Aetiology of Periodontal Diseases Biofilms Flashcards
what is periodontal disease?
Bacterially induced (these bacteria live underneath gumline or grow on the level of gumline grow in the biofilm), immune-mediated and inflammatory diseases of the tissues supporting the teeth.
How does bacteria interact with the teeth when the site is healthy?
Bacteria present live in harmony with the host. Well defined, precisely orchestrated, effective immune response.
How does bacteria interact with the teeth when the site is diseased?
Exacerbated, uncontrolled, detrimental immune response.
What is inflammation?
Inflammation can be defined as a protective tissue response to irritation, injury or infection, which serves to destroy, dilute, or wall off both the injurious agent and the injured tissues.
The classical signs of acute inflammation are pain (dolor), heat (calor), redness (rubor), swelling (tumor), and loss of function (functio laesa).
What are the risk factors of periodontitis?
It is a multi-factorial disease but the primary aetiological factor is Dental plaque or biofilm.
what are local factors?
Local factors - promote accumulation of dental plaque (calculus, restorations with overhanging margins),
What are systemic factors?
Systemic factors – modify the host-bacteria interaction (Diabetes mellitus, puberty, pregnancy, immunodeficiency)
What are the prerequisites for Periodontal Disease Initiation and Progression
- The virulent periodontal pathogens (adhesins, co-aggregation, invasion, factors that cause tissue damage)
- The local environment
- Host susceptibility is determined by gene polymorphism, PMN defects, smoking, diabetes, immunosuppression.
All of these factors can influence the level inflammation that will be ,mounted against the periodontal pathogens.
How is the oral cavity involved in the progression of peridontitis?
- More than 700 types of microorganisms reside within the oral cavity (bacteria, fungi, protozoa, viruses).
- Breakdown of harmonious relationship leads to diseases.
- Perturbation of normal microflora or presence of the microorganisms at sites not normally accessible to them lead to development of diseases.
How is the mouth a microbial habitat?
- The properties of the mouth make it ecologically distinct from all other surfaces of the body.
- Mucosal surfaces ( lips, cheek, palate –low microbial load; tongue- heavy microbial load)
- Hard, non-shedding tooth surfaces, dentures, dental biofilm can only form on these surfaces and can be located:
o Supragingival (smooth surfaces, pits and fissures stagnant proximal surfaces)
o Subgingival (this is underneath the gumline and these area are characterised by GCF, redox potential)
What factors affect the growth of the microorganism?
temperature, redox potential, pH, nutrients (endo, exo), host defence.
What microorganisms that resident in the mouth?
- Bacteria (Streptococcus (most common), Actinomyces, Eubacteria, Lactobacilus, Neisseria, Veillonella, Heamophilus, Eikenella, Capnocytophaga, Prevotella, Porphyromonas, Wolinella, Campylobacter, Treponema)
- Fungi (Candida)
- Mycoplasma
- Viruses (HSV-1, Cytomegalovirus, HPV)
- Protozoa (unicellular eukariotic m.o – Trichomonas, Entamoeba)
How can these bacteria grow in the mouth?
These bacteria can grow in the mouth in two different types that can flow in the salvia or in sessile can attach on the surface of the mouth.
Biofilm can not grow on mucosal surface as we constantly shed off the epithelial cells.
What are the advantages of bacteria growing in the dental biofilm?
- Nutrient availability
- Cell-cell signalling
- Gene transfer
- Protection from harmful factors
What is dental plaque/biofilm?
Complex microbial community that develops on the tooth surface (and other hard, non-shedding materials), embedded in a matrix of polymers of bacterial and salivary origin.
Plaque that becomes calcified is referred to as CALCULUS or TARTAR.
