Lecture 14-18 Caries part 2 Flashcards
A diet high in sugar can select for what type of bacteria
aciduric bacteria (able to tolerate high acid environments)
Give an example of bacterial succession
A diet high in sugar can select for aciduric bacteria including Strep. Lacto., and Actino.
In what scenario would an increase in aciduric bacteria such as S. mutans occur?
- Healthy gingiva
- Glucose rinse with buffer
- Glucose rinse without buffer
Glucose without buffer has a large increase. This is the case in thick plaque or a xerostomic patient
Why does bacterial succession occur?
Because each bacterial species, or strain, has a limit to its ability to grow at low pH, and in addition, has a limited acid-producing capacity depending on the pH conditions.
Caries form at 4 major locations
- Pits & Fisures, S. mutans is by far the major cause
- Smooth-surface caries, S. mutans is major cause
- Dentin, S. mutans is major but Actinomyces and Lactobacillus play increasingly bigger roles as soon as the harder enamel is cracked open)
- Root caries, similar to dentin
T or F, Endodontic infections are usually mixed infections of various G- anaerobic bacteria
True
T or F, Gingivitis & periodontitis are caused primarily by G+ aerobic bacteria
False, by G- anaerobic
Out of caries vaccines, replacement therapies and probiotic therapies, which is probably the first to be used to decrease caries?
Probiotic therapies
T or F, Throughout most of history, coronal (enamel) caries has been infrequent.
True, it was only the advent of farming, and finally the production of inexpensive sugar that the explosion of coronal caries started.
Which acid is the most powerful acid made from pyruvate
Lactic acid (pKa=3.8). Formic acid does have a lower pKa value of 3.7 but it is soluble in an aqueous solution and breaks down into CO2 and H2O so therefore Lactic acid is a more powerful acid
T or F, the presence of plaque is required to produce a pH at or below the critical value.
True, The figure in lecture showed that after a 1st glucose rinse both sides of the mouth go below the critical pH when plaque is present. If the left teeth are brushed and right are not and a 2nd glucose rinse is done, the left side that was brushed has no plaque does not go below the critical pH where the right side that was not brushed does go below the pH
The effectiveness of a given carbohydrate in promoting caries depends upon:
- The ability of cariogenic bacteria to metabolize the carbohydrate
- The ability of the carbohydrate molecule to diffuse into plaque.
T or F, Plaque bacteria have the ability to utilize complex carbohydrates much more effectively than simple sugars because of the size of the polysaccharide
False, Simple sugars are utilized much more effectively than more complex carbohydrates
T or F, the frequency of sugar consumption is much more important than amount
True
Saliva definition:
Secretions of salivary glands (main source) and minor glands of the oral mucosa (minor source)
