Anesthesia in the endodontic practice — reducing the fear of “the shot”

Dr. Gary Glassman discusses various forms of anesthesia and how to improve the patient experience

What are the biggest fears of life? There’s the fear of dying, the fear of public speaking, fear of animals and crawling insects, but one of the most prevalent, is fear of pain from the dentist’s needle. (Trypanophobia is the medical term for fear of receiving an injection.) Dentists have spent much time and money on local anesthetic products, distraction techniques, and buffered anesthetic agents.¹ And, over the years, much time and research has been spent on developing anesthetic delivery systems that are more comfortable and easier on the patient and the doctor.

Historical background

In the annals of anesthetic delivery history, Dr. Harvey S. Cook is a pioneer and visionary. In 1917 during World War I, he was a physician for the U.S. Army in France. He found that on the battlefield, it was not efficient to draw up the solution into the metal syringe every time anesthesia was needed. He created a faster and more efficient design after observing soldiers load their rifles and watching the empty shells being dispensed after firing. He cut glass tubing and filled them with anesthetic solution, creating the first prepackaged cartridges of anesthetic. For the stopper, he used the erasers from the heads of pencils. This was the forerunner to all future types of carpules and syringes. After patenting the system in 1925 after the war, he founded Cook Laboratories in Chicago, which eventually partnered with RB Waite, a dentist who also had created an improved syringe system. The result was the Cook-Waite Company, whose dental products are still available today.²

Over my 40 years of endodontic practice and treating teeth with “live” nerves, I have tried many options for anesthesia. Like many of my peers, when in dental school, I started with a foot pedal and pulley system to drive my slow handpiece, and using that traditional syringe and anesthetic reinforced the fearsome reputation of dental anesthesia. Even when improvements to the syringe were made, they were still large, cumbersome, and anxiety-producing. In my own childhood memories, I remember my dentist sneaking up with the dreaded shot. It’s one of the reasons I became a dentist — I knew there had to be a better way to induce patients to get dental care, by reducing their fear of “the shot.”

Anesthetic delivery options

I have tried many different anesthetic delivery systems over the years. I’ve tried the Ligmaject syringe with its pistol-grip handle and a ratchet system that injects a small amount of anesthetic per “click” and the Calaject Computer-Assisted Local Anesthesia unit (Aseptico). I have also used the QuickSleeper Intraosseous Anaesthesia Delivery System. It has a blue tooth-connected foot pedal to a rotating syringe mechanism providing an effective intraosseous injection, but I could not hide the large obtrusive handpiece from the patient, which, in my opinion, is very important to my objective of positive patient experience. In a 2020 study, some children reported that seeing the needle would increase their anxiety.³ The fear and pain of dental treatment also often results in not only avoiding dental care but also uncooperative behavior and unwanted movements while in the chair.⁴

Many years ago, I implemented the STA Single Tooth Anesthesia^® System instrument from Milestone Scientific, which at the time was called “The Wand,” because of its pen-like shape. Patel, et al., notes that Single Tooth Anesthesia has the advantages of “not causing anticipatory worry, not hurting, and having no lingering numbing effects on the lips, tongue, or cheeks.”¹

Often patients require an inferior alveolar nerve block, but in my opinion, that in itself is not enough to provide profound anesthesia for conditions like irreversible pulpitis; most often the lower second molar (the proverbial “hot tooth”). Single tooth anesthesia (STA) is effective because even though it is injected into the gingival tissue, it really is an intraosseous injection. The anesthetic reaches the bone itself, as it surrounds the tooth in a very painless manner. In this way, the “hot tooth” can be anesthetized without the patient experiencing pain. Studies have shown that the Wand® system resulted “in a significant reduction in the perception of pain compared with traditional injections (p=0.04), during induction of local anaesthesia.”⁴

This type of effective, profound anesthesia is very helpful in reducing fear, for both adults and pediatric patients. It helps to alleviate many of the causes of pain from syringe methods including soft tissue damage during penetration of the oral mucosa and pressure from the spread of the anesthetic solution.

C-CLAD category

The STA is in the category of C-CLAD — computer controlled local anesthetic delivery. According to Kwak, et al., the most widely known devices of this type include the Wand® (Milestone Scientific, Livingstone, New Jersey), Comfort Control Syringe (CCS; Dentsply), QuickSleeper (Dental HiTec, France), and iCT (Dentium, Seoul, Korea).⁵ Weight is a valid consideration for units such as this. The article notes that the STA is light weight, with a circumference that is about half that of traditional anesthetic syringes. In contrast, the Quicksleeper® and CCS^® devices are about three times the size and weight of traditional anesthetic syringes, which can present difficulties in handling for operators with small hands. The increased weight of the Quicksleeper® and CCS^® are due to the syringes and motors being combined in the handpiece. The Kwak, et al., article continues, “C-CLAD devices must be held stationary for long periods of time in order to ensure safe administration of anesthesia. If the device is too heavy, operation is difficult, and may lead to chance movement while the needle is inside the tissue, which may cause the needle to break and cause undo patient discomfort. Therefore, it is important for clinicians to select the right product with appropriate weight for their needs.

