Information on Root Elongation

On December 11th, after 5 long weeks of treatment for a URI, fluid on her lungs, numerous tests and 5 different vets, I found out that my beautiful Gadget had root elongation. What started out as a barely noticeable, early caught URI, progressed very quickly to her gasping to breathe because of her roots. Had I had even a clue what was causing the issues, I would not have put her through all that and I am just guilt ridden. I feel like I should have known and put her through pain for nothing. I caused her pain trying to help her when I should have known better. She was such a good baby through it all. It never even occurred to me that it was a possibility until her lungs were finally clear but her breathing just got worse. Her breathing became almost normal while on the Prednisone (to get the fluid off of her lungs) but the vet said that was because it reduced the inflammation so she could breathe better but when it was stopped, within 4 days, it was horrible. The 5th and final vet is a godsend. The only good thing to come out of this, is that I have found an awesome exotic vet for my girls. My concern now is I have her full sister (2 1/2) and 2 half sisters (just turned 4) and I am scared to death. Recently I have been told that root elongation is not considered MALO if the teeth are not involved. Is this true? What causes root elongation then? Her teeth were fine. No points. No spurs. No misalignment. I have had her and her sisters since they are a few months old (from a breeder) and they have always had quality pellets, unlimited hay and wood to chew. Some would say, I spoil them terribly. My question is...did I do something wrong? Is there something I can do differently to help give her sisters a better fighting chance? Gadget was only 2 1/2. Just a baby. She was my heffalump weighing in at 850g at her highest weight. I always gave the girls the best but that was not enough to save Gadget from this fate. I used to love the fact that I had sisters. Now it terrifies me. Thank you in advance for any insight.