Theme II Flashcards
What pre-eruptive effects does malnutrition have
- Structural defects -enamel hypoplasia and hypo mineralisation
- Delayed eruption
- salivary gland atrophy
- these contribute to increased caries risk
What is hypoplasia and hypomineralisation. What it looks like
Developmental defects in enamel that occur pre-eruptively. making teeth more susceptible to caries.
-Enamel hypoplasia: Disrupted mineralisation. Theenamelis sufficiently mineralised, but is lacking. Due to defectiveenamelmatrix formation. Surface interrupted by pits and grooves.
-Enamel hypomineralisation: suboptimal mineralisation, leading to enamel opacities due to reduced mineral content and ‘softer’ enamel. Enamel ‘chips’ post-eruptively
What 4 deficiencies lead to hypoplasia. And another factor
-protein, calcium, vitamin D, vitamin A
(not phosphate)
-also low birth weight (maternal malnutrition and placental insufficiency)
What deficiencies cause salivary gland atrophy, and therefore increased caries risk
-protein, vitamin A
Why was caries low during WWII
- rationed sugary food
- Cheap milk available, with calcium and vitamin D
- Cod liver oil free to pregnant, breast-feeding mothers, infants and children. Source of vitamin D
- Vitamins A & D was added to margarine
- Calcium carbonate was addd to flour
What is dental fluorosis. What it looks like and how it is caused. When it is likely to occur
-White opacities with subsurface brown staining
-During enamel maturation, an excess of F- ions alters the rate that matrix proteins (amelogenins) are broken down, and the rate at which the subsequent breakdown products are removed.
-Fluoride may also indirectly alter the action ofproteasevia a decrease in the availability of free calcium ions in the mineralisation environment.
= Hypomineralised which alters properties and appears opaque and lustreless relative to normal enamel. Easily chipped
-Peak age for this is birth to 2 years old
How many ppm of fluoride is added into water. How much is in tooth paste
- 1ppm
- 1450 ppm for adults. 1000ppm for children as tend to swallow
Name sources of fluoride (natural and unnatural)
- Natural: water, sea food, tea
- Dental products (toothpastes, varnishes, rinses)
- Fluoridated water, salt, milk
- Fluoride supplements
Absorption, distribution and excretion of F
- Ingested fluoride has rapid absorption. 90% is absorbed in stomach. The negative F binds to positive hydrogen ions in stomach acid and is absorbed as hydrogen fluoride.
- Absorbed into systemic circulation and 99% is distributed into calcified tissues (bones and teeth)
- The remaining is excreted in urine or faeces
-Usually in equilibrium where intake = elimination
How does composition of diet affect absorption and elimination of F (fat, veg, iron, zinc)
- Fat affects absorption of F. Fat reduces gastric emptying so F in stomach for a lot longer. More absorbed. Increasing systemic F.
- Diets rich in veg increases pH of renal tubules, so urine is more alkaline. H pass into urine to balance pH. Water and F follows so more F excreted. Negative F balance.
- High iron or zinc can bind to F which makes it unavailable to be absorbed. More excreted. Negative balance.
Why a balance in fluoride is important. What does too little, too much and the right amount do. What is the optimum amount for dental benefits
- Too little = increased risk of caries
- Too much= fluorosis, which looks bad and increases caries risk
- The right amount= 0.05-0.07mg/kg
- aids in remineralisation and reduces glycolysis and acid production. So reduces risk of caries.
What is acute and chronic fluoride toxicity
- Acute: sudden ingestion of large dose. Not common.
-causes nausea, vomiting, diarrhoea and
abdominal pain
-certain lethal dose is ~ 32-64mg/F/kg
Safe tolerated dose is 8-16 mg F/kg - Chronic: smaller dose over long time. Get build-up in body
-affects teeth during development: up to 6
years, incisors up to 3 years. Causes skeletal fluorosis, causing brittle and sore bones.
