Upper 1st premolars - roots. Lower 1st and 2nd premolars (bicuspids) - Just have root. Variability in the number of root canals.
If the mesiodistal distance distance is equal to or wider in the root than the crown, expect three roots. The number of canals each first premolar have – have canals , have canal, and have canals. Type IV, are Type II, are Type I.
Root canal morphology of the maxillary first premolar. Vertucci FJ , Gegauff A. Four hundred maxillary first premolars were decalcifie injected with dye, cleare and studied. The canal configurations were categorized as: had one canal, had two canals, and had three canals at the apex. Cams and Skidmore reported that the incidence of maxillary first premolars with three roots , three canals , and three foramina was of the cases studied. The root is considerably shorter than in the canine, and distal curvature is not uncommon.
Approximately to of maxillary first premolars have canals , while to have just canal. Three-rooted maxillary first premolars are uncommon, with an incidence of 0.
Mandibular second premolars have been shown to have root canal at the apex in 97.