vaccines that target common resistance genes
What are the different ways bacteria can translocate in the mouth?
- periodontal probe can translocate pathogens from pockets to healthy sites- drug-resistant strains can translocate to neighboring teeth- teeth act as reservoirs for colonization of implants- bacteria can infect membranes in GTR
What is Leuven’s “one-stage full-mouth disinfection”?
- full-mouth scaling and root-planing within 24 hours- subgingival irrigation with 1% chlorhexedine- tongue brushing- oral antimicrobial rinse
True or false: Plaque cannot form on implant abutments.
FALSE; plaque can form on implant abutments
Implants that fail have a microbial composition similar to ___.
periodontal disease
What is the non-specific plaque hypothesis?
- plaque control important in periodontal treatment- all plaque bacteria considered bad- any accumulation of micro-organisms at or below the gingival margin causes inflammation
What is the specific plaque hypothesis?
- specific organisms in dental plaque are the etiological agents- microbial composition of disease sites different from healthy sites- local debridement and systemic antibioitcs could control LAP
What are the prerequisites for disease initiation and progression?
- VIRULENT PERIODONTAL PATHOGEN: P. gingivalis with type II and IV fimA genotypes; virulence factors; right location in the site (adjacent to epithelium, apical part of the pocket)- LOCAL ENVIRONMENT: colonization by beneficial species dilutes and inhibits pathogens; effect of local “regulon”/subgingival environment (iron increases outer membrane protein expression in P. gingivalis and S. cristatus can inhibit fimA expression)- HOST SUSCEPTIBILITY: HIV infection; diabetes; smoking
What are the 4 different ways through which pathogens colonize?
- ADHESINS ON BACTERIA BIND HOST RECEPTORS: type I or IV collagen, sialic acid, galactosyl residues; bacteria have fimbriae or outer membrane proteins- COAGGREGATION- NUTRIENT UTILIZATION: Veillonella uses lactate made by streptococci; Campylobacter uses formate made by Selenomonas; Porphyromonas uses hermin from blood in sulcus- COMPETITIVE INHIBITION: bacteriocins; hydrogen perioxide production
What are the 3 ways through which pathogens overcome host defenses?
- DESQUAMATION OF EPITHELIUM: invade epithelium and bind to underlying cells- PREVENT ANTIBODY-BINDING: IgG and IgA proteases; mimic host antigens- PREVENT PHAGOCYTIC CELLS: leukotoxin; non-lethal suppression of immune cells
The World Workshop in 1996 designated 3 pathogens. What are they?
- P. gingivalis- A. actinomycetemcomitans- T. forsythia
Is Actinobacillus actinomycetemcomitans (AA) motile? Gram positive or negative? How does it get its energy? Aerobic or anaerobic? Shape of bacteria and colonies?
- non-motile- gram-negative- saccharolytic (breaks down carbs for energy)- capnophlic (thrive in high CO2)- round-ended rod; star-shaped colonies
What is the evidence of AA as a pathogen based on association?
- high numbers associated with agressive periodontisis- detected in active sites- detected in prospective studies
What is the evidence of AA as a pathogen based on elimination?
- elimination or suppression resulted in successful therapy- recurrent lesions harbor the species
What is the evidence of AA as a pathogen based on host response? It also inhibits ___ and induces ___.
- high levels of systemic and local antibody response- inhibits growth of commensals (S. sanguis)- induces disease in animal models
What is the evidence of AA as a pathogen based on virulence factors?
- tissue invasive (epithelial and endothelial cells)- leukotoxin- fibroblast inhibiting factor- endotoxin- collagenase
What is the evidence AGAINST AA being a pathogen?
- not seen in all cases of aggressive periodontitis- seen in periodontally healthy subjects- genetic analysis of the leukotoxin gene (13 clusters identified; II seen in severe disease; XII and XIV associated with health)- AA with 530 bp deletion is 23x more likely to be disease-associated than AA with full length promoter region
There are ___ serotypes of AA which are based on ___. ___ are the dominant antigens.
- 5- polysaccharides on the surface of an organism- serotype-specific surface antigens (SPA)
Serotype ___ of AA is most commonly associated with localized aggressive periodontitis in the USA. It has a role in resistance to ___.
- b- resistance to phagocytosis and killing by PMNs
Serotype ___ of AA is health-associated in Finland and disease-associated in Japan.
a