“Doc, can I have more Novocaine? I don’t feel very numb.” It is nice to feel numb before dental surgeries! Have you ever been in a situation in which you had difficulty getting numb?
Local anesthetic is effective in most situations, however approximately 15% of dental patients experience a partial or total lack of numbness after receiving anesthesia injections. This phenomenon usually occurs in the lower jaw, when mandibular bone is too dense for infiltrated anesthetic injections to take, unlike the upper jaw which can receive the anesthetic solution easily. The dental nerve within the lower jaw is essentially buried within the dense bone itself, so it requires a mandibular block injection for proper numbing (numbing which includes the teeth, tongue and lips in the same quadrant).
Variations in the anatomy of the “entry window location” (where the mandibular injection deposits its solution) makes it difficult for some people to receive proper numbing, even when the dentist follows the usual landmarks – don’t blame the dentist right away if your anesthesia doesn’t work! The physiology of each individual varies besides the anatomy, which will lead to different thresholds or reactions to various dental injections. Different dental injection solutions also gives different numbing effects – your dental professional should choose what is most applicable to your situation, usually epinephrine (the blood vessel constrictor) is added to give a better local numbing effect.
Speedy injections or anxious patients can cause a racy heart beat, which could be very uncomfortable. If you’ve had too many cups of coffee or if your blood sugar is low from having not eaten, you may feel uncomfortable after receive the dental injection. The wine from last night can also alter the effectiveness of the numbing. This all makes anesthesia a very delicate science. The technique of the operator (the dental professional) can occasionally be at fault for improper anesthesia, but more likely than not it is a complication with a patient variable. It is important for you to communicate with your dental professionals if you’ve had a history of difficulty with dental anesthetics.
Special oral local anesthetic techniques, such as intraosseous anesthesia, which can enhance deep pulpal anesthesia, may help to increase the numbing sensation. This process injects novocaine directly into the bone marrow – because the needle penetrates the hard cortex of the bone, it penetrates to the jaw’s deepest level and can adequately numb the site. It is important to remember that every mouth can be anesthetized, however because intraosseous anesthesia is considered a specialized procedure, it is important to find a dental professional who is experienced with such techniques.