Which of the following teeth is LEAST likely to have more than one root canal?

The maxillary lateral incisor is least likely to have more than one canal. It characteristically has a single root with a single canal (Vertucci Type I) in approximately 90 to 95% of cases. The mandibular lateral incisor has a two-canal configuration (most commonly Type III) in approximately 40 to 45% of cases, making it more likely to have multiple canals than the maxillary lateral incisor. The maxillary first premolar frequently has two canals (60 to 70%). The mandibular first premolar has a single canal in most cases but has the highest frequency of unusual canal configurations among mandibular anteriors.