Anesthetic Efficacy of Articaine and Lidocaine in a Primary Intraseptal Injection: A Prospective, Randomized Double-Blind Study
Additional studies are needed to evaluate intraseptal anesthesia in the mandibular first molar. The purpose of this study was to compare the anesthetic efficacy of a primary intraseptal injection of articaine and lidocaine, administered with a computer-controlled local anesthetic delivery (CCLAD) system, in asymptomatic mandibular first molars. Using a crossover design, 100 subjects randomly received intraseptal injections of 1.4 mL of 4% articaine and 2% lidocaine, both with 1:100,000 epinephrine, at 2 separate appointments. Injections were given in the interdental papillae, mesial (0.7 mL) and distal (0.7 mL) to the first molar. An electric pulp tester was used to test for pulpal anesthesia. Pain of injection, postoperative pain, and pulse rate were also evaluated. Data were statistically analyzed. Anesthetic success rate for the mandibular first molar was 32% for articaine and 30% for lidocaine, with no statistically significant difference (p = .8689) between the two. No significant differences were found between formulations for pain of injection. The intraseptal injection did not cause a clinically meaningful increase in pulse rate. Postoperative pain decreased each day with no significant differences between formulations. In conclusion, a primary intraseptal injection does not achieve a high success rate of pulpal anesthesia in the mandibular first molar.
Intraseptal anesthesia is the deposition of the anesthetic solution directly into the interdental septum, allowing solution to flow through the porous crestal alveolar bone and hence into the medullary bone surrounding the tooth.1–6 The injection is described by Saadoun and Malamed7 as being given in buccal keratinized tissue at a point “located at the center of the papillary triangle . . . equal distance from the adjacent teeth.” In a 2005 review of the injection technique by Woodmansey,8 the author suggests advancing the needle “until it contacts the underlying bone,” impaling the osseous crest, and then firmly advancing into the interdental septum where the anesthetic should be delivered. Woodmansey8 also recommended delivering the intraseptal injection at mesial and distal aspects of the tooth to gain pulpal anesthesia. Success rates of intraseptal anesthesia have ranged from 76% to 90% depending on how success was measured (extractions, restorative procedures, and experimental monitoring with an electric pulp tester).2–7 Pulse rate increase has been reported in some studies1,2,4 but not in others.3 Postoperative pain was reported in 71% of the injected sites.2
Articaine was approved for use in the United States in April 20009 and is available as a 4% solution with 1:100,000 or 1:200,000 epinephrine. Articaine is classified as an amide but contains a thiophene ring instead of a benzene ring like other amide local anesthetics.9 A second molecular difference between articaine and other amide local anesthetics is the extra ester linkage incorporated into the articaine molecule, which results in hydrolysis of articaine by plasma esterases.9 Only 1 study has used articaine with epinephrine for primary intraseptal anesthesia in mandibular first premolars.3 The highest dose in the study was only 0.8 mL, divided in equal doses (0.4 mL) between the mesial and distal aspects of the premolar. Further studies are indicated to determine if articaine is superior to lidocaine when using a larger volume of local anesthetic.
Traditionally, intraseptal injections have been administered with a conventional syringe.2,4–6 The computer-controlled local anesthesia delivery (C-CLAD; CompuDent, STA, Milestone Scientific, Deerfield, IL) local anesthesia system was developed to deliver a controlled amount of anesthetic solution at a precise and continuous flow rate.10 The C-CLAD has been advocated for infiltrations, nerve blocks, and intraseptal and intraligamentary injections.10 In addition, the C-CLAD is potentially capable of delivering 1.4 mL of anesthetic solution compared with only 0.8 mL with previous intraseptal injections.3 Therefore, there is a possibility of delivering more anesthetic solution intraosseously.
No study has compared the efficacy of articaine and lidocaine for intraseptal anesthesia when used as a primary technique in asymptomatic, mandibular first molars. Therefore, the purpose of this prospective, randomized, double-blind study was to compare the anesthetic efficacy of a primary intraseptal injection of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine, administered with a computer-controlled local anesthetic delivery system, in asymptomatic mandibular first molars. Pain of injection, pulse rate increase, and postinjection pain were also studied.
