After missing a mandibular block a few weeks back, I decided it was time to interview one of my instructors from dental school who has gone on to become one of the country’s leading authorities on local anesthesia. Dr. Alan Budenz is an Associate Professor in the Department of Anatomic Sciences and Chair of the Department of Diagnosis and Management at the University of the Pacific in San Francisco, Calif. By the end of the interview, Dr. Budenz had inspired me to learn at least one new injection that I wasn’t taught in dental school: the Gow-Gates. As you read the interview you may find yourself wondering, just as I was, why you are not using this injection on a daily basis. I am taking a hands-on anesthesia class with cadavers next month with Dr. Budenz, and I look forward to giving my first Gow-Gates on a cadaver and then moving on to live patients the next morning.

Question 1: What’s the most exciting thing to happen in local anesthesia in the last 5–10 years?

Dr. Alan Budenz: There’s been a lot certainly with the advent of the CompuDent^® Wand (Milestone Scientific; Livingston, N.J.) and the DENTSPLY Comfort Control syringe (DENTSPLY International; York, Pa.). Both are computer-controlled devices and more than 10 years old, but still relatively new to the field. I have both of these devices and they don’t necessarily allow me to do anything I couldn’t do with a traditional syringe, but what they do is make the process less taxing, and they let me administer the anesthetic more consistently, time after time.

The more slowly it gives the injection — particularly if it’s an anesthetic with a vasoconstrictor, because those are more acidic and would tend to cause the patient a little more burning sensation — and with consistent control, the patient feels virtually nothing. It’s all about making it more comfortable for the patient, and it doesn’t hurt that it makes it more comfortable for yourself as well.

Another exciting development recently is the VibraJect (Golden Dental Solutions; Roseville, Mich.). At first I doubted it was worth $230 for a little vibrator so I don’t have to shake the cheek anymore to distract the patient. I thought there had to be more to it, and I discovered that it’s actually a very clever device. It gives you a very low level of stimulation going down to the tip of the needle, and if the needle is in close proximity to the nerve tissue it will stimulate that nerve at a low level, which will open up more of the sodium channels. And it’s the sodium channel opening that allows the anesthetic to flow in and bind to the receptor sites in the sodium channels.

Q2: So it’s really more than a comfort and distraction device — it actually improves the quality of the injection?

AB: Yeah, it’s really not a distraction device at all. It’s not vibrating where it’s going to distract the patient from the penetration, particularly. Really, what it is all about is getting that stimulation to open up the sodium channels. It’ll tend to give you a more profound anesthesia and potentially less of that problem where you start to drill on a mandibular molar and the patient feels it even though when you check with an explorer, everything appears to be numb. But the patient still feels it when you root plane or drill because you don’t have enough of those sodium channels blocked. This device will reduce the incidence of that. I bring this up not because it’s the greatest thing in anesthetics, but because it’s a very simple device with a very brilliant idea behind it — and it works!

But bottom line, the best thing that’s happened in local anesthesia in the last 5–10 years is Septocaine^® (Septodont; New Castle, Del.) coming on the U.S. market in 2000. It’s a really good anesthetic, but there are drawbacks to it. The simple fact that there’s so much controversy about it has stimulated people to ask so many more questions about anesthetics and how they give them, that overall, I think it’s beneficial because people aren’t just taking everything for granted anymore. Typically, people would say, “I use lidocaine for everything, except when I can’t use epi, then I use mepivacaine plain, and for long-acting, I use Marcaine.” It’s made people think about what’s out there, what’s appropriate to use, what’s safe to use and what technique should be used with it.

Q3: As a 4% anesthetic, do you avoid giving blocks with it? There’s some literature about a possible increased rate of paresthesia with Septocaine.

