Perio Flashcards
(111 cards)
What is periodontitis?
Periodontists is a multi factorial, inflammatory diseases associated with dysbiotic microbial dental biofilms and characterised by non-reversible progressive periodontal tissue destruction. It manifests through: CAL, radiographically assessed alveolar bone loss, presence of periodontal pocketing, gingival bleeding and leads eventually to tooth loss.
What are the main points of the old, Non-specific Plaque Hypothesis?
- All plaque bacteria are equally pathogenic
- Quantity of plaque determines the pathogenicity
- Host has threshold capacity to detoxify bacterial products
- Disease develops if threshold is surpassed
Treatment: non-specific mechanical removal of total amount of plaque
What are the main points of the Specific Plaque hypothesis?
- Due to advancement of microbiological technologies, specific bacteria that are believed to be pathological to the periodontium were isolated
- Not all plaque is equally pathogenic
- Presence and increase of specific microorganism causes more destruction
Treatment: targeting and elimination of specific microoganisms using antimicrobials
What are the main points of the ecological plaque hypothesis?
- Disease is the result of an imbalance in the total micro-flora due to ecological stress
- Quantitative plaque increase changes local micro-environment promoting the growth of specific pathogens, qualitative shift
- Ecological factors such as the presence of nutrients and essential cofactors, pH and redox potential
Treatment: prevention of dental caries, modification of micro-environment to prevent nourishment of pathogens
Explain, briefly, the Yellow, orange and red groups that were suggest by Dr. Socranky research of 1998. Please include the names of at least 3 different bacteria in all of the groups.
- The yellow, orange and red groups are suggested groups of bacteria that are associated with periodontal health and pathology
- Yellow group - include: S. Mitis, S. Oralis and S, Snagius - are early coloniser groups that are related to healthy periodontium
- Orange group - include: P.Intermedia, P.Nigrescens and F. Nucleatum - are late coloniser that are believed to be an intermediate step and are able to facilitate red group (the most pathogenic group) in binding in the periodontal pocket
- Red group - include: P. Gingivalis, T.Forsythia, T. Denticola - believed to be the most pathogenic group
What is the microbial virulence?
Virulence is defined as the degree of pathogenicity of the ability of the organism to cause disease measured in experimental procedures.
Organism need to:
- Attach and colonise
- Multiply and gain access to appropriate nutrition
- Evade host defences
- Propagate
What is A. Actinomycetemcomitans?
A. Actinomycetemcomitans or AA is a gram negative anaerobe that is associated with localised aggressive periodontitis.
Able to produce high level os leukotoxins thus causes the lysis of PMNs.
It is equiped with adhesis and invasisn which means it can penetrate the tissue and attach to the space it has penetrated
What is P.Gingivalis?
P. Gingivalis is a gram negative anaerob that is associated with periodontits (around 79-90% of perio cases will have this bacteria)
Main cause of the inflammation to the tissue - release of endotoxin (name: P.Gingivalis LPS)
Contains invasins, adhesins and also collagenases which degrade connective tissue.
What are the main points of the Keystone Pathogen Hypothesis & Polymicrobial synergy and Dysbiosis Model?
- Keystone pathogens (e.g. P.Gingivalis) trigger inflammation even in low numbers
- Causes normal microbiome to become dysbiotic
- Manipulation of native immune responses of host
- Inflammatory byproducts sustain dysbiotic microbiota
Treatment: host modulation in adjunct to direct antimicrobial measures
What are inflammophilic bacteria?
Bacteria that are able to propagate using by-products of inflammation
What are the stages of the IMPEDE model
Stage 0 - gingival and periodontal health
Stage 1 - gingival inflammation
Stage 2 - Polymicobial emergence
Stage 3 - Inflammation - mediated dysbiosis - initial perio
Stage 4 - Late stage periodontitis
What is the consensus on how periodontal destruction actually occur?
It is widely believed that periodontal destruction occurs due to effects of the immune response and not directly due to bacteria. 80 immune response, 20 bacteria.
