Apart from not liking the look of gaps between your teeth, there are also other oral risks such as tooth decay and gum disease and treatments may include:
Orthodontics or Invisalign
The most common way to fix gaps is either with braces or Invisalign which moves the teeth into the correct position. While it is best to have orthodontic work during adolescence, these options are both still available in adulthood.
Veneers are another option to close the gaps of a very small area of your teeth and can also alter the colour, shape and size of your teeth.