Root canal anatomy maxillary premolar

This lit review is fantastic and the only one anyone needs to look at in regards to the internal anatomy of the maxillary first premolar.  Ahmad JOE June 2016

1st premolar root canal anatomy

57% have two roots, 42% have one root, and 1.7% (range is .4%-9.2%) have three roots.  The 3 rooted teeth have 2 buccal or 2 palatal roots.  If the mesiodistal distance distance is equal to or wider in the root than the crown, expect three roots. Around 94% of the first premolars end up having mutiple canals and around 50% of second premolars according to Martins 2024 JOE.

The number of canals each first premolar have – 87% have 2 canals, 11% have 1 canal, and 2% have 3 canals.  65% of the teeth are Type IV, 14% are Type II, 11% are Type I.  The rest are pretty small percentages.

4 canal upper premolar

4 canals in an upper premolar is possible but very rare and to our knowledge only a second premolar with 4 canals exists in the literature Lee JOE 2014. Below is a premolar root canal of Dr. Bauer’s. The anatomy has the look of a traditional 3 canal premolar but has a separate root that appears to be distal to the DB root.

Complex anatomy

The anatomy can have almost infinite possibilities. For instance this 2-1-2-1-2 root canal anatomy tooth.

2nd premolar root canal anatomy

60% have 1 foramen and 40% have 2 with large number of accessory foramina of 47%. Wolf JOE 2020