Infection Control and Management of Hazardous Materials for the Dental Team 5th Edition by Chris H. Miller - Test Bank

Infection Control and Management of Hazardous Materials for the Dental Team 5th Edition by Chris H. Miller – Test Bank

 

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Chapter 5: Oral Microbiology and Plaque-Associated Diseases

Test Bank

 

MULTIPLE CHOICE

 

1. What causes the critical pH to be reached during formation of dental caries?

A.	The saliva stagnates and putrefies, producing a large amount of acid.
B.	The bacteria in saliva cause an immune response to occur, lowering the pH in the mouth.
C.	Lysozyme in saliva lyses bacteria, causing the release of internal chemicals from the dead bacterial cells, which lower the pH in the mouth.
D.	Plaque bacteria convert dietary sugar into acids.

 

 

ANS:  D

 

	Feedback
A	Not enough acid is produced in saliva to reach a critical pH.
B	Immune responses do not produce a large amount of acid.
C	This does not produce enough acid to reach the critical pH.
D	The acids produced by plaque bacteria lower the pH at the tooth surface to a level (critical pH) that causes minerals in the tooth enamel and dentin to dissolve.

 

 

REF:   Caries-conductive Bacteria, page 38                                  OBJ:   5

 

2. The two most important bacteria in causing dental caries are:

A.	Mutans streptococci and Staphylococcus aureus.
B.	Lactobacillus acidophilus and Porphyromonas gingivalis.
C.	Mutans streptococci and Lactobacillus acidophilus.
D.	Aggregatibacter actinomycetemcomitans and mutans streptococci.

 

 

ANS:  C

 

	Feedback
A	Staphylococcus aureus is important in skin diseases rather than dental caries.
B	Porphyromonas gingivalis is strongly associated with chronic periodontitis.
C	Mutans streptococci consist of the most caries-conductive bacteria in the mouth. Lactobacillus acidophilus is important in the progression of carious lesions after other bacteria have initiated tooth destruction.
D	Aggregatibacter actinomycetemcomitans is strongly associated with juvenile periodontitis.

 

 

REF:   Caries-conductive Bacteria, page 37-38                             OBJ:   8

 

3. What is the most caries-conductive component of our diet?

A.	Protein
B.	Sucrose
C.	Fatty acid
D.	Cellulose

 

 

ANS:  B

 

	Feedback
A	This is a dietary component but has low cariogenicity.
B	Sucrose allows Mutans streptococci to attach to the tooth surface and accumulate rapidly in plaque. Also, sucrose is metabolized to acids by plaque bacteria.
C	This is a dietary component but has low cariogenicity.
D	This is a dietary component but has low cariogenicity.

 

 

REF:   Caries-conductive Bacteria, page 38                                  OBJ:   5

 

4. Mutans streptococci convert _____ to glucans that are used by these bacteria to form plaque.

A.	starch
B.	omega-3 fatty acids
C.	sucrose
D.	fructose

 

 

ANS:  C

 

	Feedback
A	The enzyme glucosyltransferase cannot use starch.
B	The enzyme glucosyltransferase cannot use omega-3 fatty acids.
C	Mutans streptococci have an enzyme (glucosyltransferase) that converts sucrose to glucans plus fructose.
D	The enzyme glucosyltransferase cannot use fructose.

 

 

REF:   Caries-conductive Bacteria, page 38                                  OBJ:   5

 

5. Which of the following periodontal diseases occurs in persons with normal body defense mechanisms?

A.	Chronic
B.	Rapidly progressive
C.	Prepubertal
D.	Juvenile

 

 

ANS:  A

 

	Feedback
A	The continuous presence of plaque in people with normal body defense mechanisms leads to chronic periodontitis.
B	This occurs in people with weakened body defenses.
C	This occurs in people with weakened body defenses.
D	This occurs in people with weakened body defenses.

 

 

REF:   Figure 5-4, page 39                         OBJ:   6

 

6. Oral biofilm (dental plaque) is:

A.	accumulated food debris that occurs in the absence of oral hygiene.
B.	an accumulation of glycoproteins from saliva.
C.	a microbial mass that accumulates in the absence of oral hygiene.
D.	an aggregation of white blood cells that come from the gingival sulcus.

