Lecture 1 (Part 2 - Caries Etiology, Pathogenesis and Modifying Factors of Dental Caries) Flashcards
Pellicle formation
Stage 1
Formation of an acellular layer
Stage 1
early colonization
Stage 2
Initial attachment
Stage 2
Irreversible attachment
Stage 3
Early maturation
Stage 4
Bacterial complexity increases creating anaerobic zones, food chains are established and an increased range of receptor sites for bacterial attachments.
Stage 4
Cell division and recruitment of new bacteria also allows the bacterial population to increase
Stage 4
also called maturation II
Stage 5
Mosaic microenvironments develop, particularly areas of different pH, oxygen concentrations and secondary metabolite accumulations around microcolonies.
Stage 5
The plaque microbial ecology reaches a pseudo-steady state climax community where there is constant turnover of cells but the overall composition remains the same.
Stage 5
Biogeography of a human oral microbiome at the micron scale
Mature Dental Biofilm
Dispersion
Stage 6
Enzymes that degrade the biofilm (such as dispersin B) allow some bacteria to detach themselves from the biofilm (sometimes in response to a deleterious environmental condition) in order to spread and colonize new surfaces in the oral cavity.
Stage 6
Classical microbiological techniques have estimated that plaque contains ____ distinct oral species
800
Classical microbiological techniques have estimated that plaque contains 800 distinct oral species and a healthy individual possesses ____ different species at any one time.
50-100
a new powerful molecular technique analyzing ribosomal RNA
Pyrosequencing
Pyrosequencing has estimated at least ____ phylotypes.
19,000
Microorganisms and host are in a symbiotic relationship.
pH is Neutral
There is a natural balance between the dental plaque and the tooth surface (and oral fluids)
pH is Neutral
Various species live in a co-operative, physiological equilibrium in biofilm through a complex interaction of synergism and antagonism
pH is Neutral
Acid-sensitive microorganisms like S, sanguinis are thriving. They keep acid production low and increase remineralization.
pH is Neutral
The small amount of acid produced is buffered by bicarbonates and phosphates in the oral fluids.
pH is Neutral
The small amount of acid produced is buffered by ____ and ____ in the oral fluids.
bicarbonates and phosphates
A dynamic equilibrium exists between the mineral contents of the tooth and the oral fluid* with the mineral content in the HA crystal being equal to that of the oral fluid
pH is Neutral
The HA crystals dissolve minimally and releases calcium (Ca2+), phosphate (PO43-), and hydroxyl ions (OH-)
pH is Neutral
is metabolized by bacteria
sugar
main energy generating pathway in all bacteria
by glycolysis
The by-product of glycolysis is
lactic acid
KEY FEATURES OF DENTAL CARIES:
- Multifactorial etiology
- Site-specific disease
- Time-dependent dynamic disease process modified
by protective factors
is a highly localized and complex process which occurs in areas of stagnation where plaque can accumulate undisturbed.
Dental caries
Each tooth site represents a unique environment that influences plaque:
- composition
- metabolic status
- thickness
The early stages of dental caries can be prevented, reversed or arrested, primarily through the elimination or modification of etiological factors and/or by enhancing protective factors.
TRUE OR FALSE
TRUE
Give Etiological Factors:
- dietary
- microbial
Give Protective Factors:
- Fluoride
- Sealants
- Salivary Stimulation
What are Low Concentration:
- Decrease rate of enamel demineralization
- Increased rate of enamel remineralization
- Inhibition of microbial enzyme systems
What are High Concentration:
- Formation of CaF2
- Concentrates in incipient lesions
- Bactericidal effects
Decrease rate of enamel demineralization
Low Concentration
Increased rate of enamel remineralization
Low Concentration
Inhibition of microbial enzyme systems
Low Concentration
Formation of CaF2
High Concentration
Concentrates in incipient lesions
High Concentration
Bactericidal effects
High Concentration
Provides the driving force to penetrate the dental biofilm adjacent to the tooth surface
High Concentration
What are the Main Etiological Factors:
- Tooth location and morphology
- Dental biofilm microorganisms with acidogenic and aciduric properties
- Frequent dietary exposure to fermentable carbohydrates
- Salivary flow rate
Caries as an infectious disease vs caries is a
lifestyle disease
is a complex, multifactorial disease
Caries
It cannot be controlled simply by eliminating one type of microorganism or a matter of improving host resistance
Caries
caries are formed
Demineralization
No caries
Remineralization
Predominance of cariogenic bacteria in biofilm.
what factor?
Pathological Factors
Sub-normal saliva flow and or function.
what factor?
Pathological Factors
Frequent eating/drinking of fermentable carbohydrates
what factor?
Pathological Factors
Poor oral hygiene
what factor?
Pathological Factors
Predominance of non-cariogenic bacteria.
what factor?
Protective Factors
Increased saliva flow and composition.
what factor?
Protective Factors
Frequent exposure to fluoride.
what factor?
Protective Factors
Good oral hygiene
what factor?
Protective Factors
Give “Limit Substrate”
- Substantially reduce sucrose from diet
- Eliminate sucrose from between meal snacks
Modify Microflora:
- Bactericidal mouthrinses (chlorhexidine)
- Topical fluoride treatments
- Antibiotic treatment (vancomycin, tetracycline,
polymyxin)
What is chlorhexidine?
Bactericidal mouthrinses
vancomycin, tetracycline,
polymyxin are ____
Antibiotic treatment
PLAQUE DISRUPTION/REMOVAL:
- Brushing
- Flossing
- Other oral hygiene aids (water piks, interdental brushes)
MODIFY TOOTH SURFACES:
- Systemic Fluoride
- Topical Fluoride application
- PRR
- Enameloplasty
- Prophylactic Odontotomy
STIMULATE SALIVARY FLOW:
Sugarless chewing gums (Xylitol)
RESTORE TOOTH SURFACES:
- Restore all cavitated lesions
- Seal pit and fissures at caries risk
- Correct all defects (marginal crevices, cervical
overhangs
ECOLOGICAL APPROACHES TO CARIES PREVENTION
- Antimicrobial Peptides (AMPs)
- Probiotics
- Prebiotics
- Sugar Polyols
- Quorum-sensing Targets
- Natural Products
- Replacement Therapy with “Designer” Bacteria
OTHER ECOLOGICAL APPROACHES TO CARIES PREVENTION:
- Nanoparticles
- Graphene oxide
- Ceramic water