I agree with the above, as long as you aren't hurting them, it's kind of cruel kindness. Rather force it than their teeth rot. My little one is usually ok for the first 10 seconds and let's me brush them but then she wants the toothbrush and starts kicking off, so that's when I have to sometimes force her
I would pretty much agree with Bobbie, force them to at least get a minimum brush and try and make it the least traumatic possible (when our son was refusing that meany holding his head but letting the rest of him flail) and then reward them for "co-operating" afterwards e.g. let them play with the brush, get a fun toy etc etc. My son seems to have realised the more he just let's us get on with it, the quicker he gets his reward (which is his dummy at night and tape measure toy in the morning).
So as much as I will always try to not physically force things there are some things I see as non-negotiables, so taking medication, they need to do it so if they won't then I will force it, the same goes for brushing teeth, by eldest went through a phase of refusing point blank so we forced it but now she does it herself and pretty well and then we after and just top up for her to make sure they're all done :) she's now 3 :) it's not easy to force them and I absolutely hate it but for me going to the dentist and having fillings ect is way more traumatic 😂