 

 

ANS:  C

 

	Feedback
A	Foods are not bacteria so they cannot form biofilm.
B	Glycoproteins are not bacteria so they cannot form biofilm.
C	All kinds of biofilm, including dental plaque, are composed of bacteria.
D	White blood cells are not bacteria so they cannot form biofilm.

 

 

REF:   Microorganisms, page 36-37            OBJ:   2

 

7. How many different genera of bacteria may be isolated from human mouths?

A.	At least 42
B.	100
C.	100 million
D.	200 billion

 

 

ANS:  A

 

	Feedback
A	There are at least 42 genera of bacteria represented in the mouth; however, one person may not have all of them.
B	This number is too high.
C	This number is too high.
D	This number is the average number of bacterial cells in one gram of plaque.

 

 

REF:   Some Bacterial Genera in the Mouth, Box 5-1, page 36      OBJ:   1

 

8. Calculus is:

A.	accumulated food debris that occurs in the absence of oral hygiene.
B.	mineralized plaque.
C.	a microbial mass that accumulates in the absence of oral hygiene.
D.	an aggregation of white blood cells that come from the gingival sulcus.

 

 

ANS:  B

 

	Feedback
A	Food debris does mineralize.
B	Calculus forms when calcium and other minerals build up within plaque, causing the plaque to become hard (mineralize).
C	This is the definition of oral biofilm (dental plaque).
D	White blood cells do not mineralize.

 

 

REF:   Dental Plaque (Biofilm), page 37     OBJ:   2

 

9. What actually destroys the tooth enamel in dental caries?

A.	Amino acids in the diet
B.	Acids made by bacteria
C.	Fats in saliva
D.	Nucleic acids

 

 

ANS:  B

 

	Feedback
A	The presence of amino acids does not cause a sufficient lowering of the pH to a critical level.
B	The acids made by bacteria accumulate in plaque to a critical pH, which is the level of acids needed to dissolve minerals from enamel and dentin.
C	The presence of fats does not cause a sufficient lowering of the pH to a critical level.
D	The presence of nucleic acids does not cause a sufficient lowering of the pH to a critical level.

 

 

REF:   Microbiology of Caries, page 36      OBJ:   5

 

10. Which of the following bacteria is the most important in causing the progression of a carious lesion after the lesion has been initiated?

A.	Streptococcus sanguis
B.	Lactobacillus acidophilus
C.	Porphyromonas gingivalis
D.	Prevotella intermedia

 

 

ANS:  B

 

	Feedback
A	Streptococcus sanguis is not strongly cariogenic.
B	Lactobacillus acidophilus is aciduric and thrives as a lesion becomes acidic.
C	Porphyromonas gingivalis is involved in periodontal diseases, not dental caries.
D	Prevotella intermedia is involved in periodontal diseases, not dental caries.

 

 

REF:   Caries-conductive Bacteria, page 38                                  OBJ:   5

 

11. Dental plaque is best defined as:

A.	a microbial mass.
B.	composed of pieces of food that have stuck to the teeth.
C.	mineralized proteins.
D.	dried saliva.

 

 

ANS:  A

 

	Feedback
A	Dental plaque is a microbial mass that accumulates on the teeth in the absence of oral hygiene.
B	Food is not composed of microorganisms and therefore cannot form plaque on its own.
C	Proteins are not composed of microorganisms and therefore cannot form plaque on their own.
D	Dried saliva is not composed of microorganisms and therefore cannot form plaque on its own.

 

 

REF:   Microorganisms, page 36-37            OBJ:   2

 

12. How soon do bacteria begin to reattach to the tooth surface and start forming plaque again after a prophy?

A.	Within seconds
B.	12 hours
C.	One day
D.	One week

 

 

ANS:  A

 

	Feedback
A	The pellicle followed by bacteria reattach as soon as the teeth become re-contaminated with saliva (within seconds).
B	Plaque has started to re-form long before this time period.
C	Plaque has started to re-form long before this time period.
D	Plaque has started to re-form long before this time period.

