Sorry to hear about your mother Casey! I found some pretty helpful tips on the following post.
I found this paragraph to be especially helpful:
Another place to check is your county's dental association (the
dentists' professional group). Some of these associations hold free
dental clinics, or otherwise provide limited, low-cost dental care for
low-income seniors. Also, if there is a school of dentistry – where new
dentists are trained -- at a college or university near where you live,
they may offer free or low-cost dental care at their clinic. Finally,
check with local senior centers near where you live. They may have
dentists who visit and provide free dental care, or they may provide a
referral to dentists who offer low-cost care.