MAXILLARY FIRST PREMOLAR
Typically, this tooth has two roots with two canals. In many ways this is the most difficult tooth to treat, as it can have a complex canal system. Variations range from one to three roots, (Fig. 5)
but there are nearly always at least two canals present, even if they exit through a common apical foramen. The roots of these teeth are very delicate and at the apical third they may curve quite sharply buccally, palatally, mesially or distally, so instrumentation needs to be carried out with great care (Fig. 6). In a small percentage of cases the buccal root may subdivide into two canals in the apical third, as shown in Figure 7.
An oval access cavity is cut between the cusp tips, being wider buccopalatally than mesiodistally.
but there are nearly always at least two canals present, even if they exit through a common apical foramen. The roots of these teeth are very delicate and at the apical third they may curve quite sharply buccally, palatally, mesially or distally, so instrumentation needs to be carried out with great care (Fig. 6).