Ben is 11 years old boy that came to my office with pain on his lower right first molar. Ben had a filling placed that was broken at the margin. He needed filling to be replaced but he missed the timeline. As you see here, his root apex (tip of root) is not fully closed like adults. Because it was hit before it is fully grown up. It made it really difficult to debrided inside of root canal with sparing mandibular inferior nerve and place the medicament inside of root canal.
I had to make to make a stop first, so the medication will not go beyond tooth itself. I placed high concentration of calcium to promote root formation. It is called “Apexification”
It took me couple of months to make stop at the apex of root and clean inside of canal. However, it is worth for him to save one tooth. I cannot imagine this young boy losing his molar at 11 years.