Dentaltown April 2018 - 95

continuing
education
Abstract
The inferior alveolar nerve block has the highest
failure rate not only in dental local anesthesia, but also
among all local anesthetic blocks in medicine. The
"accessory innervation to the inferior alveolar nerve"
theory supports the idea that incidents of unsuccessful
anesthesia may result from innervations of the adult
mandible arising from the cervical plexus in addition to
the auriculotemporal, buccal, mental, incisive, mylohyoid
and lingual nerves. Hence, to achieve profound pulpal
anesthesia in the posterior mandible, an accessory
innervation anesthetic protocol that anesthetizes all the
accessory nerves has been clinically proposed. Three
different accessory innervation anesthetic protocol
approaches are described in this article, as well as how
to overcome pulpal anesthesia failure by implementing
the intraoral cervical plexus anesthetic technique. This
protocol will help alleviate patients' fear to the dental
chair while improving our profession's reputation.

Educational objectives
After reading the article, participants should be
able to:
1. Understand the problems associated with anesthetic failures in permanent dentition with the
use of currently available anesthetic techniques.
2. Identify how accessory innervation may play a
pivotal role in the high percentage of anesthetic
failure on the posterior mandible.
3. Comprehend the cervical plexus nerve description and distribution in the mandible.
4. Recognize how these variations of anatomy allow
for clinical decisions for implementing supplemental anesthetic techniques.
5. Administer the intraoral cervical plexus anesthetic technique to their patients.
6. Provide the accessory innervation anesthetic
protocol to their patients.

Introduction
Achieving adequate pulpal anesthesia provides a
great first impression and the foundation for building a
great patient/dentist and specialist/referral relationship.
Traditional methods to confirm mandibular anesthesia
usually involve:

Asking the patient, "Is half of your tongue numb?
Is your lip numb?"
* Testing soft-tissue responsiveness to a sharp
instrument.
* Or simply commencing with treatment.
The presence of soft-tissue anesthesia does not
adequately indicate pulpal anesthesia. This is in contradiction to the traditional view when compared with
the maxillary arch.1
The inferior alveolar nerve (IAN) block has the
highest failure rate not only in dental local anesthesia,
but also among all local anesthetic blocks in medicine.2
Previous research illustrated several explanations for
this failure, including patient anxiety, central core
theory, lowered pH of inflamed tissues, nerve-altered
resting potentials, tetrodotoxin-resistant (TTXr) class
sodium channels, anesthetic composition, recreational
drugs, Ehlers-Danlos syndrome and having red hair,
among others.
Based on the above information, why can a patient
with anxiety, lower pH of inflamed tissues, TTXr sodium
channels and red hair be anesthetized for a medical
procedure or for a root canal in the posterior maxilla,
but not for a root canal in the posterior mandible?3
Although the use of local anesthetics dates back to at
least the 1800s, their routine application for dental
work in modern times has not alleviated this anxiety.4
From an estimated 1.96 billion anesthetic cartridges
used each year worldwide, anesthetic failed in 13 percent
of injections overall (n = 254.8 million), with 88 percent
of those (n = 224.22 million) occurring with the IAN
block. In endodontics, it has been reported that as much
as 45 percent of IAN block fails, especially in mandibular
molars with symptomatic irreversible pulpitis. In addition,
failure rates of 10.7 percent for IAN and 17.8 percent
for Akinosi technique in permanent dentition during
lower molar extractions have been established, as well
as lack of success at a rate of 14.2 percent with the IAN
during implant drilling and suturing on the edentulous
posterior mandibular ridge.2,5 No wonder that patients
in 2018 still believe that dental procedures will cause
them pain!
Accessory innervation (AI) from mental nerves and
branches from the mylohyoid have also been implicated
as a potential reason for anesthetic failures.6,7 In the

Disclosure:
The author declares that neither he nor any member of his family has a financial arrangement or affiliation with any corporate organization
offering financial support or grant monies for this continuing dental education program.

APRIL 2018 // dentaltown.com

http://www.dentaltown.com

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