Protruding (sticking-out) teeth can be the result of the whole dental arch sitting too far forward, or of just the front teeth doing so. This can affect one or both jaws and is often linked to abnormal jaw development and a bite problem.
People with this problem often find it difficult to close their lips. To move the teeth back, space has to be created for them to move into – this can be done by taking out teeth (for example wisdom teeth or premolars) or by using any existing gaps between the side teeth.
This answer is for general information. Your own case needs an examination by an orthodontist.