Dental Implants Safe in Patients With Uncontrolled Diabetes

Laird Harrison

December 10, 2014

Dentists can safely place dental implants in patients with uncontrolled diabetes, a new study shows. The finding contradicts common recommendations.

"We failed to identify any association between elevated blood sugar and implant failure or implant complications," first author Thomas W. Oates Jr, DMD, PhD, told Medscape Medical News.

Along with his colleagues, Dr Oates, a professor in the Department of Periodontics, School of Dentistry, University of Texas Health Science Center at San Antonio, published the article in the December issue of the Journal of the American Dental Association.

After 1 year, none of the implants placed in 19 patients with uncontrolled diabetes failed.

The results came as no surprise to Kim Gowey, DDS, a past president of the American Academy of Implant Dentistry, who practices in Medford, Wisconsin. He has had good results in placing implants in patients with diabetes, he told Medscape Medical News.

"I've never turned away a diabetic for treatment because they're diabetic," said Dr Gowey, who was not involved in the study. "I've always told them, 'Because you're diabetic, it could affect the collagen synthesis, and you have a higher risk of failure.' Now I can say there is not a higher risk."

Diabetes causes many problems that could theoretically affect implant survival, Dr Oates said. It alters bone formation, increases the risk for infections, compromises wound healing, and often entails comorbidities.

Some previous studies have found that implants are less stable in patients with uncontrolled diabetes. For these reasons, some consensus statements and literature reviews have warned against placing implants in these patients.

However, these studies were of short duration, mostly focusing on the status of the implants before final restorations were placed on them, Dr Oates said.

To understand longer-term outcomes, Dr Oates and colleagues followed 117 edentulous patients with 234 implants.

The patients all received two mandibular implants to retain mandibular overdentures. The researchers loaded the implants after a 4-month healing period and followed up the patients for an additional 1 year.

The researchers categorized the patients by their glycated hemoglobin A1c (HbA1c) levels: The 50 patients with HbA1c levels of 5.9% or lower did not have diabetes. The 47 patients with levels between 6.0% and 8.0% had well-controlled diabetes. The 20 patients with levels of 8.1% or more had poorly controlled diabetes.

At baseline, the highest HbA1c level was 11.1%, and the highest level recorded during the study was 13.3%.

Examiners blinded to the diabetes status of the patients assessed the implants during a 4-month healing period after placement, and then again at 3, 6, and 12 months after implant restoration.

They categorized implants as having "survived" if they lacked signs of clinical mobility, peri-implant radiolucency, clinical findings consistent with failure of the implant to integrate, pain, or other reasons preventing restoration of the implant.

Implant survival rates a year after restoration were not statistically different among the three groups. This was true even if the seven patients who did not return for follow-up were counted as having failed implants.

Table. Implant Survival Rates 12 Months After Restoration

Patients No Diabetes Well-Controlled Diabetes Poorly Controlled Diabetes P value
110 patients available for follow-up 99% 98.9% 100% NA
117 patients, with seven unavailable for follow-up counted as failed 93% 92.6% 95% .6510

The researchers also used resonance frequency analysis to measure the implant's position relative to the alveolar ridge and to determine the implant's stability.

Implant integration was delayed in the group with poorly controlled diabetes compared with that in the other two groups. In the group with poor control, the mean time to 100% stability was 7.3 months compared with 3.8 months in the group without diabetes and 4.0 in the well-controlled group.

However, this difference in healing time did not seem like a good enough reason to deny implants to people who can benefit from them, said Dr Oates, as it did not seem to affect survival rates. "Once you get past that initial delay in healing, there doesn't seem to be any problem at all," he said.

In addition, any risks could be outweighed by the benefits, he argued. "We were looking at some patients who had no teeth, and they were orally debilitated," he said. "They were putting two pieces of plastic in their mouths and trying to eat with them."

For example, one patient was trying to subsist on a diet of chocolate milk, he said. If implants allow such patients to eat a healthier diet, they could improve the patients' diabetes.

He cautioned that the findings could not be applied to all clinical situations. Circumstances could be different for implants placed in the maxilla, for example. In addition, he pointed out that the 4-month healing time before placing restorations was longer in this study than some clinicians allow. And all the patients in the study received antibiotics for a week.

Dr Gowey said he, too, typically allows implants to heal for 4 months before placing restorations. He gives only one dose of antibiotics.

However, he questioned how much the study will affect practice, as in his experience few patients will admit to having uncontrolled diabetes, and few dentists check their patients' HbA1C levels.

The study was funded by the National Institute of Dental and Craniofacial Research. The authors and Dr Gowey have disclosed no relevant financial relationships.

JADA. 2014;145:1218-1226. Abstract

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