MATERIALS AND METHODS
One hundred adult subjects participated in this study. All were in good health as determined by a health history and oral questioning. Inclusion criteria included 18 years and older and in good health (American Society of Anesthesiologists classification I or II). Exclusion criteria consisted of allergy to local anesthetics, history of a significant medical problem (American Society of Anesthesiologists classification III or greater), recently taken central nervous system depressants (including alcohol or any analgesic medications), pregnancy, lactating, or inability to give informed consent. The Ohio State University Human Subjects Review Committee approved the study. Written informed consent, Health Insurance Portability and Accountability Act authorization, and medical history were obtained from each subject.
Before the experiment, each subject was randomly assigned a 6-digit number from a random number table. Subjects randomly received intraseptal injections of articaine and lidocaine formulations at 2 separate appointments spaced at least 1 week apart, in a crossover design. The 2 anesthetic formulations to be given at each appointment and which side (right or left) was randomly distributed. The cartridges of anesthetic formulations administered were blinded by completely removing the labels. The expiration dates on the cartridges were checked before the labels were removed. Each cartridge was placed into a coin envelope and labeled with the patient's 6-digit study number that corresponded with the anesthetic to be given at each visit.
The 100 subjects received intraseptal injections of 1.4 mL of 4% articaine (56 mg) with 1:100,000 epinephrine (14 μg; Septocaine, Septodont Inc, New Castle, DE) at one appointment and 1.4 mL of 2% lidocaine (28 mg) with 1:100,000 epinephrine (14 μg; Xylocaine, Dentsply Pharmaceutical, York, PA) at the other appointment using the C-CLAD system (STA, Milestone Scientific, Deerfield, IL). With the crossover design, there were 200 sets of intraseptal injections administered, and each subject served as his or her own control. The same side randomly chosen for the first injection was used again for the second injection. The senior author (T.B.) administered all injections.
The test tooth was the mandibular first molar. The contralateral mandibular canine was used as the unanesthetized control to ensure that the electric pulp tester was operating properly and that the subject was responding appropriately during the experiment. Clinical examinations indicated that all test teeth were free of caries, large restorations, and periodontal disease and that none had a history of trauma or sensitivity.
At the beginning of the appointment and before any injections were given, the experimental tooth and control canine were tested 3 times by means of an electric pulp tester (Analytic Technology Corp, Redmond, WA) to record baseline vitality. All test teeth in the experiment were vital, as confirmed with the electric pulp tester. After isolation with cotton rolls and drying with gauze, toothpaste (Colgate Total, Colgate-Palmolive Company, New York, NY) was applied to the electric pulp tester probe tip, which was placed midway between the gingival margin and the occlusal edge of the tooth being tested. The current rate was set on the pulp tester at 25 seconds to increase from no output (0) to the maximum output (80). The numeric readout at initial sensation was recorded. Trained personnel who were blind to the anesthetic formulations administered performed all preinjection and postinjection tests.
At the beginning of each appointment, each subject was connected to a pulse oximeter (Criticare Systems, Inc, Waukesha, WI) by means of a sensor placed over the nail bed of an index finger free of any nail polish or artificial nails. Pulse rate was monitored for 5 time periods. During period 1, baseline pulse rate readings were recorded at 1-minute intervals during the 8-minute preinjection resting period while the subject was sitting upright. During period 2, pulse rate readings were recorded at 15-second intervals during anesthetic solution deposition on the mesial aspect of the mandibular first molar. In period 3, pulse rate readings were recorded at 15-second intervals during anesthetic solution deposition on the distal aspect of the first molar. During period 4, pulse rate readings were recorded at 15-second intervals for 2 minutes immediately after both injections were complete. During period 5, pulse rate readings were recorded at 2-minute intervals for 28 minutes following completion of the period 4 readings.
