When you should rely on your working length ?

[al-nasser]

I was asking my self many times that when shoul I say this radiograph gives me working length which will not change during my apical preparation ?

I think Every one should evaluate first the presence or abscence of curvature of cervical as well as middle part of the root ( direct line access to the apical part ) schilder 1974

for example the first R.G shows that I should do alot of flaring in cervical & middle root Before I take my final W.L


http://www.arb-up.com/files/arb-up-2008-6/RYl71172.jpg

while the 2nd R.G show thad I am in a good shape & I can proceed to take my final working length

http://www.arb-up.com/files/arb-up-2008-6/IBW71231.jpg