How important is brushing teeth in the early years?

My two year old daughter HATES brushing her teeth. I started brushing her teeth with training toothpaste around 18 months and it was pretty easy going until the last couple of months. She started demanding to do it on her own, which is just her chewing on the toothbrush, and I complied with this. After a minute or so I put a little more toothpaste back on the brush and “help” finish by brushing over all her teeth, tongue, and then rinsing with a little water. Lately she has started screaming and throwing a fit, resisting this so intensely that I have to actually force the toothbrush in her mouth. It’s a nightmare and it makes me feel terrible.

Should I continue to force her to brush her teeth if it has gotten this bad? Is this a normal phase that will just pass if I keep firm that this is part of our daily routine? I don’t feed her a lot of sugar, but I worry a lot about cavities and feel that dental health is very important.

What are your techniques for teaching your toddlers to brush teeth? When did you start and how often did you do it?