Toothbrush
The correct method is the Bass technique, which means tilting the brush head approximately 45° towards the gums. This allows for excellent cleaning between the teeth and in the gumline area:
Incorrect is the usual “straight” placement of the brush:
The Bass toothbrush technique in the mouth. The photo clearly shows that the toothbrush is placed at an angle towards the gums (approx. 45°), then small circles or vibrating movements are made:
Further reading: More about dental floss.