Local anaesthesia is the standard of care during dental extractions. With the
advent of newer local anesthetic agents, it is often difficult for the
clinician to decide which agent would be most efficacious in a given
clinical scenario. This study assessed the efficacy of equal-milligram doses
of lidocaine and articaine in achieving surgical anaesthesia of maxillary
posterior teeth diagnosed with irreversible pulpitis.
Material and Methods
This case-series evaluated a total of 41 patients diagnosed with irreversible
pulpitis in a maxillary posterior tooth. Patients randomly received an
infiltration of either 3.6 mL (72 mg) 2% lidocaine with 1:100,000
epinephrine or 1.8 mL (72 mg) 4% articaine with 1:100,000 epinephrine in the
buccal fold and palatal soft tissue adjacent to the tooth. After 10 minutes,
initial anaesthesia of the tooth was assessed by introducing a sterile
27-gauge needle into the gingival tissue adjacent to the tooth, followed by
relief of the gingival cuff. Successful treatment was considered to have
occurred when the tooth was extracted with no reported pain. Data was
analyzed with the Fisher's exact test, unpaired t-test and normality
test.
Results
Twenty-one patients received lidocaine and 20 received articaine. Forty of
the 41 patients achieved initial anaesthesia 10 minutes after injection: 21
after lidocaine and 19 after articaine (P = 0.488). Pain-free extraction was
accomplished in 33 patients: 19 after lidocaine and 14 after articaine
buccal and palatal infiltrations (P = 0.226).
Conclusions
There was no significant difference in efficacy between equivalent doses of
lidocaine and articaine in the anaesthesia of maxillary posterior teeth with
irreversible pulpitis.
In recent years, a significant amount of research has been conducted to investigate
the efficacy of 2% lidocaine versus 4% articaine [1-5]. One common topic of
investigation is to compare the effectiveness of these two anesthetics in
challenging situations, such as the ability to anesthetize maxillary teeth with
irreversible pulpitis [1,6]. Several studies comparing the efficacy of 2% lidocaine and
4% articaine have had contradictory outcomes [1-7]. Some studies and literature
reviews have shown a statistically significant advantage to the use of articaine,
especially on teeth with irreversible pulpitis [6,8]. One such study found that 4%
articaine was 1.59 to 3.76 times more likely to produce anesthetic success than of
2% lidocaine, and 3.81 times more likely when given as an infiltration [8]. Similarly, a separate study found 4%
articaine with 1:100,000 epinephrine to be superior to 2% lidocaine with 1:100,000
epinephrine in patients with irreversible pulpitis when given as a maxillary buccal
infiltration [6]. Still other studies have
found there to be no significant difference in the efficacy of 2% lidocaine
(1:100,000) and 4% articaine (1:100,000) in achieving anaesthesia of maxillary teeth
with irreversible pulpitis [1,7,10].
One major consideration in reviewing many of these studies is that the comparison of
the efficacy of 2% lidocaine versus 4% articaine is made using equal volumes of
anesthetic instead of equal doses. Considering that a given volume of 4% articaine
contains twice as much active drug as an equivalent volume of 2% lidocaine, no
direct milligram-to-milligram comparison is being performed. As has been discussed
by other authors, it would be expected that a 4% solution would perform better than
a 2% solution given equal volumes of fluid [8].
Consequently, the purpose of this case-series study was to investigate the efficacy
of 2% lidocaine (1:100,000) and 4% articaine (1:100,000) in the surgical anaesthesia
of teeth with irreversible pulpitis using a milligram-to-milligram comparison of
both solutions. The null hypothesis of the present study is that there is no
difference in obtaining surgical anaesthesia of maxillary posterior teeth with
irreversible pulpitis with the use of 2% lidocaine (1:100,000) or 4% articaine
(1:100,000) when equal-milligram doses are administered. The primary outcome measure
was a pain-free extraction procedure of a maxillary posterior tooth diagnosed with
irreversible pulpitis.
MATERIAL AND METHODS
Patient recruitment and data collection for this study took place over the course of
8 months, commencing in August of 2011. Patients were evaluated and treated either
in the private dental practice setting in Fort Collins, Colorado, USA, or in the
hospital setting in Ann Arbor, Michigan USA.
Forty-one adult patients who presented to one of these two clinical settings on an
emergency basis and who were diagnosed with irreversible pulpitis were initially
included in this study. Only those patients with a single symptomatic maxillary
posterior tooth in the quadrant to receive treatment were included.