AB: All of the reports I’ve seen are anecdotal. There’s no real scientific study that shows that absolutely the 4% anesthetics are the cause of paresthesia, but there’s enough anecdotal material out there to make me think there is a greater risk of paresthesia using the 4% solutions, both articaine and prilocaine. I’m not hesitant to use Septocaine for blocks, when it’s indicated, except for the inferior alveolar block. I’m extremely hesitant about Septocaine for that one because we’ve seen numerous reports that the greatest incidence of paresthesia is with that injection technique and the 4% anesthetics.

But personally, I don’t choose to give inferior alveolar nerve blocks the conventional way. I prefer the Gow-Gates technique, which from all the evidence I can gather is a safer injection with any solution. I use it on a regular basis.

Q4: Say, someone’s been practicing for 15–20 years and has been giving lower blocks, and knows there’s something better but is just a little nervous about shooting that high with the Gow-Gates versus the typical target point — what do you think is the best way for a GP to learn how to do the Gow-Gates technique comfortably?

AB: The ideal way is to go to a hands-on course. Mostly you’ll find this in a dental school setting, occasionally at a larger meeting, but that’s pretty rare. Another alterative is to find a practitioner in your area who knows the technique. A lot of oral surgeons are familiar with the technique. More recent dental school grads are more likely to have been taught the technique. Watch them do it and have them observe you doing it to give you feedback as you do it. A “study club” setting like that is the ideal way to do it outside of a dental school course/CE course.

Q5: I have seen numbers published on the mandibular block stating that up to 20% of blocks are missed on the first attempt. Do you agree with that?

AB: Yes, but it always seems to go in spurts. Practitioners tell me, “I can’t miss a block for weeks and all of a sudden I’m missing every one.” I published a literature review paper some time ago and the range I saw was 63% to 86%, with some studies reporting it into the 90% range. Now that’s with the first injection. But most of us get it with the second attempt. I think the true incidence of failed anesthesia is well below 1%. But on the first attempt, I’d say 15%, plus or minus 5%, is about average.

Q6: One of the most frustrating experiences most of us GP’s have are with “hot teeth.” Any tips you can give us on accessory innervation and how to anesthetize these patients?

AB: On a mandible, of course, the No. 1 nerve to anesthetize is the inferior alveolar nerve; No. 2 is the long buccal nerve. The long buccal has been shown to have a lot of accessory innervation to the teeth, particularly the molars. When you look at the retromolar pad area, there are a lot of accessory foramina there. You may wonder, are they there for blood vessels, are they for nerves, or are they just air holes? You cannot tell just by looking at the bone. But there are a lot of holes there. By doing micro-dissection, the long buccal nerve is seen to send little branches into the bone. It’s not just the main pathway like we instructors have always taught. There are a lot of accessory nerve branches coming off all along the long buccal pathway.

The No. 3 nerve to anesthetize is the mylohyoid nerve. In anatomy, we teach that this is a motor nerve to the mylohyoid muscle at the floor of the mouth and also out to the anterior belly of the digastric under the chin. What is not taught from the anatomy literature, is that there are also pain and temperature fibers in that nerve. And those pain fibers have been tracked through micro-dissection into teeth. So yes, it is an accessory nerve pathway. All along the pathway to the mylohyoid, it is giving off little branches into the bone and many of those branches are accessory innervation to teeth.

Q7: I recall being taught that the long buccal just innervated buccal tissue, and for crown preps it was necessary, but only for soft tissue anesthesia. With all these nerves branching off, it sounds like nature is not as simple and straightforward as we want it to be.

AB: Exactly. That is a great summary. We teach the basic nerve pathways, but we probably don’t do a decent enough job of teaching that any nerve that exists in the neighborhood of a tooth is likely to be carrying some accessory innervation to that tooth. No nerve is purely sensory or purely motor. They all have a mixture. Some of those fibers are proprioceptive, but some of those are also primary pain fibers and going to tooth structures. Unfortunately for us, as dentists and dental hygienists, we have to be aware of all of the possible nerve pathways in the oral cavity.

