CAP L7- Prevention of dental caries Flashcards
What 4 factors are needed for caries?
• Teeth • Plaque bacteria • Sugar • Time – for above to interact
Describe the teeth factor affecting caries.
– improve diet • resistant – add trace elements • fluoride – use protective coatings • fissure sealants
Describe the plaque bacteria factor affecting caries.
– removal
• mechanical or chemical
– vaccination
• cariogenic bacteria (S. mutans)
Describe the sugar factor affecting caries.
– improve diet
– restrict fermentable carbohydratres (simple)
Describe the time factor affecting caries.
– sugar in contact with teeth
– avoid snacking
Describe the mechanical method of plaque control.
• Acidogenic Plaque bacteria • Complete Removal – oral hygiene is not 100% – bacteria recolonise tooth – Flossing – Professional removal (Hygenist or Dentist)
Describe the mechanical method of removing plaque via toothbrushing.
• Toothbrushing – effective – fluoride – electric/sonic • Reduces Gingivitis – overwhelming evidence
Describe the experiment that tested the “Efficacy of Removal of Sucrose-Supplemented Interproximal Plaque by
Electric Toothbrushes in an In Vitro Model”.
- Constant Depth Film Fermentors (CDFFs)
- Expose to mucin containing artificial saliva
- Study using 10% Sucrose
- Sonicare plus
- Braun Oral B 3D
What were the result of this experiment?
– Sonicare Plus - 32% removed
– Braun Oral B 3D
- 15% removed
What are ideal disclosing agents?
– non-toxic
– acceptable taste
– easily removed from mouth after use
– good colour contrast with teeth and soft tissues
– indicate oldest and most metabolically active areas of plaque
– be inexpensive
Name some common dyes and chemicals (disclosing agents).
• Bismark brown • Basic fuschin • Fast green • Fluorescin – requires blue/UV lamp to see plaque • Erythrosin – common – stains tongue, lips & other soft tissues as well as plaque
Name 3 chemical methods of plaque control.
- Antibiotics
- Antiseptics
- Enzymes
Describe the chemical method of antibiotics in plaque control.
– historical interest – major problems • Disrupt natural flora – C. albicans • Resistance • Hypersensitivity • Storage
Describe the chemical method of antiseptics in plaque control.
– Chlorhexidine (0.12% - 0.2%)
– Active on Gm +ve & Gm -ve
– S. mutans more sensitive than S. sanguinis
– slow releasing varnish/Gel/mouthwash
when is cholorhexidine (+ve) and fluoride (-ve) used?
- high risk patients
* radiation caries
Is sodium chloride antibacterial?
sodium fluoride is not antibacterial , it is the fluroide that dissicoates and crosses wall, this happens at pH4 which is good because this is when reminerlaization is needed
Why are chlorohexidine usually used for a restricted period.
– Staining (yellow/brown)
– Taste
– Disrupts oral flora
What does STAMPS stand for?
Specifically-targetted anti-microbial peptides
Describe the action of STAMPS.
– co-joined peptides
– Specificity & antimicrobial
– In vitro activity
– Combine with replacement therapy
What was the outcomes of experiments that tested antimicrobial agents?
“recent findings indicate that surrogate end points, such as the effect of an antimicrobial agent on levels of mutans streptococci (MS) or plaque reduction may not always correlate with eventual caries reduction.”
What was the outcomes of experiments that tested cholrohexidine gels, varnishes, rinses, or a combination chlorohexidine -fluoride therapy?
“suggestive but incomplete”
Describe the chemical method of enzymes in plaque control.
– Single or mixtures – Dextranases – Mucinases – Polysaccharidases _ DNAses (huge component of biofilm)
What are the disadvantage of anti-plaque enzymes?
• Not very effective
• Enzymes do not store well in toothpastes etc.
• Enzymes usually very specific
– dextranase does not breakdown other glucans and vice versa
• Enzymes are proteins
– hypersensitivity reactions may occur
Describe the action of sucrose.
– Populations exposed to sucrose diets & higher caries rates.
– clinical association studies
– short term human experiments
– long term animal studies
Name some sugar substitutes.
– artificial sweeteners:
• saccharine (intensive sweetener)
• Xylitol (bulk sweetener also encourages saliva flow)
Name some detersive (tough , fibrous) foods.
– propose a mechanical role in removing dental plaque
– apples, carrots etc.
– little evidence this reduces dental caries
Describe Xylitol.
• Sugar alcohol
• Sucrose replacement or additive
• Reduces MS bacteria & acid production
• Reduction in children whose mothers chewed xylitol gum
– Reduced MS transmission
How is Xylitol an excellent agent in reducing caries risk?
– Timing? How often? 3-5 Xs a day? effect persists beyond use
– Delivery ? Chewing gum, snack foods,
– Use in combination with chlorohexidine & fluoride?
– Targeting? Children & high risk groups
Describe how raw starch affects caries.
– Not cariogenic
– Poorly degraded by α-amylase
– S. mutans, S. mitis & A. viscosus (no decrease pH)
Describe how cooked starch affects caries.
– Non-cariogenic in Monkeys – Cariogenic in rats
– Cariogenic in man
• (potato chips, popcorn, rice crackers)
Overal is starch cariogenic?
starch itself is not cariogenic,
only when starch is metabolised do they cause caries
what inhibits starch metabolism?
α-amylase inhibitors (acarbose)
What inhibits glycolysis?
Xylitol
what does replacement therapy do?
Replace pathogenic bacteria by non-pathogenic
What is the role of replacement therapy?
– 1) reduced cariogenic potential
– 2) Displace existing S. mutans
– 3) Persist in S. mutans sites (prevent recolonisation)
– 4) Safe
• i.e. doesn’t make host susceptible to other diseases e.g. endocarditis
What harmless effector strains can be used for replacement?
– Inoculate host at early age • avirulent Streptococci
– Displace existing strains with new strains
• S. salivarius displaces S. mutans
what do harmless effector strains do in replacement therapy?
• fails to make lactic acid rather ethanol & acetoin (pH 0.4-1.2 points higher) • also produces antibiotic • colonised rodents -displaced S. mutans -premptive colonisation -aggresive-displacement colonisation -no change in overall plaque
