MICROANATOMY

Detailed explanation-1: -The maxillary first premolar is the most commonly bi-rooted tooth with occasional presentation of three roots system; it is a transitional tooth between incisors and molars. Although it usually has two canals, it may rarely have three and this third canal can easily be missed.

Detailed explanation-2: -Maxillary second premolar is generally considered to have one root and one canal [2, 3, 6, 14]. In the present study only 13.8% had one root canal end in one apical foramen (type I, Figure 1).

Detailed explanation-3: -The number of roots for each type of tooth varies. Typically incisors, canines and premolars will have one root whereas molars will have two or three.

Detailed explanation-4: -A study of 150 extracted maxillary first premolars from citizens of Seville, Andalusía, southern Spain, revealed 60 teeth with one root (40.0%), 85 teeth with two roots (56.7%) and five teeth with three roots (3.3%).