Dentaltown July 2017 - 107

buffering also raises the inherent pH of the local anesthetic toward
physiologic pH, reducing the discomfort often associated with
dental injections. Recent meta-analyses of the available research
concluded that buffered local anesthetic solutions are associated
with a statistically significant decrease in pain of infiltration,
compared with unbuffered local anesthetic solutions. The addition
of a concentration of 8.4 percent sodium bicarbonate to local
anesthetic solution, regardless of presence of adrenaline and local
anesthetic concentration, is enough to buffer the solution without
risk of precipitation.
Though the act of buffering local anesthetics has been in the
literature for years, most of the time this buffering was achieved
by drawing local anesthetic solution from one vial or carpule and
then pulling a bolus of buffering solution from another vial and
mixing by hand. Clinically, this is effective in administering a
buffered solution of anesthetic, but it was laborious and requird
two different individual sources: one for anesthetic and one for
buffering solution.

The Anutra System
The Anutra System from Anutra Medical is a self-contained
system of 2 percent lidocaine and 8.4 percent sodium bicarbonate,
which is mixed in an ergonomic dispenser by a system that includes
everything from the buffering materials to the syringe and needles.
A closed-circuit internal mixing cartridge draws the optimum
amount of buffering solution into each milliliter of anesthetic
solution desired. The syringe is placed on the port, and buffered
anesthetic is drawn into the hospital-type syringe. The doctor is
now ready for administration (Fig. 3).
Another advantage of this system is the ability to draw up to
6ml into the syringe. This alleviates multiple carpule changes in
cases that require three carpules or less.

technique (1.0cc) and a separate long buccal block (0.5cc).
The patients were not told which type of anesthetic was being
used for each side. A digital timer was started after completion
of the administration of anesthetic for the Gow-Gates block and
before the long buccal injection was administered.
To negate any technique or injection accuracy differences (the
clinician is right-handed) to either side, the delivery of anesthetic
with either buffered or nonbuffered solutions was alternated between
sides for every patient.
The study consisted of 20 patients, with a total of 40 mandibular
blocks given. The patients were asked to signal when they "felt"
numb on their lips and chins. The numbness was verified with a
tactile test of a cotton wisp in the area innervated by the mental
nerve (Fig. 5, p. 108).
Eighteen of the 20 patients were adequately anesthetized with
a single injection. If readministration of anesthetic was necessary,
the patient was excluded from data collection. It is pertinent to
note that in both patients who fell into this category, the failure
occurred in the nonbuffered side.
Once anesthesia was attained, the patients' mandibular third
molars were extracted. In none of the patients who were adequately
anesthetized was a readministration of anesthetic necessary to
complete the procedure.

Discussion
From the collected data, the use of buffered anesthetic appears
to enhance the speed of anesthesia onset when delivering IAN
Blocks. In this study, potential extraneous factors were removed
and anesthesia of the area innervated by the mental nerve was an
adequate indication of IAN anesthesia. This was confirmed by the
Fig. 4: Peripheral innervation of the mental nerve

Materials and methods
A single-blind, split-mouth protocol was used for this in-office
study. All patients in the study presented for bilateral extraction of
mandibular third molars. They were informed that I would be using
two different anesthetic formulations and each would adequately
anesthetize the area, but no mention of the differences of expected
onset were discussed.
A 1.2cc injection of 2 percent lidocaine with 1:100K epinephrine
from Cooke-Waite was given, utilizing a Gow-Gates technique
(Fig. 4).
Approximately one-quarter of a carpule (0.5cc) was then used to
deliver a long buccal block. On the contralateral side, a 2cc draw of
anesthetic was used to deliver an IAN Block utilizing a Gow-Gates
Journal of Clinical and Experimental Dentistry

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