Two clinicians confirmed the diagnosis, administered the anesthetic, and performed
the extractions. For each individual patient, diagnoses were made and data collected
by the same author administering treatment. Diagnosis of irreversible pulpitis was
made utilizing the results of cold testing, electronic pulp testing, palpation and
percussion sensitivity tests, and radiographic analysis.
All conventional treatment options constituting regional standard of care were
verbally presented and discussed with patients for management of their irreversible
pulpitis. Various types of treatment were discussed, including root canal therapy,
extraction, implant with fixed prosthesis, fixed partial denture or removable
prosthesis. Only patients who elected extraction as their treatment of choice were
included in this analysis.
Over a period of 8 months, forty-one patients presented for extraction using the
criteria defined above and whose data are included in this study. All patients gave
verbal consent for data to be collected during their treatment. Patients randomly
received one of two types of local anesthetic in equivalent doses. The two compounds
administered during this study were 2% lidocaine HCL with 1:100,000 epinephrine
(Lidocaine; Cook-Waite Laboratories, Inc, New York, USA) and 4% articaine HCL with
1:100,000 epinephrine (Zorcaine; Cook-Waite Laboratories, New York, USA). Each
carpule contained 1.8 mL solution. The goal was to administer equal doses (mg) of
either solution in a fashion that approximates standard clinical administration for
a dental extraction.
Each patient received approximately ¾ of the total anesthetic volume as a buccal
infiltration and approximately ¼ of the total anesthetic volume as palatal
infiltration. The two treatment groups were as follows:
1. Lidocaine infiltration group: each patient received a total of 3.6 mL (72 mg) 2%
lidocaine with 1:100,000 epinephrine solution. Approximately ¾ of the solution
volume (2.7 mL) was administered as a buccal infiltration and approximately ¼ (0.9
mL) as a palatal infiltration.
2. Articaine infiltration group: each patient received a total of 1.8 mL (72 mg) 4%
articaine with 1:100,000 epinephrine solution. Approximately ¾ of the solution
volume (1.35 mL) was administered as a buccal infiltration and approximately ¼ (0.45
mL) as a palatal infiltration.
Local anesthetic solution was administered via infiltration at the level of the
mucobuccal fold adjacent to the symptomatic tooth, in addition to a palatal
infiltration approximately 12 - 15 mm apical to the free gingival margin. All
solutions were injected using a 27-gauge 20 mm sterile needle and standard dental
aspirating syringe that accepts 1.8 mL carpules. Each solution, in each site, was
deposited over the course of one minute after negative aspiration.
A medical history and vital signs were collected and reviewed with each patient. Any
patients with a medical history that contraindicated the use of amide- or
ester-containing local anesthetics with epinephrine (e.g., uncontrolled
hypertension) were excluded from this study. Patients with an unstable medical
history (e.g., recent history of myocardial infarct or poorly controlled diabetes),
or other contraindications to oral surgery were also excluded. Patients currently
taking any prescription or over-the-counter analgesics were excluded. Patients with
allergies or reported adverse events specific to lidocaine, articaine, or their
components or who exhibited factors that would compromise data collection (e.g.,
neuralgia, undergoing pain management) were also excluded from analysis. Prior to
administration of local anesthetic, patients were asked to rate the level of
discomfort in the affected tooth on a scale of 0 to 10, with 0 being no pain and 10
being the worst pain ever experienced.
After a period of 10 minutes following the administration of anesthetic solution,
initial anaesthesia was assessed by penetrating the buccal and palatal gingival
tissues with a sterile 27-gauge needle and asking the patient if any discomfort was
experienced. If 0 pain was reported on a scale of 0 to 10, the gingival cuff around
the symptomatic tooth was relieved, and again the patient was asked to report any
discomfort. Failures of either test resulted in recording the patient as failure of
initial anaesthesia and failure of treatment due to pain. The patient was then
managed with further supplementary anesthetic injections as needed.
Upon verification of successful initial anaesthesia, the clinician proceeded to
perform extraction of the symptomatic tooth using the usual non-surgical extraction
protocol. Before any elevation or forceps application was attempted, a #7
mucoperiosteal elevator was introduced into the mesial and distal PDL space to
verify anaesthesia and aid in atraumatic extraction. If any pain was reported at any
point between initial verification of anaesthesia and complete delivery of the
symptomatic tooth, the patient was recorded as failure of pain-free treatment and
managed with further supplementary anesthetic injections as needed.
