Although chocolate in general is thought to be bad for teeth, chocolate with high cacao content may actually help prevent cavities and tooth decay. Research on theobromine, the active ingredient in chocolate, has shown the substance can remineralize damaged tooth enamel with the same efficacy as fluoride. Don’t start brushing your teeth with chocolate, because sugar is a known cause of cavities. Zero sugar chocolate may not harm teeth as much as chocolate-with-sugar, but either way, it's essential to practice proper oral hygiene to prevent tooth decay. Chocolate using sugar alternatives like Erythritol can.