16
insulators [Picture 14].
d) There is a crack on the tooth root
In this case, the crack may cause the electric
leakage which will affect the accuracy of
measurement [Picture 15].
e) A retreatment to an endo which was filled with
gutta-percha.
Clean the remaining material in the root canal
and fill it with little normal saline before a measurement [Picture 16].
f) There is a metal crown which has connected to the gingival.
It will cause inaccuracy when the endo file touches metal crown [Picture 17].
Picture 15 Picture 16 Picture 17
Sometimes, the results of the Apex Locator and X-rays do not meet each
other,which is neither because the machine is not normal, nor the photo is incorrect
taken.The actual position of the apical foramen is different from the anatomical
one, it is very common that the apical foramen slightly to the side of the root canal
crowns.In this case, according to the shooting angle as the belowing pictures show,
it will cause illusion that the front tip of the root canal haven’t reached the canal tip.
