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A comparison of the local anesthetic efficacy of the extraoral versus the intraoral infraorbital nerve block
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A Comparison of the Local Anesthetic Efficacy of the Extraoral Versus the Intraoral Infraorbital Nerve Block Bradley Karkut, Al Reader, Melissa Drum, John Nusstein and Mike Beck JADA 2010;141(2):185-192 10.14219/jada.archive.2010.0137 The following resources related to this article are available online at jada.ada.org (this information is current as of September 29, 2014): Updated information and services including high-resolution figures, can be found in the online version of this article at: http://jada.ada.org/content/141/2/185
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A comparison of the local anesthetic efficacy of the extraoral versus the intraoral infraorbital nerve block Bradley Karkut, DDS, MS; Al Reader, DDS, MS; Melissa Drum, DDS, MS; John Nusstein, DDS, MS; Mike Beck, DDS, MA
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✷ Background. The efficacy of the extraoral infraorbital ® nerve block has not been studied sufficiently to ensure its appropriate clinical use. To compare the local anesthetic N C efficacy of the extraoral versus the intraoral infraorbital U U IN G ED A 4 nerve block, the authors conducted a prospective, randomRT ICLE ized crossover study. Methods. Forty adult participants randomly received extraoral infraorbital nerve blocks of 1.8 milliliters of 2 percent lidocaine with 1:100,000 epinephrine at one appointment and intraoral infraorbital nerve blocks of 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine at another appointment in a crossover design. After administering the injections, the authors used an electric pulp tester to assess the maxillary central and lateral incisors, canine, premolars and first molar for pulpal anesthesia in four-minute cycles for 60 minutes. They considered anesthesia to be successful when the participant had no response to two consecutive 80 readings (the maximum output) with the electric pulp tester. Conclusions. The authors found that the extraoral and intraoral infraorbital nerve blocks were ineffective in providing profound pulpal anesthesia of the maxillary central incisor (15 percent success rate) and lateral incisor (22 percent success rate). The pulpal anesthesia success rate was 92 percent for the canine for both types of nerve blocks, 80 to 90 percent for first and second premolars and 65 to 70 percent for the first molar, with no significant differences (P < .05) between the two nerve blocks. Pulpal anesthesia did not last for an hour in any of the teeth. Needle insertion pain and postoperative sequelae were more common after the extraoral infraorbital nerve block was administered. Clinical Implications. Both nerve blocks would be ineffective in the central and lateral incisors. Both nerve blocks would be somewhat successful in the canine and premolars but not in the first molar. Key Words. Lidocaine; extraoral infraorbital nerve block; intraoral infraorbital nerve block; maxillary. JADA 2010;141(2):185-192. I
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alamed1 described the maxillary infraorbital nerve block as an effective method for achieving profound pulpal anesthesia in the area from the maxillary central incisor through the canine. The pulps of the premolars and the mesiobuccal root of the first molar also are anesthetized in about 72 percent of patients who receive maxillary infraorbital nerve blocks.1 Few clinical studies have evaluated the efficacy of the infraorbital nerve block. Feige2 evaluated the effectiveness of the intraoral infraorbital nerve block by using 0.5 milliliters of 2 percent lidocaine with 1:80,000 epinephrine and found that pulpal anesthesia was attained in the canine and premolars but not in the incisors. Berberich and colleagues3 found that the intraoral infraorbital nerve block was ineffective in providing profound pulpal anesthesia (no participant response to two consecutive 80 readings with the electric pulp tester) in the maxillary central incisor (10 to 15 percent success rate),
At the time this study was conducted, Dr. Karkut was a graduate student in endodontics, College of Dentistry, The Ohio State University, Columbus, Ohio. He now is in private practice in Delaware, Ohio. Dr. Reader is a professor and the director of advanced endodontics, Division of Endodontics, College of Dentistry, The Ohio State University, 305 W. 12th Ave., Columbus, Ohio, 43210, e-mail “[email protected]“. Address reprint requests to Dr. Reader. Dr. Drum is an assistant professor, Division of Endodontics, College of Dentistry, The Ohio State University, Columbus. Dr. Nusstein is an associate professor and the chair, Division of Endodontics, College of Dentistry, The Ohio State University, Columbus. Dr. Beck is an emeritus associate professor, Division of Oral Biology, College of Dentistry, The Ohio State University, Columbus.
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R E S E A R C H
The 40 participants randomly received 1.8 mL lateral incisor (25 to 30 percent success rate) and of 2 percent lidocaine with 1:100,000 epinephrine first molar (50 to 62 percent success rate). Success rates in the canine and premolars ranged (Xylocaine, Astra Pharmaceutical Products, from 85 to 92 percent and 75 to 85 percent, Worcester, Mass.) using the extraoral infraorbital respectively. However, pulpal anesthesia did not nerve block at one appointment and an intraoral last for 60 minutes. infraorbital nerve block at another appointment. We spaced the appointments at least one week Kleier and colleagues4 evaluated the extraoral apart using a crossover design. Before the experiinfraorbital nerve block in 20 participants by ment began, we randomly assigned five-digit using 1 mL of 3 percent mepivacaine. They numbers from a random number table to the two reported a 90 percent success rate in the maxilinfraorbital nerve blocks (extraoral and intralary central incisor, lateral incisor, canine and oral). We randomly assigned each participant to first premolar. The second premolar had a 45 perreceive the nerve blocks on the right or the left cent success rate. Therefore, on the basis of the side of his or her mouth. We also randomly results of Kleier and colleagues’4 study, we assigned the order in which the infraorbital nerve hypothesized that the extraoral approach to the blocks were administered at each appointment by infraorbital nerve may provide better anesthesia using random numbers. The senior than would the intraoral approach. author (B.K.) administered 20 sets The efficacy of an extraoral infraof nerve block injections on the orbital nerve block needs to be The efficacy of an right side of participants’ mouths investigated further to ensure its extraoral infraorbital and 20 sets on the left side of parappropriate clinical use. We connerve block needs ticipants’ mouths. The side randucted a prospective randomized to be investigated domly chosen to receive the first study to compare the local anesfurther to ensure nerve block injection was used thetic efficacy of the extraoral again to receive the second nerve versus the intraoral infraorbital its appropriate block injection. We chose the maxilnerve block. clinical use. lary right and left central incisors, PARTICIPANTS, MATERIALS the ipsilateral lateral incisor, AND METHODS canine, first and second premolars, and first molar as the test teeth for the experiment. We Participants. Forty adult men and women parused the contralateral mandibular canine as the ticipated in this study. We recruited participants unanesthetized control tooth to ensure that the from a population of patients, students and staff electric pulp tester was operating properly and at the College of Dentistry at The Ohio State Unithat the participant was responding appropriversity and The Ohio State University by using ately during each experimental portion of the direct recruitment and advertisements approved study. The results of clinical examinations indiby The Ohio State University Human Subjects cated that all of the teeth were free of caries, Review Committee. Our exclusion criteria were as large restorations and periodontal disease. No follows: younger than 18 years, older than 65 teeth had a history of trauma or sensitivity. years, allergic to local anesthetics or sulfites, Electric pulp tester. At the beginning of each pregnant, history of significant medical condiappointment before we administered any injections, active sites of pathosis in area of injection, tions, we tested the experimental teeth and coninability to give informed consent. We determined trol mandibular canine three times using the elecvia the participants’ written health histories and tric pulp tester (Kerr, Analytic Technology, by oral questioning that they were in good health Redmond, Wash.) to record baseline vitality.3 and were not taking any medication (over-thecounter pain-relieving medications, narcotics, Trained research personnel, who were masked to sedatives, antianxiety medications or antidepresthe type of injection technique used, performed all sant medications) that would alter pain perceppreinjection and postinjection tests. tion. The Ohio State University Human Subjects Recording injection pain. We instructed Review Committee, Columbus, approved both the each participant on how to rate the pain of needle protocol and informed consent document. We insertion, needle placement and solution deposiobtained written informed consent from each tion on a scale ranging from 0 to 3, in which 0 participant. indicated no pain, 1 indicated mild pain defined 186
