**Question:** Which strain of yeast is found in the root canal:

A. Candida albicans
B. Saccharomyces cerevisiae
C. Torulopsis glabrata
D. Cryptococcus neoformans

**Core Concept:** Root canals are the narrow, tube-like spaces within the roots of teeth, containing a complex environment that can support the growth of microorganisms. Yeasts are a group of fungi that can cause infections in various parts of the body, including the oral cavity.

**Why the Correct Answer is Right:** Candida species, particularly Candida albicans, are known to inhabit the oral cavity, including the root canals of infected teeth. This yeast is a facultative anaerobe, meaning it can grow in both aerobic and anaerobic conditions, allowing it to thrive in the variable environment of the root canal.

**Why Each Wrong Option is Incorrect:** Saccharomyces cerevisiae is a common yeast strain found in fermented foods and alcoholic beverages, but it is not typically associated with root canal infections. Torulopsis glabrata is another yeast species, but it is less commonly found in the oral cavity and less likely to cause infections in the root canals. Cryptococcus neoformans is a pathogenic yeast primarily associated with causing infections in immunocompromised individuals, not typically found in root canals.

**Clinical Pearl:** Understanding the correct answer helps healthcare professionals to differentiate between infections caused by Candida species versus other yeast strains, which is essential for appropriate diagnosis and treatment planning for patients with oral and dental infections.

**Correct Answer:** Candida albicans