Each intraseptal injection was administered using the C-CLAD unit. This system is a microprocessor-driven device that delivers a rate-controlled infusion of anesthetic solution. The unit accepts standard dental anesthetic glass cartridges. The microprocessor monitors and varies the infusion pressure while maintaining a constant flow rate. An electronically driven plunger contacts the rubber plunger in the cartridge and expels the anesthetic solution at a precisely regulated rate. Sterile tubing connects the cartridge receptor to a penlike, handheld plastic wand that is attached to a Luer-Lok needle, together forming a disposable syringe assembly. To prevent cross-contamination, the handpiece, micro tubing, and anesthetic cartridge are designed for single use only. A foot pedal is used to control flow rate, initiation and cessation of flow, and aspiration. When the disposable syringe assembly was connected to the unit, the foot pedal was depressed once to purge the air from the tubing. This filled the tubing with anesthetic solution and prepared the unit for injection. A small portion of solution from a standard cartridge was lost during the purge cycle, and some of the solution remained in the cartridge and tubing; thus, only 1.4 mL of anesthetic solution from a standard cartridge was delivered. A cartridge of the blinded anesthetic formulation was placed into the plastic barrel of the unit's handpiece assembly that was then placed into the cartridge holder socket with a quarter turn in a clockwise direction. A 25-gauge ½-inch Luer Lok needle (Monoject; Sherwood Services, Mansfield, MA) was attached to the opposite end of the tubing. The cap was removed from the needle, and the foot pedal was depressed once to activate the purge cycle.
Before administration of the injections, the subjects were instructed on how to rate any discomfort during needle insertion and deposition of the anesthetic solution using a Heft-Parker visual analogue scale (Figure 1).11 The visual analogue scale was divided into 4 categories. No pain corresponded to 0 mm. Mild pain was defined as greater than 0 mm and less than or equal to 54 mm. Mild pain included the descriptors of faint, weak, and mild pain. Moderate pain was defined as greater than 54 mm and less than 114 mm and included the descriptor moderate. Severe pain was defined as equal to or greater than 114 mm. Severe pain included the descriptors of strong, intense, and maximum possible.
Citation: Anesthesia Progress 64, 4; 10.2344/anpr-64-04-10
The primary author (T.B.) investigated the intraseptal injection clinically on cadaver and live subjects before beginning this study to further assess the appropriate gauge and length of the needle to use in order to penetrate the alveolar crestal bone of the interdental septum with enough force to prevent bending. A 25-gauge ½-inch needle was chosen based on this investigation.
The intraseptal injection was administered as follows. The subject was placed in a supine position. The 25-gauge ½-inch Luer-Lok needle was inserted on the buccal side through the center of the intradental papilla on the mesial aspect of the mandibular first molar at an approximate 30° angle to the long axis of the tooth in a buccal-lingual plane until bone was contacted (needle insertion). The bevel of the needle faced inferiorly. The investigator slowly pressed the needle into the crestal bone with continuous pressure until it could not be advanced any farther. The needle was never advanced to the hub. Approximately 0.7 mL of the anesthetic solution was deposited using the slow rate setting of the C-CLAD (solution deposition phase). The C-CLAD system was activated at the slow rate by partially depressing the foot pedal for 8 seconds (continuous flow of anesthetic solution at the slow rate). One chime from the C-CLAD machine corresponded to 1 second, allowing audible monitoring of the elapsed time. Visually monitoring the green lights on the unit and audibly monitoring the corresponding chimes determined when the deposition of solution was complete. The time to administer 0.7 mL of anesthetic solution was approximately 2 minutes. The foot pedal was then depressed once again to stop the flow of anesthetic. The researcher waited 10 seconds after the flow of anesthetic was stopped before slowly removing the needle from the injection site. The intraseptal injection was then immediately repeated on the distal aspect of the experimental tooth using the same technique and sequence of steps as described above. The amount of anesthetic solution delivered with the distal injection was 0.7 mL. The senior author (T.B.) administered all injections. The subject rated the pain of needle insertion and solution deposition for both the mesial and distal intraseptal injections using the visual analogue scale.
For both injection sites, the author had direct vision of the injection site to monitor if anesthetic solution was expressed from the papilla or sulcus. If notable solution was identified as escaping, the injection was stopped and the needle was rotated with firm apical pressure into the papilla and the injection resumed. However, this did not occur with any of the included subjects.