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R E S E A R C H
as pain that was recognizable but not discomforting, 2 indicated moderate pain defined as pain that was discomforting but bearable, and 3 indicated severe pain that caused considerable discomfort and was difficult to bear. Pilot study. We performed a pilot study using 17 human skulls to determine the location of the infraorbital foramen. We found the distance between the center of the infraorbital foramen and the lower border of the orbit was 7.4 millimeters (range: 5-9 mm). The distance between the center of the infraorbital foramen and the intersection of the frontonasal suture and the internasal suture was 43.3 mm (range: 40-47 mm). We also found the angulation of the infraorbital canal in a vertical direction was 25 degrees (range: 1033 degrees), which we measured by the angle formed by an orthodontic wire inserted into the infraorbital canal and the intersection of a line extending from the maxillary occlusal plane. The angulation of the infraorbital canal in a horizontal direction was 77 degrees (range: 67-85 degrees), which we measured by the angle formed by an orthodontic wire inserted into the infraorbital canal and the intersection of a line extending parallel to the lower border of the orbits. Therefore, we determined that the needle path would be backward, upward and outward to penetrate the infraorbital canal (Figure 1). Extraoral infraorbital nerve block. We used a variation of the extraoral infraorbital nerve block described by Kleier and colleagues4 and Sicher5 in this study. We administered the injection by using a 27-gauge 1½-inch needle (Sherwood Medical, St. Louis) and a standard aspirating syringe. By using the distance measurements we obtained from the pilot study, the senior author (B.K.) used a compass to mark the distance between the nasal bone and the foramen (43.3 mm). He traced an arc on the participant’s cheek using an indelible pencil and measured a distance of 7.4 mm from the lower border of the orbit until it crossed the previous mark and marked the intersection using an indelible pencil (Figure 2). While applying gentle pressure, he palpated the outline of the infraorbital foramen. If the participant felt an aching sensation, the clinician used this pressure point to help locate the foramen. He disinfected the participant’s skin surface with a sterile 70 percent alcoholdampened gauze square and allowed the skin to dry for 60 seconds. He then inserted the needle 2 to 3 mm and asked the participant to rate the pain of needle
Figure 1. The direction of the needle path for the extraoral infraorbital nerve block would be backward, upward and outward to penetrate the infraorbital canal.
insertion. After depositing approximately 0.2 mL of anesthetic solution, he advanced the needle slowly using a probing motion until it entered the infraorbital foramen. He recorded the time it took to locate and enter the foramen. He advanced the needle to the maximum depth negotiable for each participant; the maximum depth was 11 mm— that is, the average thickness of the soft tissue overlying the infraorbital canal would be approximately 7 mm4 and the maximum depth within the canal 4 mm.5 The participant rated the pain of needle placement at the target site. After performing aspiration, the clinician administered 1.6 mL of the anesthetic solution at a rate of 1 mL/ minute. The participant then rated the pain of solution deposition. The clinician measured the depth of the needle insertion by using the rubber stopper on the needle as a depth guide. He applied firm finger pressure over the injection site for 30 seconds after solution deposition to increase the diffusion of the anesthetic solution into the infraorbital foramen. Intraoral infraorbital nerve block. We used the intraoral infraorbital nerve block described by Malamed,1 Feige,2 and Berberich and colleagues.3 The senior author administered the injection using a 27-gauge 1½-inch needle and a standard aspirating syringe. He marked the approximate location of the infraorbital foramen on the participant’s cheek as described previously for the extraoral infraorbital injection. Using this guideline, he applied gentle pressure over the infraorbital JADA, Vol. 141
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Figure 2. The intersection of the two marks on the cheek corresponded to the approximate location of the infraorbital foramen for the extraoral infraorbital nerve block.
Figure 3. The direction of the needle path for the intraoral infraorbital nerve block was parallel to the long axis of the second premolar until it approximated the infraorbital foramen.
foramen. If the participant felt an aching sensation, the clinician used this pressure point to help locate the foramen. With the needle bevel facing bone, he inserted the needle 2 to 3 mm in the mucobuccal fold over the second premolar. The participant then rated the pain of needle insertion. After depositing approximately 0.2 mL of anesthetic solution, the clinician oriented the syringe toward the previously identified infraorbital foramen and advanced the needle parallel to the long axis of the second premolar until it approximated the position of the infraorbital foramen (Figure 3). The participant then rated the pain of needle placement. After performing aspiration, the clinician 188
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administered 1.6 mL of the anesthetic solution at a rate of 1 mL/minute. The participant rated the pain of solution deposition after needle withdrawal. The clinician measured the depth of needle insertion by using the rubber stopper on the needle as a depth guide. He applied firm finger pressure over the injection site for 30 seconds after solution deposition to increase the diffusion of the anesthetic solution into the infraorbital foramen. He practiced both the extraoral and intraoral infraorbital injections on 18 cadavers and on clinical patients requiring endodontic treatment before beginning our study. Testing. At one minute after completion of the injection, we obtained electric pulp test readings for the central and lateral incisors. At two minutes, we obtained electric pulp test readings for the canine and first premolar. At three minutes, we obtained electric pulp test readings for the second premolar and first molar. At four minutes, we obtained electric pulp test readings for the contralateral maxillary central incisor and contralateral mandibular canine. We repeated the testing cycle every four minutes for 60 minutes. Every fourth cycle, we used an inactivated electric pulp tester to assess “pain” of the control tooth and, thus, the reliability of the participant. At the completion of each cycle, we asked the participant if her or his lip, side of nose and lower eyelid (terminal branches of the infraorbital nerve) were numb. If the participant did not have any signs of subjective anesthesia 20 minutes after the nerve block was administered, we considered the nerve block to be a failure. However, we did not exclude any participants because they did not achieve soft-tissue anesthesia. We recorded instances of positive aspiration for both the extraoral and intraoral nerve blocks. When a positive aspiration occurred, we used a new cartridge of anesthetic solution. We asked all participants to complete surveys after each infraorbital nerve block was administered. Using the same pain scale as we described previously, they rated pain in the injection area immediately after the numbness wore off and each morning for three days. We instructed the participants to describe and record any other problems they experienced. Our criterion for pulpal anesthesia was an absence of response from the participant at the maximum output (an 80 reading) of the electric pulp tester. We considered anesthesia successful when we obtained two consecutive 80 readings.
