Inferior alveolar nerve blockLet's say you are to restore # 19 with an MO composite restoration so you have given a 2% Lidocaine 1:100k epinephrine inferior alveolar nerve block to the patient. After 10 minutes of waiting, you start the prep on the tooth and the patient reports pain. What would be the approach of choice to establish profound anesthesia?

Depending on the design of the study, the reported failure rate for inferior alveolar nerve block ranges between 5 to 30 percent.

So if you numb three to five patients with inferior alveolar nerve blocks on any given day, the statistical probability of running into this problem happens almost every other day.

(Click here to learn more about the steps to take after the inferior alveolar nerve block for soft-tissue anesthesia.)

That is a significantly frequent occurrence and it would help to improve on the success rate.

In the example above, what could we do? Let’s consider the following:

Anesthetic: While it is a common belief that articaine is more effective than lidocaine, no research has been able to demonstrate the advantage.1

Elapsed time: Onset of lip anesthesia takes about four to six minutes and pulpal anesthesia onset takes 10 to 15 minutes. Often doing nothing more than waiting an additional amount of time is all that is needed for adequate anesthesia to take effect.

Missed injection: If there is no lip numbness even after 10 minutes, it is likely that the location of injection was incorrect and another injection should be attempted.

Supplementary injection: If lip numbness is present, buccal infiltration in #19, #20 with Atricaine 4% would be the next step.2

Use buffered anesthetic: Recently there has been a new product in the market, which allows for convenient alkalization of lidocaine right before injecting.3 Buffered anesthetic hastens the onset of anesthesia. So if you have deposited the anesthetic in an incorrect location, you will be able to detect this quicker. Besides, buffered anestehtic can make the injection less painful for the patient.4

Use of a timer: The moment you pick up the syringe to inject the patient, have the assistant start a timer. Its amazing how much this objective consistent measurement of time helps with the anesthesia procedure.

  • It helps to slow down the speed of injection. Injecting a 2 ml volume of solution over one minute is the ideal speed to ensure patient comfort and improve success.5
  • Timer helps to objectively quantify wait times after the injection.
  • If the patient is not numb in the first five minutes and one needs to wait another 10, there is an objective measurement possible.

Technique: Two most common causes of a missed injection are:6

  • Positioning the tip of the needle too far medially resulting in inadequate anesthesia.
  • Positioning the tip of the needle too far inferiorly resulting in anesthesia of only the lingual nerve.

Ideally, one would expect to hit bone at around 20–25 mm of needle insertion. While in both of the above types of errors, most likely, one would not have hit bone. When injecting the second time, it becomes even more crucial to feel for the bone. Often choosing the point of needle insertion, which is more lateral and higher than the first insertion point, helps. During the process if you hit bone too soon you have to just retract slightly and redirect the needle a little to the medial. In this manner as the needle is advanced you have an assurance that the needle is just lateral to the medial surface of the ramus and you avoid the needle from going too far medially.

Intraosseous injection: When this first line of management fails, an intraosseous injection would be the approach of choice. Some studies would suggest that intraligamentary injection could work just the same but intraosseous injection seems to be more effective.

Resources

1. Mikesell P, Nusstein J, Reader A, Beck M, Weaver J. A comparison of articaine and lidocaine for inferior alveolar nerve blocks. J Endod. 2005 Apr;31(4):265–70.

2. Haase A, Reader A, Nusstein J, Beck M, Drum M. Comparing anesthetic efficacy of articaine versus lidocaine as a supplemental buccal infiltration of the mandibular first molar after an inferior alveolar nerve block. J Am Dent Assoc. 2008 Sep;139(9):1228–35. Erratum in: J Am Dent Assoc. 2008 Oct; 139(10):1312.

3. Onset by OnPharma

4. Kashyap VM, Desai R, Reddy PB, Menon S. Effect of alkalinisation of lignocaine for intraoral nerve block on pain during injection, and speed of onset of anaesthesia. Br J Oral Maxillofac Surg. 2011 Dec; 49(8):e72–5. doi: 10.1016/j.bjoms.2011.04.068. Epub 2011 May 18.

