The pain (and expectation of pain) of getting a local anesthetic injection can cause significant anxiety for many patients. Anxiety surrounding pain is the main reason many patients avoid going to the dentist when they have an oral health problem. Besides just improving the patient’s rating of their experience, better pain control before injections can lead to better oral health as well. Patients who experience less pain at their appointments have less anxiety and are more likely to call their dentist with oral health concerns. There is a wide variety of literature, educational courses, videos, and more that have been produced on the subject of injection technique. We will just discuss a few that are specifically related to reducing needlephobia in patients.
Needlephobia
Needlephobia, sometimes referred to clinically as trypanophobia, can be both inherited and acquired. Trypanophobia may more accurately refer to a blood-injection-injury type of phobia however so there may not be a term specifically for dental injections yet. Dental phobia can also include needle phobia but is more general and can affect between 10-25% of people. Dental phobia can be complex and have multiple possible causes. Psychologists have put significant effort into studying these types of fears and there are different methods to help get over the anxiety.
A phobic level reaction to injections can produce a significant vasovagal response in a patient that can result in first an increase in heart rate, then a rapid decrease in heart rate and blood pressure, sometimes causing fainting. Patients may have an anxiety about injections that does not result in a dramatic physical response but is enough that they will do everything to avoid them.
In many cases with dental phobia, a dentist can only do so much, as many of the anxieties are not based on the dentist’s behavior but on the patient’s fears. Needlephobia however is more specific – and reducing the pain of the injection may significantly reduce the patient’s anxiety. The pain of an injection can be managed in a variety of ways. While there may not be a way to get 100% pain free injections for all patients, dentists and researchers have come up with a few methods that often work.
Vibration – The Pain Gateway Theory
Vibration at the injection site and surrounding areas may help inhibit pain. The pain gate control theory says that by inducing a stimuli to the nerves that is not painful, like vibration, the neural gate can be closed and prevent the transmission of pain signals. This is the principle behind devices like the Vibraject and DentalVibe.
Vibraject is an attachment that vibrates the needle at a high frequency. According to Vibraject, “It works because the light pressure of a Vibraject injection is carried rapidly to the brain on thicker more insulated nerve tissues. By contrast, the needleprick travels on thinner nerve tissues, arriving too late for the brain to register the sensation.”
The DentalVibe is a separate device that is used to apply vibration around the injection site. According to the DentalVibe website, “Research has shown that when vibration and injection sensations are occurring simultaneously, the vibration feeling reaches the brain first and essentially blocks the feeling of the injection from being perceived by the brain.”
Other types of vibration have also been used including devices that are applied to the face and stimulate the muscles and jaw. In one study that used a vibrating body massaging device, it was noted that IAN blocks were more painful than infiltrations but when vibration was applied, there was no significant difference in pain scores.
Some dentists take advantage of the gate control theory of pain management and simply massage the area around the injection site with their finger. While vibration may not work for every patient, it is a commonly utilized method for reducing injection pain.
Distraction – Changing the Subjective Pain Experience
Many of the methods used to reduce injection pain and anxiety around needles do not involve using any devices. Dentists will always alert the patient that they will be injecting with a needle. During the injection, distraction is an effective pain reduction technique. Distracting conversation and talking in a calm, reassuring voice can decrease heart rate and lower the subjective experience of pain. For pediatric patients, using visual aids, movement, talking, toys, etc. to distract can improve compliance with the injection and make the dental experience easier for the child, the parents, and the practitioner.
Methods that have been used to distract pediatric patients include WITAUL (Writing In The Air Using Leg), audiovisual glasses, breathing techniques, watching videos, and playing video games. These techniques have been found to reduce the patient’s anxiety before an injection and also reduce stress for the dentist during procedures.
Needle Bevel Type and Needle Size
Different needle bevel types have been associated with varying degrees of pain. In a randomized study of 150 patients, injection needles with a scalpel-designed bevel demonstrated significantly less injection pain. While the bevel style has been associated with pain levels, the actual gauge size of the needle is not as significant. In one study of 810 adult patients using 25- and 27-gauge needles for mandibular inferior alveolar block injections and 25-, 27-, and 30-gauge needles for maxillary buccal infiltration or palatal injections, it was shown that there was no significant difference in pain scores between the gauges.
The angle of the needle is important as well as the technique of the dentist. Choosing an angle that minimizes contact with the nerves can reduce pain. As can using a slow injection technique vs. injecting all of the topical anesthetic quickly. While dentists are aware of all these techniques, it might be good for patients to know the effort that is going into making the experience as comfortable as possible.
Topical Anesthetic – Profound Numbing with Topicals
Topical anesthetics are a common method of reducing the pain of local anesthetic injections. A topical anesthetic is applied to the injection area and allowed to sit for a few minutes. Once it is wiped off, the area can be tested for numbness with an instrument. It may take a few additional minutes to obtain full numbness. The topical will make most types of injection almost completely painless. While there are some topical anesthetics available from dental suppliers, they often have very low concentrations of anesthetic ingredients. Compounded topical anesthetics are widely used by dentists and are significantly more powerful than commercially available products.
Some compounded topical anesthetic formulations include:
BTT “The Baddest Topical in Town” – Lidocaine 12.5%, Tetracaine 12.5%, Prilocaine 3%, Phenylephrine 3%
TAC 20 Alternate – Lidocaine 20%, Tetracaine 4%, Phenylephrine 2%
Profound – Lidocaine 10%, Prilocaine 10%, Tetracaine 4%
A compounded topical anesthetic blocks pain signals so patients will barely know they are having an injection. In addition to its ability to block pain, the actual process of applying topical anesthetic often has a psychological effect. Knowing that they are being numbed, the patients have less anticipation of pain which can slow their heart rate and improve their subjective pain experience.
Topical anesthetics can be compounded in a variety of flavors. Park Compounding Pharmacy uses mint, strawberry, blueberry, bubblegum, grape, and pina colada. Since the taste of topical anesthetics can be one of their downsides, adding a flavor is essential to making it palatable.
Reducing Needlephobia Improves Dental Outcomes
For pediatric patients, negative experiences at the dentist can make them less likely to seek dental care in the future. This makes reducing needlephobia essential for children. Still, patients of all ages avoid the dentist because of a fear of needles and pain. Using a good injection technique, a powerful topical anesthetic, and distraction methods can lead to improved dental treatment outcomes.