Glimpse of TENS in Dentistry: A Literature Review

ABSTRACT

Transcutaneous electrical nerve stimulation (TENS) therapy has been accepted to treat a wide range of illnesses, including phantom limb pain, joint pain, low back pain, and cervical discomfort. TENS is not frequently used in dentistry, despite its potential advantages. 3, 4 Therefore, the rationale of present review is to discuss its dental applications in order to spread awareness of them among the dental profession.

INTRODUCTION

Pain that is nociceptive, neuropathic, or musculoskeletal in nature is treated with a non-invasive analgesic technique called transcutaneous electrical nerve stimulation (TENS).[1] The TENS unit is a compact, frequently battery-operated device that seldom even fits in a pocket. It uses electrodes applied to the skin and connected to the device to address a specific treatment objective. The devices are allegedly titratable, allowing for a high level of user tolerance with the least negative effects. The gadget carries little overdose danger in comparison to numerous drugs. TENS devices frequently provide a wide range of adjustment, allowing the subjects to regulate pulse width, intensity, and frequency.[2]

Health professionals frequently utilize TENS to alleviate both acute and ongoing pain. Although TENS has potential benefits in dentistry, it is not widely employed.[3,4] Therefore, the goal of this article is to discuss its dental uses in order to increase knowledge of its dental applications among the dental community.

Parts of TENS Machine:

1. TENS unit: Electric pulses are produced by it. Two varieties are available: The “clinical” model: Dentists in the clinic utilize this, and it generates electricity by being connected to the building’s electrical outlet. The “Patient” model. Patients can carry this small, portable device in their pocket, attach it to their belt, or wear it as part of their clothing. As a power source, it contains a battery.[2]

2. Lead wires: These enable the electrodes and the TENS unit to connect electrically.[5]

3. Electrodes: By using electrodes, the TENS unit’s electric flow is transformed to an ionic current flow in live tissue. Implantation of electrodes within and outside the mouth is both conceivable. Extra-oral electrodes come in two varieties: With the aid of an electrically conductive gel, flexible electrodes composed of silicone rubber that has been impregnated with carbon are connected to the skin’s surface. To keep them in place, surgical tape is applied. Using cotton pads or sponges soaked in tap water, tin plate or aluminum electrodes that do not conform to the body are connected to the skin’s surface. The intra-oral electrodes are cotton roll electrodes, clamp electrodes, and sticky electrodes. The most popular electrode type today is sticky electrode.[6]

Clinical applications in dentistry

Alternative Dental Anesthesia in Pediatric Patients: The most frequently seen negative behavior in pediatric patients is dread of syringes or electrodes. TENS treatment has a good impact on pediatric patients’ behavior, which lowers anxiety levels by removing their “fear of needles” According to studies, TENS is preferred by youngsters over local anesthetics.[7,8] TENS was proven to be similarly effective as 2% lignocaine in recent trials by Dhindsa et al.[3] and Varadharaja et al.[9] when performing minor pediatric dental operations.

Temporomandibular Joint Disorder: The term “temporomandibular joint disorders” (TMDs) refers to a collection of illnesses that functionally impair the masticatory system, including the temporomandibular joint and the masticatory muscles. Numerous etiologies with particular treatments, such as TENS, have been established.[10]

TMD has been successfully treated by TENS, either alone or in conjunction with other methods. A pilot study was carried out on bruxism patients to assess the effectiveness of TENS and electromyographic bio-feedback. The researchers came to the conclusion that TENS was more efficient at reducing the electromyographic action of the masseter muscle, despite the fact that both therapies led to a relaxation of the muscles of mastication.[11]

Trigeminal Neuralgia: Trigeminal nerves that supply teeth, jaw, and face are frequently affected by trigeminal neuralgia. Despite the fact that the cause is typically unknown, numerous therapeutic options have been tested, including medication, alcohol injections, peripheral neurectomy, rhizotomy, and micro-vascular decompression. A new and promising treatment option for these patients is TENS.[12]

Myofascial pain dysfunction syndrome: A persistent pre-auricular ache that may be radiating and diffuse in nature is a hallmark of the myofascial pain dysfunction syndrome (MPDS). It typically includes clicking and uncomfortable or limited mouth opening. Considering that the disorder has a complex origin, it is challenging to pinpoint the starting point. By activating big peripheral A-delta fibers with the TENS unit, which closes the “gate” and blocks pain input from small C-fibers, active TENS therapy is applied to patients with MPDS to relieve pain. TENS is an effective, non-invasive treatment that can be used as an adjunct to traditional therapy for patients with MPDS. The findings of our study are promising, and TENS therapy has demonstrated better outcomes in the care of MPDS patients when compared to placebo TENS therapy.[13]

DISCUSSION

The early proponents of TENS for the management of chronic pain were Wall and Sweet. Later, it was successfully utilized to treat neuropathic pain syndromes, phantom limb pain, rib fracture pain, and knee osteoarthritis pain, among other types of pain.[12]

TENS uses endogenous pain inhibitory mechanisms, physiological blockade, and gate control theory as part of its analgesic action. The gate control hypothesis of pain is the most widely recognized theory to explain the mechanism of action of TENS. This theory proposes that the spinal cord’s substantia gelatinosa functions as a gate control system. It is believed that pre-synaptic inhibition of substantia gelatinosa cells in the dorsal horn is made possible by activation of vast myelinating fibers that serve touch, pressure, and vibration. This reduces the transmission of pain.[14]

The endogenous opioid theory showed that electrical stimulation of the peri-aqueductal gray region of the mid-brain results in analgesia that is comparable to morphine’s. Endorphins, which are found at various levels of the pain-control pathway, are a group of morphine-like chemicals that were finally discovered as a result of this. TENS may also boost endogenous opioid release in the spinal cord as a result of stimulating local spinal cord circuits or descending pain-inhibitory pathways, which is another idea for how TENS functions.[15]

CONCLUSION

For various pain conditions, such as trigeminal neuralgia, TMD, and MPDS, TENS should be regarded as a safe, straightforward, and first line of treatment. This is especially true in rural areas where there is a lack of procedural expertise for therapeutic management and in patients who have experienced adverse drug reactions, refuse to take medication, or cannot afford invasive surgical intervention.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.