Which of the following is true about the cariogenic potential of carbohydrates?
A. Starch has been shown to produce a large number of caries.
B. Starch and sucrose have the same cariogenic potential.
C. Of all the sugars, only sucrose, fructose and glucose are cariogenic.
D. Maltose sugars are not cariogenic.
What is one main finding of the Australian Hopewood House study?
A. Restricting sugar intake only reduces caries risk.
B. Dietary restriction of fermentable carbohydrates and cooked starches reduce the level of cariogenic organisms.
C. After years of sugar restriction, one can develop resistance to caries.
D. After returning to a normal diet, caries incidence in the study subjects did not increase.
Which of the following physical traits of food confers the highest potential for dental caries?
A. Soft and mushy
B. Liquid
C. Sticky
D. Hard and brittle
What is one main finding of the Swedish Vipeholm study?
A. Liquid foods cause little to no caries.
B. When study subjects ingested sugar with meals, a lower caries rate was observed than when study subjects ingested the same amount of sugar as snacks between meals.
C. Retentive foods are not significantly cariogenic.
D. Only teeth with pits and fissures are prone to caries.
Why does snacking more often increase caries risk?
A. Just one snack acidifies oral pH for a long period of time.
B. The snacks must only be of the retentive type to cause caries.
C. The mechanism is not known.
D. Because increasing the frequency of sugar intake extends the duration of acid production and exposure.
What explains the phenomenon that eating five sweets in succession is better than having just one?
A. Five sweets in a row causes dental plaque pH to fall below 5.5.
B. The pH of saliva becomes less acid.
C. The levels of sucrose may be toxic to bacteria and there may be a greater salivary stimulatory effect.
D. All of the above.
Once exposed to fermentable carbohydrates, how long does it take on average for plaque pH to reach its minimum?
A. 5 to 10 minutes
B. 20 to 30 minutes
C. 30 to 60 minutes
D. There is no average; it depends entirely on the individual.
After exposure to fermentable carbohydrates, how long does it take on average for pH levels to return to its starting value?
A. 15 to 20 minutes
B. 30 to 60 minutes
C. 90 minutes
D. There is no average; it depends entirely on the individual.
Which of the following best describes plaque in resting pH?
A. This is plaque that has not been exposed to fermentable carbohydrates for approximately 2 hours and generally has a pH between 6 and 7.
B. Plaque in resting pH has a pH of 8 to 9.
C. Plaque in resting pH is not very stable.
D. None of the above.
Which of the following is true about the chemical composition of resting plaque?
A. Ammonia is not present.
B. There are relatively high concentrations of (less acidic) acetate compared to (more acidic) lactate.
C. The amino acids glutamate and proline are not present.
D. There is more lactate than acetate.
Which factor below affects the rate of decrease in plaque pH?
A. The rate of pH decrease is affected by the buffering capacity of unstimulated saliva.
B. The rate of pH decrease is influenced by the density of plaque.
C. The rate of pH decrease is dependent on the speed with which plaque bacteria are able to metabolise dietary carbohydrates.
D. All of the above.
What factors affect the recovery of plaque pH?
A. The buffering capacity of saliva and whether fermentable carbohydrates remain in the mouth.
B. The speed with which plaque bacteria are able to metabolise dietary carbohydrates.
C. The source of the acid attack.
D. The frequency with which the oral environment comes under attack.
What is the importance of Veillonella bacteria?
A. Veillonella use lactate as a substrate, metabolising it to less acidic products, raising plaque pH.
B. The presence of Veillonella reduces salivary flow.
C. The presence of Veillonella increases caries risk.
D. Veillonella increases the acidity of plaque.
Why does cheese have a beneficial effect on saliva?
A. Cheese has the advantage of raising the plaque concentrations of calcium and phosphate, increasing the chance of remineralising teeth.
B. Cheese is a strong sialogogue, an agent that increases the flow of saliva.
C. The chewing of cheeses rich in nitrogenous compounds gives rise to pH increases, despite the cheese itself being acidic.
D. All of the above.
What is the critical pH at which saliva and plaque fluid cease to be saturated with calcium and phosphate, permitting the hydroxyapatite in dental enamel to dissolve?
A. It is generally accepted to be 6.5.
B. It is the highest pH at which there is a net loss of enamel from the teeth, which is generally accepted to be about 5.5 for enamel.
C. It is generally accepted to be 4.5.
D. Enamel can dissolve at any pH.
