The key is holding the brush at a 45-degree angle so the bristles slip under the gums and in between the teeth, wiggling in small circles to disrupt the plaque and swishing up on the lower teeth and down on the upper teeth. Vigorous back-and-forth scrubbing can harm gums and roots. A soft toothbrush is all that is needed. I personally like the Sea Turtle Bamboo toothbrush. 

Flossing is an important part of daily oral hygiene. It removes the plaque/biofilm from the teeth surfaces that touch each other. This is an area where cavities can form - called "interproximal" cavities. Flossing after brushing with a remineralizing toothpaste helps clean and remineralize these surfaces.

Note in the videos that the floss is wrapped forward and back around that surface and gently slid under the gum till you feel resistance. Then slide up and down 3 times to thoroughly deplaque. I prefer to avoid Teflon-coated floss because it can be a toxic substance. 

When there is gum recession - and this is a common thing, I see this in over 90% of patients - roots and spaces between the teeth become exposed. Root surfaces are convex making a regular brush and floss sometimes ineffective at cleaning these areas. The End Tuft Brush works great in these areas because it is a small tuft of bristles able to get in tight areas and the head is angled so it is better able to reach around corners.

When there are large spaces between the teeth, the ProxaBrush, and a version of the ProxaBrush called SoftPic, are excellent at cleaning these areas. These devices are especially effective at applying remineralizing products to these hard-to-reach areas.

The Sonicare is very effective at removing plaque and biofilm. The sonic vibrations get the remineralizing products into hard-to-reach areas, especially the deep pits and grooves on the chewing surfaces of the back teeth.