Experts recommend spending at least 50 seconds cleaning the inside of your teeth. However, most users spend between 4 and 5 seconds. The conventional toothbrush does not adapt to the curved anatomy of the human dentition. Brushing inside the teeth is hampered by poor visibility and difficult access, and depends on the user's will, time and attention. Most of the time is spent brushing the outside of the teeth. A clean smile on the outside may be hiding plaque build up on the inside.