I have very strong teeth and only three cavities--at age 58! The downside to this is plaque. I need to be vigilant to prevent gingivitis. For years, I have used Interplak electric toothbrushes. They are less expensive than Sonic and outperform Sonic as well. The biggest difference is the way they clean. Sonic heads spin in one direction, Interplak heads spin in both directions. While I am very pleased with Interplak, this model did not last very long. For some reason, it quit taking a charge after only approx. 1 year. I have an older one (different model) that is still running! The only reason I bought the new one was to get a new head. The heads are about as much as a new toothbrush.