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R E S E A R C H
Statistical analysis. All participants we included in our data analysis underwent softtissue anesthesia. We compared the extraoral and intraoral infraorbital nerve blocks for anesthetic success and incidence of pulpal anesthesia (percentage of 80 readings across time) using multiple exact McNemar tests adjusted using the stepdown Bonferroni method of Holm. With a nondirectional α risk of .05 and assuming a success rate of 50 percent, we determined that a sample size of 40 participants was needed to demonstrate a difference in anesthetic success of ± 30 percentage points with a power of 0.90. We statistically analyzed between–nerve block differences in pain ratings for needle insertion, needle placement, solution deposition and postinjection survey ratings using multiple Wilcoxon matchedpair, signed-ranks tests adjusted using the stepdown Bonferroni method of Holm. We considered comparisons to be significant at P < .05. RESULTS
Twenty-three men and 17 women ranging in age from 19 to 35 years (average age: 26 years) participated in the study. Table 1 shows the percentages of successful pulpal anesthesia. There were no significant differences between the extraoral and intraoral infraorbital nerve blocks. The incidences of pulpal anesthesia (80 readings across time) for the two nerve blocks are shown in Figure 4. Pain ratings for each injection phase are shown in Table 2 (page 191). Needle insertion with the extraoral nerve block was statistically more painful than that with the intraoral nerve block. The average depth of needle penetration for the extraoral infraorbital nerve block was 9.75 mm with a range of 9 to 11 mm. One participant had a positive aspiration as the clinician administered the extraoral infraorbital nerve block. No participants had a positive aspiration as the clinician administered the intraoral infraorbital nerve block. Postinjection pain ratings are shown in Table 3 (page 191). We found small but significant differences in mean pain levels from day one to day three between the two nerve blocks. A total of 2.5 percent of the participants reported experiencing facial bruising for three days after the clinician administered the extraoral infraorbital nerve block. No participants reported experiencing facial bruising after the clinician administered the intraoral infraorbital nerve
TABLE 1
Percentages and number of participants (N = 40) who experienced anesthetic success after receiving infraorbital nerve blocks. SITE OF NERVE BLOCK
ANESTHETIC SUCCESS* (% [NO. OF PARTICIPANTS]) Extraoral
Intraoral
Central Incisor
15 (6)
15 (6)
Lateral Incisor
22 (9)
22 (9)
Canine
92 (37)
92 (37)
First Premolar †
87 (26)
90 (27)
Second Premolar
82 (33)
80 (32)
First Molar
65 (26)
70 (28)
0 (0)
0 (0)
Contralateral Central Incisor
* There was no significant difference (P > .05) between the extraoral and intraoral infraorbital nerve blocks. † Some teeth were missing because of extractions for orthodontic treatment.
block. Two participants (5.0 percent) reported experiencing double vision (diplopia) after the clinician administered the extraoral infraorbital nerve block, which resolved when soft-tissue anesthesia ended. No participants reported experiencing diplopia after the clinician administered the intraoral infraorbital nerve block. DISCUSSION
The success rates for both infraorbital nerve blocks were highest for the canine (92 percent) and first premolars (ranging from 87 to 90 percent) with no significant differences between the two nerve blocks (Table 1). The success rates of the nerve blocks for the second premolars were 80 to 82 percent. Berberich and colleagues3 reported success rates for the canines, first premolars and second premolars of 85 percent, 82 percent and 75 percent, respectively, after administering infraorbital nerve blocks using 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine. The success rates in our study were higher than those recorded by Berberich and colleagues3 and probably relate to individual variation in participant populations. Kleier and colleagues4 used the extraoral approach to the infraorbital nerve block and reported a 90 percent success rate in the central and lateral incisors, canines and first premolars. The results of our study did not show such JADA, Vol. 141
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■ Intraoral Infraorbital
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First Premolar
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◆ Extraoral Infraorbital
Canine PERCENTAGE OF 80 READINGS
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PERCENTAGE OF 80 READINGS
R E S E A R C H
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TIME (MINUTES)
First Molar
Figure 4. Incidence of pulpal anesthesia as determined by lack of response to electric pulp testing at the maximum setting (percentage of participants achieving 80 readings using the maximum output [80 reading] of the electric pulp tester) at each postinjection interval for the extraoral and intraoral nerve blocks. There were no significant differences between the extraoral and intraoral infraorbital nerve blocks for any of the teeth.
high success rates. We could not directly compare the results of our study with those of Kleier and colleagues4 because they tested the teeth with cold immediately after the injection and again at 15 minutes. Because children and elderly patients may require less anesthetic, the results of our study may not apply to these patients. The success rates of the central and lateral incisors ranged from 15 to 22 percent with no significant differences between the two nerve blocks (Table 1, Figure 4). Berberich and colleagues3 found 15 percent and 28 percent success rates of the central and lateral incisors, respectively, after administering infraorbital nerve blocks using 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine. Their results were similar to the results we obtained in our study. There are several theories to explain inadequate pulpal anesthesia of the central and lateral incisors. Francis6 states that the central incisor may demonstrate partial anesthesia owing to 190
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arborizing fibers from the opposite side of the midline. However, Sicher5 cites anatomical evidence to support the fact that the anterior superior alveolar nerves are restricted to one side of the maxilla. Accessory innervation from the nasopalatine nerve also has been implicated in failure.7-9 However, Olsen and colleagues10 found that 26 percent of the dissected human specimens had branches arising from the nasopalatine nerve at the nasal end of the incisive canal but none of the nerves entered the apex of the central incisor in any specimen. Because the anterior superior alveolar nerves arise in the infraorbital canal behind the infraorbital foramen, Sicher5 stated that to achieve full anesthesia of these nerves, the injection must be made into the infraorbital canal and not at the foramen’s entrance. Other investigators11-13 have contended that depositing anesthetic solution at the infraorbital foramen and allowing it to move into the canal will provide reliable anesthesia.
