If a single tooth is your desired treatment option, one implant and a crown can replace it. A dental implant replaces both the lost natural tooth and its root. If performed by a trained professional a dental implant looks and functioning like a natural tooth, a dental implant replaces a single tooth without sacrificing the health of adjacent teeth. 

If an area of the mouth has a tooth missing for an extended period of time the supporting bone resorbs significantly. Dental implants not only replace the root of the tooth but also prevent bone form resorbing further.