No, I would think all trials are random with people assigned brushes > 5068 participants were randomised to receive either a powered toothbrush or a manual too

No, I would think all trials are random with people assigned brushes > 5068 participants were randomised to receive either a powered toothbrush or a manual toothbrush. Majority of the studies included adults, and over 50% of the studies used a type of powered toothbrush https://www.cochrane.org/evidence/CD002281_poweredelectric-toothbrushes-compared-manual-toothbrushes-maintaining-oral-health https://www.cochrane.org/evidence/CD002281_poweredelectric-t...