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R E S E A R C H
TABLE 2 The 65 to 70 percent success rates in the first molar in our study would not Participants’ pain ratings for needle provide predictable pulpal anesthesia insertion, needle placement and solution (Table 1, Figure 4). Berberich and col3 deposition for infraorbital nerve blocks leagues found a success rate of 52 percent after administering the intraoral (N = 40). infraorbital nerve block. Therefore, we INJECTION PHASE PAIN RATINGS conclude that the extraoral or intraoral (% [NO. OF PARTICIPANTS]) approach to the infraorbital nerve None Mild Moderate Severe will not anesthetize the first molar Needle Insertion * predictably. Extraoral nerve block 3 (1) 58 (23) 40 (16) 0 (0) For the canine and premolars in our Intraoral nerve block 53 (21) 48 (19) 0 (0) 0 (0) study, both types of nerve blocks † Needle Placement resulted in a decreasing incidence of Extraoral nerve block 38 (15) 45 (18) 15 (6) 3 (1) pulpal anesthesia across the 60-minute Intraoral nerve block 58 (23) 35 (14) 8 (3) 0 (0) test period (Figure 4). Berberich and Solution Deposition † colleagues3 also recorded a decreasing Extraoral nerve block 75 (30) 20 (8) 5 (2) 0 (0) Intraoral nerve block 88 (35) 10 (4) 3 (1) 2 (1) incidence of pulpal anesthesia after administering the intraoral infraorbital * There was a significant difference (P < .05) between the extraoral and intraoral infraorbital nerve blocks. nerve block. Therefore, we conclude † There was no significant difference (P > .05) between the extraoral and intraoral that both the extraoral and intraoral infraorbital nerve blocks. infraorbital nerve blocks will result in a declining rate of pulpal anesthesia for TABLE 3 the canine and premolars. Participants’ postinjection pain ratings for In our study, all of the participants extraoral and intraoral infraorbital nerve reported experiencing soft-tissue anesblocks (N = 40). thesia of the lower eyelid, lateral nose and upper lip after receiving both types INJECTION PHASE POSTINJECTION PAIN RATINGS (% [NO. OF PARTICIPANTS]) of infraorbital nerve blocks. Because not all teeth were pulpally anesthesized None Mild Moderate Severe successfully (Table 1, Figure 4), softDay Zero (Day of Injection When Soft-Tissue tissue anesthesia does not necessarily Anesthesia Wore Off) * indicate pulpal anesthesia. Extraoral nerve block 78 (31) 15 (6) 8 (3) 0 (0) The higher pain ratings for needle Intraoral nerve block 83 (33) 18 (7) 0 (0) 0 (0) insertion during the extraoral infraorDay One † bital nerve block administration (Table Extraoral nerve block 82 (33) 15 (6) 3 (1) 0 (0) 2) might have been related to the Intraoral nerve block 98 (39) 3 (1) 0 (0) 0 (0) † thicker and denser skin of the cheek. Day Two Extraoral nerve block 88 (35) 12 (5) 0 (0) 0 (0) The higher pain ratings of needle placeIntraoral nerve block 98 (39) 3 (1) 0 (0) 0 (0) ment during the extraoral infraorbital Day Three † nerve block administration might have Extraoral nerve block 95 (38) 5 (2) 0 (0) 0 (0) been related to the time it took to find Intraoral nerve block 100 (40) 0 (0) 0 (0) 0 (0) and negotiate the infraorbital canal * There was no significant difference (P > .05) between the extraoral and intraoral (mean time: two minutes, 14 seconds). infraorbital nerve blocks. † There was a significant difference (P < .05) between the extraoral and intraoral The clinician spent this time ensuring infraorbital nerve blocks. that the needle entered the canal. 4 Kleier and colleagues also found that they required time to probe and enter pain: 40 percent; moderate pain: 32 percent; the infraorbital canal. severe pain: 0 percent). However, Berberich and Solution deposition pain ratings (Table 2) colleagues3 combined the results for needle placewere lower than were the ratings reported by ment pain and solution deposition pain, possibly Berberich and colleagues3 for the intraoral infraleading to a higher reported incidence of pain orbital nerve block (no pain: 28 percent; mild associated with solution deposition.
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R E S E A R C H
Positive aspirations occurred in one of 80 injections (1.25 percent), which was similar to the incidence reported by Malamed1 for infraorbital nerve blocks. Facial bruising and diplopia occurred only after the clinician administered the extraoral infraorbital nerve block. When diplopia occurs, the patient should be reassured that the diplopia is transient and will not result in any permanent damage. Placing a patch over the eye may help the patient see more easily because the contralateral eye will retain normal movement. The low postinjection pain ratings (Table 3) and low incidence of postoperative sequelae in our study indicate that the intraoral and extraoral nerve blocks are clinically safe. CONCLUSIONS
We found that the extraoral and intraoral infraorbital nerve blocks were ineffective in providing profound pulpal anesthesia of the maxillary central and lateral incisors. The pulpal anesthesia success rate for the canine was 92 percent for both types of nerve blocks, the success rate for the first and second premolars ranged from 80 to 90 percent, and the success rate for the first molar ranged from 65 to 70 percent, with no significant differences (P < .05) between the two nerve blocks.
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Pulpal anesthesia did not last for an hour in any of the teeth. Needle insertion pain and postoperative sequelae were more common after administration of the extraoral infraorbital nerve block. ■ Disclosure. None of the authors reported any disclosures. 1. Malamed SF. Handbook of Local Anesthesia. 5th ed. St. Louis: Mosby; 2004:198-202. 2. Feige I. Technic and evaluation of the effectiveness of infraorbital anesthesia using the approach along the axis of the second premolar [in German]. Stomatol DDR 1978;28(9):649-653. 3. Berberich G, Reader A, Drum M, Nusstein J, Beck M. A prospective, randomized, double-blind comparison of the anesthetic efficacy of two percent lidocaine with 1:100,000 and 1:50,000 epinephrine and three percent mepivacaine in the intraoral, infraorbital nerve block. J Endod 2009;35(11):1498-1504. 4. Kleier DJ, Deeg DK, Averbach RE. The extraoral approach to the infraorbital nerve block. JADA 1983;107(5):758-760. 5. Sicher H. Oral Anatomy. 4th ed. St. Louis: Mosby; 1965:428-430. 6. Francis JC. Extraoral approach to the infraorbital block of the anterior and middle superior alveolar nerves. J Southern Calif Dent Assoc 1960;28(7):216-218. 7. Sicher H. Aspects in the applied anatomy of local anesthesia. Int Dent J 1950;1(1):70-82. 8. Phillips WH, Maxem HA. The nasopalatine block injection as an aid in operative procedures for maxillary incisors. Am J Orthod Oral Surg 1941;27(8):426-434. 9. Phillips WH. Anatomic considerations in local anesthesia. J Oral Surg 1943;1(2):112-121. 10. Olsen NH, Teuscher GW, Vehe KL. A study of the nerve supply to the upper anterior teeth. J Dent Res 1955;34(3):413-420. 11. Bennett CR. Monheim’s Local Anesthesia and Pain Control in Dental Practice. 3rd ed. St. Louis: Mosby; 1983:76-82. 12. Nevin HR. Simplifying the infraorbital injection. Modern Dent 1952;19(1):14-19. 13. Allen GD. Dental Anesthesia and Analgesia: Local and General. 2nd ed. Baltimore: Williams & Wilkins; 1979:104-106.