Q8: Say, I come to your office and I need crowns on #18, #19 and #20. Walk us through exactly what you’re going to do in terms of local anesthesia.

AB: I would start with a Gow-Gates injection. It has the best likelihood of anesthetizing the inferior alveolar, the lingual, the long buccal and the mylohyoid nerves all with one injection. I’ll use a 27-gauge long needle and I’m going to drop a full cartridge of lidocaine. I could use prilocaine or Septocaine if I felt that you were a person who expressed to me that you were very hard to get numb or you had a history of getting numb but not staying numb very long, or had a history of drug abuse. Then I might use one of the “big boys,” the 4% solutions. Ideally, I’d just use lidocaine because it’s pretty safe. I find that with the Gow-Gates technique, I have a good success rate using one cartridge of lidocaine, in the upper 80s to mid-90% range. Occasionally, I will need to chase it with a full second cartridge in the same location. The one nerve that is hardest to get consistently is the long buccal. So I may sometimes have to inject that separately. With a Gow-Gates injection, I’ve never had to give a separate mylohyoid.

If you have a hot tooth, a tooth you’re going to extract or that you need to do a root canal procedure on because it’s abcessed, that’s a lot harder to get numb. I’m still going to do the Gow-Gates and then I might use an intraosseous around the tooth, or PDL injections to get it. But the Gow-Gates works well because you’re so high up on the innervation pathway. You target the anterior-medial aspect of the neck of the condyle. With the mouth wide open, the condyle translates out just immediately lateral to the foramen ovale. So you’re right next to where this whole big nerve trunk is coming in to the infratemporal fossa. If you drop your anesthetic bolus there and keep the patient’s mouth wide open — Dr. Gow-Gates recommended for a full 90 seconds after you finish the injection — you keep that bolus right there next to the nerve. If there are any accessory branches coming off of anywhere along the trigeminal nerve pathways, you’re still catching them right at the source.

Q9: How long do you wait after a Gow-Gates injection to test for anesthesia?

AB: Gow-Gates has a slower onset because you’re approaching such a large nerve trunk. The most peripheral fibers are going to the back of the mouth. The fibers at the center of that big nerve bundle are coming out to the tip of the tongue and the lip, and so you must wait at least five minutes. The study I like to quote, shows that it’s at 10 minutes when the Gow-Gates injection is really going to give you the absolute best result. Within the five-minute window I should be getting some signs that the anesthesia has taken effect, and if so I’m going to wait a little longer and double-check it for signs of full anesthesia. If I’m not getting signs after five minutes, I may conclude that I’ve missed it and give a second Gow-Gates injection.

Q10: Some esthetic clinicians are advocating the use of the anterior middle superior alveolar injection, the AMSA, because it numbs all the maxillary anterior teeth. Do you use this injection if you are working on eight anterior teeth rather than going around and giving numerous infiltrations? It seems counterintuitive, being a palatal injection. Tell us a little about it.

AB: There are actually two AMSA techniques: a facial approach and a palatal approach. The palatal injection technique is actually one that was first described in the 1920s. When the Wand first came out, they really pushed this palatal AMSA technique, but it has never really caught on. The whole principle of this technique is that rather than doing the standard facial approach AMSA injection, which is properly called the infraorbital block injection given on the face just below the eye, which is a true block, when you do the palatal approach you’re further down on the pathway of the anterior and middle superior alveolar nerves, at the junction where the vertical process of the maxilla meets the horizontal hard palate. If you take a line perpendicular to the midline palatal raphe and extend it out to where it meets the two bicuspids halfway along that line, you’ll be at that junction. Drop your anesthetic there, a small amount, very slow injection, and you’ll get anterior and middle superior alveolar anesthesia. Now, the beauty of this injection is that you don’t get lip anesthesia like you do with the infraorbital, but you do get buccal soft tissue anesthesia around the teeth. You get palatal, pulpal and buccal anesthesia so you can do work from the second bicuspid forward. It might be a little fuzzy at the second bicuspid because you’re getting a little innervation coming in from the posterior, the PSA, so I always give a little infiltration behind there as well. By the way, infiltrations on the maxilla, pretty much the only thing I’m giving these days is Septocaine. Lots of times it gives me palatal anesthesia as well buccal. Not on everybody, but most of the time.

