Module 1 Flashcards
Four exposures/risk factors for dental caries?
Dental plaque (cariogenic bacteria)
Dietary sucrose (and other refined carbohydrates)
Fluoride insufficiency
Saliva insufficiency
what is an acquired pellicle?
acellular, homogenous organic film which forms on enamel and other hard surfaces through selective absorption of salivary proteins.
difference between pq and calculus?
pq is nonmineralized whereas calculus is mineralised
what are the observable effects of dental caries?
hole in the tooth or cavity
difference between active and arrested lesion?
active is one that is progressing in its activity, arrested white spot lesion is the remaining scar following treatment
what are the risk factors associated with dental caries?
pq, dietary sucrose or refined carbohydrates, fluoride insufficiency and saliva insufficiency.
is dental caries considered communicable or non-communicable?
non-communicable.
what process occurs in dental caries of teeth?
demineralisation of inorganic part of the tooth and dissolution of the organic portion.
what are the requirements of that facilitate dental caries?
cariogenic/acidogenic bacteria, pq, stagnation areas, fermentable substrate for bacteria, susceptible tooth surface and time.
how does frequent sugar exposure affect the carious process?
it changes the ecology of the oral cavity resulting in an upset of the balance between health and disease
is pq alone sufficient to cause dental caries?
no-pq needs to be exposed to refined carbs, especially sucrose, sucrose is fermented to acid by specific bacteria and the acid is trapped against tooth surface by the pq which diffiuses through enamel layer then dentin.
what does the acid dissolve?
apatite which is crystalline calcium phosphate
what is the first sign of dental caries?
white spot lesion which is revealed when thick pq is removed
what is the first radiographic sign of dental caries?
radiolucency on enamel
how is saliva important in cavity development?
prior to cavity development, is pq is removed by TB, saliva will bathe the tooth surface and result in lesion arrest and remineralisation as saliva is alkaline and super saturated with calcium and phosphate
fluoride is —- most common element in the earth’s surface
13th
of the factors listed below which one is a specific risk factor for dental caries? manual tb, dental pq containing cariogenic bacteria, brushing twice, fl, drinking water
pq
one way to distinguish active vs arrested caries?
active is soft, arrested is hard
what are the cariogenic bacterial species?
streptococcus mutans, lactobaccilus spp, strep mitis, strep gordoni, strep sobrinus, actinomyces spp, strep oralis, strep anginosus.
what are the steps of initiation of dental caries?
cariogenic diet high in refined carbs causes organisms in the pq to synthesise extraceccular polysaccharides like glucan and fructan together with intracellular polysac like glycogen, they are broken down by intrinsic enzymes to sugar, sugar is metabolized to acid causes lower pH within pq (below 6.8-7) , acid is trapped against the tooth surface by biofil, and diffisues through enamel and reaches dentin.
what are the events are bacteria penetrate dentin?
dentin is less mineralised and has more proteins than enamel, other bacteria will come, continue to spread and advance towards pulp eventually infect it.
what is the sign of loss of enamel and that dentin is reached?
pitting and cavitation-looks radiolucent/drk on radiograph.
when does hole develop?
when enamel is lost, dentin is reached and mushy soft, brown
what happens if the infection reaches the nerve?
it spreads to the bone, pus forms, abscess forms
where does caries ususally occur?
sites where pq is left undisturbed i.e. along ging margins, interproximal between teeth, within grooves/pit and fissure on occlusal are the most vulnerable sites
dental caries is mainly a —- disease.
social
is it the amount of sucrose that’s important?
no the frequency of consuption
how do we quantify pq?
pq index- score 0 no visible pq, score 1 no visible pq but it can be wiped off with perio probe, score 2 visible pq that appears after 24 h after tb, score 3 thick visible pq present for days.
how is scoring pq calculated?
choose 6 teeth, score from B then L, total is out of 36, convert to %
what is extended ecological caries hypothesis ?
the balance between microorganism and host is disturbed- not symbiotic anymore due to sucrose, and it changes to parasitism.
how many species of healthy oral bacteria ?