Statistical analysis
Data were analysed with the Fisher's exact test, unpaired Student's t-test and
normality test. The statistical significance level was defined at 0.05. All analysis
was recorded and analyzed with InStat statistical analysis software.
RESULTS
Table 1 summarizes the patient population in
the present study. 41 patients were included, 26 females and 15 males. The patient
age ranged between 19 and 63 years, with a median of 38 years and a mean of 38.5
years, standard deviation (SD) 12.25 years. The age distribution passed the
normality test (P > 0.10). There was no significant difference between females
and males in this study with respect to age (Mean ± SD = 37.8 ± 12.9 for females and
39.7 ± 11.8 for males, t = 0.46, P = 0.65). There was no significant difference
between the proportion of males to females between the lidocaine and articaine
groups (Fisher's Exact Test, P = 0.341). There was no significant difference between
the lidocaine and articaine groups with respect to the reported pain (0 - 10) before
initiating treatment (averages were 4.8 and 4.2, respectively).
Patient demographics, initial pain and categories of teeth
anesthetized
Patient variable and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Number of patients
21
51.2
20
48.8
41
100
Sex
Male
6
14.6
9
22
15
36.6
0.341b
Female
15
36.6
11
26.8
26
63.4
Initial pain (1 - 10)
4.8
4.2
0.46c
Premolars
9
22
5
12.2
14
34.1
0.326b
Molars
12
29.3
15
36.6
27
65.9
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
cNon significant, unpaired Student's t-test.
Of the 41 patients, 21 patients received 3.6 mL of 2% lidocaine with 1:100,000
epinephrine, and 20 patients received 1.8 mL of 4% articaine with 1:100,000
epinephrine. There was no significant difference in gender distribution or initial
pain between patients treated by the two examiners.
Table 1 also illustrates that there was no
significant difference found between the categories of teeth anesthetized with 2%
lidocaine or 4% articaine (Fisher's Exact Test, P = 0.326). Table 2 illustrates that there was no significant difference
found in success of initial anaesthesia when tested with sterile 27-gauge needle, or
during relief of the gingival cuff between the lidocaine and articaine groups
(Fisher's Exact Test P = 0.488). Overall, the success of initial anaesthesia was
97.6%, with the only initial anaesthesia failure occurring during release of the
gingival cuff around a molar in the articaine group.
Successful initial anaesthesia 10 minutes after infiltration
Successful initial anaesthesia and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Success
21
100
19
95
40
97.5
0.488b
Failure
0
0
1
5
1
2.5
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
The data in Table 3 show that of those
patients who achieved successful initial anaesthesia, there was no significant
difference between lidocaine and articaine groups with respect to the categories of
teeth anesthetized (Fisher's Exact Test, P = 0.324). Of the 40 patients for whom
initial anaesthesia was successful, 33 (82.5%) went on to experience elevation and
extraction of the affected tooth without pain, while 7 (17.5%) experienced
discomfort during the extraction procedure. Table
4 shows that there was no significant difference in success rates of
treatment between the lidocaine and articaine infiltration groups (Fisher's Exact
Test, P = 0.226). There was also no significant difference in success rates of
treatment between providers. With respect to the categories of teeth anesthetized,
success rates of treatment were similar for both premolars and molars (Fisher's
Exact Test, P = 0.387) for the 40 patients for whom initial anaesthesia was
successful (Table 5).
The number (%) of patients with successful initial anaesthesia in
different categories of teeth after lidocaine and articaine
infiltrations
Tooth type anesthetized and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Premolar
9
22.5
5
12.5
14
35
0.324b
Molar
12
30
14
35
27
65
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
Treatment success after lidocaine and articaine infiltrations in 40
patients with successful initial anaesthesia
Treatment outcome and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Successful treatment without pain
19
90.5
14
73.7
33
82.5
0.226b
Failure of treatment due to pain
2
9.5
5
26.3
7
17.5
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
Treatment outcomes by tooth category after lidocaine and articaine
infiltrations in 40 patients with successful initial anaesthesia
Treatment outcome and tooth category
Premolars
Molars
Total
P valuea
N
%
N
%
N
%
Successful treatment without pain
13
32.5
20
50
33
82.5
0.387b
Failure of treatment due to pain
1
2.5
6
15
7
17.5
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
Combining the results of anaesthesia success at all stages of treatment, overall
treatment success was noted in 33 of 41 patients (80.5 %). Table 6 illustrates overall success rates in the lidocaine and
articaine groups. Successful treatment was achieved in 19 of 21 patients (90.5%) who
received 3.6 mL 2% lidocaine (1:100,000) and in 14 of 20 (70%) patients who received
1.8 mL 4% articaine (1:100,000). There was no significant difference in the
incidence of pain-free treatment between lidocaine and articaine groups
(Fisher's Exact Test, P = 0.13). Table 7
provides an overall summary of the present results for the lidocaine and articaine
groups.
