Faster onset and more comfortable injection with alkalinized 2% lidocaine with
epinephrine 1:100,000.
Author(s): Malamed SF(1), Tavana S, Falkel M.
Affiliation(s): Author information:
(1)Herman Ostrow School of Dentistry, University of Southern California, Los
Angeles, California, USA.
Publication date & source: 2013, Compend Contin Educ Dent. , 34 Spec No 1:10-20
BACKGROUND: The pH of lidocaine with epinephrine in dental cartridges ranges
between 2.9 and 4.4. In this pH range, less than 0.1% of the anesthetic is in the
de-ionized or "active" form. The acidity of the anesthetic may delay onset and
contribute to injection pain.
OBJECTIVE: The study compared anesthetic latency and injection pain for
alkalinized versus non-alkalinized anesthetic in inferior alveolar nerve blocks
(IANBs).
METHODS: The study buffered the anesthetic directly in the cartridges using a
mixing pen device. The study included 20 participants, each receiving one control
and one test IANB injection. The control solution was non-alkalinized 2%
lidocaine/epinephrine 1:100,000 at pH 3.85. The test solution was 2% lidocaine/
epinephrine 1:100,000 alkalinized to pH 7.31. Latency was measured using
endodontic ice confirmed with an electric pulp tester (EPT), and injection pain
was measured using a visual analog scale (VAS). ONSET TIME: With the alkalinized
anesthetic, 71% of participants achieved pulpal analgesia in 2 minutes or less.
With non-alkalinized anesthetic, 12% achieved pulpal analgesia in 2 minutes or
less (P = 0.001). The average time to pulpal analgesia for the non-alkalinized
anesthetic was 6:37 (range 0:55 to 13:25). Average time to pulpal analgesia for
alkalinized anesthetic was 1:51 (range 0:11 to 6:10) (P = 0.001). INJECTION PAIN
RESULTS: 72% of the participants rated the alkalinized injection as more
comfortable, 11% rated the non-alkalinized injection as more comfortable, and 17%
reported no preference (P = 0.013). Forty-four percent of the patients receiving
alkalinized anesthetic rated the injection pain as zero ("no pain") on a 100-mm
VAS, compared to 6% of the patients who received non-alkalinized anesthetic (P =
0.056).
CONCLUSIONS: Alkalinizing lidocaine with epinephrine toward physiologic pH
immediately before injection significantly reduces anesthetic onset time and
increases the comfort of the injection.
CLINICAL IMPLICATIONS: Clinicians can begin procedures more quickly and give a
more comfortable injection by alkalinizing their lidocaine/epinephrine
immediately before delivering the injection.
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