I've been looking for studies/articles done on the subject of vertically vs. horizontally brushing ones teeth and I've only found a few traces in my search. If you guys know of a trial or have any links to some article I'd greatly appreciate the help.
There is a right way to brush and then there is everything else that most people end up doing. But brushing is neither an art nor a science – it is as simple as following the right instructions and forming the right habits.