What is the aetiology of periodontitis?
- Predominance of PMNs in pocket epithelium/activation in connective tissue
- Elevated activity of macrophages
- Plasma cells dominate the infiltrate
- Increase of pro-inflammatory cytokine production (like IL-6 and IL-8 and more)
- This results in disturbed tissue homeostasis leading to destruction of collagen, connective tissue matrix and bone
- This results in true pocket development from the junction epithelium
What are MMPs?
Matrix metalloproteinases (MMPs) are a large family of calcium-dependent zinc-containing endopeptidases, which are responsible for the tissue remodeling and degradation of the extracellular matrix (ECM), including collagens, elastins, gelatin, matrix glycoproteins, and proteoglycan.
They are regulated IL-6 and IL- 8.
They are released by many cells like PMNs.
What causes bone resorption?
- RANKL - produced by osteocytes in large quantities, due to stimulation of pro-inflammatory cytokines like IL-6 and IL-8, able to activate osteo clasts - bone resorbing cells
- RANK - receptor on osteocalst - binding site of RANKL
- OPG - scavenger receptor that prevents RANKL binding thus preventing bone resorption
RANKL:OPG ratio: relative amount regulate the bone turn over
What is the importance of T helper cells in periodontitis?
They help to propagate the process of secretion of pro-inflammatory cytokines and messengers
What is a risk factor?
Health risk factor are attributes, characteristics or exposures that increase the likelihood of a person developing a disease or health disorder.
What are some of the pre-disposing factors for periodontitis?
Any factor that result in retention of biofilm or prevents ts removal thus predisposing for disease progression.
E.g.:
Anatomical factors: root proximity, tooth malposition, concavities and furcation
Aquired/Iatrogenic factors: overhangs, open contacts and appliances
All this needs to happen in a susceptible host.
What are modifying or systemic factors?
They are factors that modify disease expression and may influence disease progression by altering host’s immune response
e.g. in periodontitis: smoking and diabetes
How does smoking increases the risk of periodontitis and by how much on average does it increase the instance of periodontitis according to latest studies?
The mechanisms:
1. Chronic reduction in blood flow and vascularity
2. Increase the prevelance of potential periodontal pathogens in the sulcus
3. Shift in neutrophil function towards destructive activities
4. Shift to a dysbiotic, pathogen enriched microbiome
5. Affects PMNs making them more aggrevated
6. Increase the number of aggravated T cells that produce inflammatory cytokines
It increases the risk of periodontitis by 85%!
Smoking cessation has beneficial effect on therapy outcomes and disease progression - this should be attempted for patient with nicotine dependence/
What are two useful statistics to give to a smoker patient in order to discourage them from smoking?
- Regular smokers have around 50% less improvement in clinical parameter after nonsurgical therapy
- Regular smoker have 2x implant failure rate compared to nonsmokers
How does diabetes increases the risk of periodontitis and by how much on average does it increase the instance of periodontitis according to latest studies?
- No solid evidence of causal relationship between poorly controlled diabetes and periodontal microbial dysbiosis in humans, but there some evidence in vitro thus it is biologically plausible
- Osteogenesis reduction due to apoptosis of osteoblasts and PDL fibroblasts
- Increase in RANKL expression and OPG expression is decreases
- Increase in collagenase activity
It increases the risk of periodontitis by 3x to 4x!
Multidisciplinary control and treatment of diabetes is ESSENTIAL to treatment of periodontitis.
What can be seen intraorally in a patient with diabetes and perio?
- No specific phenotypic features
- Pronounced clinical and radiographic signs
- Signs of progression
- Multiple reoccuring periodontal abscesses
- Unpredictable responses to therapy
- Increases risk of future attachment loss
If you suspect undiagnosed or poorly controlled diabetes, refer to GP for further investigations or management
What is the relationship between diabetes and periodontitis?
There is a bi-directional relationship between diabetes and periodontitis, meaning improvement in diabetes improve periodontitis but also improvement in periodontitis improve diabetes!