It's not right!
When I received SSDI in 2010, I had to wait 29 months from my disability date, 2009, not the filing date, to start receiving medicare in 2012. Initially, I was covered by limited dental care through my employers private dental insurance, which I extended with COBRA for two years once my short and long term disability ended until medicare kicked in, although 29 months is permitted if SS is filed by a specified period. I'm not sure what dental care is allowable through private insurers as far as this medicare rule, and may all differ, although they may be similar to medicare, CMS, since that's who sets most of the paying standards, I think. My pre-treatment dental care was limited to one extraction, filling, and a root canal that my dental insurance covered, so I had pretty good teeth otherwise.
After all my cancer treatments ended in 2014, and had no cancer recurrences for 6 months, I finally had my much needed dental extractions after the 20/10 HBOT, which HBOT was covered, but the surgical extractions weren't. I think my CCC felt sorry for me, a least my dental oncologist there did, so I didn't have a problem with that so far, but the anesthesiologist was looking for $6,000.
I still have no teeth since 2014, mainly due to ORN, Surgeries, and healing times, but dentures or implants, which implants my ENT doubts I can have based on all my radiation treatments totaling over 200Gy, are not covered by medicare, even though my teeth caries/damage was from radiation.
I hope these insurance rules change for post treatment care, and for automatic pre-treatment care without out-of-pocket expense, but doubt it, without an uproar or other event(s).