You can prevent dental disease by protecting your mouth against three things: bacteria, force and harmful chemicals.
By brushing and flossing your teeth then rinsing with antiseptic mouthwash, you can wipe out the majority of bacteria living in your mouth. Doing this atleast twice a day would be very beneficial for your smile. Maintaining a stable bite by using a night guard for sleeping (if you suffer from bruxism) and a sport guard while playing sports will protect your teeth from traumatic force. Harmful chemicals are in many foods and drinks, but tobacco products and sodas are the worst offenders. Stop smoking or chewing, and switch to water to keep your teeth and gums healthy and glowing.