There are multiple options to close the gaps between the teeth. This can be accomplished via orthodontic treatment using braces or Invisalign; or even via cosmetic dentistry, veneers or crowns. With orthodontic treatment, the teeth are moved into the correct position to close the gaps. However, with cosmetic dentistry, the teeth are not moved, but the gaps are closed utilizing fillings, veneers or crowns. Cosmetic dentistry would be the fastest way to close the gaps, but this may not be the best option for your mouth or teeth. Orthodontic treatment is the best way to level and align your teeth, but again, this may not be the best option if the size of teeth is mismatched, thereby making some cosmetic work necessary even after orthodontic work. There are several advantages of orthodontic treatment, but the disadvantage is that it takes much longer than other means. It would be best to consult a local dentist or an orthodontist to discuss the options that would be best for your individual situation because an option that is best for another person may not be the best option for you for the long-term health and stability of your teeth. There are many factors that influence the decision-making process in this situation; for example, the existing health of your gums and teeth, your facial appearance, size of your teeth, to name a few. Therefore, a consultation with a dental health professional would be the best starting point in my opinion.