In addition to brushing Scottie's teeth, I use the
PetzLife gel which seems to have helped in reducing buildup. The hard yellow buildup is actually going away with the brushing! I bought mine at a local pet store for $20. If your local pet store doesn't have it, you can see if they can order it!
PetzLife Oral Care - Natural Pet Products, Dog Dental Care - PetzLife
It comes in both a gel or a spray. If yours won't let you brush her teeth, I've read user reviews who found the spray
very effective. Maybe you can use the spray and gradually train her to let you brush her teeth?
I trained Scottie to 'let' me brush his teeth by...
First with my fingers touching his gums & treat, then with my finger rubbing his gums and teeth & treat, then toothbrush touching his gums & treat, then finally brush with toothbrush & treat.
Try that over a span of weeks. Start with a few seconds and gradually build up to 30s, then to a minute if you can. Also, if you wrap her up in a towel so that her arms cannot