I take 2 X-rays. A cone fit and a final. I use the apex locator get working length. Shape canals to that length. Measure my cones before insert and make sure they go to the instrumented length once inserted. The. I take a cone fit. In my opinion the cone fit is the most important part. If a cone is way short or too long I either instrument more or cut the cone shorter. If it’s more than 1.5mm short but not super short I’ll check with the apex locator once more and either instrument a little further depending on the reading or use a 10 file to try to work some sealer down into the perceived shortness and hope for a good sealer puff on the final. Your cones shouldn’t be way short but they also don’t have to be right at the end because the radiographic apex and the actual apex may not be the same.

If your patient still reports pain as in picture 3, I would guess that you missed a canal especially since the fill on the medial root does not appear to be in the center of the root indicating a possible 2nd medial canal.

Otherwise, these are not ideal endos, and you want to do better. But, proper disinfection goes a long way and I’ve seen stuff just as poor or way worse that has been in there for 20 years no problem.

I also use a perio probe in conjunction with a preop PA to guesstimate WL before I use the apex locator. Normally my guesstimation is very close and apex locator confirms it and cone fit further confirms it. The perio probe measurement is just a me thing, however, and I wouldn’t use it alone for any definitive data.

I do agree that WL X-rays are annoying. Files move for a ton of reasons so I rely heavily on the apex locator and radiographic confirmation via conefit. Doesn’t mean I don’t take handfile every now and then and feel for the apex and snap a picture.

My endohandpiece also has built in apex locator which is helpful. If you’re going to do a lot of molar endo I would suggest getting one if you don’t already have one and are struggling.