David Cochran, DDS, PhD
This study is truly unique in that it was a completely randomized evaluation of implants in a huge population of patients. There was no bias in the implant placement or in the population. Through this randomized data, this work demonstrates that the tissue-level implant was very efficacious and performed better than bone-level implants from other brands studied. To me, that’s powerful information, especially because of the way the study was performed.
These researchers took a random sampling of all the patients who received implants in Sweden in the year 2003, so there was no bias for which implant or implant system or practitioner (specialist or generalist). Out of about 25,000 patients, they randomly selected 2,700 records to review: a large number of patients for an implant study.
Every system experiences implant loss. The authors looked at this in relation to odds ratio: what is the chance of losing an implant? These patients experienced early loss of only about 1.5% of implants, which confirms that dental implants are a very successful treatment. Regarding the implant and implant brands, by looking at the chance of losing an implant, they found that tissue-level implants did better than bone-level implants. When they looked at late loss (how many were lost after they’d been restored), again, it was a rather low percentage, about 2% of those implants. In addition, the tissue-level implant was lost less often than the bone-level implant from other brands.
The uniqueness of this dataset is extremely informative, and I think it reinforces some points that we have known for a long time. For example, regarding crestal bone loss, we have done some work on this over the years. Where the abutment or the crown attaches to the implant, there is a connection between those metal pieces where bacteria can enter, causing inflammation. With a tissue-level implant, there is less inflammation around the bone tissues, and in the long run the patient experiences less inflammation and bone loss. This data reinforces that, in a randomly selected group of people, tissue-level performs better than bone-level.
The tissue-level implant minimizes inflammation at the bone level, and we know that inflammation causes bone loss. Everything we do from a dental point of view should reduce inflammation in a patient’s mouth, which has an effect throughout the body. We’ve demonstrated this effect in a number of studies, and that’s why a tissue-level implant makes a lot of sense to me.
I’ve been using the Straumann implant system for years, and I’ve placed many of the tissue-level implants. I find that to be the best type to use, because when I place the implant, it has a little bit of a flare at the top. This gives that implant an advantage over the others that don’t lock in. I appreciate the tissue-level implant not only because of its design, but also the fact that the connection is a couple of millimeters above the bone. In 25 years of research, we’ve seen that it is always better to have the connection a couple millimeters above the bone level, rather than at the bone crest. The same with teeth: we always lower the bone a bit around teeth when we place a crown, so there is a biologic width, which is the soft tissue on the end of the crown and the bone. The Straumann tissue-level implant allows you to have that biologic width and to have healthy tissues around the top of the bone. I believe that’s why we see less bone loss and fewer problems with the tissue-level implants.
David Cochran, DDS, PhD
Professor and Chairman, Department of Periodontics
University of Texas Health Science Center
San Antonio School of Dentistry
San Antonio, Texas
Dr. Cochran has received honoraria from Straumann.
