Shorter Dental Implants ?

Ted, a dentist, asks:
A doc friend of mine recently recommended that I try shorter dental implants. So I’ve been trying to get some opinions on these implants. Dentists on OsseoNews.com: What has been your experience with these shorter dental implants?

Are these shorter dental implants just as stable and tight fitting as the longer ones? Supposedely, the shorter implants help do away with bone grafting in the sinus area. But do they really work in the upper jaw area in the molar regions? In what other settings would these shorter dental implants be appropriate? Are there any studies supporting the use of these implants and the benefits thereof? Thanks.