9. Oral biofilms and calculus Flashcards
Stages in the formation of dental plaque
- Acquired pellicle
- Initial collonisation
- Secondary colonisation
- Maturation and biofilm growth
- Plaque mineralisation and calcification
Acquired pellicle
- Formed instantly after brushing
- Salivary and glycoproteins
- Thin film that is attachment site for bacteria
Intial colonisation
- Within a few hours
- S. Sanguis, S. Oralis
Secondary colonisation
- 24-72 hours
- More diverse microorganisms including actinomyces, preveotella and fusobacterium
- Adhere to initial colonisers
Maturation and biofilm growth
- After a few days
- Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola
- Gram negative and positive bacteria
Plaque Mineralization and Calcification
- Over longer period
- Biofilm hardens due to salivary minerals
Types of plaque
- Supragingival
- Subgingival
Calculus composition
- Inorganic(mineral) components
- Organic(cellular and extracellular matrix) components
Inorganic component of calculus(mineral)
- 40-60% depending on location
- Calcium phosphate crystals organised into four mineral phases=>Octacalcium phosphate, hydroxyapatite, whitlockite and brushite
Organic component of calculus
- 85% cellular and 15% extracellular matrix
- Cellular density within calculus very high
- Extracellular matrix mostly proteins and lipids
200,000,000 cells per milligram
-Cells primarily bacterial, some fungal-candida and species of archaea
Common sites for calculus formation
- Buccal surfaces on maxillary molars
- Lingual surfaces of mandibular incisors
-Due to proximity to parotid and sublingual salivary glands
Bacteria present in fissures
- Gram positive bacteria
- Facultative anaerobes
- Streptococcus
- Actinomyces
Bacteria present in proximal plaque
- Gram positive and negatve
- Facultative and obligate anaerobic bacteria
- Streptococcus
- Actinomyces
- Neisseria
- Veillonella
- Prevotella
Bacteria present in gingival crevice
- Gram positive and negative
- Obligate anaerobes
- Streptococcus
- Actinomyces
- Eubacterium
- Fusobacterium
- Treponema
Bacterial complexes
- Green
- Orange associated
- A-a
- Orange
- Red
Bacteria in green complex
- E.corrodens
- Capnocytophagia species
-C.gingivalis
-C.Ochracea
-C.Spitigena
E= Eikenella
Bacteria in orange associated complex
- C.rectus(Cr)
- E.nodatum(En)
C=Campylobacter
E=Eubacterium
Bacteria in A-a complex
A.Actinomycetemcomitans(Aa)
Bacteria in orange complex
- P.Intermedia(Pi)
- P.micra(Pm)
- F. nucleatum(Fn)
Pi=Prevotella
Pm- Parvimonas
Fn=Fusobacterium
Red complex bacteria
- P.gingivalis(Pg)
- T.forysthia(Tf)
- T.denticola
Pg=Porphyromonas
Tf=Tannerella
Td-Treponema
