Aetiology of periodontal disease Flashcards
What groups can periodontal diseases go into?
- Periodontal health, gingival diseases and conditions (only affecting soft tissues)
- Periodontitis (affecting all the periodontal apparatus e.g. gingiva, periodontal ligament, cementum and the alveolar bone)
- Other conditions affecting the periodontium
- Peri-implant diseases and conditions
Give a definition of periodontal disease and how this changes in healthy and diseased sites
- Bacterially-induced, immune-mediated inflammatory diseases of the tissues supporting the teeth
- Healthy = well defined, precise locations, effective immune response
- Diseased = exacerbated, uncontrolled, detrimental immune response
(Normal bacteria shown on the left and can form in healthy-areas. There is a constant flow of neutrophils, low level of inflammation that protects us from the bacterial invasion.
In the diseased periodontal mouth, there is a different set of bacteria which are present in the sub gingival areas. These bacteria can cause detrimental host responses. The host immune response on the disease side, this is uncontrolled and leads to tissue damage.)
Give a definiton of inflammation
A protective tissue response to irritation, injury or infection, which serves to destroy, dilate or wall off both the injurious agent and the injured tissues. Clinical signs are pain, heat, swelling and loss of function.
All cells of the periodontal tissue are involved in this inflammatory response apart from the red blood cells.
All the immune cells produce enzymes and inflammatory mediators to damage the connective tissue. This is why we see the damage to alveolar bone during the development of periodontal disease.
What are the 3 prerequisites for periodontal disease initiation and progression?
- The virulent periodontal pathogens (adhesins, co-aggregation, invasion)
- Local environment
- Host susceptibility (gene polymorphism, smoking, diabetes, immunosuppression)
What are the 3 main factors which need to be in a harmonious relationship?
- Susceptible host
- Micro-organisms
- Environmental trigger
Breakdown of this leads to disease.
Why is the mouth a good microbial habitat?
The properties of the mouth make is ecologically distinct from all other surfaces.
It has mucosal surfaces (lips, cheek, palate, tongue) and it has hard shedding tooth surface. Hard surfaces are where the biofilm forms.
There are supra gingivial surfaces that as smooth with pits and fissues and sub - gingival surfaces which have gingival crevicular fluid.
What is the main bacteria present in the mouth?
Streptococcus
What is the difference between planktonic and sessile bacteria?
Planktonic cells can float in saliva or sessile cells are attached to the mucosa or hard surfaces.
Why cant bacteria form on the soft surfaces?
these surfaces are constantly shedding and the biofilm takes time to grow
What are the advantages to a bacteria of living in plaque?
- nutrient availability
- cell-cell signalling
- gene transfer
- protection from harmful factors
What is the definition of plaque?
A complex microbial community that develops on the tooth surface and other non-shedding materials, embedded in a matrix of polymers of bacterial and salivary origin.
Give some differences between supra and sub gingival plaque?
Supra:
- nutrients are diet and saliva
- carbohydrates are the principal energy source
- firmly adhered
- higher oxygen tension
- aerobes
Sub:
- nutrients from gingival cervicular fluid
- proteins as a source of energy
- many motile forms
- reduced redox potential
- anaerobes
What was the main discovery found from the gingivitis exeriment?
When the plaque is removed, the gingival inflammation is restored.
What are the two main local factors (plaque retentive factors) for periodontitis?
- dental calculus
- lack of saliva
Give some details on dental calculus
Mineralised dental plaque covering the enamel or root surface
Calcium and phosphate crystals
Supra-gingival: found in sites of saliva pooling, light coloured and frosted
Sub-gingival : found in periodontal pockets, hard and dark, difficult to remove
Acts as a plaque trap
Removed professionally
Give 7 local plaque retentive factors
- Tooth position
- Gingival anatomy
- Tooth shape / abnormalities
- Root anatomy
- Carious cavities
- Overhanging restorations
- Removable prostheses / appliances
How does tooth position lead to plaque retention?
malalignment and crowding (increase space for plaque accumulation, need to teach patient how to remove plaque), open contacts (food packing, need to show the patient how to remove the food from here)
How does gingival anatomy lead to plaque retention?
gingival overgrowth will be a plaque trap, tooth surfaces covered, difficult to remove plaque
Give one example of tooth abnormalities that can lead to plaque retention
Enamel projections
What are the 3 root abnormalities that can lead to plaque retention?
- Furcations of molars / premolars (where the roots divide, usually covered by bone but if there is bone loss it will provide an additional surface for plaque retention
- Root depression e.g. canine fossa 1st premolars - bone loss will expose the area
- Root groves - unevenness in the tooth surface is another plaque retentive feature
What are the two ways that caries and restorative margins lead to plaque retention?
Carious cavities
Overhanging restorations
How can lack of saliva lead to plaque retention? Gove some details on lack of saliva.
- Xerostomia (dry mouth) - lack of salivary flow that can increase gingival inflammation due to lack of salivary antibacterial factors
Commonly seen in …
- Mouth breathers
- Incompetent lips
- Drying of labial tissues
- Patients taking poly pharmacy (many medications) can cause it
- Patients with certain condition e.g. Sjogren’s syndrome
- Salivary gland disease - damage to these can results in less saliva and may cause gingival inflammation secondary to increased plaque accumulation
What are systemic factors leading to periodontitis and give 5 examples?
These modify the prevention of periodontal disease and may determine susceptibility to periodontitis.
Including: Smoking Diabetes Pregnancy Medications that cause gingival enlargement Genetic factors
How does smoking increase likelihood of periodontitis?
More likely to develop periodontitis and experience greater bone loss than non smokers. They are more likely to develop periodontal pockets and loose teeth. Smokers respond less well to treatment than non-smilers. Smoking masks gingivitis effects so will experience less bleeding (reduced gingival blood flow), it impairs wound heeling and increases inflammation.
Give some details on diabetes and how it can lead to periodontitis
- Type 1 diabetes (insulin dependant)
- Type 2 diabetes (insulin resistant) - associated with diet and obesity
- Uncontrolled / poorly controlled (poor glycemic control) increases risk of periodontal disease and disease progression
- Impaired immune response
- Impaired wound healing
- Recurrent / multiple periodontal accesses
- Dentist should stress importance of good glycemic control in the patient
- Successful periodontal treatment improves glycemic control
How does pregnancy increase likelihood of periodontitis?
hormones may increase gingival response to plaque
Increased progesterone results in increases gingival blood flow
Similar effects also seen at puberty and associated with the contraceptive pill
Give some examples of medication affecting likelihood of periodontitis?
Drugs that induce gingival overgrowth, gum covers many tooth surfaces
Calcium channel blockers - for hypertension
Phenytoin - for epilepsy
Ciclosporin - immunosuppressant prescribed for some autoimmune disorders
In severe cases, treatment won’t work and may need to communicate with patients GP to consider alterations to their medication
What is the difference between genetic polymorphism and single gene defects?
Genetic polymorphisms are common: normal variations in gene structure, may occur in regulatory or coding regions of the gene
Hereditary conditions are rare: single point genetic mutations