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A Comparison of the Local Anesthetic Efficacy of the Extraoral Versus the Intraoral Infraorbital Nerve Block Bradley Karkut, Al Reader, Melissa Drum, John Nusstein and Mike Beck JADA 2010;141(2):185-192 10.14219/jada.archive.2010.0137 The following resources related to this article are available online at jada.ada.org (this information is current as of September 29, 2014): Updated information and services including high-resolution figures, can be found in the online version of this article at: http://jada.ada.org/content/141/2/185
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A comparison of the local anesthetic efficacy of the extraoral versus the intraoral infraorbital nerve block Bradley Karkut, DDS, MS; Al Reader, DDS, MS; Melissa Drum, DDS, MS; John Nusstein, DDS, MS; Mike Beck, DDS, MA
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✷ Background. The efficacy of the extraoral infraorbital ® nerve block has not been studied sufficiently to ensure its appropriate clinical use. To compare the local anesthetic N C efficacy of the extraoral versus the intraoral infraorbital U U IN G ED A 4 nerve block, the authors conducted a prospective, randomRT ICLE ized crossover study. Methods. Forty adult participants randomly received extraoral infraorbital nerve blocks of 1.8 milliliters of 2 percent lidocaine with 1:100,000 epinephrine at one appointment and intraoral infraorbital nerve blocks of 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine at another appointment in a crossover design. After administering the injections, the authors used an electric pulp tester to assess the maxillary central and lateral incisors, canine, premolars and first molar for pulpal anesthesia in four-minute cycles for 60 minutes. They considered anesthesia to be successful when the participant had no response to two consecutive 80 readings (the maximum output) with the electric pulp tester. Conclusions. The authors found that the extraoral and intraoral infraorbital nerve blocks were ineffective in providing profound pulpal anesthesia of the maxillary central incisor (15 percent success rate) and lateral incisor (22 percent success rate). The pulpal anesthesia success rate was 92 percent for the canine for both types of nerve blocks, 80 to 90 percent for first and second premolars and 65 to 70 percent for the first molar, with no significant differences (P < .05) between the two nerve blocks. Pulpal anesthesia did not last for an hour in any of the teeth. Needle insertion pain and postoperative sequelae were more common after the extraoral infraorbital nerve block was administered. Clinical Implications. Both nerve blocks would be ineffective in the central and lateral incisors. Both nerve blocks would be somewhat successful in the canine and premolars but not in the first molar. Key Words. Lidocaine; extraoral infraorbital nerve block; intraoral infraorbital nerve block; maxillary. JADA 2010;141(2):185-192. I
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alamed1 described the maxillary infraorbital nerve block as an effective method for achieving profound pulpal anesthesia in the area from the maxillary central incisor through the canine. The pulps of the premolars and the mesiobuccal root of the first molar also are anesthetized in about 72 percent of patients who receive maxillary infraorbital nerve blocks.1 Few clinical studies have evaluated the efficacy of the infraorbital nerve block. Feige2 evaluated the effectiveness of the intraoral infraorbital nerve block by using 0.5 milliliters of 2 percent lidocaine with 1:80,000 epinephrine and found that pulpal anesthesia was attained in the canine and premolars but not in the incisors. Berberich and colleagues3 found that the intraoral infraorbital nerve block was ineffective in providing profound pulpal anesthesia (no participant response to two consecutive 80 readings with the electric pulp tester) in the maxillary central incisor (10 to 15 percent success rate),
At the time this study was conducted, Dr. Karkut was a graduate student in endodontics, College of Dentistry, The Ohio State University, Columbus, Ohio. He now is in private practice in Delaware, Ohio. Dr. Reader is a professor and the director of advanced endodontics, Division of Endodontics, College of Dentistry, The Ohio State University, 305 W. 12th Ave., Columbus, Ohio, 43210, e-mail “[email protected]“. Address reprint requests to Dr. Reader. Dr. Drum is an assistant professor, Division of Endodontics, College of Dentistry, The Ohio State University, Columbus. Dr. Nusstein is an associate professor and the chair, Division of Endodontics, College of Dentistry, The Ohio State University, Columbus. Dr. Beck is an emeritus associate professor, Division of Oral Biology, College of Dentistry, The Ohio State University, Columbus.
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The 40 participants randomly received 1.8 mL lateral incisor (25 to 30 percent success rate) and of 2 percent lidocaine with 1:100,000 epinephrine first molar (50 to 62 percent success rate). Success rates in the canine and premolars ranged (Xylocaine, Astra Pharmaceutical Products, from 85 to 92 percent and 75 to 85 percent, Worcester, Mass.) using the extraoral infraorbital respectively. However, pulpal anesthesia did not nerve block at one appointment and an intraoral last for 60 minutes. infraorbital nerve block at another appointment. We spaced the appointments at least one week Kleier and colleagues4 evaluated the extraoral apart using a crossover design. Before the experiinfraorbital nerve block in 20 participants by ment began, we randomly assigned five-digit using 1 mL of 3 percent mepivacaine. They numbers from a random number table to the two reported a 90 percent success rate in the maxilinfraorbital nerve blocks (extraoral and intralary central incisor, lateral incisor, canine and oral). We randomly assigned each participant to first premolar. The second premolar had a 45 perreceive the nerve blocks on the right or the left cent success rate. Therefore, on the basis of the side of his or her mouth. We also randomly results of Kleier and colleagues’4 study, we assigned the order in which the infraorbital nerve hypothesized that the extraoral approach to the blocks were administered at each appointment by infraorbital nerve may provide better anesthesia using random numbers. The senior than would the intraoral approach. author (B.K.) administered 20 sets The efficacy of an extraoral infraof nerve block injections on the orbital nerve block needs to be The efficacy of an right side of participants’ mouths investigated further to ensure its extraoral infraorbital and 20 sets on the left side of parappropriate clinical use. We connerve block needs ticipants’ mouths. The side randucted a prospective randomized to be investigated domly chosen to receive the first study to compare the local anesfurther to ensure nerve block injection was used thetic efficacy of the extraoral again to receive the second nerve versus the intraoral infraorbital its appropriate block injection. We chose the maxilnerve block. clinical use. lary right and left central incisors, PARTICIPANTS, MATERIALS the ipsilateral lateral incisor, AND METHODS canine, first and second premolars, and first molar as the test teeth for the experiment. We Participants. Forty adult men and women parused the contralateral mandibular canine as the ticipated in this study. We recruited participants unanesthetized control tooth to ensure that the from a population of patients, students and staff electric pulp tester was operating properly and at the College of Dentistry at The Ohio State Unithat the participant was responding appropriversity and The Ohio State University by using ately during each experimental portion of the direct recruitment and advertisements approved study. The results of clinical examinations indiby The Ohio State University Human Subjects cated that all of the teeth were free of caries, Review Committee. Our exclusion criteria were as large restorations and periodontal disease. No follows: younger than 18 years, older than 65 teeth had a history of trauma or sensitivity. years, allergic to local anesthetics or sulfites, Electric pulp tester. At the beginning of each pregnant, history of significant medical condiappointment before we administered any injections, active sites of pathosis in area of injection, tions, we tested the experimental teeth and coninability to give informed consent. We determined trol mandibular canine three times using the elecvia the participants’ written health histories and tric pulp tester (Kerr, Analytic Technology, by oral questioning that they were in good health Redmond, Wash.) to record baseline vitality.3 and were not taking any medication (over-thecounter pain-relieving medications, narcotics, Trained research personnel, who were masked to sedatives, antianxiety medications or antidepresthe type of injection technique used, performed all sant medications) that would alter pain perceppreinjection and postinjection tests. tion. The Ohio State University Human Subjects Recording injection pain. We instructed Review Committee, Columbus, approved both the each participant on how to rate the pain of needle protocol and informed consent document. We insertion, needle placement and solution deposiobtained written informed consent from each tion on a scale ranging from 0 to 3, in which 0 participant. indicated no pain, 1 indicated mild pain defined 186
