Vit D's function is to maintain normal blood levels of calcium and phosphorus and it also aids in the absorption of calcium into the bones and teeth, it has also shown to help prevent periodontal disease of the gums-a silent infection that causes tooth loss and shows up more often than you think in pet chinchillas. I feel it is important to use the full spectrum lighting for chinchilla dental health, JMO. I do have experience in using UV light therapy on a malocclusion chin that had a moderate degree of success, but that alas is another long story and I don't want to hijack the OPs thread.