5. Kanaa MD, Meechan JG, Corbett IP, Whitworth JM. Speed of injection influences efficacy of inferior alveolar nerve blocks: a double-blind randomized controlled trial in volunteers. J Endod. 2006 Oct; 32(10):919–23. Epub 2006 Jul 7.

6. Milles M. The missed inferior alveolar block: a new look at an old problem. Anesth Prog. 1984 Mar-Apr; 31(2):87–90.

Vivek Mehta DMD, FAGD, Visiting Faculty, Spear Education. Follow him on Twitter @Mehta_DMD. 


Comments

Commenter's Profile Image Pierre Morin
May 22nd, 2013
If necessary I will use Carbocaine 3% without epi with articaine1:200 000. It is said that epinephrine blocks the anecthetic which is contradictory but epi is used to prolong the anesthetic effect.Using an anesthetic without epi will dilute the effect of epinephrine and you then get a more profound anesthetic effect. Plus the way the inferior alveolar block is tought in school is another story... Very rarely the use of Gowgates is apropriate
Commenter's Profile Image Vivek Mehta
May 22nd, 2013
Pierre Morin Thanks for the comment. There is a clinical trial underway which compares the efficacy of the protocol which you have suggested. http://clinicaltrials.gov/ct2/show/study/NCT01574807 Another study : link http://www.ncbi.nlm.nih.gov/pubmed/8509754?dopt=Abstract An evaluation of 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. Found : " ........no statistically significant differences in onset, success, or failure were found among the solutions. We conclude that the three preparations are equivalent for an inferior alveolar nerve block of 50-min duration". Again, Thank you for the comment.
Commenter's Profile Image Kay Henry
May 23rd, 2013
Mel Hawkins is a genius on this topic. What I learned from him is to give 1/2 carpule of an Akinosi after 1 minute topical anesthetic. Set the timer for 3.5 minutes. This injection is fairly painless and closed mouth which is essentially a deep topical that allows you to painlessly get to bone on your next injection and find your proper landmark without the worry of hurting the paitent. Give an additional 1.5 carp of a Gow Gates and wait additional 10 minutes. Set the timer. Don't inject unless you are on bone. This technique has changed my life; I never miss a mandibular block, rare occasion one additiona carp is needed on those "hard to numb" patients. He says no more than 3 total carps should be used ever; wouldn't be effective anyway due to the ph. We also give almost all our patients Advil after their procedure so they stay comfy the rest of the day. Longer procedures we give them an additional packet of Advil to take with them for later. All mandibular blocks can make the patients achy for 1 to 2 days. Mel says Articaine is safe to use; this is, of course, hotly debated. It took me about 20 injections to get confident with this but I have used this technique for years now. Don't be afraid of the Gow Gates; it's a fabulous injection if done right. Mel claims that there is a lower number of cases of parasthesia than IAN.
Commenter's Profile Image Gerald Benjamin
May 23rd, 2013
The older that I became the more profound the anesthesia has become. My protocol: 1 Carp Citanest Plain followed by 1 carp xylo w epi. If no effect then 1 carp xylo w eli using the Gow Gates approach and Articaine w eli as an infiltration. This covers 99.9% of all situations. If this fails: a glass of Phelps Insignia (Napa)
Commenter's Profile Image Barry Musikant
May 23rd, 2013
Everytime I give an inferior alveolar block, I also give an intraosseous injection using the PeriPress via the ligament. It works 100% of the time and the onset is almost immediate. I save time and know I will not lose an appointment because of inadequate anesthesia. I would give this injection alone, but it seems to work for about an hour. My endodontic appointments are generally longer than that and I don't want the patient in any discomfort by the end of the procedure. Even a poorly given inferior alveolar block will have at least some effect within 45 minutes and that will cover the period when the effective but shorter acting intraosseous injection loses its effect. I would also add that the depth of anesthesia is greater with the intraosseous injection than the inferior alveolar. Regards, Barry
Commenter's Profile Image Lee Krahenbuhl
May 30th, 2013
The Gow-Gates will usually work.
Commenter's Profile Image Vivek Mehta
June 3rd, 2013
Thank you Barry for your comment. I am a big fan of your work. It was a pleasure and an honor to see your comment. You must have a great technique to get that kind of success.
Commenter's Profile Image Roger Briggs
June 24th, 2013
