You can keep wearing your continuous glucose monitor (CGM) for almost any dental visit. The sensor on your arm or abdomen sits a long way from your mouth, and a check-up, clean or filling does not involve it at all. The two things worth a minute of planning are dental imaging, where the advice differs between devices, and what you want the team to do if an alarm goes off while you are in the chair.
This article is about the sensor. If you also use an insulin pump, that raises separate questions about insulin delivery, so mention it as well.
A CGM only measures
A CGM reads glucose through a fine filament under the skin and sends the result to a phone, reader or watch. It does not give any insulin. That means there is no dosing decision to make because of the dental visit itself. What matters is where the sensor sits, whether imaging affects it, and how its alerts are handled during treatment.
Imaging advice depends on your device
Dental X-rays are aimed at the teeth and jaws, so a sensor on the upper arm or abdomen is outside the area being imaged. Even so, manufacturers word their guidance differently, and it changes between models, so check the instructions for the exact sensor you wear.
As examples, Dexcom's patient information for the G7 suggests keeping the sensor out of the scanned area during X-rays or CT scans, and its guidance for the older G6 says not to wear the system during a CT scan. A dental cone beam CT (a 3D scan of the jaws) is a type of CT scan, so G6 wearers should raise this before a 3D scan. In the United States, the FDA has cleared the FreeStyle Libre 2 and 3 sensors to be worn during common imaging such as X-ray, CT and MRI. If your device's instructions say to remove the sensor for a particular scan, follow them, and tell us so we can plan the timing.
At Lumi Dental, our Orthophos unit takes panoramic images (OPG) and 3D scans. A 3D scan is only taken when the dentist needs it for planning, such as before an implant or a wisdom tooth removal, and we will tell you in advance.
Sensor position and the dental chair
The back of the upper arm and the abdomen are clear of the headrest, the bib and most of the equipment. If your sensor is somewhere less usual, or you are worried about it being knocked when you lean back, let the team know. A knock is more likely to loosen the adhesive or cause a short-lived odd reading than to cause any harm, but it is easily avoided.
Agree on alarms before treatment starts
There is no single right setting for high and low alerts during a dental appointment. Some people leave them audible, some switch to vibrate, and some keep the phone in view on the tray. What matters is that you and the clinician agree beforehand on what happens if an alarm sounds. For most people that simply means the dentist or OHT pauses, you check the reading, and you decide together whether to carry on.
It also helps to tell the team your usual pattern. If your glucose tends to drop mid-morning, or your appointment runs across a usual mealtime, that is worth knowing in advance. Eat as you normally would before the visit unless you have been told otherwise, and bring a fast-acting carbohydrate with you.
Know the signs of a low yourself
With your mouth open and the light on, you may not see your phone, and the team will be focused on your teeth. Healthdirect defines hypoglycaemia as a blood glucose level below 4 mmol/L and lists symptoms such as shakiness, sweating, weakness, dizziness, hunger, tingling of the lips or tongue, a racing heartbeat, blurred vision and irritability. Some of these can be mistaken for dental nerves, so raise your hand if you feel any of them.
Healthdirect's first-aid advice for someone who is alert and can swallow is about 15 g of fast-acting carbohydrate, such as glucose tablets or six or seven jelly beans, then a recheck after 10 to 15 minutes, repeating if the level is still under 4 mmol/L. Your own diabetes plan from your doctor or diabetes educator takes priority over general advice.
What to tell us when you book
- that you wear a CGM, and which brand and model
- where the sensor is placed
- how you would like alarms handled during treatment
- any insulin pump or other diabetes medicines you use
- any low glucose episode you have had at a medical or dental visit before
If you are considering sedation, wearing a CGM does not usually rule it out, but your overall diabetes management is part of that discussion and your doctor may need to be involved. Ask us about sedation options at your consultation.
Diabetes also affects the gums and saliva. Our articles on diabetes and gum disease and dry mouth explain why regular dental care matters, and our guide to hearing aids, cochlear implants and dental treatment covers another common device question.
If you wear a CGM and have questions before your visit, the team at Lumi Dental in Melrose Park is happy to talk them through when you book. New patient offers are listed on our current deals page.