While Milestone Scientific actually created the C-CLAD category with their debut of the Wand in 1997, the technology of this system is unique because it allows for certain injections that cannot be accomplished with other C-CLAD devices, such as areas of the oral cavity with difficult access. Kwak, et al., notes that the STA cartridge is installed in the main unit, which allows for the cartridge to be changed during anesthesia without having to change the needle position. During an inferior alveolar nerve block for instance, clinicians using traditional syringe methods must remove the needle from the tissue, reload with a new anesthetic carpule, and once again search the landmarks to provide a predictable nerve block. With the STA, the needle is already in position, and practitioner can change the anesthetic carpule on the unit to continue an almost uninterrupted delivery of additional anesthetic. This is especially helpful if the patient needs two or three carpules for the nerve block.

The STA device offers the needles in the 30G ½”, 30G 1” and 27G 1-1/4” to do all the different types of injections. For the mandibular block, the needle of choice would be the 27G 1-1/4”.

The STA is a plastic wand with a little needle at the end of a small tube. The practitioner can actually break down the plastic cover that holds the delivery tubing along specific scored indentations in order to make the handpiece shorter. This is particularly useful with young patients or patients with “needlephobia” as the needle is barely visible and can be covered by the doctor’s hand.

Speed of anesthetic delivery is a concern as an injection that is performed too fast may distend the soft tissues too quickly and lead to increased discomfort for the patient compared to a slow measured delivery. Because of its computerization, the STA system provides a slow, controlled flow of anesthetic, greatly reducing pain or discomfort during its delivery due to the slow distension of the soft tissue. The injection is delivered in a controlled flow rate of one drop every other second, which allows the bone to absorb the anesthetic, prevents “oozing” of the anesthetic, and ultimately delivers the injection under the patient’s pain threshold. Continuous positive pressure yields a constant anesthetic drip that precedes the needle during its insertion.4 With some patients, the total quantity of required anesthetic is markedly reduced, due to a very precise injection and consequent rapid onset of anesthesia.⁶

While some say that local anesthesia is not necessary for sedation patients, in my practice, sedation patients are anesthetized while they are sedated so they will not have pain after awakening.

The Dynamic Pressure Sensing (DPS) technology replaces the traditional hand syringe, which is much harder to control. The technology allows the anesthetic to be precisely administered to just the treatment site — allowing for complete numbness of the tooth being treated, while eliminating the numbing and morbidity effect on the cheek, lip and tongue.

That avoids the patient chewing on their lip, which is especially helpful with children, since they are more likely to cause tissue damage from biting themselves after the procedure while they are still numb. And because the anesthesia is so exact, patients don’t have to worry about 4 to 6 hours of numbness after treatment.

With lower anterior teeth, due to cross innervation, it is not uncommon where clinicians must give bilateral mandibular blocks or technically savvy bilateral mental nerve blocks to provide adequately profound anesthesia. The following case shows how I was able to complete endodontic treatment comfortably on multiple mandibular anterior teeth without the need for nerve blocks or infiltrations which would have caused the patient to have a “numb” lip, chin, and tongue for several hours. Rather STA about each tooth allowed for profound anesthesia without the soft tissue morbidity issues.

Case report No. 1

A 58-year-old female with a non-contributory medical history presented with a dental history of porcelain veneers on her lower anterior teeth. Teeth Nos. 32, 31, and 42 were diagnosed with pulpal necrosis with symptomatic apical periodontitis. Tooth No. 41 was asymptomatic with a normal pulp with normal apical tissues. Anesthesia was delivered with the STA at the buccal and lingual papillas of the involved teeth, and endodontic treatment was completed painlessly without lip, chin, and tongue anesthesia. The 6-month recall revealed excellent periapical healing, and tooth No. 41 remained asymptomatic with a normal pulp and normal apical tissues.

Contraindications⁷

As with any dental technology, there are some contraindications. For severe periodontal cases with deep pockets, the area would not become sufficiently anesthetized.

According to Milestone Scientific, the single tooth injection can be an adjunct to a traditional injection in the case of areas of primary apical periodontitis and infection in general. The single tooth injection may not be indicated as a primary injection for surgical procedure, like an apicoectomy. I often use the Wand for traditional injections, (i.e., infiltration, IANB) for these procedures as the delivery is slower, more comfortable for the patient, and may provide longer duration of anesthesia.

Ergonomics

Another advantage of the STA is its ergonomics for the dentist. With repeated use of a traditional syringe, some dentists report overuse injuries to their wrists and hands because of the pushing and pulling of the wrist while injecting.⁸ The STA is a very tactile handpiece. The computer does the pushing and pulling for the clinician. For doctors suffering from carpal tunnel syndrome and/or repeated strain syndrome this may provide relief.

Patient loyalty and improved practice reputation

Positive patient experience may influence the reputation and growth of a dental practice. A negative patient experience may lose a whole family’s support.

When going to the dentist, especially an endodontist, patients imagine the worst. This generates real anxiety around any procedure and the injection process in particular, since they often are already in pain. If the process is indeed painful, often they will not return to the practice, or will seek out a practice with better pain management. According to Ost, 56% of patients who had injection phobia could trace their fear back to negative conditioning from a health-care experience.⁹ Moreover, 24% of patients could trace their fear to having seen another child, often a sibling, experiencing a negative event (i.e., painful or traumatic) associated to needles.¹⁰ If their expectation of pain is eliminated, patients will tell their family, friends, and post favorable comments on their social media platforms.

A number of studies investigating the origin of dental fear have been published. Most of them indicate needle phobia as the primary etiological factor, potentially leading to avoidance of dental treatment.^11,12,13 Having an anesthesia option that is digital, quick, efficacious, and flexible enough to meet the diverse needs of various ages is a valuable asset to any dental practice.