Overall success rates of treatments after lidocaine and articaine
infiltration for all 41 patients included in the present study
Treatment outcome and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Successful treatment without pain
19
90.5
14
70
33
80.5
0.13b
Failure of treatment due to pain
2
9.5
6
30
8
19.5
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
Summary of results after lidocaine and articaine infiltrations for all 41
patients included in the present study
Outcomes measure and solution used
Lidocaine
Articaine
Total
P valuea
N
%
N
%
N
%
Total number of patients
21
51.2
20
48.8
41
100
Sex
Male
6
14.6
9
22
15
36.6
0.341b
Female
15
36.6
11
26.8
26
63.4
Successful initial anaesthesia
21
100
19
95
40
97.5
0.488b
Successful treatment without pain
19/21
90.5
14/19
73.7
33/40
82.5
0.226b
Overall rate of pain-free treatment
19/21
90.5
14/20
70
33/41
80.5
0.13b
aTested between lidocaine and articaine groups.
bNon significant, Fisher's Exact Test.
DISCUSSION
In 2000, 4% articaine (1:100,000) was given FDA approval for use in the United States
and has been steadily growing in popularity [12]. Following its FDA approval, 4% articaine has proven to be safe and
effective for use as a dental local anesthetic for both maxillary and mandibular
procedures [1,4,7,9,13,14]. For dental procedures, 2% lidocaine with epinephrine is
considered the "gold standard", and the anesthetic to which others are often
compared [12]. A wide variety of studies have
been conducted to compare the safety and efficacy of 4% articaine to the standard
local anesthetic, 2% lidocaine, with varying outcomes [1-10]. These two local
anesthetic solutions were selected because they are two of the most commonly used
preparations used in the practice of dentistry in the United States, and this study
aimed to approximate standard clinical practice [11].
As discussed by Kanaa et al. [1], inconsistent
results have been obtained in the comparison of 2% lidocaine to 4% articaine, with
the latter proving to be more effective in obtaining pulpal anaesthesia after
mandibular infiltration [1,3-5],
while no difference in efficacy was noted after inferior alveolar nerve block [1,15-18]. A similarly inconsistent
set of results emerges when comparing lidocaine and articaine solutions administered
via infiltration in the maxilla. The volunteer trial by Kanaa et al. [1] found no significant difference in ability to
achieve pulpal anaesthesia when evaluating the efficacy of these two solutions when
administered via buccal infiltration. This finding was mirrored by another study by
Costa et al. [7], which found no statistical
difference in anesthetic success of lidocaine and articaine in the anaesthesia of
maxillary posterior teeth. Other studies have failed to demonstrate a difference in
efficacy between these two solutions in the anaesthesia of maxillary central
incisors and maxillary canines [8,10,15].
On the contrary, a study by Evans et al. [13]
found 4% articaine to be superior to 2% lidocaine in the anaesthesia of maxillary
lateral incisors. In the investigation of the anaesthesia of maxillary posterior
teeth with irreversible pulpitis, Srinvasan et al. [6] found 4% articaine to be superior to 2% articaine at a highly
significant level. In perhaps one of the most extensive reviews of the literature to
date, Brandt et al. [8] found in their meta
analysis that 4% articaine proves to be 2.44 to 3.81 times more effective than 2%
lidocaine when given as infiltration.
Because of these highly varied results in the anaesthesia of maxillary teeth, the
results of the present study are congruent with some prior research, but
contradictory to others. We found no statistically significant difference in the
anesthetic efficacy of lidocaine and articaine in the anaesthesia of maxillary
posterior teeth with irreversible pulpitis. Our results are consistent with those
obtained by Kanaa et al. [1], which is most
similar in methodology to the present study. In their study, no significant
difference was found in the efficacy of lidocaine and articaine with respect to
pain-free treatment of maxillary teeth with irreversible pulpitis. Kanaa et al.
[1] found a 96.2% success rate of
pain-free extraction, while our success rate was slightly lower at 80.5%.
Our results differ from the study by Srinivasan et al. [6], in which the efficacy of these local anesthetic solutions in
maxillary posterior teeth with irreversible pulpitis was investigated. In that
study, it was found that 4% articaine offered a significant advantage in the
anaesthesia of both premolars and molars, whereas the present study found no
differences in efficacy between lidocaine or articaine solutions.
