Microbiological considerations

Question 1

What characteristics of the oral microbiome make it suitable for caries prevention and treatment?

Answer 1

• It is diverse and acts like any other micobiome

* You can aim for restoring the biome to a state of symbiosis

Question 2

What are the bacterial specific approaches to preventing caries?

Answer 2

PREVENTS rather than TREATS

1. Salivary diagnostic kits
2. Immunisation

Question 3

Describe salivary diagnostic kits as a bacterial specific approach to caries prevention.

Answer 3

• Detect acidogenic microbes using saliva to assess caries risk
• Target s. mutans and lactobacilli

• Newer kits: have a more non-specific approach. The Salivary Immune and Metabolic Marker Analysis (SIMMA) looks at acidity of saliva and plaque, adhesion capacity of microbes and the immune system (whether you have high IgA in saliva)

Question 4

Describe immunisation kits as a bacterial specific approach to caries prevention.

Answer 4

• Stimulates salivary glands to secrete IgA which targets s. mutans
• Can be administered intranasally or orally
• Can be passive immunisation, or active immunisation
• Target group is children

Question 5

What are the three antigen candidates of S. mutans?

Answer 5

• Surface fibrillar adhesins (AgI/II) –> this is what helps S. mutans to adhere to tooth
• Glucosyltransferase (GTF) –> sucrose meatbolism
• Glucan binding proteins (GBP) –> this is what helps S. mutans to adhere to tooth

Question 6

Describe PASSIVE immunisation kits as a bacterial specific approach to caries prevention.

Answer 6

• Transfers antibodies that are protective against all S mutans
• Can be topically applied, or through dietry supplements
• Animal studies have shown success via mother to infant
• In humans, a 9 day application prevented S. mutans for 2 years

Question 7

Describe ACTIVE immunisation kits as a bacterial specific approach to caries prevention.

Answer 7

• Provides direct vaccination against s mutans antigens

* It aims to develop IgA antibodies against s. mutans naturally

Question 8

Describe how effective the bacterial specific caries prevention methods have been

Answer 8

Overall issues:
• Only targets specific bacteria, whereas a diverse range of bacteria have been implicated in caries
• Salivary diagnostic kits aren’t great because their counts are not accurate predictors of caries risk
• Passive immunity doesn’t last very long, and antibodies are derived from elsewhere

Good things:
• Passive immunisation: animal studies have shown success via mother to infant
• In humans, a 9 day application prevented S. mutans for 2 years

Question 9

What are the non-specific microbiological approaches to preventing caries?

Answer 9

• Probiotics
• Prebiotics
• Antimicrobials

Question 10

Describe PROBIOTICS as a non-specific microbiological approaches to preventing caries.

Answer 10

• Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host
• Some probiotics are: Lactobacillus, Bifidobacterium, Streptococcus (these come from gut rather than mouth)
• The human microbiome is made of many different types of stuff. When these things are in homeostasis, it is known as symbiosis and so it provides health
• Thus, the rationale for probiotics is to restore a disturbed bacterial community to a state of homeostasis
• Probiotics can bind to teeth (prevent other colonisation), they can produce antimicrobial products, alter environmental conditions of mouth and reduce the inflammatory respons

Question 11

Describe PREBIOTICS as a non-specific microbiological approaches to preventing caries.

Answer 11

• Food ingredient or substrate that is non-digestable to humans, but digestible for bugs, and affects the proliferation of commensal bacteria and then may exert a probiotic effect
• Basically feeds the pro-biotic and allows them to flourish
• Limited studies in dental caries

Question 12

Describe ANTIMICROBIALS as a non-specific microbiological approaches to preventing caries.

Answer 12

• Food ingredient or substrate that is non-digestable and affects the proliferation of commensal bacteria and then may exert a probiotic effect

Question 13

Describe SMALL MOLECULES as a non-specific microbiological approaches to preventing caries.

Answer 13

• The oral microbiota manufactures a massive array of small molecules: some of which are correlated with health and are likely to antagonise pathogens
• 3F1 selectively dispersedS. mutansbiofilms and served to modestly reduce caries in rodent model

Question 14

Describe how effective the different non-specific, microbiological caries prevention methods have been

Answer 14

Issues with probiotics:
• Lack of consistent evidence
• Lack of long-term, follow-up studies
• Also, we are using one bug/ pro- biotic to fix a complex oral microbiome. Is that feasible?
• Not a one size fits all probiotic for all diseases; can’t use same tablet for caries and then perio
• Specific strains have specific effects
• Strains vary in effect for different oral health conditions

Probiotic: streptococcus salivarius
• Study with 100 caries active children, 50 got the probiotic, 50 didn’t
• After a 3 month follow, the test group showed reduction in plaque, and reduction in S. mutans