Which of the following best describes the etiology of caries? Caries is ____________.
A. an infectious disease caused by oral bacteria
B. caused when acidic byproducts of oral bacteria come into contact with tooth enamel
C. a disease caused by snacking frequently and not brushing the teeth
D. entirely preventable
At what pH does tooth enamel begin to demineralize?
A. 8.3
B. 7.5
C. 5.5
D. 3.2
Which researcher(s) first suggested an association between acid production and caries?
A. Miles and Underwood (1881)
B. Miller (1889)
C. Viperholm (1945-1954)
D. Orland and Keyes (1954)
Which factors play an essential role in caries development?
A. A food substrate
B. Oral bacteria
C. Time
D. All of the above.
Which trio of factors listed below increases the risk of caries?
A. Eating frequently, high proportion of acidogenic bacteria, lower fluoride levels.
B. Brushing only once daily, eating often, high flow of saliva.
C. Eating apples, higher fluoride levels, do not brush teeth in the evening.
D. Snacking between meals, high counts of oral streptococci, using a toothpick after eating.
Which trio of factors listed below reduces the risk of caries development?
A. Presence of more bacteria that thrive in very acidic conditions, using a toothpick to remove food particles, having adult (permanent teeth).
B. Presence of bacteria that do not thrive in very acid conditions, infrequent snacking, and little consumption of sucrose.
C. High presence of acidogenic bacteria, high saliva flow rate, infrequent snacking.
D. All of the above.
Which of the following best describes biofilm?
A. It is composed mostly of extracellular polysaccharides.
B. It can develop on shedding surfaces.
C. Bacterial cells join it only by sticking to the tooth surface.
D. All of the above.
Which bacteria are linked to caries development?
A. S. mutans and S. oralis
B. S. mutans and Lactobacilli
C. S. sanguinis and S. mutans
D. All of the above.
Which of the following best describes S. mutans ?
A. The first colonizer to form biofilm.
B. Present in all humans.
C. The strain of bacteria most strongly implicated in acid production and caries.
D. Does not produce acids.
In the late maturation phase, biofilm is ____________.
A. homogenous
B. two-dimensional
C. made up of several microenvironments
D. characterized by increase rates of cell division
Which of the following is not true about biofilm?
A. In the late maturation stage of development there is no turnover of cells.
B. Biofilm always forms on the acquired pellicle.
C. Bacteria can become detached from the biofilm in order to spread to new surfaces of the oral cavity.
D. Biofilm is a microbial system.
Which of the following describes the plaque ecosystem?
A. It contains no known species of bacteria.
B. It contains only one species of bacteria.
C. Once established, it cannot be removed.
D. The plaque ecosystem can influence its environment, and the environment can influence the plaque ecosystem.
According to the ecological plaque hypothesis:
A. A neutral pH is linked to proliferation of S. mutans in plaque and demineralization.
B. Sugar drives the shift in plaque ecology that leads to caries.
C. A neutral pH is linked to proliferation of S. sanguinis and remineralization.
D. A pH of 5.5 can destabilize plaque ecology, leading to demineralization.
Which of the following is not a mechanism of sucrose metabolism?
A. Enzymes in saliva cleave sucrose polysaccharides.
B. Glucose is polymerized by glycosyltransferases.
C. Fructose is polymerized by fructosyltransferases.
D. Sucrose is transported across the cell membrane and cleaved by extracellular invertase.
Which of the following is not true about glycolysis:
A. It an energy-producing mechanism.
B. It is an acid-producing mechanism.
C. All bacteria use glycolysis to break down sugars.
D. It produces only lactic acid.
