Question

Which bacterium is primarily responsible for initiating root caries?

• A. Streptococcus mutans
• B. Actinomyces viscosus
• C. Staphylococcus aureus
• D. Lactobacillus acidophilus

Hint:

Enamel caries initiation → Streptococcus mutans.
Root caries initiation → Actinomyces species.

Answer 1

The Correct Option is B

The question asks which bacterium is primarily responsible for initiating root caries. Root caries are dental cavities that occur on the root surfaces of the teeth, usually affecting older individuals with gum recession. Understanding the microbiology of dental caries is essential for diagnosing and treating this condition.

Bacterial Factors in Root Caries:

• Streptococcus mutans: This species is a major causative agent of dental caries but is typically more associated with coronal caries (the caries on the enamel surfaces of teeth) rather than root caries.
• Actinomyces viscosus: Actinomyces species, such as A. viscosus, are primarily associated with root caries. They are capable of colonizing exposed root surfaces and are involved in the initial stages of root surface demineralization.
• Staphylococcus aureus: This is not typically associated with dental caries; it is more commonly linked to other types of infections.
• Lactobacillus acidophilus: Although involved in the progression of carious lesions due to its acidogenic nature, Lactobacillus is not responsible for the initiation of root caries.

After evaluating the purpose and functions of these bacteria, the correct answer is Actinomyces viscosus because it is primarily responsible for the initiation of root caries due to its capability to adhere to root surfaces and participate in plaque formation and mineral demineralization.

Conclusion: The correct bacterium linked with initiating root caries is Actinomyces viscosus, which differentiates itself by colonizing the root surface and causing demineralization, thereby initiating caries.