Summary:

Purpose: to describe the morphology of three rooted maxillary premolar from clinical aspect

• Morphologically, they found three basic categories of three-rooted maxillary premolars can be seen:
• Category 1: fusion of all three roots or only the two buccal ones, and a semi-fused or free palatal root. It is the most difficult category to be radiographically assessed.
• Category 2: normal separation of the buccal roots at the level mid-root or apical third, with either a semi fused or free palatal root.
• Category 3: normal separation of the buccal roots up to the cervical level, with a free palatal root and a classic tripod appearance (mini molar).
• In radiographs of maxillary premolars, changes in radiographic density about the mid-root level in which the root canal system suddenly becomes ill defined should be carefully assessed for either two or three canal systems.
• A pulp chamber that appears to deviate from this normal configuration and appears to be either triangular in shape or too large in a mesiodistal plane should be regarded for a possible three canal system

Clinical Significance

• The eccentric placement of the orifices of root canals may be an indication of canals that are in a mesial and distal plane, with the possibility of a third canal
• Pre-operative radiographs should be carefully assessed with different angulation.