These kinds of missing gaps is often filled up with help from tooth dentures and dental implants. Although there's a news that researchers have recently been capable to grow back teeth naturally across the missing location yet a great deal of work needs to be done in that course.
This actually works, I promise. Mix together some baking soda, hydrogen peroxide and some lemon juice. Play with amounts of baking soda and HP until you get a pasty consistency. Put it on your tooth brush and brush your teeth with it. I saw instant results. I know people have doubts but you'll never know until you try for yourself.