DENTAL STUDENT BLOG POST: Diabetes and Dental Implants
Let me tell you a story about our imaginary friend Anna.
Anna came to Canada with her family 30 years ago. Since then, her son has graduated college, is earning a very respectable income, and is planning on starting a family of his own. Anna is finally comfortable prioritizing her own dental needs. However, Anna has a problem – her years of supporting her children meant that she hadn’t been comfortable getting her own dental work done. Years later, Anna has unfortunately lost some of her teeth as a result. Her son tells us about how he remembers his mother’s beaming face as a kid. Now she’s self-conscious, barely managing a small smile. Of course, dentures are a valid option. But Anna has issues with dentures. So how can we help her?
If this were the ’70s, this would be a problem. But dentistry has made huge leaps within the last 50 years. Dental implants have been transformed many times over since their introduction in the ’80s. These implants resemble natural teeth: they have a metal portion that is embedded in bone like the roots of our own teeth, and a portion replacing the teeth that are missing. Dental implants have now become such an extensive topic of research and use that they are slowly becoming the new standard of care, or default option, to replace missing teeth. They function similar to hip replacements that have been common for many years now – in fact, both dental implants and hip replacements are mainly made of the same metal, titanium! This specific metal is known for being both strong and lightweight, but there’s another key to its use, and that’s a term known as biocompatibility.
You see, it’s not enough that we can put something into the human body – the body has to accept it. You could have all the free cilantro in the world, but you wouldn’t be happy if you hated cilantro. Similarly, implants could technically be made of any metal, but they wouldn’t be much use if the body wasn’t happy with it. What’s so special about titanium is that our bodies don’t react negatively to it – they’re compatible with it. Modern research is even taking this a step further by trying to make new implants that are bioactive – that our bodies want to react positively with. Once the implant is in place, this body-friendly material then undergoes a process known as osseointegration. The bone surrounding the implant grows around it, locking it in place rather than trying to reject it. The result is a very stable connection between the implant and bone, locking it in place. But Anna has a condition that might complicate things.
Yes, Anna has diabetes. Specifically, she has Type II diabetes, which usually happens later in life. You probably know at least one person with Type II diabetes – after all, it’s one of the most common conditions in North America. You’ve probably heard that diabetes is linked to obesity and heart disease. But what does it have to do with our teeth? And why does your dentist need to know if you have diabetes or not?
The answer lies in the molecules of our body. The hallmark of uncontrolled diabetes is a higher level of sugar in our blood, or hyperglycemia. It may sound innocent enough – “you’re a sweetheart! ” – but this excess sugar can have a variety of surprising effects. The one that dentists are most interested in is that hyperglycemia actually causes a weaker immune system and more inflammation. Now some inflammation in small amounts can be a good thing. That redness, heat, and occasional itching actually means that your body is actively healing itself. But too much inflammation over too long can actually prevent good healing. That’s why it’s important to make sure that the medications that people with diabetes take are working properly to control the sugar levels in blood.
II. Measuring Control of Diabetes
So how do we figure out if Anna’s diabetes is under control? You may have heard of blood sugar tests that people with diabetes take regularly: a drop of blood on a test strip, and a machine provides a real-time measurement of their blood sugar levels. But our blood sugar levels change throughout the day, and those tests only tell you what the levels were when they took the test. Is there something that we can use to measure blood sugar over a longer period of time?
That measurement exists, and it’s a little piece of medical lingo known as an HbA1c level. This handy measurement, that’s done through a doctor, provides a measurement of the blood sugar as a percentage of glycosylated hemoglobin (sugar carried by red blood cells) in blood over the last 3 months. A reading around 6% is normal for a person without diabetes. A reading between 6% - 8% means the medications are successfully controlling diabetes. If it’s above 8% though, it’s considered uncontrolled, and you may need to visit your doctor to consider other medications.
III. Diabetes and Implants
So how does this relate to implants? Let’s take stock of all we’ve learned so far. Remember how inflammation is related to healing? A healthy amount of inflammation helps the osseointegration of the implant. But uncontrolled diabetes results in hyperglycemia, which we know causes too much inflammation, and too much inflammation can get in the way of healing. Do you see where this is leading? The hyperglycemia from uncontrolled diabetes can block the osseointegration process from proceeding, and the implant won’t bind well with the surrounding bone. We call this an implant failure, and it’s definitely something we want to avoid.
At least, that’s the theory. In reality, there’s a whole bunch of different factors that happen in a real person that may change that outcome. So in order to test that theory, research has been done to answer that exact question: “Are people with uncontrolled diabetes at a higher risk for dental implant failure?”
For these types of specific questions, we turn to meta-analyses as our research paper of choice. A meta-analysis is basically a numbers-based summary of other research – there’s a lot of papers out there, and not nearly enough time in the world to read all of them. So we turn to meta-analyses to gather all the relevant results of research out there and summarize it neatly.
A 2016 meta-analysis conducted by Shi et al. took a closer look at uncontrolled diabetes and implant failure. And the results were interesting: there were no significant difference in implant failure rates between well-controlled and not well-controlled diabetics. In other words, you can’t predict if an implant will fail based on diabetic control and HbA1c levels.
But the story isn’t quite as simple as that. Another paper conducted in 2016 by Naujoket et al. in Germany looked at a few other parts to the implant story. Like the first study, they found that within the first 6 years, there was no significant difference in implant failure rates. But after 6 years, uncontrolled diabetics had an increase in failure rates. Moreover, uncontrolled diabetics were also found to have more peri-implantitis, or inflammation around the implant, a few years after implant placement as well. Finally, they also found that the process of osseointegration took twice as long in uncontrolled diabetics compared to controlled diabetics. According to this paper, implants in uncontrolled diabetics might last just as long in the short term, but they have a higher risk of failing years down the road. And the amount of time it takes for those implants to bind into bone is significantly longer as well.
IV. So What Now?
Back to our imaginary friend Anna. Luckily for her, our office is well-equipped to place implants. We go through our routine checklist to make sure that she’s a good candidate for implants. After our previous appointment with Anna, she had gone back to her doctor to address her previous HbA1c reading after she learned that 8.7% was too high. This time, when we get to the question of her diabetes, she brings out a paper with her most recent HbA1c results: 6.2%. She’s in the clear thanks to her new meds. Now we can schedule her for her implant appointment, safe in the knowledge that she’s a good candidate because of her well-controlled diabetes. And Anna can finally have the carefree smile that her son so fondly remembers.
Oh, and Anna? It’s only her name that we made up. She’s just one of many patients who have come to us with a similar story. And we’ve been able to help each one of them.
Naujokat, H., Kunzendorf, B. & Wiltfang, J. Dental implants and diabetes mellitus—a systematic review. Int J Implant Dent 2, 5 (2016). https://doi.org/10.1186/s40729-016-0038-2
Quan Shi, Juan Xu, Na Huo, Chuan Cai, Hongchen Liu. Does a higher glycemic level lead to a higher rate of dental implant failure?: A meta-analysis. The Journal of the American Dental Association147, 11 (2016). https://doi.org/10.1016/j.adaj.2016.06.011