What makes a good smile and otherwise?

So, y'all know that a smile is very important to a person. As what Joanie (from America's Next Top Model Cycle 6) has quoted, a smile is a sword to beauty... What makes a great smile? In my opinion, it has to be natural, not too wide, not too narrow, and with a clean, bright, white set of teeth. Nonetheless, it has to come with practices and good habits. Eating the right food is one of them, according to this article.

In the article, it concluded that the following food are smile spoilers!

• Soda, fruit juice and sports drinks - Damn, I love drinking juices, especially watermelon juice. As acidic and sugary drink, drinking with straw will lessen the bad effects.
  
• Sticky stuff - Gosh, bread is also one of them? Staying in our teeth for 20 minutes after consumption doesn't bother me much. Bread is too delicious to be ousted.
  

And the following will greatly contribute to a better smile...

• Cheese - Hehe, I just have to be cannibalized and start eating myself huh?
  
• Crunchy things - Apples and carrots are natural scrubbers! Yummy yummy!
  
• Tea - Most people would know that tea kills germs. Both black/green tea will do.
  
• Shiitake mushrooms - Heard of this type of mushroom before, but couldn't illustrate how it looks like. Anyway, it fights tooth plaque and the bacteria in it.