The depth of anesthesia of the test teeth was monitored with the electric pulp tester. At 1 minute after completion of the distal intraseptal injection, pulp test readings were obtained for the first molar and contralateral control canine. The testing continued in 4-minute cycles for a period of 60 minutes. In addition, subjective lip anesthesia was evaluated every 5 minutes for an hour by asking the subject if his or her lip was numb.
No response from the subject to the maximum output (no response at the 80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive 80 readings were obtained.
All subjects completed postinjection surveys after each set of intraseptal injections. The subjects rated pain in the injection area, using the visual analogue scale as previously described, for 3 consecutive days in the morning upon awakening. Patients were also instructed to describe and record any problems, other than pain, that they experienced.
The second appointment was completed at least 1 week after the first appointment following the protocol outlined above, using the anesthetic solution that was not used at the first appointment. The same right or left side was used for both intraseptal injections.
The data were statistically analyzed. Differences in pain of injection and postinjection pain between anesthetic solutions were analyzed using multiple Wilcoxon matched-pairs, signed-ranks tests with p values adjusted using the step-down Bonferroni method of Holm. Pulse rate values were analyzed using repeated-measures, factorial analyses of variance with anesthetic formulation, evaluation period, and subject gender as the factors. Post hoc testing was done using the Tukey-Kramer procedure. Between-solution differences in anesthetic success were evaluated using the exact McNemar test. With a nondirectional alpha risk of .05 and assuming a success rate of 30%, a sample size of 100 subjects was required to demonstrate a difference of ±15% in anesthetic success with a power of 83%.12 Comparisons were considered significant at p < .05.
RESULTS
One hundred patients participated in this study (49 women and 51 men), ranging in age from 19 to 43 years, with a mean age of 25 years.
The injection pain ratings for mesial and distal insertion and deposition of articaine and lidocaine are found in Table 1. There were no statistically significant differences between the articaine and lidocaine formulations for either male or female subjects or between any injection phases or mesial and distal locations.
Anesthetic success for the first molar was 32% (32/100) with the articaine formulation and 30% (30/100) with the lidocaine formulation. There were no statistically significant differences found between articaine and lidocaine (p = .8689). Figure 2 illustrates the percentage of 80 readings across time for the first molar. Anesthesia peaked immediately following injection and began to decline immediately thereafter. Subjective lip numbness occurred in 69% (69/100) of subjects with articaine and in 65% (65/100) with lidocaine.
Citation: Anesthesia Progress 64, 4; 10.2344/anpr-64-04-10
Mean pulse rate readings by period, gender, and anesthetic formulation are summarized in Table 2. Pulse rate decreased from baseline values during mesial and distal solution deposition phases, with a slight increase occurring immediately postinjection (Figure 3). This was followed by a further decrease in pulse rate during pulp testing. No statistically significant differences were found between the articaine and lidocaine formulations at each period or for subject gender.
Citation: Anesthesia Progress 64, 4; 10.2344/anpr-64-04-10
Table 3 summarizes postoperative pain ratings. Sixteen percent to 24% moderate pain ratings were reported on day 1, 4% to 23% on day 2, and 2% to 14% on day 3. No statistically significant differences were found between articaine and lidocaine for any of the 3 days. Table 4 summarizes postoperative complications. The most common complications were injection site soreness; pain or bleeding with eating, chewing, brushing, or flossing; and bruising or gingival discoloration.