 

 

REF:   Dental Plaque (Biofilm), page 37     OBJ:   2

 

13. Removing dental plaque and instituting good oral hygiene will reverse which of the following diseases?

A.	Gingivitis
B.	Periodontitis
C.	Dental caries in dentin
D.	Strep throat

 

 

ANS:  A

 

	Feedback
A	Gingivitis is a reversible disease. When plaque is removed, gingival tissue returns to normal.
B	Progression can be stopped but will not reverse the damage already done.
C	Progression can be stopped but will not reverse the damage already done.
D	Strep throat is unrelated to plaque.

 

 

REF:   Types of Periodontal Diseases, page 39                             OBJ:   5

 

14. The three mechanisms of action of topical fluoride are (1) inhibiting bacterial metabolism after diffusing into the bacteria as hydrogen fluoride, (2) inhibiting demineralization when present at the crystal surfaces of teeth during an acid challenge, and (3):

A.	enhancing remineralization.
B.	stopping plaque formation.
C.	killing all oral bacteria.
D.	enhancing saliva flow.

 

 

ANS:  A

 

	Feedback
A	When fluoride adsorbs to a demineralized tooth site, it attracts minerals from saliva such as calcium, which contributes to re-mineralization.
B	Fluoride will not stop plaque formation.
C	Fluoride may retard acid production by some bacteria but will not kill all oral bacteria.
D	Fluoride will not greatly enhance saliva flow.

 

 

REF:   Prevention of Plaque-associated Diseases, page 40             OBJ:   9

 

15. Untreated dental caries can lead to:

A.	strep throat.
B.	necrotizing ulcerative gingivitis.
C.	pulpitis.
D.	fever blisters.

 

 

ANS:  C

 

	Feedback
A	Strep throat is caused by b-hemolytic group A Streptococcus that is not related to dental caries.
B	This is caused by different bacteria than those that cause dental caries.
C	As the bacteria progress deeper through the dentin, they can reach the tooth pulp and cause inflammation.
D	These are caused by a herpes virus.

 

 

REF:   Acute Dental Infections, page 40      OBJ:   4

 

16. The pellicle is best defined as:

A.	part of the outer membrane of gram-negative bacterial cells.
B.	a proteinaceous layer that coats the teeth exposed to saliva.
C.	that part of the bacterial gene that codes for acid production.
D.	the protein coat of viruses.

 

 

ANS:  B

 

	Feedback
A	The parts of this are a lipid bi-layer and endotoxin.
B	Glycoproteins from saliva are first absorbed onto the tooth surface to form a thin proteinaceous layer called the pellicle that coats all tooth surfaces exposed to saliva.
C	This is unrelated to the pellicle.
D	The protein coat of a virus is called the capsid.

 

 

REF:   Dental Plaque (Biofilm), page 37     OBJ:   2

 

17. Most of the bacteria important in causing periodontal diseases are:

A.	in the group called Mutans streptococci.
B.	gram-positive.
C.	gram-negative.
D.	also important causes of strep throat.

 

 

ANS:  C

 

	Feedback
A	These are the bacteria most important in causing dental caries.
B	These are more important in causing dental caries than periodontal diseases.
C	Although caries-conducive bacteria are gram-positive, most of the periodontopathogens are gram-negative.
D	Periodontopathogens do not cause strep throat. This is caused by b-hemolytic group A Streptococcus.

 

 

REF:   Microorganisms in Periodontal Diseases, page 40              OBJ:   8

 

18. Where do periapical infections occur?

A.	Around the tooth pulp
B.	In the outer portion of the tooth enamel
C.	In the deep part of the tooth dentin
D.	In the tissue around the tooth apex

 

 

ANS:  D

 

	Feedback
A	This would be in the dentin.
B	This is where many caries begin.
C	Enamel caries can progress through the dentin.
D	Progression of caries into the pulp may extend the infection through the canal and the tooth apex, causing a periapical infection.

 

 

REF:   Acute Dental Infections, page 40      OBJ:   4

 

19. Further progression of a periapical infection may cause:

A.	strep throat.
B.	cellulitis.
C.	pulpitis.
D.	enamel caries.

 

 

ANS:  B

 

	Feedback
A	The bacteria that cause periapical infections are not the same as the causative agent of strep throat.
B	The periapical infection can spread to connective tissue, causing a cellulitis.
C	Pulpitis usually occurs before a periapical infection.
D	Enamel caries occurs long before a periapical infection.

