Summary:

Purpose: to determine MB root canal configuration and incidence of MB2  in maxillary 1st molar.

N=208 extracted maxillary 1st molars.

Materials/Methods:

• from the mesial side of the tooth, teeth were sectioned in buccolingual direction using coarse sandpaper disk.
• Then they were viewed and classified.

Most highlighted Results:

• 3 canals configuration were observed:
• Type I: single canal/single foramen.(48.5%).
• Type II: 2 canals/ 1 foramen, joining 1-4 mm from apex.(37.5%).
• Type III: 2 canals/2 foramina.(14%).
• Type IV: 1 canal / 2 foramina

Clinical significance:

• Established simple classification system (aid in communication).