DISCUSSION
Success for the primary intraseptal injection of the first molar was 30% and 32%. This success rate is much lower than other studies of intraseptal injection. Brkovic et al2 studied intraseptal anesthesia during the extraction of maxillary lateral incisors in patients who were pain free preoperatively. The authors used an intraligamentary syringe to administer 0.2 mL of 2% lidocaine with 1:100,000 epinephrine at four separate sites around each tooth (mesial and distal on both the buccal and palatal surfaces). Extractions were successful (ability to perform the extraction without severe pain) in 76% of patients with intraseptal anesthesia alone. Another intraseptal study by Borodina and Petrkas4 reported an 88% success rate for pain-free treatment during restorative procedures on asymptomatic patients using only intraseptal anesthesia. Similarly, Doman5 found that the intraseptal injection of 4% articaine with 1:100,000 epinephrine allowed for restorative cavity preparation to be completed in mandibular molar and premolar teeth without pain or with only very minor pain in 87% of patients. Marin6 reported 96% success (pain was determined by the operator and not the patient) for anesthesia when the intraseptal injection was given using 0.2 mL of 2% lidocaine with 1:100,000 epinephrine both mesial and distal to the tooth being treated using the intraligamentary syringe. Intraseptal anesthesia has also been reported to be 98% successful for soft-tissue periodontal surgery using 2% lidocaine with 1:50,000 epinephrine.7 However, the standards for success using the current model of asymptomatic mandibular first molars and electric pulp testing for determining pulpal anesthesia is very different than success rates for soft-tissue anesthesia,7 nonsurgical extractions,2 and restorative procedures.4,5 In the studies by Borodina and Petrkas4 and Doman,5 the depth of cavity preparation, type of restorative procedure, anterior versus posterior tooth, gender and age of the patients, and length of the procedure were not standardized. the study by Biocanin et al,3 a 90% success rate was reported for pulpal anesthesia in vital and asymptomatic mandibular first premolars, as tested by an electric pulp tester, after the administration of mesial and distal intraseptal injections using 0.4 or 0.8 mL of 4% articaine with 1:100,000 epinephrine administered with the C-CLAD. While the current study and the Biocanin et al3 study used mesial and distal injections in asymptomatic subjects, 4% articaine with epinephrine, and the C-CLAD to administer the anesthetic formulation, there are a number of differences in study design that may have led to this discrepancy in success rates. Biocanin et al3 anesthetized the mandibular first premolar. In the current study, the mandibular first molar was targeted. Cone-beam computed tomography images have shown that cortical bone is thicker in the molar region than in the premolar region.13 The thinner cortical bone could potentially allow penetration of anesthetic through the cortex more readily in the premolar region as compared with the molar region of the mandible. This could lead to a higher success rate. The anatomy of the molars with two divergent roots versus the premolar with only one root may have affected the success of pulpal anesthesia. Additionally, Biocanin et al3 used 27 subjects in the subgroup receiving the intraseptal injection, while the current study used 100 subjects. Perhaps the higher number of subjects might have accounted for a lower success rate.
The success rate was not significantly different between articaine (32% success) and lidocaine (30% success). While Berlin et al12 showed higher success rates, 86% for articaine and 74% for lidocaine, using intraligamentary injection with the C-CLAD, they did not find a significant difference between anesthetic formulations. A number of studies have found articaine superior to lidocaine for buccal mandibular infiltrations14 but not for inferior alveolar nerve blocks,15,16 maxillary molar infiltrations,15,16 intraligamentary anesthesia,12 and intraosseous anesthesia.10 Therefore, from the results of the current study, articaine does not appear to be superior to lidocaine for intraseptal injections.
The low success rate for both anesthetic formulations found in this study is likely due to failure of the anesthetic to penetrate the alveolar cortex and reach the cancellous bone. This could have been due to the inability of the needle to perforate the intraseptal bone. Of interest is the subjective lip numbness occurring in 65% to 69% of the subjects. This is probably related to the anesthetic solution gaining access to the mental nerve.
Regarding the use of the intraseptal injection for supplemental anesthesia, Webster et al17 determined the anesthetic efficacy of the supplemental intraseptal technique in mandibular posterior teeth diagnosed with symptomatic irreversible pulpitis when the conventional inferior alveolar nerve (IAN) block failed. They found the supplemental intraseptal injection achieved profound pulpal anesthesia in 29% of patients when the IAN block failed. This low level of success would not provide predictable levels of anesthesia for patients requiring emergency endodontic treatment for symptomatic irreversible pulpitis in mandibular posterior teeth. Other supplemental techniques such as intraosseous and intraligamentary would result in higher success rates.
Even though success was 30% and 32% for the first molar, Figure 2 shows the rather rapid decline of pulpal anesthesia over the first 30 minutes. Therefore, considering anesthetic success and the decline of pulpal anesthesia, intraseptal anesthesia as performed in this study would be relatively poor.