 

 

REF:   Acute Dental Infections, page 40      OBJ:   4

 

20. For microorganisms to colonize the mouth (become established members of the oral microbiota), they must:

A.	not be infected with bacteriophages.
B.	be gram-positive bacteria that are aciduric.
C.	attach to oral surfaces and be able to multiply in the oral environment.
D.	come from the nonhuman environment (e.g., water, dust, soil).

 

 

ANS:  C

 

	Feedback
A	Bacteriophage infection is not related to oral colonization.
B	These bacteria do colonize the mouth, but being gram-positive is not a requirement for colonization.
C	For microorganisms to become established members of the oral microbiota, they must attach to oral surfaces and be able to multiply in the oral environment. If they do not attach to an oral surface, they will be washed away in salivary flow.
D	Members of the oral microbiota come from other humans.

 

 

REF:   Normal Oral Microbiota, page 36     OBJ:   1

 

21. Members of the normal oral flora can cause:

A.	tetanus.
B.	measles.
C.	actinomycosis.
D.	mumps.

 

 

ANS:  C

 

	Feedback
A	This is caused by the bacterium Clostridium tetani, which is not a member of the normal oral flora.
B	This is caused by the measles virus, which is not a member of the normal oral flora.
C	This is caused by the bacterium Actinomyces israelii, which is a member of the normal oral flora.
D	This is caused by the mumps virus, which is not a member of the normal oral flora.

 

 

REF:   Other Infections, page 40                 OBJ:   5

 

22. The slightest trauma to the mouth that results in bleeding can lead to:

A.	dental caries.
B.	transient bacteremia.
C.	chronic periodontitis.
D.	necrotizing ulcerative gingivitis.

 

 

ANS:  B

 

	Feedback
A	This is caused by the build-up of plaque along with a diet containing substances used by the plaque bacteria to make acids that cause demineralization of the teeth.
B	Bleeding allows members of the normal oral flora to enter the bloodstream causing a bacteremia that is usually short-lived.
C	This is caused by the accumulation of bacteria in the gingival sulcus that damages the gingival and periodontal tissues.
D	This is caused by predisposing factors such as stress along with the accumulation of bacteria in the gingival sulcus that damages the gingival tissues.

 

 

REF:   Other Infections, page 40                 OBJ:   5

 

COMPLETION

 

1. After a prophylaxis, plaque begins to re-form within __________.

 

ANS:  seconds

 

REF:   Dental Plaque (Biofilm), page 37     OBJ:   2

 

2. The best approach to preventing periodontal disease is to ________ and _________.

 

ANS:

brush, floss

floss, brush

 

REF:   Prevention of Plaque-associated Diseases, page 40             OBJ:   9

 

3. The names of different types of caries are based upon___________.

 

ANS:  the tooth site affected

 

REF:   Microbiology of Caries, page 36      OBJ:   3

 

TRUE/FALSE

 

1. Simple or acute gingivitis involves the bone in which the teeth are set.

 

ANS:  F

Simple or acute gingivitis involves only the soft tissue around the tooth.

 

REF:   Types of Periodontal Diseases, page 39                             OBJ:   6

 

2. The same bacteria that cause dental caries also cause periodontal diseases.

 

ANS:  F

Caries-conducive bacteria are gram-positive; most of the periodontopathogens are gram-negative.

 

REF:   Microorganisms in Periodontal Diseases, page 40              OBJ:   7

 

3. Plaque causes periodontal diseases.

 

ANS:  T

Plaque accumulated in the gingival sulcus and the bacteria present in the plaque cause damage to the hard and soft tissues surrounding the tooth.

 

REF:   Types of Periodontal Diseases, page 39                             OBJ:   7

 

4. Periodontitis occurs only in older adults.

 

ANS:  F

Juvenile periodontitis can occur in the early teen years and prepubertal periodontitis occurs around primary teeth.

 

REF:   Types of Periodontal Diseases, page 39                             OBJ:   6