Isthmi were found in (10%) of cases in mesial roots.
This helps to maintain the external shape and internal morphology of canals with their isthmi and interconnections.
26 The presence of isthmi and apical deltas may be of clinical significance, because it may be difficult to debride and fill these ramifications adequately.
As isthmi are observed in mesial roots and apical deltas in distal roots, efficient delivery and activation of irrigants are more essential.
A few interesting ones not in the above lists: AGNATE / IGNITE, ASTHMA / ISTHMI
, BOOTHBAY (ME) / SOOTHSAY, DOWNSIDE / TOWNSITE, ELOPE / SLOPS, FREIHEIT (TX) / FRESHEST, LEGLESS / REGRESS, LINE COULEE (MT) / PINE COUPEE (LA), PIKE LAKE (WI) / PINE LANE (NJ).