1) An overjet refers to the horizontal overlap of the upper teeth over the lower teeth. It is a common dental malocclusion.
2) Many factors can cause an overjet, including digit sucking as a child, use of dummies or pens/nails, inherited jaw structure, or tongue thrusting.
3) Invisalign is an effective treatment for reducing overjets, though it may take 12-15 months to see results. No jaw surgery is typically needed.