A gap in teeth can be an embarrassing cosmetic feature to have. There are many different ways to close gaps in teeth. The methods of correction depend upon the individual, his or her budget, other teeth and jaw problems, and the pain or embarrassment he or she is willing to undergo in order to correct the problem.
A veneer is a common solution, especially for those who cannot afford braces. Usually they are made out of porcelain and require little in terms of an installation process. The fit directly over the tooth and cap it. These can be used exactly the same way as regular teeth--they will not fall out or be able to be removed easily. You can chew with the perfectly fine.
The one major draw-back is that if the gap is extremely large, they would look funny. Because they cap your teeth, the veneers would have to be big enough to cover your whole tooth and cover the space in between your teeth. This can give people the appearance of having huge front teeth.
A better option for huge gaps would be to wear a manner of braces or orthodontic devices. Braces can be expensive and embarrassing for adults to wear. They are the most effective, though, and can sort out a great number of dental problems. They will slowly push your teeth together over a long-enough period to make the roots settle in those locations and stay there.
For adults who dislike the idea of pubescent looking braces, they can get clear ones that may take a little longer to close the gap. They will not be quite ...