Q11: You’re absolutely right about the Septocaine. It seems as though I can pack cord on the lingual on nearly everybody without any problems. Maybe once or twice every couple of months I am not able to and need to give a little palatal soft tissue anesthesia. So you like the AMSA injection?

AB: Well, with the palatal AMSA, you’ve got maxillary anterior anesthesia without having the lip numb, which is helpful for esthetic dentistry. But there are two drawbacks with it. One, it’s a palatal injection, so you have to give it real slow, and number two, it doesn’t have as good duration because it’s not a true block. It’s in between a block and an infiltration. For veneer cases, where you want to keep the smile line and you’re not going to be in there very long, it’s a real efficient way to do it. But if you’re going to be doing crown preps from bicuspid to bicuspid, in my opinion, I’d rather use the infraorbital and the nasopalatine.

Q12: So you’re going to be giving an infraorbital and a nasopalatine if you are doing crowns from second bicuspid to second bicuspid? As opposed to giving eight infiltrations over those teeth?

AB: Yes. I want blocks. As a rule of thumb a block will give you twice as long a duration of anesthesia as an infiltration. That’ll depend a little bit on your anesthetic and other variables. But if you want hemostasis, if you’re gong to be doing root planing or surgery or subgingival preps, anything where you know you’ll be getting some bleeding, I will do local infiltration using ideally lidocaine with 1 to 50,000 epinephrine. That one little infiltration will give me a great deal of hemostasis in a localized site. If I use 1 to 50,000, for an IA block, my anesthesia will be about the same duration as 1 to 100,000, but it won’t give me good hemostasis. So for blocks, I want to use as low a concentration of vasoconstrictor as I can. For example, Septocaine now has the 1 to 200,000 epi solution available and there are a number of studies now, which are all quite similar, that there is no significant difference in duration. It’s a little bit shorter duration with 1 to 200,000 than 1 to 100,000, but clinically it’s not really significant. So why not use the safest one with the lowest concentration? But if I am going to use it for hemostasis as a local infiltration, I am going to use the highest one I can get my hands on.

Q13: I have to tell you that I don’t know any of my friends who are giving infraorbital injections with a nasopalatine for anterior crowns like that; I think most of them are still giving eight infiltrations. Do you think there are a lot of GP’s using your technique?

AB: No.

Q14: Can you explain to me how exactly you do it? Or do you even recommend that the average GP does this?

AB: Absolutely, I have no hesitation. So what you do is feel the lower rim of the orbit. You feel for the lowest part of the rim, but it’s not right in the center. It is actually more toward the base of the nose. Drop your finger down 1 cm below that rim and your finger is right over the foramen. And with many people, if they’re a little bit thin there, you can press and they can feel a little bit of nerve tingling. So you are right over the foramen. Keep one fingertip there and I take my other fingertip, usually my thumb, and slide it up into the top of the maxillary vestibule in the area of the cuspid to bicuspid. That distance between those two fingertips is going to be the depth of my penetration of the needle.

Q15: I am doing it on myself as you talk, and it doesn’t feel very deep. It feels like a quarter-inch or a half-inch to me.

AB: Yeah, for most people it’s less than 10 mm, less than a centimeter. So it’s not a big deal. So then I’m going to insert a needle up into the top of the vestibule paralleling the slope of the maxillary bone there until I feel that needle right up underneath my fingertip that’s outside over the foramen.

Q16: So where’s the puncture point in relation to the crowns on the teeth?

