I was surprise it was this low. The wording of the study result is a bit different, it’s not % of effectiveness, it’s a % reduction in plaque.
The evidence produced shows benefits in using a powered toothbrush when compared with a manual toothbrush. There was an 11% reduction in plaque at one to three months of use, and a 21% reduction in plaque when assessed after three months of use. For gingivitis, there was a 6% reduction at one to three months of use and an 11% reduction when assessed after three months of use. The benefits of this for long-term dental health are unclear.
I played the second late and then the third. I think it simplified too much some parts of the gameplay to please the mass, but the atmosphere and writing are still really good.