Golden Nuggets:Top Tips for IDBS with Christine MacLeavy

I remember asking my clinical director (on behalf of the Oxford Deanery) if she would be happy to undertake extended duties training in ID Blocks back in 2003! Thankfully she agreed (her IDB's nearly always worked first time and the patients....all children and adults with special needs hardly ever complained).

As I facilitated these extended duties courses on behalf of the deanery, I sat through the lecture eight times, at eight different venues and was demonstrated on... eight times!

My first IDB refresher was a couple of years after completing my extended duties. It was at Stoke Mandeville Post Grad Centre with Wayne Williams.

When we went around the room introducing ourselves, it appeared that there was only one other therapist there, the rest were dentists!

Wayne then asked each of the group why we were there and what percentage of our IDB's failed or did not get the patient numb enough! The consensus was about 30-40%! Wayne then asked me - 'Well in the couple of years I've been doing them’ I said, ‘I've have one not work!'

He asked me how many I did per week - I said it varied but I gave local a lot and IDBs pretty much daily! Plus supervising students every Thursday at the Eastman School of Dental Hygiene and Dental Therapy!

Since those early days of IDBs to date I have been picking up tips and learning from other dentists including Mike Gow on the PG Diploma in Hypnosis Applied to Dentistry and Chris Bell from Bristol. So I felt highly honoured to be asked to write this piece!

So, these are my top tips based on what I have learned, coupled with my experience as a clinician and teaching others:

Prepare your patient
Preparation is vital. This may all seem really obvious, but it’s so important I am going to state it all anyway!

Has the patient experienced LA before? Either way some explanation is necessary, either simply to inform patient or to allay fears and dispel myths! 'No, the needle isn't that long!' – (as patient demonstrates something that equates to a good six to twelve inches!!)

Explain what you are going to do, what it will feel like (eg ‘fat and funny) and how long it will last and what areas will be affected. Make sure you are using language appropriate to the age and understanding of the patient!

Check medical history/medication/ recreational drugs? Yes, every time! Boring I know but extremely important. Unfortunately we are more reticent to ask about recreational drugs, yet it is import to ascertain as someone using cocaine for example, will be more prone to arrhythmia.

Choose your local anaesthesic agent - lidocaine is still the gold standard for IDBs; suitable for anyone over the age of two (weight dependent).

There has been a longstanding debate about the use of Articaine for IDBs. According to some, Articaine may be more toxic to the nerve tissue and the risk of parasthesia higher (about the same as Citanest).

While there is debate about the risks of Articaine for IDBs, with some saying the risk is realistically no greater, many choose to avoid it anyway - just in case/ When you consider the fact that it has been suggested that Articaine is no more effective for IDBs than other anaesthetics anyway, it begs the question why you would use it anyway.

Some clinicians suggest using Articaine infiltration for lower teeth rather than a block.

This may work in some cases, but due to the density of the mandibular bone, success can vary between individuals. My preference is to go for a block with lidocaine every time! Using Articiane with the Wand STA can however mean that IDBs, and ‘collateral numbness’ can be avoided in some cases.

Whatever anaesthetic you choose- be aware of the dose limits. These vary depending on the anaesthetic, it’s concentration and presence of epinephrine (adrenaline). A recent article on maximum doses can be read here: http://onlinelibrary.wiley.com/doi/10.1111/anae.12679/pdf

The injection
Look for and identify the landmarks- pterygo mandibular raphe, buccal pad of fat, retro mandibular triangle and feel with your thumb for the coronoid notch.

Apply topical on the end of a cotton wool roll (CWR) and get the patient to bite on CWR thereby holding between teeth -then wait! Lidocaine topical can take 2-4 minutes to work!

Remove the CWR and any excess topical

Ask the patient to open as wide as they can - the wider they open the more comfortable they will be. Get good retraction and pressure with the thumb of the no- injecting hand, push firmly with thumb and support the jaw with the rest of your fingers.

Sometimes it is a good idea (especially with anxious patients) to do a little rehearsal with the cap on the syringe prior to actually injecting - helps to prepare patient and gauge their reaction.

At point of penetration - get patient to open their eyes (distraction). Instead of being internally focused with eyes closed their senses are swamped with light, and shade and colour! This rehearsal and distraction technique is outlined in a case study by Mike Gow and can be read at http://bscw.rediris.es/

Advance wide bore, long needle to 3/4 of its length - it is not necessary to hit bone (this actually damages the bevel of the needle).

Deposit 3/4 of the solution, withdraw to half the length of the needle and deposit the final quarter (lingual nerve and lingual mucosa).

Push firmly with the thumb of the non-injecting hand to prevent drag and a 'ping' of the tissues as the needle is removed!

Massage with thumb (This may be partially psychological - the pushing sensation the patient feels is then related to your thumb and not the injection but the massaging is likely helping disperse the anesthetic into the foramen)

Wait a good 5 minutes - use this time to chat to patient, give OHI, explain length of analgesia etc

If lip is tingling – it is a good sign! I personally would wait up to 10 minutes before giving another block as it can take as long as this to work for some people.

If I do another- it is a back to basics moment, re-establish my landmarks, make sure my retracting thumb is in the right place. I often use my retracting thumb as a landmark - bisecting my thumb, (providing it is in the right place) is also a good indicator that you are in the right place!

I often tell students that if they are sure of their landmarks and have hit bone too soon, they either have to come out and try again or use the indirect approach.

Case Study
One interesting adaptation I’ve adopted along the way was a two injection - short needle and long needle approach that I learned from Chris Bell!

I had a patient with Reflex Anoxic Seizure. She was referred to CDS as whenever she experienced pain she collapsed- and her heart stopped for approximately 3 minutes before restarting! She was understandably terrified of dentistry! My clinical director suggested some hypnosis with me in the first instance. She was 16 years old and was happy to try, and after a few sessions of hypnosis which included ego strengthening and desensitization - we reached the point where she was ready to have her filling done. On a lower 6! I had also used Mike Gow’s ‘Six Step Needle Desensitisation’ which I mentioned earlier.

I applied the topical anaesthetic as usual but then used a short needle and mepivacaine plain to inject half a cartridge (as if giving a block but only to half the depth of the needle)

The anaesthetic was left to work for five minutes. Then with a long needle and lidocaine an IDB was given as normal.

The mepivacaine successfully anaesthetised the area that the ‘long’ needle will travel through and as it has a closer pH to the tissues it was therefore far more comfortable.

In this case, it worked well and the patient had her restoration carried out with no pain or discomfort.

I have successfully used this approach for several really anxious patients. One of the problems treating anxious patients is that they can have a high expectation of pain and therefore can become hypersensitive, which of course results in them feeling tense instead of relaxed. It becomes a vicious cycle and a self-fulfilling prophecy.

I run LA refresher and IDB courses for Hygienists and Therapists (although dentists do also attend and enjoy the relaxed approach). It is always good to have dentists in the group as many hygienists and therapists feel terrified about giving IDBs and it can be reassuring for them to accept that we all lose a bit of confidence at times and attending a refresher course is a great way to regain that confidence and refresh our knowledge.

Christine MacLeavy