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as pain that was recognizable but not discomforting, 2 indicated moderate pain defined as pain that was discomforting but bearable, and 3 indicated severe pain that caused considerable discomfort and was difficult to bear. Pilot study. We performed a pilot study using 17 human skulls to determine the location of the infraorbital foramen. We found the distance between the center of the infraorbital foramen and the lower border of the orbit was 7.4 millimeters (range: 5-9 mm). The distance between the center of the infraorbital foramen and the intersection of the frontonasal suture and the internasal suture was 43.3 mm (range: 40-47 mm). We also found the angulation of the infraorbital canal in a vertical direction was 25 degrees (range: 1033 degrees), which we measured by the angle formed by an orthodontic wire inserted into the infraorbital canal and the intersection of a line extending from the maxillary occlusal plane. The angulation of the infraorbital canal in a horizontal direction was 77 degrees (range: 67-85 degrees), which we measured by the angle formed by an orthodontic wire inserted into the infraorbital canal and the intersection of a line extending parallel to the lower border of the orbits. Therefore, we determined that the needle path would be backward, upward and outward to penetrate the infraorbital canal (Figure 1). Extraoral infraorbital nerve block. We used a variation of the extraoral infraorbital nerve block described by Kleier and colleagues4 and Sicher5 in this study. We administered the injection by using a 27-gauge 1½-inch needle (Sherwood Medical, St. Louis) and a standard aspirating syringe. By using the distance measurements we obtained from the pilot study, the senior author (B.K.) used a compass to mark the distance between the nasal bone and the foramen (43.3 mm). He traced an arc on the participant’s cheek using an indelible pencil and measured a distance of 7.4 mm from the lower border of the orbit until it crossed the previous mark and marked the intersection using an indelible pencil (Figure 2). While applying gentle pressure, he palpated the outline of the infraorbital foramen. If the participant felt an aching sensation, the clinician used this pressure point to help locate the foramen. He disinfected the participant’s skin surface with a sterile 70 percent alcoholdampened gauze square and allowed the skin to dry for 60 seconds. He then inserted the needle 2 to 3 mm and asked the participant to rate the pain of needle
Figure 1. The direction of the needle path for the extraoral infraorbital nerve block would be backward, upward and outward to penetrate the infraorbital canal.
insertion. After depositing approximately 0.2 mL of anesthetic solution, he advanced the needle slowly using a probing motion until it entered the infraorbital foramen. He recorded the time it took to locate and enter the foramen. He advanced the needle to the maximum depth negotiable for each participant; the maximum depth was 11 mm— that is, the average thickness of the soft tissue overlying the infraorbital canal would be approximately 7 mm4 and the maximum depth within the canal 4 mm.5 The participant rated the pain of needle placement at the target site. After performing aspiration, the clinician administered 1.6 mL of the anesthetic solution at a rate of 1 mL/ minute. The participant then rated the pain of solution deposition. The clinician measured the depth of the needle insertion by using the rubber stopper on the needle as a depth guide. He applied firm finger pressure over the injection site for 30 seconds after solution deposition to increase the diffusion of the anesthetic solution into the infraorbital foramen. Intraoral infraorbital nerve block. We used the intraoral infraorbital nerve block described by Malamed,1 Feige,2 and Berberich and colleagues.3 The senior author administered the injection using a 27-gauge 1½-inch needle and a standard aspirating syringe. He marked the approximate location of the infraorbital foramen on the participant’s cheek as described previously for the extraoral infraorbital injection. Using this guideline, he applied gentle pressure over the infraorbital JADA, Vol. 141
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Figure 2. The intersection of the two marks on the cheek corresponded to the approximate location of the infraorbital foramen for the extraoral infraorbital nerve block.
Figure 3. The direction of the needle path for the intraoral infraorbital nerve block was parallel to the long axis of the second premolar until it approximated the infraorbital foramen.
foramen. If the participant felt an aching sensation, the clinician used this pressure point to help locate the foramen. With the needle bevel facing bone, he inserted the needle 2 to 3 mm in the mucobuccal fold over the second premolar. The participant then rated the pain of needle insertion. After depositing approximately 0.2 mL of anesthetic solution, the clinician oriented the syringe toward the previously identified infraorbital foramen and advanced the needle parallel to the long axis of the second premolar until it approximated the position of the infraorbital foramen (Figure 3). The participant then rated the pain of needle placement. After performing aspiration, the clinician 188
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administered 1.6 mL of the anesthetic solution at a rate of 1 mL/minute. The participant rated the pain of solution deposition after needle withdrawal. The clinician measured the depth of needle insertion by using the rubber stopper on the needle as a depth guide. He applied firm finger pressure over the injection site for 30 seconds after solution deposition to increase the diffusion of the anesthetic solution into the infraorbital foramen. He practiced both the extraoral and intraoral infraorbital injections on 18 cadavers and on clinical patients requiring endodontic treatment before beginning our study. Testing. At one minute after completion of the injection, we obtained electric pulp test readings for the central and lateral incisors. At two minutes, we obtained electric pulp test readings for the canine and first premolar. At three minutes, we obtained electric pulp test readings for the second premolar and first molar. At four minutes, we obtained electric pulp test readings for the contralateral maxillary central incisor and contralateral mandibular canine. We repeated the testing cycle every four minutes for 60 minutes. Every fourth cycle, we used an inactivated electric pulp tester to assess “pain” of the control tooth and, thus, the reliability of the participant. At the completion of each cycle, we asked the participant if her or his lip, side of nose and lower eyelid (terminal branches of the infraorbital nerve) were numb. If the participant did not have any signs of subjective anesthesia 20 minutes after the nerve block was administered, we considered the nerve block to be a failure. However, we did not exclude any participants because they did not achieve soft-tissue anesthesia. We recorded instances of positive aspiration for both the extraoral and intraoral nerve blocks. When a positive aspiration occurred, we used a new cartridge of anesthetic solution. We asked all participants to complete surveys after each infraorbital nerve block was administered. Using the same pain scale as we described previously, they rated pain in the injection area immediately after the numbness wore off and each morning for three days. We instructed the participants to describe and record any other problems they experienced. Our criterion for pulpal anesthesia was an absence of response from the participant at the maximum output (an 80 reading) of the electric pulp tester. We considered anesthesia successful when we obtained two consecutive 80 readings.
