Hi all,
I found lots of links on the internet/usenet regarding how to use a
manual toothbrush, but none of them for an electric toothbrush. In
particular I am interested to the Oral-B 3D excel which I'm most likely
going to buy in the next few days.

Given the shape of the brush, I guess it's not possible to make an angle
towards the gum line as it's recommended with the manual toothbrushes.
I guess the only possibility is to use it orthogonal to the tooth and
gum surface, correct?

Should I put the circular brush so that half of it's area is on the
tooth and half is on the gum, or should I keep it so that it's 100% on
the tooth and not touch the gums?

Another question: for manual toothbrushes it is recommended to change
them often because when they lose their original shape they can sting
the gums with the threads which are bent out, and so make the gums
recess. For the same reason (stinging the gums) it's not recommended to
keep a manual toothbrush orthogonal to the gums and teeth. Well... an
electric toothbrush seems MUCH more harsh on the gums to me than it's a
whatever-old manual toothbrush, and also it's to be used orthogonally!
What am I missing here?

Also I heard of someone saying bad things of the rotary motion electric
toothbrushes: he claimed that with their rotary motion they were likely
to push debris down the gum line which is very bad. Anybody here
believes this? And if yes: any recommendation on the usage in order to
prevent this?

Thanks in advance