Which tooth is LEAST likely to contain more than one root canal?

Maxillary lateral incisors almost universally have a single root with a single root canal. The incidence of two canals in maxillary lateral incisors is very rare (<5%). In contrast: mandibular central and lateral incisors have two canals in approximately 40-45% of cases (the second canal is frequently missed as it is in the labiolingual plane). Maxillary first premolars have two canals in approximately 90% of cases (buccal and lingual canals). Therefore, the maxillary lateral incisor is LEAST likely to have more than one canal.