Snyder Test

Question 1

What is the main purpose of the Snyder test?

Answer 1

• Lactobacillus in saliva
• The Snyder test measures dental caries susceptibility by detecting the presence of lactobacilli in saliva

Question 2

How does Lactobacill dissolve tooth enamel?

Answer 2

• Lactobacilli are capable of lowering the pH of their environment enough to dissolve tooth enamel.

Question 3

How does the Snyder test medium favor the growth of lactobacilli and discourage the growth of most other species?

Answer 3

• The Snyder test medium is designed to favor the growth of lactobacilli and discourage the growth of most other species.
• This is accomplished by adjusting the pH of the medium to 4.8 and by adding glucose, a carbohydrate easily fermented by Lactobacillus.

Question 4

• Lactobacilli thrive in _____(high/low) pH environments and ferment the _____, producing more _____.

Answer 4

• Lactobacilli thrive in the low pH environments and ferment the glucose, producing more acid which reduces the pH even more.

Question 5

What is the pH indicator used?

Answer 5

• The medium includes the pH indicator, bromocresol green
  
  • green at pH 4.8 and above
  • yellow below pH 4.8.

Question 6

• High susceptibility to dental caries is indicated if the medium turns yellow within ___ hours.
• Moderate and slight susceptibility is indicated by a change within ___ and ___ hours, respectively.
• No change within ___ hours is considered a negative result.

Answer 6

High susceptibility to dental caries is indicated if the medium turns yellow within 24 hours.

• High susceptibility to dental caries is indicated if the medium turns yellow within 24 hours.
• Moderate and slight susceptibility is indicated by a change within 48 and 72 hours, respectively.
• No change within 72 hours is considered a negative result.