Aetiology of Periodontal Disease: Dental Biofilm

• What are periodontal diseases?

  Bacterially-induced, immune-mediated inflammatory diseases of the tissues supporting the teeth
• How do periodontal diseases affect the immune response?

  Detrimental immune response

  
• What is inflammation?


  A protective tissue response to irritation, inury or infection which serves to destroy, dilute or wall off both the injurious agent & the injured tissues

  
  

  The classical signs of inflammation are pain (dolor), heat (calor), redness (rubor), swelling (tumor) & loss of function (functio laesa)
• What are the risk factors for periodontitis?

  Dental plaque- primary aetiological factor

  
  

  Local factors- promote accumulation of dental plaque (calculus, restorations with overhanging margins)

  
  

  Systemic factors- modify the host-bacteria interaction (diabetes mellitus, puberty, pregnancy, immunodeficiency)
• What are the prerequisites for periodontal disease & progression?

  Virulent periodontal pathogens (adhesins, co-aggregation, invasion, factors that cause tissue damage)

  
  

  Local environment

  
  

  Host susceptibility (gene polymorphism, PMN defects, smoking, diabetes, immunosuppression)

  
• Why is the mouth a good microbial habitat?

  
• What are some pathogens known to be able to infect the mouth?

  Bacteria(Streptococcus, Actinomyces, Eubacteria, Lactobacillus, Neisseria, Veillonella, Haemophilus, Eikenella, Capnocytophaga, Prevotella, Porphyromonas, Wolinella, Campylobacter, Treponema)

  Fungi(Candida)

  Mycoplasma

  Viruses(HSV-1, Cytomegalovirus, HPV)

  Protozoa(unicellular eukaryotic m.o- Trichomonas, Entameoba)
• Is the dental biofilm planktonic or sessile?


  The microorganisms on it undergo a transition from free-floating, planktonic microorganisms to a sessile, surface-attached one so whilst it may initially be planktonic, it's not later on
• planktonic vs sessile


  planktonic- floating

  sessile- embedded, not free flowing
• What is dental plaque (biofilm)?

  Complex microbial community that develops on tooth surface (& other hard, non-shedding materials), embedded in a matrix of polymers of bacterial & salivary origin
• What is calculus/tartar?


  Calcified plaque

  
• State the differences between supragingival & subgingival dental plaque.