Mandibular 1st Molar

TYPE TRAITS OF MANDIBULAR 1ST MOLAR •

BUCCAL SURFACE 1. Widest MD diameter of all molars 2. MBC, DBC, DC 3. MBC & DBC are equal in height and are separated by MBG 4. DC more conical & is separated from DBC by the DBG 5. O3rd & M3rd of the M profile are concave 6. C3rd is concave 7. Entire D crown profile is convex 8. M & D crown profiles converge cervically 9. BCR 10. MR & DR are widely separated 11. The apex of the MR lies in line with MBCT 12. DR projects distally from the root base • LINGUAL SURFACE 1. MLC & DLC equal in size and separated by Lingual Groove 2. Li cusps are higher & more conical than the Bu cusps 3. Li widths of the 2 roots are less than their Bu widths

* MAX 1st MOLAR’s Li width is sometimes wider than Bu because of the TALON •

MESIAL SURFACE 1. MLC is slightly higher than MBC 2. Both exhibit Triangular ridges 3. Prominent MMR marked by MMG (more occlusally positioned) 4. BCR 5. MR is broadest Bu-Li of all molars and has a blunt apex 6. Proximal root concavity • DISTAL SURFACE 1. DBC, DLC, DC 2. DMR is shorter than MMR and has a DMG 3. At least half of the Bu surface is seen 4. Almost half of the D surface is made up of the DC 5. DR is broad Bu-Li with a blunt apex 6. Shallow depression on the DR • OCCLUSAL SURFACE 1. OCO – Pentagonal

2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Bu profile longer than Li profile M profile wider than D profile Maximum Bu-Li diameter MB angle is sharp while DB angle is rounded M & D profiles straight and show Li convergence 2/3 of the Bu surface is visible O3rd of Li surface is visible OTO – Hexagonal 3 FOSSAE: MTF, DTF & CF Y Groove Pattern Has a lot of SG -Rosette Go 091108 