Premolars often have wild anatomical variations in their pulpal anatomy. Not only do we need to locate and adequately clean this anatomy for successful treatment, but we need to do so without needlessly weakening the tooth. Premolars will often branch from one to two or three canals. When they do this in a single-rooted tooth, there will often be deep concavities on the external root surface. These concavities mean that the dentinal walls surrounding the canals are thin in this area, and strip perforations are very common when “standardized” shaping techniques are used.
Pre-operative CBCT evaluation can be used to identify these risky cases, and root-form appropriate cleaning and shaping techniques can be used to conservatively locate the secondary anatomy and avoid iatrogenic errors.