Week 13 - Caries and Carbohydrates Flashcards
What are carbohydrates
Organic compounds composed of carbon, hydrogen and oxygen atoms and serve as a primary source of energy for living organisms.
What are simple carbohydrates
- Monosaccharides - simplest form of carbohydrates (1 sugar unit) e.g. glucose, fructose, galactose
- Disaccharides - composed of 2 sugar units e.g. sucrose, maltose, lactose
What are complex carbohydrates
large sugar molecules
- Oligosaccharides - 3-10 sugar units
- Polysaccharides (>10 sugar units)
What are sugars classified as (2)
- Intrinsic
- Extrinsic
What are intrinsic sugars
- Occur naturally within cellular structures of food e.g. sugar in fruit
- Not thought to have adverse effects on general and dental health
- Found in whole foods (fruits, vegetables and unprocessed grains)
Examples of intrinsic sugars
- whole fruits
- whole vegetables
- unprocessed grains
What are extrinsic Sugars
- Includes milk sugars and “free sugars”
- They can be naturally occurring but are not bound within the cellular structure of foods e.g. fruit juices and fruit concentrates
- Free sugars the sugars which are added to foods and beverages by manufacturers, cooks or consumers e.g. in soft drinks, cakes, biscuits
- Free sugars are detrimental to health and contribute to both dental caries and obesity
Examples of extrinsic sugars
- honey
- syrups
-fruit juices - fruit juice concentrates
- sweets
- cakes
- biscuits
- sugary drinks
What are dental biofilms
microbial biomass on a tooth surface composed of resident oral bacteria in a proteinaceous pellicle
What are dental caries
localized chemical dissolution of a tooth surface brought about by metabolic activity in the dental biofilm
What are fermentable carbohydrates
Sugars that can be metabolized by bacteria in the biofilm
e.g. sucrose, lactose, glucose
How do caries form
- The bacteria metabolizes these sugars and produce acids as a by-produce
- These acids lower the biofilm pH
- When the biofilm pH drops below 5.5 (critical pH) demineralization occurs on the tooth surface
- Remineralization occurs when the biofilm pH increases after approximately 60min as saliva flows in to buffer acidity
- De and remineralization occurs at the tooth surface numerous times each day (state of dynamic equilibrium)
- When there is more demineralization than remineralization eventually enough tooth mineral is lost and caries form
What percentage of minerals needs to be lost for caries to form
30-40%
Define critical pH for enamel
the pH at which enamel begins to demineralize
What is the critical pH
5.5
How long does it take for pH of the oral cavity to return to normal levels and what causes this
60 min as saliva flows in to buffer acidity demineralizing the tooth surface
What is aciduric bacteria
acid tolerant bacteria
What is acidogenic bacteria
acid producing bacteria
What are the main bacterial species which cause caries formation
streptococcus mutans
lactobacilli
What are 3 factors which influence the carbohydrates capacity to cause caries
- Cariogenic potential
- Frequency of intake
- Food form
How does cariogenic potential influence
Cariogenic potential refers to the capacity of the carbohydrate to cause caries
- Simple carbohydrate = harmful - diffuse into plaque and are metabolized by biofilm bacteria
- complex carbohydrates = less harmful
what is the most cariogenic sugar
sucrose
what are examples of cariogenic sugars
- glucose, fructose
- sucrose
- lactose
- starch
How does frequency of intake influence capacity for carbohydrates to cause caries
Repeated and frequent consumption of sugar leads to sustained low pH, increasing the amount of time during which demineralization is occurring. As a result the teeth are demineralizing more than they are demineralizing over time (shift equilibrium towards demineralization) resulting in:
- cumulative loss of tooth mineral
- caries formation
how does food form influence capacity for carbohydrates to cause caries
Referring to sticky, hard or soft which influences the duration of exposure and retention of carbohydrates on teeth.
High starch foods (potato chips, doughnuts) remain on teeth longer - extending the periods of acid production and demineralization
What is some advice for patients to reduce caries
- Reduce total amount of sugar intake - around 6 teaspoons (25g) per day
- Reduce frequency of sugar intake and avoid snacking in between meals
- Avoid sticky or retentive foods
What are some high caries risk groups
- Infants and toddlers provided with bottles of milk (contains sugar lactose)
- Patients who frequently consume snacks or drinks which contain added sugar
- Athletes using sports drinks
- Those with xerostomia
What are some safe snacks and drinks
- Cheese
- Nuts
- Water and milk
- intrinsic sugars in fruits are not generally considered harmful and the dietary fibres are good for you
What are the two types of sugar substitutes
- Non-nutritive (non caloric) sweeteners
- Nutritive (caloric) sweeteners
What are examples of no-nutritive (non caloric) sweeteners
- Saccharine
- Acesulfame-K
- Aspartame
- Thaumatin
What are examples of nutritive (caloric) sweeteners
Nutritive (caloric) sweeteners are sugar alcohols so they mostly end in -ol
-Sorbitol
- Xylitol
- Mannitol
- Hydrogenated glycose syrup (Lycasin)
- Isomalt (palatinit)
What are non nutritive sweetners
- Much sweeter than sucrose
- Cannot be fermented by biofilm bacteria, hence is safe for teeth
- Not suitable for infants/young children
- No effect on blood sugar
- Acidic and can contribute to dental erosion
- No suitable for infants/young children
e.g saccharine, acesulfame-K, Aspartame, sucralose
What are nutritive sweeteners
- Increase blood sugar
- used in sugar free sweets, chewing gum, toothpaste and medicine
- Xylitol cannot be fermented by oral bacteria and hence is safe for teeth
- Sorbitol and mannitol may be slightly fermentable
e.g. Xylitol, sorbitol, mannitol
Is xylitol safe for teeth
yes as it cannot be fermented by oral bacteria
Is Saccharine safe for teeth
Yes, it cannot be fermented by biofilm bacteria
Is sorbitol safe for teeth
No, may be slightly fermentable
Is fresh fruit good for teeth
Fruit contains intrinsic sugars. These are thought to be not particularly harmful in whole fruit.
The fiber is also beneficial for health.
However the overconsumption of acidic fruits are not recommended (lemon, limes)
Is canned fruit good for teeth
No, as canned fruits often contain sugar sprue which are extrinsic/ free sugars which is causes acid fermentation
Is fruit juice good for teeth
No, because the blending/juicing process releases the intrinsic sugars into free sugars from the fruit.
It also removes all fiber
The fruit sugar is more concentrated as there’s more than 1 fruit in a serving of fruit
If dried fruit good for teeth
No, dried fruit contains super-concentrated sugar due to the reduced water content
Dried fruit is also normally sticky thus it can remain in the mouth for a longer period of time acting as a reservoir for bacteria
Are dairy products good for teeth
Cow’s milk contains lactose - probably the least cariogenic of all the dietary sugars.
Casein in milk is thought to have a protective effect on teeth.
Cheese and milk are safe snacks and drinks.
some dairy products such as yogurt are not good for the teeth as they contain hidden extrinsic sugars which are harmful to teeth
However, parents should be told that infants should never be put to bed with milk in a bottle.
Is honey good for teeth
no, honey is a naturally occurring free sugar and sugar is highly concentrated in honey
