News

Aug 02, 2023

Cardiac Implantable Devices and Electronic Dental Instruments

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

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) 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, which may also increase the possibility of electromagnetic interference from electronic dental equipment.

There is a known history of common electronic devices, even cellphones and tablets,7, 8 interfering with CIEDs. In dentistry, there have been conflicting reports regarding whether electronic apex locators, curing lights or ultrasonic devices (e.g., scalers) might interfere with automatic electronic functions of CIEDs.9 Electromagnetic interference may cause an interruption in or a change of pacing, or send a positive signal that a shock is needed. Previous in-vitro tests indicated that ultrasonic electronic dental devices caused interference in pacing and other functions.2, 4, 5, 10 However, other investigators assert that laboratory tests do not adequately replicate in-vivo conditions, including the proximity of electronic devices used in dental procedures or the shielding of surrounding tissues in the human body.2, 4, 5 Additionally, most newer models of CIEDs are considered to have more adequate shielding from electromagnetic interference than older devices.2, 4, 9

In the United States and globally, the number of individuals with CIEDs has increased steadily in recent decades, particularly among adults over 70 years of age.11, 12 As a result, more patients with CIEDs are receiving treatment in dental settings, so clinicians should remain aware of the risk of potential interactions between common electronic dental equipment and implanted cardiac devices.1-6, 13

CIEDs include pacemakers, which regulate cardiac pacing with low-energy electrical pulses, and implantable cardioverter-defibrillators, which analyze cardiac rhythm and deliver an impulse when an anomaly is detected.2, 3, 7, 13-17 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, 14-17 Pacemakers have been in use since the 1960s,14 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, 17

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, 18 using sealed casing, filters, rejection circuits, and bipolar modes to limit the risks of such interference.2 The fact that older pacemaker models lacked these protective measures may have led to many early reports of the high risks of interference with these devices.3-5, 15, 18, 19

In May 2021, the U.S. Food and Drug Administration (FDA) released a statement20 recommending that “consumer electronic devices” that may create magnetic interference, including cellphones 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,21 wearable smart devices, 21, 22 and even electronic cigarettes23 contain magnets that can produce magnetic fields with sufficient strength to affect CIED performance, including disabling the cardioverter-defibrillator function or switching the mode of a pacemaker.20

Various 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. Some researchers claim that human tissue provides shielding and other protection from electromagnetic interference that cannot be replicated in a laboratory setting.2, 6, 16 Various instruction manuals for electronic dental devices discourage use of these devices with patients who have CIEDs,1, 19, 24 but other researchers attest 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,”24 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, 25

A 2015 in-vivo prospective cohort study15 exposed 32 patients with CIEDs to a magnetostrictive scaler, an ultrasonic cleaning system, a curing light, electric toothbrush, and battery-operated pulp tester. The study found minor electromagnetic interference when the scaler and cleaning system were less than 18 inches from CIED leads.15 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.15 Several studies have cited these interactions with telemetry and device monitoring as evidence of electromagnetic interference associated with dental equipment use.5, 15, 28, 29

There is evidence that piezoelectric scalers (commonly used in Europe) are safer than magnetostrictive devices1, 24, 25 and may pose no risk to patients with CIEDs.4, 17, 18, 25, 30 Several in-vitro studies4, 6, 16 present some evidence of electromagnetic interference by magnetostrictive scalers, whereas a 2013 in-vivo study reported 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.18

Apex locators and osseointegration monitoring tools have been found in in-vitro tests to be a low risk for light electromagnetic interference.2, 16 However, in one in-vivo study, a symptomatic interruption of pacing was induced in patients by two brands of apex locators.13 A 2018 in-vivo study of an apex locator found only minor telemetry interference in 3.3% of patients.18

Although pulp testers were shown to be associated with “severe” electromagnetic interference (stimulation inhibition or inappropriate discharge) in in-vitro studies from 2015 and 2016,6 a number of other in-vitro studies found no interference,4, 15, 19, 27 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.18

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, 19, 27 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,”31 and that head and neck region electrosurgeries using monopolar equipment “pose more of a risk for oversensing and damage to the CIED system.”31

Battery-operated curing lights were shown to induce pacing inhibition in a 2010 in-vitro study,4 but more recent studies from 201515, 27 did not report 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.15 Both the 2010 and the 2015 studies found little or no risk from electric toothbrushes.4, 15

Gutta-percha heat carriers, but not gutta-percha guns, have been shown to produce electromagnetic interference in the form of background noise,2, 13 as well as cause an asymptomatic pause, as demonstrated in a 2015 in-vivo study.13 However, a 2015 in-vitro study found no interference between gutta-percha devices and implantable cardioverter-defibrillators.27

Although the available evidence is limited (and in some cases conflicting), consideration should be given to the possible effects ultrasonic or electronic devices could have on dental patients or staff who have implantable cardiac devices. Some manufacturers offer recommendations on use of their devices in the vicinity of such implants, and reports of interference from a dental device are generally within 37.5 cm (~15 inches) to the device or the leads. As noted in a 2022 guideline from the British Heart Rhythm Society, at a distance of at least 15 centimeters (approx. six inches), interference from ultrasonic scalers, apex locators and other dental devices is not considered likely to present any clinical risk to individuals with CIEDs.32 The same guideline also advises clinicians that “[p]eople with implantable devices should be carefully observed during dental procedures.”32

According to a 2020 systematic review, most dental instruments are safe and compatible for use in routine dental practice while maintaining an appropriate distance away from the CIEDs.9 Dentists also may consult with the treating cardiologist to determine if ultrasonic or electronic devices can be safely used when providing dental treatment to a patient with a CIED. If ultrasonic or electronic dental devices (or other such equipment) are used, it may help reduce risk to avoid waving the device and avoid placing electrical cords on or over the patient’s pectoral region, and to turn off this equipment when not in use.

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Topic last updated: February 20, 2023

Prepared by:

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

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