What is the recommended daily amount of F. The optimum amount for dental benefits in children
- Safe tolerated dose is 8-16 mg /kg
- Optimum safe daily dose for dental health benefits is 0.05-0.07 mg/kg body weight per/day in children <12 years of age
What effects does fluoridation have on caries levels in permanent, primary teeth, and lower socioeconomic individuals. And in general how much does fluoridation reduce dental caries by
- Primary= 40-50% decrease in caries
- Permanent= 50-60% reduction
- Biggest reduction in lower income people
-Water fluoridation by 1ppm reduces dental caries by 20- 50%
How much fluoride is in milk. Is it effective
- 0.03ppm
- Beneficial although evidence isn’t as good as water fluoridation
- Cessation associated with worsening dental health. Effective in caries prevention. However It may increase milk flurosis
Pros and cons of F delivery by public water, school milk, and salt
1-Water: reduces caries, free, available to all, very beneficial for lower socioeconomic status. Large targets
-However takes away choice
- Milk: reduces caries risk, ensures children are getting the correct daily dose. Developing teeth.
- However problem for vegans or lactose intolerant - Salt: reduces caries, gives the consumer choice, useful when fluoridated water and milk are not possible.
- Increases BP
What are free sugars
added sugars, plus sugars in honey, syrups, fruit juices, and fruit juice concentrates. ( not including sugars in fruit, veg, milk)
Name starchy staple food, and highly processed starchy food involved in caries and obesity
-Starchy staple foods: Bread, Potatoes, Unsweetened, cereals, Rice, Pasta, Bulgar wheat, Millet
=no relationship with caries
-Highly processed starchy foods: Sweetened breakfast cereals, Biscuits, Cakes, Processed corn and potato snacks, Sweetened popcorn, fizzy drinks etc. Foods where sugar has been added
Give examples of studies that show sugar increases risk of caries
- In WWII when sugar was rationed, low caries
- Fructose intolerant patients have low caries
- lower sugar diets reduces caries levels (although doesn’t eliminate caries). high sugar diets and high frequency have increased caries levels
- Countries with low availability of sugar (eg. Nigeria) have lower caries rates
- Western diet have higher rates of caries
- When transport links improved importing sugar it increased caries on islands (Tristan da Cunhan)
- Sugar free v sugar gum affects DMFT scores
Is fruit, fruit juice and dried fruit good for you
- Fresh fruit is healthy. No free sugars. Sugars in cells. Good source of micronutrients and fibre.
- Fruit juices are high in added sugars so should be limited to 150ml a day. The juicing process also releases the sugars from cells.
- Died unmodified fruit are perfectly fine. Although a problem if sugars have been added such as coating in syrups etc.
Describe briefly the types of studies (meta analysis, systematic reviews, randomised, case-controlled, cohort, case reports)
- Meta/ systematic: gathers and analyses all available evidence and data from all studies to draw a conclusion
- RCT: randomised to reduce bias. Evaluating effectiveness of an intervention by comparing to a control
- Case-control: comparing people with the disease, to people without the disease. Looking retrospectively to see what has caused it.
- Cohort: Comparing 1 group with exposure of interest to another group without. Maintaining what they already do. Looking prospectively to see what disease is going to be caused. Change in study cohort over time.
- Cross sectional studies – measure at one point in time, to compare prevalence. Don’t know when exactly disease was caused.
- Case studies – report on a single patient. No control group. weak evidence, only suggestive
How much sugar a day for 4-6 years 7-10 years, 11+ years
- 4-6 years: 5 cubes (19g)
- 7-10 years: 6 cubes (24g)
- 11+ years: 7 cubes (30g)
Explain how intervention, cohort and ecological studies show the relationship between free sugars and caries
-Intervention studies: Turka sugar study showed that removing sugar from diet and replacing it with xylitol over a 2 year period
lead to 85% caries reduction in adults.
The Vipeholm study showed that consumption of – sugars inbetween meals increased caries.
Withdrawing sugars stopped caries activity.
-Cohort: 8 cohort studies show higher caries with higher sugars. 5 cohort studies show lower caries when intake of
free sugars is<10% energy.
Some low levels of dental caries occurs at <10% sugars.
-Ecological|: These provide data to show that dental caries is lower when the sugars availability is below 5% or energy
compared with above 5 but below 10%.
Limitations of the following study types for caries: dental plaque pH, animal experiments, cross sectional epidemiological studies, population based ecological studies, cohort studies
-Plaque pH Indirect measure of dental caries as only measures acidogenicity.
-Animal: Differences in tooth morphology and salivary composition
-Cross sectional: Current diet may be different from diet several years previously when dental caries
was initiated. Only measures disease and diet at one time point.
-Population based: Do not account for confounding factors and use per capita sugars data that assumes equal consumption across population – e,g, all age groups
-Cohort: do not provide as such strong data as RCT. Bias. Not all have controlled for confounding factors such as fluoride exposure, oral hygiene.
