Everyone who's experienced their first “stab lab” knows that
injections can be nerve-racking the first few times around. There is a lot
going on and, when you have a real patient in the chair, the complexity of the
situation increases even more. In order to successfully practice “pain-free dentistry,” it is essential that
you learn to be systematic and consistent in your local anesthetic
The inferior alveolar (IA) nerve block is arguably the most
critical injection to master, as it is more technique-sensitive than simple
It must be used anytime invasive dentistry is being performed anywhere on the
mandible. Even for experienced dentists, achieving profound anesthesia with an
IA can be less than straightforward—with failure rates ranging from 5% to 30%
depending on the design of the study1
It is imperative that you are well-acquainted with intraoral
anatomy if you are to be successful in administering an effective IA block.
However, this will only get you so far, as every patient varies anatomically.
For example, if you are attempting to administer a block on a patient with
drastically flared mandibular rami, there will be a certain amount of impromptu
adjustment required before you will be able to locate the mandibular foramen
and deliver the anesthetic.
Here are some tips to help you perform a successful and
comfortable IA block:
is key. Do not put a needle in the patient's mouth until you have palpated and
identified the key anatomical landmarks.
A.Palpate the mid-coronoid notch. This landmark
determines the level on the axial plane at which you will insert the needle.
B. Palpate the pterygomaxillary raphe. Insert the
needle just lateral to this border, at the level of the notch.
that the window of the syringe is facing towards you. If not, you will be
unable to visualize aspirate.
that the bevel of the needle is towards bone. If you are not depositing your
anesthetic towards the mandibular canal, you will have a lesser chance of
delivering enough anesthetic to properly block the nerve.
aware of your angulation. Start out with the barrel of your syringe just over
the contralateral mandibular premolars, just above the occlusal plane. In many
cases you will have to adjust the angulation, but this is the most reliable
forget to aspirate prior to injecting! Never inject without first achieving a
negative aspiration. You DO NOT want to inject the local anesthetic
comfort is the main goal. You can perform a perfect injection, but if the
patient is in pain the entire time they will not appreciate it. Stable and
gentle needle control and tugging on the cheek during administration will help
keep the patient comfortable.
It’s my hope that you’ll keep this advice in mind and be a bit
more confident the next time you deliver an IA block. Also, always keep in mind
that a calm and collected demeanor goes a long way in assuring your patient
that there is nothing to worry about. Happy anesthetizing!
M. The missed inferior alveolar block: a new look at an old problem. Anesth
Prog. 1984 Mar-Apr; 31(2):87–90.