**10. For custom made posts**

These are used in canals that have a noncircular cross section or extreme taper. Little preparation is sufficient for custom made post. i.e. removal of undercuts and additional shaping.

**CAUTION:** Mandibular molars distal wall of mesial root is particularly susceptible. in maxillary molars the curvature of the mesio buccal root makes mesial or distal perforation more likely.