It should be noted, however, that while the efficacy of lidocaine and articaine in
the present study did not differ at the statistically significant level (P = 0.13),
the lidocaine group did show a 20.5% higher success rate in achieving treatment with
no reported pain, which could be significant in a clinical setting considering the
limited number of patients included in this study.
The results of the present study and other studies which demonstrated contradictory
results exhibit differences in sample size, tooth type variances, anesthetic doses,
concentration of vasoconstrictor, and the study definition of success. In the
current study, 3.6 mL of 2% lidocaine with 1:100,000 epinephrine and 1.8 mL of 4%
articaine with 1:100,000 epinephrine were compared. Kanaa et al. [1] employed 2.0 mL volumes of 2% lidocaine with
1:80,000 epinephrine and 4% articaine with 1:100,000 epinephrine. Srinivasan et al.
[6] employed a 1.7 mL volume of solutions
in their study. The 3.6 mL lidocaine and 1.8 mL articaine volumes were used in the
present study in an attempt to elucidate any difference in efficacy when equal doses
(in milligrams) of each anesthetic were employed.
The definition of treatment success in the present study was similar to that employed
by Kanaa et al. [1], in that success was
defined as pain-free treatment. Other studies included mild pain in their definition
of treatment success [1,6,15], which may help to
explain the differences in reported outcomes. In the present study, successful
treatment was completed on 33 of 40 (82.5%) patients with successful initial
anaesthesia, or 33 of the total 41 (80.5%) patients initially included. This figure
is higher than the study by Kanaa et al., who achieved pain-free treatment in 84.9%
of patients with successful pulpal anaesthesia and 62% of all patients recruited
[1].
The likely difference in treatment success rates between the present study and those
by Kanaa et al. [1], Srinivasan [6], and others, is that treatment success in the
present study depended solely on a pain-free extraction. Other studies included
extraction as well as other treatment modalities such as pulp extirpation in their
outcomes measures [1-10]. This is something that should be considered when comparing
the present results against other investigations, since it has been shown that
obtaining anaesthesia for extraction procedures on teeth with irreversible pulpitis
is simpler and more successful than procedures such as pulp extirpation [1,18,19]. When comparing the
present results with the study by Kanaa et al. [1], and limiting the comparison to extractions only, an 80.5% success
rate is found in the present study, versus a 70% success rate in the previous study.
This may be attributable to the increased quantity of vasoconstrictor administered
in the lidocaine group (0.036 mg epinephrine versus 0.022 mg) in the present study
versus the previous study by Kanaa et al. [1],
although present research may not support this assertion [20].
The present symptoms or reason for extraction of maxillary teeth may play an
important role in evaluating the outcomes of research directed at evaluating
efficacy of anesthetic solutions. Teeth with irreversible pulpitis are 8 times more
likely to experience failure of anaesthesia than normal teeth, so the results of the
present study may not be applicable to patients undergoing extraction or other
treatment of maxillary teeth that are not experiencing irreversible pulpitis [21,22].
The present study was conducted as a case-series, and as such, only a small patient
pool was utilized with no patient or clinician blinding. This may lead to
significant selection, operator, or patient biases. A future full clinical trial
should include multiple treatment modalities and a blinded randomized protocol to
mitigate these problems. Furthermore, future research would require a specific
number of patients in order to achieve the desired confidence interval and level of
statistical significance required for a full prospective clinical trial. Without
making such attempts to eliminate bias and increase the size of the subject pool, no
specific clinical recommendations can be made from the results of the present study.
It is up to the reader to draw their own conclusions and to hopefully investigate
the subject further through future research.
CONCLUSIONS
A combined buccal and palatal infiltration with 72 mg 2% lidocaine with 1:100,000
epinephrine or 72 mg 4% articaine with 1:100,000 epinephrine exhibited similar
success rates of preliminary anaesthesia and similar pain-free treatment in patients
undergoing simple extraction of a single tooth with irreversible pulpitis in the
posterior maxilla. Success rates of treatment were the same for molars and premolars
undergoing extractions, both within the same anesthetic group, and between the
lidocaine and articaine groups.
ACKNOWLEDGEMENTS AND DISCLOSURE STATEMENTS
The authors do not report any conflicts of interest related to this study. The
authors do not have any financial interests, either directly or indirectly, in
the products or information listed in the paper.