Let's analyze the actual thought process we go through for probing a canal with the conventional method that most of us were taught in dental school and which is still practiced by the majority of dentists world wide.
- We open a tooth and insert, usually a size 15 K-file.
- It goes into the canal until it hits something.
- We know that secondary dentin does not form in smooth sheets centifugally around a canal walls, so what has probably happened is that we have hit a lump of dentin on one of the walls.
- The assumption we are about to make is that their may be space enough between the lumps on each side of a canal but that the file needs to be curved now to avoid the lump we are hitting and to negotiate the space between the lumps so we
- bend the file slightly and try moving the tip in different directions and if that does not work we
- pick up the next size smaller file, a #10 , based on the assumption that the space between the lumps is too small for the file we have chosen.
- If after trying and curving this one we pick up the next smaller, a #8 and if we cannot get through with that one, or after we bend several, trying to get through we assume that we are not going to be able to find our way through and we
- pick up the phone and call a specialist, hoping that perhaps the endodontist has some tricks we don't or maybe has some special smaller instruments that can do what we cannot.