Biofilms Flashcards
Below which pH leads to demineralisation
PH 5.5
List the 6 microbial stages of caries
Adhesion
Survival and growth
Biofilm formation
Complex plaque
Acid
Caries
What are some of the key carcinogenic foods
Fermentable carbohydrates
Along with cooked startches (retentivity bin the mouth- slowly leach out and become fermentable carbs).
4 elements of remineralisation
Saliva
Fluoride
Plaque control
Dietary modification
Which type of bacteria are endo infections derived from?
Endogenous microflora
Opportunistic
Which bacteria are involved in endodontic infections?
Primary endo infection- dominated by gram -ve anaerobic rods (poly microbial)
Secondary endo infection- gram +ve (enterocuccus faecalis)
Bacteroides, prevotella (gram -ve)
Strep
Etc.. other microorganisms
List 5 virulence factors of enterocuccus faecalis
Endotoxins
Adhesions
Collagenases
Hyaluronidase
Immune evasion
Which 2 organisms can support each other in endo infection and can be treated with NaOCl and EDTA
C. albicans and E. faecalis
What is the keystone pathogen of perio and list some virulence factors
Porphyromonas gingivalis (gram -ve anaerobe)
Virulence factors- endotoxin, fimbriae, collagenases, gingipains (activate MMPs, degrades cytokines and innate receptors) etc…
What are some influence on the oral microflora
Host factors- medication, systemic disease, OH
Diet
Saliva
Gingival crevicular fluid (anti microbial components)
Microbial interactions (competition and co-operation)
Gaseous environment (oxygen concentration)
Describe the development of periodontitis
Proportion of periodontopathogenic bacteria increases causing mild inflammation at the edge of the gum (gingivitis)
This progresses to high concentration of bacteria causing severe inflammation and pocket formation, resulting in degradation of soft tissue and bone.
Conditioning film- linking film (strep)- co aggregation/ re-conditioning film (actinomyces)- accumulation of biofilm.
Which type of bacteria are associated with periodontitis?
Gram -ve anaerobe
P gingivalis
T forsythia
T denticola
What are the stages of biofilm development?
Adhesion
Colonisation
Accumulation
Complex community
Dispersal
What are some bacteria found in health?
Oral streptococci- actinomyces, veillonella
What bacteria are associated with gingivitis?
Actinomyces, prevotella intermedia, Bacteroides
What is the local and systemic effect of a dysbiotic biofilm?
Local- destructive inflammation of tissues
Systemic- host immune response including pro inflammatory cytokines and antibodies to host cross reactive antigens (can target organs)
What is the effect of prebiotics
Can change the micro biome by providing with correct, healthy microorganisms.
What are the 4 main types of candida in the oral cavity
Psuedomembranous (thrush)
Erythematous (atrophic, denture related)
Hyperplastic (Candida leukoplakia- associated with pre malignancy)
Angular cheilitis
What are the 2 most opportunistic pathogenic yeasts and what are the differences?
Candida albicans, candida glabrata
Albicans is sensitive to fluconazole and myconozol whereas glabrata is not
What is the function of hyphe (on Candida albicans)
Grows in reaction to stress
Allows it to adhere and invade tissue (reaching bloodstream).
Give 3 examples of hydrolytic enzymes present in biofilm
Phospholipases
Haemolysin
Proteinase
How is a candida infection diagnosed and treated
Oral rinse/ swab taken from site (or biopsy is candida leukoplakia)
Grown on chromogenic agar
- differentiate between albicans and glabrata (treat with an -azol or nystatin)
What is the mode of action of antifungals
Fungistatic (eg fluconazole) - Inhibit the ability of ergosterol synthesis (molecule on cell membrane)
Fungicidal (nystatin) - bind with ergosterol directly, causing pores which lead to leakage of cytoplasmic contents and cell death. (Can be toxic)
Echinocandins- act on enzyme producing beta glucans, which de stabilises the cell wall causing cell death - not yet used in dentistry
What is the role of cholorhexidine in a fungal infection
Antiseptic and anti-candidal
Give an example of a novel antifungal compound
Diluted tea tree oil
Why is it difficult to establish causality for a specific bacteria in endo infection?
It is dificultades to obtain a sample without contamination
