Single-visit root canal therapy is most appropriate in an asymptomatic vital tooth because the pulp is still alive, and there is minimal infection, allowing for effective cleaning and obturation in one appointment. The absence of symptoms indicates a low risk of spreading infection or post-operative complications. In contrast, teeth with active inflammation or infection (symptomatic irreversible pulpitis, chronic abscess, necrotic pulp with acute apical periodontitis) require multiple visits for adequate disinfection and control of microbial load. Performing single-visit treatment in asymptomatic vital cases enhances patient compliance and reduces treatment time without compromising success.

Reference: Ingle’s Endodontics, 7th Edition.