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Statistical analysis. All participants we included in our data analysis underwent softtissue anesthesia. We compared the extraoral and intraoral infraorbital nerve blocks for anesthetic success and incidence of pulpal anesthesia (percentage of 80 readings across time) using multiple exact McNemar tests adjusted using the stepdown Bonferroni method of Holm. With a nondirectional α risk of .05 and assuming a success rate of 50 percent, we determined that a sample size of 40 participants was needed to demonstrate a difference in anesthetic success of ± 30 percentage points with a power of 0.90. We statistically analyzed between–nerve block differences in pain ratings for needle insertion, needle placement, solution deposition and postinjection survey ratings using multiple Wilcoxon matchedpair, signed-ranks tests adjusted using the stepdown Bonferroni method of Holm. We considered comparisons to be significant at P < .05. RESULTS
Twenty-three men and 17 women ranging in age from 19 to 35 years (average age: 26 years) participated in the study. Table 1 shows the percentages of successful pulpal anesthesia. There were no significant differences between the extraoral and intraoral infraorbital nerve blocks. The incidences of pulpal anesthesia (80 readings across time) for the two nerve blocks are shown in Figure 4. Pain ratings for each injection phase are shown in Table 2 (page 191). Needle insertion with the extraoral nerve block was statistically more painful than that with the intraoral nerve block. The average depth of needle penetration for the extraoral infraorbital nerve block was 9.75 mm with a range of 9 to 11 mm. One participant had a positive aspiration as the clinician administered the extraoral infraorbital nerve block. No participants had a positive aspiration as the clinician administered the intraoral infraorbital nerve block. Postinjection pain ratings are shown in Table 3 (page 191). We found small but significant differences in mean pain levels from day one to day three between the two nerve blocks. A total of 2.5 percent of the participants reported experiencing facial bruising for three days after the clinician administered the extraoral infraorbital nerve block. No participants reported experiencing facial bruising after the clinician administered the intraoral infraorbital nerve
TABLE 1
Percentages and number of participants (N = 40) who experienced anesthetic success after receiving infraorbital nerve blocks. SITE OF NERVE BLOCK
ANESTHETIC SUCCESS* (% [NO. OF PARTICIPANTS]) Extraoral
Intraoral
Central Incisor
15 (6)
15 (6)
Lateral Incisor
22 (9)
22 (9)
Canine
92 (37)
92 (37)
First Premolar †
87 (26)
90 (27)
Second Premolar
82 (33)
80 (32)
First Molar
65 (26)
70 (28)
0 (0)
0 (0)
Contralateral Central Incisor
* There was no significant difference (P > .05) between the extraoral and intraoral infraorbital nerve blocks. † Some teeth were missing because of extractions for orthodontic treatment.
block. Two participants (5.0 percent) reported experiencing double vision (diplopia) after the clinician administered the extraoral infraorbital nerve block, which resolved when soft-tissue anesthesia ended. No participants reported experiencing diplopia after the clinician administered the intraoral infraorbital nerve block. DISCUSSION
The success rates for both infraorbital nerve blocks were highest for the canine (92 percent) and first premolars (ranging from 87 to 90 percent) with no significant differences between the two nerve blocks (Table 1). The success rates of the nerve blocks for the second premolars were 80 to 82 percent. Berberich and colleagues3 reported success rates for the canines, first premolars and second premolars of 85 percent, 82 percent and 75 percent, respectively, after administering infraorbital nerve blocks using 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine. The success rates in our study were higher than those recorded by Berberich and colleagues3 and probably relate to individual variation in participant populations. Kleier and colleagues4 used the extraoral approach to the infraorbital nerve block and reported a 90 percent success rate in the central and lateral incisors, canines and first premolars. The results of our study did not show such JADA, Vol. 141
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■ Intraoral Infraorbital
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Figure 4. Incidence of pulpal anesthesia as determined by lack of response to electric pulp testing at the maximum setting (percentage of participants achieving 80 readings using the maximum output [80 reading] of the electric pulp tester) at each postinjection interval for the extraoral and intraoral nerve blocks. There were no significant differences between the extraoral and intraoral infraorbital nerve blocks for any of the teeth.
high success rates. We could not directly compare the results of our study with those of Kleier and colleagues4 because they tested the teeth with cold immediately after the injection and again at 15 minutes. Because children and elderly patients may require less anesthetic, the results of our study may not apply to these patients. The success rates of the central and lateral incisors ranged from 15 to 22 percent with no significant differences between the two nerve blocks (Table 1, Figure 4). Berberich and colleagues3 found 15 percent and 28 percent success rates of the central and lateral incisors, respectively, after administering infraorbital nerve blocks using 1.8 mL of 2 percent lidocaine with 1:100,000 epinephrine. Their results were similar to the results we obtained in our study. There are several theories to explain inadequate pulpal anesthesia of the central and lateral incisors. Francis6 states that the central incisor may demonstrate partial anesthesia owing to 190
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arborizing fibers from the opposite side of the midline. However, Sicher5 cites anatomical evidence to support the fact that the anterior superior alveolar nerves are restricted to one side of the maxilla. Accessory innervation from the nasopalatine nerve also has been implicated in failure.7-9 However, Olsen and colleagues10 found that 26 percent of the dissected human specimens had branches arising from the nasopalatine nerve at the nasal end of the incisive canal but none of the nerves entered the apex of the central incisor in any specimen. Because the anterior superior alveolar nerves arise in the infraorbital canal behind the infraorbital foramen, Sicher5 stated that to achieve full anesthesia of these nerves, the injection must be made into the infraorbital canal and not at the foramen’s entrance. Other investigators11-13 have contended that depositing anesthetic solution at the infraorbital foramen and allowing it to move into the canal will provide reliable anesthesia.
