Cardiac Implanted Devices and Electronic Dental Instruments

In May, 2021, the U.S. Food and Drug Administration (FDA) released a statement15 recommending that “consumer electronic devices” that may create magnetic interference, including cell phones and smart watches, be kept six inches (~15cm) or more away from the implanted device, as the FDA had confirmed previous research that such personal devices may inhibit normal functioning of the CIED.  Recent studies have found that personal electronic devices such as cellphones,16 wearable smart devices, 16, 17 and even electronic cigarettes18 contain magnets that can produce magnetic fields strong enough to affect CIED performance, including disabling of the cardioverter-defibrillator function or switching the mode of a pacemaker.15

Key Points

  • A number of studies have shown some electronic dental devices may cause interference with implanted cardiac devices.
  • Newer cardiac devices are better shielded and may be less susceptible to interference.
  • Piezoelectric dental scalers may be safer than magnetostrictive models.
  • Electrosurgery devices have the highest potential of electromagnetic interference.
  • Proper use and distance are two important factors affecting risk of interference.

Electronic dental instruments, like ultrasonic scalers or apex locators, could potentially interfere with some implantable cardiac devices, such as pacemakers or implantable cardioverter-defibrillators.

Cardiovascular implantable electronic devices (CIEDs) (see below) use electrical impulses to maintain proper heart rhythm. They are becoming more common as the initial population into which they were introduced ages with an increased life expectancy, and as implantations have increased.1-6 This means patients, dental professionals and staff are more likely to have CIEDs, increasing the possibility of electromagnetic interference from electronic dental equipment.

There is a known history of common electronic devices, even cellphones and tablets,7 interfering with CIEDs. In dentistry, there have been conflicting reports regarding whether ultrasonic devices such as scalers and curing lights might interfere with automatic electronic functions of CIEDs. Electromagnetic interference may cause an interruption in or a change of pacing, or send a positive signal that a shock is needed. A number of in-vitro tests in the 1990s and early 2000s found that ultrasonic electronic dental devices caused interference in pacing and other functions, but many argue that in-vitro laboratory tests do not exactly mimic the human body and dental procedure conditions, and newer models of CIEDs should be more adequately shielded from electronic interference.2, 4, 5 As more people enter dental operatories with CIEDs, it is important to be aware of the risk of potential interactions with ultrasonic dental devices.1-6, 8

Cardiovascular Implantable Electronic Devices (CIEDs)

CIEDs include pacemakers, which regulate cardiac pacing through an electric current, and implantable cardioverter-defibrillators, which analyze cardiac rhythm and deliver an impulse when an anomaly is detected.2, 3, 7-12  CIEDs consist generally of two main components: a sealed capsule containing the power source, usually implanted inferior to the left clavicle (the subclavian pocket), subcutaneously or subpectorally, with a wire lead that follows the subclavian vein into the heart.2, 3, 7, 9-12  Pacemakers have been in use since the 1960s,9 and early versions could only provide a static pulse; more modern versions can provide ‘on demand’ pacing, which can inhibit or trigger cardiac pulse as needed.3, 12

Early pacemaker models also were not well protected or shielded from electromagnetic interference, but more modern CIEDs have been designed with potential electromagnetic interference in mind,2, 5, 13 using “hermetically sealed casing”2 and “filters, rejection circuits, and bipolar modes”2 to limit the risks of such interference.  The fact that older models lacked these protective measures may have led to many early reports of the high risks of interference with these devices.3-5, 10, 13, 14

CIEDs and Consumer Electronic Devices

In May, 2021, the U.S. Food and Drug Administration (FDA) released a statement15 recommending that “consumer electronic devices” that may create magnetic interference, including cell phones and smart watches, be kept six inches (~15cm) or more away from the implanted device, as the FDA had confirmed previous research that such personal devices may inhibit normal functioning of the CIED.  Recent studies have found that personal electronic devices such as cellphones,16 wearable smart devices, 16, 17 and even electronic cigarettes18 contain magnets that can produce magnetic fields strong enough to affect CIED performance, including disabling of the cardioverter-defibrillator function or switching the mode of a pacemaker.15

Electronic Dental Devices and Electromagnetic Interference

All types of tested electronic dental devices have shown some potential for causing electromagnetic interference in CIEDs (Table 1).  However, there is conflicting evidence, and most of the positive results come from in-vitro studies.  It is thought that human tissue provides shielding and other protection from electromagnetic interference that cannot be replicated in a laboratory setting.2, 6, 11  Many instruction manuals for electronic dental devices discourage use of these devices with patients who have CIEDs,1, 14, 15 but many researchers believe that newer CIEDs are designed to lower the risk of interference from electromagnetic sources.6 While some researchers claim that clinical interference from ultrasonic dental devices is “highly improbable,”15 the theoretical possibility remains. A number of studies mention the increasing likelihood of electromagnetic interference if a device comes within 37.5 cm (~15 inches) of the CIED or lead wire.3, 7, 16

 Device  Reported Electromagnetic Interference
   In-Vitro (laboratory testing) In-Vivo (in people)
 Ultrasonic dental scalers    
      Piezoelectric None,15 Minor to Severe6, 11 None,1 Minor13
      Magnetostrictive None,15 Minor4 Minor10
 Electronic apex locators None,14, 21, 22 Minor2, 6, 11 Minor8, 13 to Severe8
 Electric pulp testers None,4, 14 Minor,6, 11, 18 Severe6, 11 None,10 Minor13
 Electrosurgery instruments  None,4 Minor6, 11, 18 to Severe6, 11, 14, 18 N.A.
 Curing lights Minor,18 Severe4 None10 
 Gutta percha devices None,18  Minor2 Minor8 
 Ultrasonic cleaning systems Severe4 Minor10
 Electric toothbrushes None4  Minor (rare)10 
 Osseointegration tools Minor to Severe6, 11  N.A.

