By: Jean Johnson for Dental1Part One
The serendipitous beginning of implant technology began in a Swedish professor’s laboratory in 1952 when the titanium microscopes he was using for an experiment bonded irreversibly to living bone tissue. The rest was history for Per-Ingvar Brånemark, Ph.D. He named the phenomenon osseointegration, and the first implantation of titanium posts in a patient was in 1965. More than 30 years later the non-removable teeth attached to the fused titanium were still functioning perfectly.
This is reassuring considering just placing the implant can be costly and does not include the expense of making the restorations that screw into the implants. Further, statistics indicate that implants are successful 94 to 98 percent of the time, and those that fail (generally in the first year) can generally be replaced with a second attempt. Still, it’s helpful to understand factors known to be predictors for higher risk of failure.
In the world of implant technology, location is especially important. Implants in the back of the upper jaw fail most often followed by front implants in the upper jaw, and those in the back lower jaw. The highest rates of success are seen in implants of the front lower teeth because the bone is denser there.
After location, it’s the company we keep. The specialist that does the implant needs to be the kind of person that elevates dotting all the i’s to a new level. Director of the Division of Operative Dentistry in the Department of Restorative Dentistry at Oregon Health & Science University, John C. Lee, D.D.S., said, “Some of the problems with implant failure arise when not enough time was taken to figure out proper placement in relation to a person’s bite. Case analysis and treatment planning is an essential aspect that can’t be overlooked.”
Lee explained that ”implants work best when the force of the bite is perpendicular to the biting surface without too much force in lateral directions,” and that the use of carefully custom-fabricated molds, or stents, that guide the surgeon into exactly right placement are critical to success. “In some cases even a millimeter can make a difference,” said Lee.
Placement is only part of the trick in getting implants to succeed over the long haul. Getting the titanium implant to fuse with the bone, the process of osseointegration, is another biggie.
One key here is heat. And that’s related to speed. So get ready to truly be patient. “The idea is to keep the bone from heating up under the drill,” Lee said. “Most surgeons are very aware of this and so go very, very slowly with the implant drill. Copious irrigation also helps keep the tissues as cool as possible.”
Finally, loading – putting a weight-bearing appliance on the titanium fixture – is an issue in the long-term success of implants. There are new systems on the market that decrease the wait time for getting teeth affixed to implants, and one German study from early 2005 noted that with specially coated titanium implants immediate loading is possible.
“The thing is,” said Portland prosthodontist, Nadar Rassouli, D.D.S., M.S., “We don’t have long-term data on how these new immediate-loading systems will work over time.” Lee concurred. “There are a lot of new studies in the literature, but the gold standard for implants is those that are left submerged and immobile for four – six months while the bone integrates with the implant.”
Thousands of implants have been done since Brånemark’s discovery first paved the way toward a conjoining of metal and bone back in the 1950s. That most of these enjoy success links back around to the precision involved in the science, the craft, and the art.
(Continued in Part Two)