more than 500
what are some bacteria species found to be abundant relatively in healthy individuals than ones with caries/
higher abundance of Neisseria, haemophilus, fusobacterium
bacterial composition of white spot lesions?
more strep mutans than healhy enamel, but non-mutans strep are still predominant soecies
bacterial composition in cavitated lesions?
strep mutans make up 30% of total flora and are associated with enamel breakdown
bacterial composition in mushy carious dentine?
lactobacilli, prevotellae, bifidobacterium more prevalent
when does pq pH rise and fall?
rises when saliva rate is high by chewing, gum chewing, cheese. Fall at night time when saliva slows, sugar gum is chewed, sweet foods are consumed between meals and when flow velocity of saliva is low.
why is saliva necessary for oral health?
saliva has buffering and rinsing capacity , also contains calcium and phosphate ions for remin, has libricants, immunoglobulins and enzymes that assist with first stage of carb metabolism
two bacteria species strongly associated with dental caries? and how do they function?
strep mutants initiates tooth decay, lactobacilli promotes progression,
what is the primary association of dental caries disease?
diet related
What is the commonly cited critical pH for enamel demineralization
5.5 derived from theoretical enamel solubulity in saliva, not pq.
Q: Why does the critical pH vary?
It depends on the composition of plaque fluid and can be as low as 5.1, especially for dentine and cementum, which have lower mineral content
What happens to plaque pH after sugar intake?
The more frequently sugar is ingested, the longer the plaque stays acidic, increasing caries risk
How does plaque on cavity-free teeth compare to plaque on carious teeth in pH recovery?
Plaque on cavity-free teeth returns to resting pH values much quicker than plaque on carious lesions.
What does slower pH recovery in plaque with caries suggest?
Caries-associated plaque retains acidity longer, promoting continued enamel demineralization.
Which jaw is more prone to acidogenic plaque?
Plaque in the upper jaw is significantly more acidogenic than plaque in the lower jaw.
What is the main byproduct of S. mutans sugar metabolism?
Lactic acid, which lowers oral pH and causes enamel demineralization.
What metabolic process does S. mutans use to break down sugars
Glycolysis- glucose into lactic acid
Why is sucrose particularly cariogenic?
It serves as a substrate for glucan synthesis, helping bacteria adhere to teeth and form biofilms (plaque)
Does the same sugar intake lead to the same caries severity in different populations?
No, there is a 50% variance in caries severity between populations.
list the form of sugar consuption and time of consumption from worst to less
worst, sticky form between meals, then sticky form with meal, then solution at meal,
which one is more cariogenic sucrose or fructose?
not sure- non conclusive
is xylitol cariogenic?
no- it has been shown with less pq development, less strep mutants, it also increases acticity in oq and saliva, rises ph so it could be said that its anti-cariogenic.
refined carbs or unrefined carbs effects the same?
no refined is worst
does past caries experiences makes the risks of development higher?
yes they are more prone
how does fluoride incorporate into developing teeth?
Fluoride replaces hydroxyl groups in hydroxyapatite, forming fluorapatite, which is more resistant to acid attack.
2️⃣ Q: Why is fluorapatite more resistant to caries?
A: Fluorapatite is less soluble in acid than hydroxyapatite, reducing enamel demineralization.
What determines the optimal fluoride level in community water?
What determines the optimal fluoride level in community water?
What is the optimal fluoride level in Australia?
1 ppm (parts per million), but in Sydney, where natural levels can reach 2 ppm, the target is 0.5 - 0.7 ppm.
hat happens if someone consumes too much fluoride?
Fluorosis, which causes discoloration and mottling of enamel.
What is the difference between mild and severe fluorosis?
Mild fluorosis appears as white streaks, while severe fluorosis causes brown staining and enamel pitting
Does water fluoridation depend on socio-economic status?
No, but it depends on whether people actually drink tap water.
By how much does water fluoridation reduce caries?
60% in permanent teeth and 50% in primary teeth.
Why is water fluoridation important for community health?
It provides continuous, low-dose fluoride exposure to strengthen teeth and reduce cavities in populations.
is the effect of water fl different in primary and permanent teeth?
fl water consumption effect stronger in primary dentition
