Which organisms are principally associated with Class V (cervical/root surface) caries?

Correct answer: D. Actinomyces and Lactobacillus species

• A. Incorrect. Candida is a fungus associated with denture stomatitis and angular cheilitis, though it has been detected in some root caries lesions.
• B. Incorrect. P. gingivalis is a periodontal pathogen with no established role in caries.
• C. Incorrect as a sole answer. S. mutans is the principal INITIATOR of enamel caries (coronal, pit and fissure), and it does contribute to root caries — but the Actinomyces association is what distinguishes root surface lesions.
• D. Per the recall source. Root surface and cervical caries are characteristically associated with Actinomyces species (notably A. viscosus and A. naeslundii) together with Lactobacillus in the progressive phase.

Note: ⚠️ The recall source phrasing was ambiguous. The clean rule: ENAMEL caries initiation → S. mutans. CARIES PROGRESSION (deep dentin) → Lactobacillus. ROOT SURFACE caries → Actinomyces.