FREE NBDE Caries Etiology and Prevention Questions and Answers

Question 1

A 25-year-old patient presents with multiple new carious lesions, despite reporting consistent brushing and flossing.
Clinical examination reveals generalized gingival recession and exposed root surfaces.
Which of the following factors is most likely contributing to the increased caries risk in this patient?

Accepted Answer

Increased susceptibility of root cementum to demineralization.

Answer

Increased consumption of fermentable carbohydrates.

Answer

Reduced salivary flow due to medication.

Answer

Presence of Streptococcus mutans in dental plaque.

Question 2

Which of the following describes the primary role of fluoride in preventing dental caries?

Accepted Answer

It promotes remineralization and inhibits demineralization of enamel.

Answer

It neutralizes acids produced by cariogenic bacteria.

Answer

It increases the solubility of hydroxyapatite crystals.

Answer

It enhances bacterial adhesion to the tooth surface.

Question 3

A patient asks why they develop cavities even though they limit sugary snacks. They consume several cups of coffee daily, sweetened with sugar, and often sip on it throughout the morning. Which aspect of their dietary habit is most contributing to their caries risk?

Accepted Answer

The frequency and duration of acid exposure.

Answer

The type of sugar used in their coffee.

Answer

The total quantity of sugar consumed per day.

Answer

The temperature of the coffee.

Question 4

What is the critical pH at which enamel begins to demineralize?

Accepted Answer

5.5

Answer

7.0

Answer

6.5

Answer

4.5

Question 5

Which of the following is considered the primary etiologic agent in the initiation of dental caries?

Accepted Answer

Streptococcus mutans

Answer

Lactobacillus acidophilus

Answer

Actinomyces viscosus

Answer

Porphyromonas gingivalis

Question 6

A patient has a high caries risk. Which of the following preventive strategies would be least effective if the patient also has severely xerostomic conditions?

Accepted Answer

Application of dental sealants.

Answer

Daily fluoride mouthrinse.

Answer

Dietary counseling to reduce sugar intake.

Answer

Chewing sugar-free gum after meals.