Brush your teeth with smaller children
Here is a tip, how the teeth cleaning works well with smaller children. I got from a dentist specializing in children.
Sit in the bathroom on the floor and spread your legs slightly, keeping your knees on the floor. The child cuddles his head into this "cave". Now mum or dad can brush his teeth from above. You can see everything, the child can not move so much, and if necessary, the child can be easily fixed.
Also goes when mom or dad sits cross-legged. Just be careful here so that the neck is not overstretched when the child lays his head on his lower legs!
It works well with us! Both with electric toothbrush as well as manually.
