L60: Aetiology and Pathogenesis Flashcards
L60: In the traffic light system, what are the main changes happening between green (health) and orange (gingivitis)?
- Change from symbiosis to dysbiosis of the biofilm;
- Low biomass to high biomass;
- Acute resolution of inflammation becomes chronic (persisting over time).
L60: In the traffic light system, what are the main changes happening between orange (gingivitis) and red (periodontitis)?
- Further dysbiosis of the biofilm;
- Disproportionate host immune response, hyper-inflammatory;
- Failed resolution of inflammation;
- Connective tissue and bone damage.
L60: What are some local plaque retention features for contributing to the trigger of gingivitis?
- Calculus;
- Restoration margins;
- Crowding;
- Mouth breathing.
L60: What are the main systemic modifying factors that influence the host’s response to plaque accumulation?
- Sex hormones;
- Medication.
L60: Does plaque accumulation always cause gingivitis?
No, this can sometimes pass as gingival inflammation but without progression to gingivitis
L60: What are the signs of gingival health?
- Well defined gingival margin;
- Stippling (not always);
- Pale pink (however colour also depends on race and lifestyle habits);
- No BOP.
L60: In health, what makes epithelial barriers hard for bacteria to invade?
Rapid cell turnover therefore continuously shedding
L60: Provide details of the immune response occurring at sulcular epithelial barriers, during health.
- Cellular level;
- Small, controlled response;
- Immune cells in GCF;
- Inc. antibodies, lymphocytes, neutrophils
L60: What is GCF?
- Gingival crevicular fluid;
- Inflammatory exudate from periodontal tissues.
L60: What are the signs of gingivitis?
- Inflamed;
- Loss of stippling;
- Shiny, red appearance.
L60: Microbially, what happens to cause gingivitis?
Altered microbial colonisation of the biofilm, with increased biomass
L60: What happens to the immune response with gingivitis?
- Increased immune response;
- Increased flow of GCF;
- Influx of immune cells (lymphocytes, monocytes, neutrophils);
- Infiltration of plasma cells;
- Proliferation and ulceration of the epithelium.
L60: Why do gingiva BOP with gingivitis?
Holey, instead of continuous but also inflamed and increased blood supply
L60: In terms of immune cells, what are more dominant with periodontitis, compared to gingivitis (and health)?
Plasma cells (B cells that produce antibodies)
L60: Besides a changed immune response, what other tissue changes occur with gingivitis and subsequently periodontitis?
- Dilated vessels;
- Vascular proliferation;
- Collagen loss;
These progress further from gingivitis to periodontitis.
L60: What is the main clinical difference between gingivitis and periodontitis?
- Irreversible loss of attachment (LOA);
- Increase of pocket depth;
- Apical migration of the junctional epithelium.
L60: What is a false pocket?
‘Pocket’ formation due to proliferation (+ inflammation) of the gingiva, no loss of epithelial attachment
L60: For a true pocket, there must be…
Loss of attachment (junctional epithelium to tooth)
L60: What lifestyle habit can often hide signs of pocketing before probing?
Smoking, due to vasoconstriction
L60: Once periodontitis is triggered, what is the typical range of LOA per year
0.05- 0.1 mm per year, but can be worse (2mm). Can be continuous or episodic.
L60: What are the properties of biofilms in health?
- Protection against colonising species from competing organisms/ environment;
- Facilitate uptake of nutrients;
- Removal of metabolic products;
- Maintaining appropriate physiochemical environment;
- Bacterial communication.
L60: What are the three bacteria commonly associated with periodontitis?
P. gingivalis, B. forsythias, T. denticola
L60: What are the two theories of the common bacteria found with periodontitis?
Causation or Association
L60: Describe two different mechanisms for how neutrophils attack pathogens.
- Generation of reactive oxygen species, kill bacteria but can also cause bystander damage to host;
- Release traps to trap bacteria and release mediators.
L60: Alongside cytokines, what other mediators control inflammation/ bone resorption?
- MMPs;
- TNFa;
- Prostaglandins;
- Interleukins.
L60: In terms of immune cells, how does the dominance of these change over the progression of periodontitis?
- Initial lesion: mainly T-lymphocytes;
- B cells and plasma cells at a later stage;
- Locally produced antibodies (but can also be seen in the blood).
L60: What are the protective functions of antibodies?
- Inhibition of adhesion/ invasion;
- Complement activation;
- Neutralisation of toxins;
- Opsonisation and phagocytosis.
L60: Why do gums recede with periodontitis?
Protective function - to prevent biofilm entering circulation and having systemic impacts
L60: What are MMPs and what are they responsible for in periodontitis?
- Matrix metalloproteinases, a family of zinc and calcium dependent proteolytic enzymes;
- Include collagenases;
- Degrade connective tissue matrix.
L60: What is the normal bone level, measurement away from ACJ?
1-2 mm
L60: What are the two types of bone loss?
Horizontal and vertical (angular)
L60: Which type of bone loss is usually easier to treat and why?
Vertical (angular) bone loss as there is already bone on one side of the tooth, regenerative material can be packed into the other side
L60: How does vertical (angular) bone loss arise?
Immune response and tissue destruction in one area around a tooth, 2mm from tooth
L60: What is horizontal bone loss?
Immune response and tissue destruction that encompasses the whole tooth surrounding
L60: What are the risk factors for periodontitis?
- Smoking;
- Diabetes;
- Stress;
- Drugs;
- Systemic disease;
- Nutrition.
L60: What are the risk determinants for periodontitis?
- Genetics (male);
- Gender;
- Socioeconomic factors.
L60: How does diabetes increase your risk of periodontal disease?
- Can reduce blood supply to teeth and gums;
- High blood sugar can also cause dry mouth, making gum disease worse;
- Prone to oral infections (immunocompromised).
L60: How does smoking increase your risk of periodontal disease?
- Effects function of immune system (for the worse);
- Depressed numbers of lymphocytes;
- Increased production of inflammatory markers;
- Change in bacteria (for the worse);
- Vasoconstriction to oral tissues;
- Impaired antibody production.
L60: What other illnesses are periodontal disease often linked to?
- Alzheimer’s;
- Rheumatoid arthritis;
- Poor pregnancy outcomes.
L60: Remember, plaque is x but not y?
- x: necessary;
- y : sufficient.
