Topical anesthetics are designed to make the use of local anesthesia as comfortable as possible, something that is appreciated by patients and dentists alike.
As a youngster I hated the “shots” I got from my “doctor”. I would recoil in horror if the appointment included a visit at the end from the nurse. While it seemed to me then that she took a cruel joy in applying the poke, she undoubtedly enjoyed these encounters no more than me since I was always a less-than-cooperative patient. I was incredibly fearful of needles, so much so that I carefully avoided any needles being used on me well into adulthood. There’s a story about a wedding license and a blood test that might fit in here but I’ll save that for another time.
Topical Anesthetics = Painless Injections
With this background and experience you might expect me to have hated my dental visits as well, but I had no fear about going to the dentist even though I had my fair share of fillings as a youngster. When we began to learn about local anesthesia, I realized that I had been unaware that I was having a “shot” whenever I visited the dentist for a filling because it didn’t feel the same as it did from that cruel nurse. I decided that I wanted my patients to have that same experience with me and I set out to learn how Dr. John had been able to fool me.
My childhood dentist was a friend of the family, my mother and his wife had become acquainted through a club they both belonged to and his office was close enough that we could ride a bicycle there. When I returned to visit him as a dental student he was happy to share how he did things and how he had been able to keep me blissfully unaware of what he was actually doing to get me numb enough so that I would hold still. “I have always used topical anesthetic and made sure that I gave it enough time to do its job,” he told me as he prepared to treat a patient.
As I observed his technique, two things stuck with me. One, the topical was applied and left in place for a long time. Two, the patient would never see that a needle was involved in what followed removal of the topical. These two lessons have served me very well over the past 38 years. The third thing I learned about anesthesia I learned from experience, and it too has served me well, inject very slowly. In my decades in Pemberville, many of my patients referred their friends because I was painless.
What Does the Research Say About Topical Anesthetics?
Hoping to make this digest a little more scientific, I looked at a few studies to discover what the researchers consider as the appropriate amount of time to leave the topical anesthetic in place. Over the years, I have always advised leaving it in at least three minutes before beginning the injection. While that seems like an eternity to a dentist eager to get in, get out, go on to the next one, it led me to great anesthetic success.
In the studies I looked at there was some variability in the amount of time that the topical anesthetic was left in place depending on the study and on the topical anesthetic being applied. Benzocaine 20 percent seems to have the most rapid onset, while EMLA 5 percent has the slowest; the least amount of topical application time used in any of the studies with any material was two minutes. I’m taking that as my new standard since the results of the application achieved the goal, a successful injection without pain in most cases.
The second thing I learned from Dr. John was to be sure that my technique kept the syringe out of the sight of the patient. This is accomplished by a transfer from the assistant while I am retracting the lips and tipping the patient’s head back to retrieve my application tip. They don’t see it, they don’t feel it – and they tell their friends. It doesn’t take much practice to have this transfer happen so quickly and smoothly that patients are literally through with it before they know it has begun. I’m happy to make a video of this transfer if anyone thinks that would be beneficial in helping them apply it. E-mail me here at Spear Education and I’ll get it on the production schedule.
Slow Down for a Painless Injection
That third thing is one that most dentists learn very quickly. Inject slowly and they hold still, inject fast and they move because it hurts. There are products and techniques that attempt to deal with this. One of my best friends practices near me and I have the privilege of being her dentist. She uses The Wand. When I see her at her office I use The Wand.
My personal observation is that we have equal success with anesthesia; she leaves the topical in for two minutes too. Her reason for using The Wand is the ability to inject slowly, and for quite awhile, I teased her for her inability to make her hands do the same. Then I looked at her hand on a syringe. It’s really easy for me to relax completely with the syringe in my hand and go VERY slowly; it’s a stretch for her to comfortably manage her hand placement on the syringe. The Wand makes slow injection a comfortable process for her.
Of course, there are other tricks and distractions that we all employ – wiggling the tissue, heavy pressure or a quick movement to load the sensory input prior to the insertion of the needle, and they all work. But the single most important determinant of comfortable dental injections is the use of topical anesthetic for an appropriate time before getting your patient numb. It’s good to be known of as painless.
- Nayak R, Sudha P: Evaluation of three topical anesthetic agents against pain: a clinical study Indian Journal of Dental Research 2006, Vol 17, Issue 4, 155-60
- Primosch R, Rolland-Assensi G: Comparison of topical EMLA 5% oral adhesive to benzocaine 20% on the pain experienced during palatal anesthetic infiltration in children American Journal of Pedriatic Dentistry; 2001, Nov 11-14
- Dhwan P, Dhawan G: Topical Anesthetics: How effective are they International Journal of Dental Clinics Vol 3 Issue 2 April-June 2011 11-13
- Deepika A, Chandrasekhar R, Vinay C, Uloopi KS, Rao V: Effectiveness of two flovored topical anesthetic agents in reducing injection pain in children: A comparative study The Journal of Clinical Pedriatric Dentistry Vol 37, Num 1/2012 15-18
- Bhushan N, Nayak R: A comparison of the efficacy of topical application of lignocaine hydrochloride 5% gel and bupivicane hydrochloride 5% gel for extraction of teeth Journal of Maxillofacial Oral Surg Jun 2010; 9(2) 119-126