I have been using the Wand by milestone scientific for years. I have up graded all of the units that we have in the office now with the STA (single tooth anesthetic) model. I can not endorse them enough. The STA can be used routinely to do single tooth anesthesia, even for single crowns. The beauty of the system is that when the block does not get profound anesthesia I know almost with out doubt that I can put on the short needle and another carpule of lido and by the time I place 1/4 to 1/2 of a carpule I can put it down go right back to work
Commenter's Profile Image Roger Briggs
June 24th, 2013
I would add that the risk of a reaction to the local is far less that an I/O which is equivalent to an I/V of local.
Commenter's Profile Image David Slaughter
July 25th, 2013
The STA is wonderful for those difficult to numb patients. A missed mandibular block is the most stressful situation I encounter as you can sense the stress of the patient. I've used the STA on people with a history of never having adequate anesthesia with great success. They have become great patients now, and neither of us have to stress about their appointment. they don't have the post-operative discomfort of a traditional pdl injection.
Commenter's Profile Image Vivek Mehta
July 28th, 2013
David and Roger: Thank you for posting your comments. It is very helpful for all the readers to know about your success with STA also known as CCLAD (Computer Controlled Local Anesthetic Delivery) http://bit.ly/14qSYCK The relevant follow up question would be what makes CCLAD/STA successful? Part of the answer must be the slow speed of anesthetic delivery? What else.....? Would love to hear. Thank you!
Commenter's Profile Image Larry Langer
August 17th, 2013
I totally agree with Barry. I use 3% Carbocaine for inferior nerve block, than immediately give intraligament injection with 4% septocaine. Patient is ready to go almost immediately, although on rare occasions i will re-inject a block. works for all my operative, and C&B procedures like a charm. BTW, great for hemostasis as well.
Commenter's Profile Image Dr.Haroon
November 29th, 2013
Good&informative interaction after an embarrasing mandibular block failure with ones patient.
Commenter's Profile Image Laura Fauchier
December 8th, 2013
I have been using the STA for years and have to second the positive comments. I have several patients who had never known what it was like to have dental work done without pain until they came to me. It really reduces stress in the office when we know that a failed IA block can be corrected almost instantly with STA. And to answer the question about why it works, the machine offers feedback to assist in proper placement of the anesthetic tip in a successful location. If you haven't placed the syringe tip in a spot where its going to be effective, you don't get the same beeping sounds from the machine, thus allowing you to try another spot until you find success. If you choose to purchase STA units keep in mind there is a learning curve!
Commenter's Profile Image Wes Blakeslee DMD
January 11th, 2014
Regarding the STA technique, an added benefit that I've found is that for those difficult lower posteriors on patients who cannot tolerate epi, I've never had a so-called epinephrine rxn to STA with 2% lido 1:100,000. Straight carbocaine never seems to deliver profound anesthesia either in depth or duration, so piggy-backing STA to carbocaine can be a nice option.
Commenter's Profile Image GREG
April 11th, 2015
I have used STA on many occasions with good success but some patients have reported ulceration of the gingiva at the injection site, despite careful administration of the local anaesthetic!! Any thoughts or comments on this?
Commenter's Profile Image Kim
May 12th, 2015
Greg- in regards to your comment on reported ulcerations after STA...we experienced this for awhile until we went back and discovered that we were not using the recommended anesthetic. According to the training videos you should only use Lidocaine HCI 2% with Epi 1:100,000. I have never noticed or had any reports of an ulceration since.
Commenter's Profile Image Cynthia B.
December 9th, 2015
I have also used The Wand or STA for over 20 years. There are no longer any cold barrelled syringes in my office! I have used this device with GREAT success. I do think part of the success is the speed of the administering of the anesthetic. For a patient that has had a history of missed blocks, I can overcome this is by using the MULTI BARREL button (1 3/4 carpules of 2% 1:100,000 Lidocaine) which allows me to keep the needle in the site while my assistant reloads for me. Also the benefit of the STA allowing me to treat both #19 and #30 at the same visit for example, is key. I look forward to administering the anesthetic especially to a new patient because there is always a WOW! associated with it that makes my day. Lastly, the administering of the anesthetic is less taxing to my hand.