That's.. actually very harmful. A necessity like that should be covered, even if it's dental. Are you in the US?
Have you/your family tried applying for Medicaid? Because if this counts as a disability than you should be covered for Medicaid. I don't know all the details as I'm not on it, but you should check an eligibility test. They do accept children (if you're under 18) and low-income adults.
I recently went through the system again for my own health insurance so I'm like geared up for a fight lmao