AB: I’m coming in really more over the bicuspids. I use a little more posterior approach because it’s more comfortable — you know, away from the midline. The technique I was taught in school, you came in over the lateral to cuspids, and that brought you in close to the base of the nose, and patients always feel that, so you go further posterior and it’s not as sensitive. I’m coming into the vestibule over the bicuspids and paralleling the bone until my needle is in about a centimeter so it’s right up underneath my fingertip. I stop, aspirate, drop my bolus of anesthetic and then, with that same finger that’s been outside the mouth the whole time, I just massage the bolus into the foramen. I give the injection with the patient lying down and I keep the patient lying down. Then that anesthetic is either going to dissipate into the soft tissue or it’s going to flow down into that foramen.

Q17: How often do you get a positive aspiration on that infraorbital injection?

AB: Not very often. There are little blood vessels there, but they’re small enough to be of little consequence. And I give it slowly. I give all my injections very slowly. To me it’s all about patient comfort, but it’s also about safety. If I see any blanching there, I’m giving it too fast. I shouldn’t see that.

Q18: So when you successfully give the infraorbital block, what gets anesthetized?

AB: It’ll anesthetize the lip, the buccal soft tissue and the pulps of the anterior teeth cuspid to central. It won’t get palatal soft tissues and it may or may not get the pulps of the bicuspids. So I may have to infiltrate over the bicuspids in some cases, maybe 25% of the time.

Q19: Do you think it’s safe to say that in dental school 50 years from now or in general practices 50 years from now that the Gow-Gates might be the routine and the IA blocks kind of the thing of the past?

AB: It could be, but I honestly don’t think of it in those terms, Mike, because to me, I want to know as many tricks as possible, if “tricks” is the right word. No two people are put together the same, and there are always these oddball situations where it helps to know different techniques. The conventional IA technique has been around since the 1880s; it’s got a good track record. You know, I started using the Gow-Gates initially because when my regular lower block didn’t work, I wanted a backup technique. And the Gow-Gates technique usually worked. Then I started reading about it and I was seeing the higher success rates in the literature, and I thought, if this is so successful, then why don’t I do this all the time and use the other one, the conventional technique, just when I need to for an alternative? And so now I almost exclusively use the Gow-Gates. But I think it’s good to know all the techniques. That’s my opinion.

And another troubleshooting tip is that I advocate caution giving additional inferior alveolar injections if the first one doesn’t work. If I give an inferior alveolar nerve block conventional technique, I was taught, if you didn’t get it the first time, to go a little higher and little deeper the second time, and, you know, it usually worked.

Q20: By higher, by deeper, do you mean to the hub, or do you mean medially versus laterally? What do you mean by deeper?

AB: Well, that’s a great question because you are never quite sure what people are referring to when they say that’s what they do. By going a little bit higher, I’m talking about a quarter of an inch at the most higher up on my thumbnail at the anterior border of the mandible. As far as deeper, what I’m referring to is a slightly more posterior injection site, not necessarily going in deeper with the needle because the bone should still be in the same place, so it’s just that my injection site is slightly more posterior than my initial one.

But what I’ve found reading the literature is that that higher and deeper technique also led to increased incidents of positive aspirations. I don’t really want to be more successful with anesthesia at the risk of causing more bleeding. And that again is what led me to look more closely at the Gow-Gates.

I didn’t start out using the Gow-Gates — I started out using it only for backup, and the more I used it, the more I got comfortable with it. Everything points to it being safer, being more effective, being more efficient, and that’s why I’m a big believer in it now.

Dr. Michael DiTolla: I’ve learned some great stuff today, and if we just inspire one or two people to take a look at their local anesthetic procedures, and they can add a new technique that will keep a patient comfortable while they are having dentistry done, I think we’ve done our job. I look forward to taking your cadaver course at the CDA meeting, and thank you so much for your time today.

AB: My pleasure, Mike — I enjoyed talking with you.