“Minor” refers to non-clinically significant interference (noise, telemetry); “Severe,” to clinically significant outcomes (i.e., pacing disturbances or shock); “N.A.” (Not Applicable), no studies available.

A 2015 in-vivo prospective cohort study10 exposed 32 patients with CIEDs to a magnetostrictive scaler, an ultrasonic cleaning system, a curing light, electric toothbrush, and battery-operated pulp tester. They found minor electromagnetic interference when the scaler and cleaning system were less than 18 inches from CIED leads.10 Other asymptomatic minor interactions occurred with other devices at smaller distances but appeared to be interference with the monitoring devices (telemetry) and not the pacing or functioning of the CEID itself.10  This interference with telemetry and device monitoring has been argued to have been the cause of electromagnetic interference in a number of studies.5, 10, 23, 24

There is evidence that piezoelectric scalers (commonly used in Europe) are safer than magnetostriction devices1, 19, 20and may pose no risk to patients with CIEDs.4, 12, 13, 20, 25 A 2000 position paper26 by the American Academy of Periodontology warned “[m]agnetostrictive ultrasonic scalers should not be used by clinicians or on patients with a pacemaker”20 though this warning was later retracted.1, 3, 27  Several in-vitro studies4, 6, 11 showed interference by magnetostrictive scalers though a 2013 in-vivo study found no interference between piezoelectric scalers and 5 different implantable cardioverter-defibrillator types in 12 patients.1 A 2018 in-vivo study of piezoelectric scalers found only minor interference (noise) in telemetry, and no adverse events in pacemaker function.13

Apex locators and osseointegration monitoring tools have been found in in-vitro tests to be a low risk for light electromagnetic interference.2, 11  However, in one in-vivo study, a symptomatic interruption of pacing was induced in patients by two brands of apex locators.8 A 2018 in-vivo study of an apex locator found only minor telemetry interference in 3.3% of patients.13

Although pulp testers were shown to be associated with “severe” electromagnetic interference (stimulation inhibition or inappropriate discharge) in in-vitro studies from 201511 and 2016,6 a number of other in-vitro studies found no interference,4, 10, 14, 22 nor was interference found in a 2015 in-vivo study.10 A 2018 in-vivo study found minor interference in telemetry in 7.5% of patients.13

Electrosurgical units are used to remove and cauterize tissue, and are available as monopolar (which requires an electrical current to pass through the patient’s body) and bipolar (in which the current is completed between two electrodes at the device tip) devices. In-vitro studies have consistently shown clinically significant electromagnetic interference to CIEDs from monopolar electrosurgery, including pacing interruptions and electrical shock.6, 14, 22  The Heart Rhythm Society/American Society of Anesthesiologists published a consensus statement on management of CIED patients, which states that “[m]onopolar electrosurgery is the most common source of [electromagnetic interference] and CIED interaction in the operating room,”28 and that head and neck region electrosurgeries using monopolar equipment “pose more of a risk for oversensing and damage to the CIED system.”28

Battery-operated curing lights were shown to induce pacing inhibition in an in-vitro study in 2010,4 but more recent studies from 201510, 22 did not result in any electromagnetic interference from curing lights. Ultrasonic cleaning systems were shown to produce significant electromagnetic interference in the 2010 study,4 and while minor interference with telemetry was encountered in the 2015 in-vivo study, pacing or sense functions were not affected.10 Both the 2010 and the 2015 studies found little or no risk from electric toothbrushes.4, 10

Gutta percha heat carriers, but not guns, have been shown to produce electromagnetic interference in the form of background noise,2, 8 as well as cause an asymptomatic pause in an in-vivo study published in 2015.8 However, an in-vitro study in 2015 found no interference between gutta-percha devices and implantable cardioverter-defibrillators.22

Dental Care Implications

Although evidence is conflicting, consideration should be given to the possible effects ultrasonic or electronic devices could have on patients or staff who have implantable cardiac devices. Some manufacturers offer recommendations on use of their device in the vicinity of such implants, and reports of interference are from a dental device generally within 37.5 cm (~15 inches) to the device or leads. Dentists also may consult with the treating cardiologist to determine if ultrasonic or electronic devices can be safely used.  If ultrasonic or electronic dental devices (or other such equipment) are used, it may help reduce the risk to avoid waving the device or its cords over the patient’s pectoral region, and turn off this equipment when not in use.

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Topic last updated: May 14, 2021

Prepared by:

Department of Scientific Information, Evidence Synthesis & Translation Research, ADA Science & Research Institute, LLC.