December 17, 2014
By: Dr. Colin Richman
Despite the high success rate of dental implants, patients should hang onto problem teeth as long as possible, a new literature review suggests.
The review found that 15-year tooth loss rates range from 3.6% to 13.4%, whereas implant loss rates range from 0% to 33%.
Liran Levin, DMD, from the Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, and the Harvard School of Dental Medicine, Boston, Massachusetts, and Michal Halperin-Sternfeld, DMD, MSc, from the Department of Periodontology, School of Graduate Dentistry, Rambam Health Care Campus, Haifa, published the review in the October issue of the Journal of the American Dental Association.
“The results of this systematic review show that implant survival rates do not exceed those of compromised but adequately treated and maintained teeth, supporting the notion that the decision to extract a tooth and place a dental implant should be made cautiously,” the authors write.
Implant technology has steadily improved in recent decades, making implants a reliable replacement for missing teeth. Their success has encouraged some clinicians to recommend them as an alternative to treating severely diseased teeth. However, even teeth classified as “hopeless” may survive, especially if periodontal treatment addresses the underlying problem, the researchers note.
To get some perspective on the probable success of the 2 approaches, the researchers scoured the literature for studies that measured the long-term survival of teeth and implants. They found 9 studies of teeth and 10 studies of implants with good data on the survival over the course of at least 15 years.
Those studies reporting reasons for tooth loss indicated that periodontal disease was by far the most common reason, but even when periodontal patients did not get periodontal therapy, a couple of studies found tooth loss rates of 6% or less over the course of more than 5 years.
Loss rates for “questionable” teeth ranged from 11.3% to 31.1%. For “hopeless” teeth, the loss rate was 34.3% in patients with chronic periodontitis and 40.5% in patients with aggressive periodontitis, according to a study the investigators reviewed.
The researchers note that some tooth loss reported in these studies resulted from clinicians’ subjective decisions to extract diseased teeth, suggesting potential loss rates might have been even lower.
Studies on implants did not generally report the reasons for failure, but they did report various techniques used. In one review, success rates for implants placed in augmented bone ranged from 61.5% to 100% during follow-up periods of 1 to 11 years.
More conical implants had higher stresses than did cylindrical and screw-shaped implants, and textured implants had better outcomes than those with machined surfaces. Implants were more likely to fail in patients with periodontitis-related tooth loss, in those who smoked, and in those with diabetes mellitus, a history of radiotherapy, or impaired bone quality.
The investigators caution that it is difficult to compare implant and tooth studies directly because the 2 types of studies generally had different designs: Most tooth studies used an epidemiological approach, whereas most implant studies followed-up a distinct group of patients. In addition, most tooth studies were in patients with periodontal disease, but the periodontal status of the patients was not recorded in most of the implant studies.
Other factors could muddy the results as well. For example, researchers have studied tooth loss longer than implant loss, and implant technology is improving, so the periods in which the studies were conducted could bias the results.
Moreover, many implant studies had the support of implant manufacturers, and the studies looked at different types of implant.
Still, the researchers found the comparison of survival rates meaningful. They pointed out that a tooth extraction is irreversible, and that implant surgery itself poses some risks.
“In light of the above review, the decision to retain properly treated and maintained teeth for as long as possible seems to provide an overall solution that can reduce the treatment risks over the long term,” they conclude.
The authors have disclosed no relevant financial relationships.
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