Before we place implants on any of our patients we always take a 3D x-ray called a CBCT scan. This allows us to measure the amount of bone present, and the proximity of any anatomical structures that we wouldn't want to stick an implant into (like your nerves, blood vessels, or sinuses).
Sometimes we when we virtually place the implant on the CT scan we find that the bone is wide enough, but not long (or high) enough. Ideally we like to place 10+ millimeter long implants, but it is not uncommon for us to lack 10mm of bone. In those cases we can often place short implants. We can place implants as short as 5mm. This can often allow us to avoid expensive, time consuming, and less predictable grafting procedures.
In the past few years there have been several studies published that showed, somewhat surprisingly, that short dental implants have comparable success rates to normal dental implants. This was surprising because the opposite has been shown to be true for natural teeth. The longer the root the stronger the tooth. The most popular current theory explaining this difference, is that because implants have a different connection with the bone, most of the forces on the implant are distributed towards the top of the implant. With a natural tooth they are spread out along the whole length of the tooth.
We still like to place longer implants when possible, but short implants are a great tool for areas where there might not be enough bone present. Another important consideration is the crown-to-implant ratio. Check back soon to see another post addressing crown-to-implant ratio.
Jonathan Geleris, DDS, FICOI
Disclaimer and disclosures: I'm a dentist who performs dental implant treatments, and general dentistry in Walnut Creek, California. I don't work for any dental companies (other than my practice). Nobody pays me to write this. As much as possible, I hope to present factual information supported by solid science, however, humans are complex, and the science in this field is constantly evolving. Some of what I present may be based on my opinion.