In the current study, the mesial site of the intraseptal injection was always given first and was found to have higher mean pain than the distal injection site (Table 3). This is similar to the results found for intraligamentary injection pain in the study by Berlin et al,12 who administered the mesial injection first. The distal injection pain was less than mesial injection pain probably because of soft-tissue anesthesia at the distal injection site from the mesial injection and because of patient familiarity with injection pain from the mesial injection. Moderate pain was reported by 25% to 57% of the patients for needle insertion and 8% to 22% for solution deposition (Table 3), which would indicate that some pain might be experienced during a primary intraseptal anesthesia.
Mean pulse rates during mesial and distal anesthetic deposition were slightly lower than baseline readings (Figure 3; Table 2). The readings at 2 minutes postinjection were slightly higher than baseline. These pulse rate values would indicate that the intraseptal injection did not cause a clinically meaningful increase in pulse rate. Brkovic and coauthors2 found a significant increase in pulse rate following intraseptal injection of 0.8 mL of 2% lidocaine with 1:100,000 epinephrine for maxillary lateral incisor extractions. Pulse rate was measured with an electrocardiogram monitor. Average baseline pulse rate was 92 beats per minute, and the highest pulse rate was found 15 minutes after injection at 105 beats per minute. Biocanin et al3 reported no significant differences in pulse rate before administration of anesthetic, during administration of anesthetic, or at 5, 10, 15, or 30 minutes after injection of 0.4 mL, 0.6 mL, and 0.8 mL of 4% articaine with 1:100,000 epinephrine. An electrocardiogram was used to monitor and record pulse rate.6 Although Biocanin et al3 did not report actual values of pulse rate for each testing period, they did include a box plot that indicated that pulse rate ranged from approximately 63 bpm to 87 bpm throughout the experiment, with no significant increase in pulse rate during and after the injection. Their results were similar to those found in the current study. Intraseptal anesthesia does not appear to have a significant effect on pulse rate when given in the mandibular first molar. Although intraseptal anesthesia is an intraosseous anesthetic technique, it did not increase pulse rate significantly, as would intraosseous injections.10 The intraligamentary injection is also considered an intraosseous technique, but similar to the intraseptal injection in the current study, it did not cause an increase in pulse rate.12
Postoperative pain is summarized in Table 3. On average, the participants' postoperative pain was reported to be in the mild range for all 3 days following the injection. Pain levels were highest at day 1 and decreased with each consecutive day. Articaine and lidocaine did not have a statistically significant difference at any day; however, pain ratings were slightly higher for articaine for all 3 days. In comparing the intraseptal injection to the intraligamentary injection, Nusstein et al18 reported similar findings for postoperative pain. Moderate to severe pain was reported on day 1 in 31% and 20% for articaine and lidocaine, respectively.18 In the current study, moderate-to-severe pain was reported on day 1 in 24% and 18% for articaine and lidocaine, respectively. In both studies, there was no significant difference between articaine and lidocaine, and pain decreased over the next 2 days.
The most commonly reported complications were soreness, pain, or bleeding with chewing, brushing, or flossing, and bruising or gingival discoloration. The complications decreased over the 3 days but were not completely resolved by day 3 (Table 4). Of concern are the 2 subjects who had papilla necrosis. While further follow-up of the 2 subjects showed healing (without periodontal intervention) with minimal loss of gingival architecture, it is possible that some patients may need periodontal therapy. Biocanin and coauthors3 reported 3 of 90 participants experienced a hematoma in the area of the papilla after receiving the intraseptal injection. Brkovic and coauthors2 administered intraseptal anesthesia for maxillary lateral tooth extractions and reported that no side effects or complications were recorded during a 5-day postoperative period. A previous study of the intraligamentary injection reported a 35% incidence of soreness or swelling, a 27% incidence of sensitivity to chewing, and an 8% incidence of ulceration.18 The sequelae occurred with both articaine and lidocaine formulations.
In conclusion, the anesthetic efficacy of articaine was not significantly better than lidocaine for primary intraseptal anesthesia of the mandibular first molar. A primary intraseptal injection does not achieve a high success rate of pulpal anesthesia.
Heft-Parker visual analogue scale.
Percentage of 80/80 readings for each time period for the first molar.
Mean pulse (heart) rate by period, solution, and male and female gender.
Contributor Notes