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TABLE 2 The 65 to 70 percent success rates in the first molar in our study would not Participants’ pain ratings for needle provide predictable pulpal anesthesia insertion, needle placement and solution (Table 1, Figure 4). Berberich and col3 deposition for infraorbital nerve blocks leagues found a success rate of 52 percent after administering the intraoral (N = 40). infraorbital nerve block. Therefore, we INJECTION PHASE PAIN RATINGS conclude that the extraoral or intraoral (% [NO. OF PARTICIPANTS]) approach to the infraorbital nerve None Mild Moderate Severe will not anesthetize the first molar Needle Insertion * predictably. Extraoral nerve block 3 (1) 58 (23) 40 (16) 0 (0) For the canine and premolars in our Intraoral nerve block 53 (21) 48 (19) 0 (0) 0 (0) study, both types of nerve blocks † Needle Placement resulted in a decreasing incidence of Extraoral nerve block 38 (15) 45 (18) 15 (6) 3 (1) pulpal anesthesia across the 60-minute Intraoral nerve block 58 (23) 35 (14) 8 (3) 0 (0) test period (Figure 4). Berberich and Solution Deposition † colleagues3 also recorded a decreasing Extraoral nerve block 75 (30) 20 (8) 5 (2) 0 (0) Intraoral nerve block 88 (35) 10 (4) 3 (1) 2 (1) incidence of pulpal anesthesia after administering the intraoral infraorbital * There was a significant difference (P < .05) between the extraoral and intraoral infraorbital nerve blocks. nerve block. Therefore, we conclude † There was no significant difference (P > .05) between the extraoral and intraoral that both the extraoral and intraoral infraorbital nerve blocks. infraorbital nerve blocks will result in a declining rate of pulpal anesthesia for TABLE 3 the canine and premolars. Participants’ postinjection pain ratings for In our study, all of the participants extraoral and intraoral infraorbital nerve reported experiencing soft-tissue anesblocks (N = 40). thesia of the lower eyelid, lateral nose and upper lip after receiving both types INJECTION PHASE POSTINJECTION PAIN RATINGS (% [NO. OF PARTICIPANTS]) of infraorbital nerve blocks. Because not all teeth were pulpally anesthesized None Mild Moderate Severe successfully (Table 1, Figure 4), softDay Zero (Day of Injection When Soft-Tissue tissue anesthesia does not necessarily Anesthesia Wore Off) * indicate pulpal anesthesia. Extraoral nerve block 78 (31) 15 (6) 8 (3) 0 (0) The higher pain ratings for needle Intraoral nerve block 83 (33) 18 (7) 0 (0) 0 (0) insertion during the extraoral infraorDay One † bital nerve block administration (Table Extraoral nerve block 82 (33) 15 (6) 3 (1) 0 (0) 2) might have been related to the Intraoral nerve block 98 (39) 3 (1) 0 (0) 0 (0) † thicker and denser skin of the cheek. Day Two Extraoral nerve block 88 (35) 12 (5) 0 (0) 0 (0) The higher pain ratings of needle placeIntraoral nerve block 98 (39) 3 (1) 0 (0) 0 (0) ment during the extraoral infraorbital Day Three † nerve block administration might have Extraoral nerve block 95 (38) 5 (2) 0 (0) 0 (0) been related to the time it took to find Intraoral nerve block 100 (40) 0 (0) 0 (0) 0 (0) and negotiate the infraorbital canal * There was no significant difference (P > .05) between the extraoral and intraoral (mean time: two minutes, 14 seconds). infraorbital nerve blocks. † There was a significant difference (P < .05) between the extraoral and intraoral The clinician spent this time ensuring infraorbital nerve blocks. that the needle entered the canal. 4 Kleier and colleagues also found that they required time to probe and enter pain: 40 percent; moderate pain: 32 percent; the infraorbital canal. severe pain: 0 percent). However, Berberich and Solution deposition pain ratings (Table 2) colleagues3 combined the results for needle placewere lower than were the ratings reported by ment pain and solution deposition pain, possibly Berberich and colleagues3 for the intraoral infraleading to a higher reported incidence of pain orbital nerve block (no pain: 28 percent; mild associated with solution deposition.
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R E S E A R C H
Positive aspirations occurred in one of 80 injections (1.25 percent), which was similar to the incidence reported by Malamed1 for infraorbital nerve blocks. Facial bruising and diplopia occurred only after the clinician administered the extraoral infraorbital nerve block. When diplopia occurs, the patient should be reassured that the diplopia is transient and will not result in any permanent damage. Placing a patch over the eye may help the patient see more easily because the contralateral eye will retain normal movement. The low postinjection pain ratings (Table 3) and low incidence of postoperative sequelae in our study indicate that the intraoral and extraoral nerve blocks are clinically safe. CONCLUSIONS
We found that the extraoral and intraoral infraorbital nerve blocks were ineffective in providing profound pulpal anesthesia of the maxillary central and lateral incisors. The pulpal anesthesia success rate for the canine was 92 percent for both types of nerve blocks, the success rate for the first and second premolars ranged from 80 to 90 percent, and the success rate for the first molar ranged from 65 to 70 percent, with no significant differences (P < .05) between the two nerve blocks.
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Pulpal anesthesia did not last for an hour in any of the teeth. Needle insertion pain and postoperative sequelae were more common after administration of the extraoral infraorbital nerve block. ■ Disclosure. None of the authors reported any disclosures. 1. Malamed SF. Handbook of Local Anesthesia. 5th ed. St. Louis: Mosby; 2004:198-202. 2. Feige I. Technic and evaluation of the effectiveness of infraorbital anesthesia using the approach along the axis of the second premolar [in German]. Stomatol DDR 1978;28(9):649-653. 3. Berberich G, Reader A, Drum M, Nusstein J, Beck M. A prospective, randomized, double-blind comparison of the anesthetic efficacy of two percent lidocaine with 1:100,000 and 1:50,000 epinephrine and three percent mepivacaine in the intraoral, infraorbital nerve block. J Endod 2009;35(11):1498-1504. 4. Kleier DJ, Deeg DK, Averbach RE. The extraoral approach to the infraorbital nerve block. JADA 1983;107(5):758-760. 5. Sicher H. Oral Anatomy. 4th ed. St. Louis: Mosby; 1965:428-430. 6. Francis JC. Extraoral approach to the infraorbital block of the anterior and middle superior alveolar nerves. J Southern Calif Dent Assoc 1960;28(7):216-218. 7. Sicher H. Aspects in the applied anatomy of local anesthesia. Int Dent J 1950;1(1):70-82. 8. Phillips WH, Maxem HA. The nasopalatine block injection as an aid in operative procedures for maxillary incisors. Am J Orthod Oral Surg 1941;27(8):426-434. 9. Phillips WH. Anatomic considerations in local anesthesia. J Oral Surg 1943;1(2):112-121. 10. Olsen NH, Teuscher GW, Vehe KL. A study of the nerve supply to the upper anterior teeth. J Dent Res 1955;34(3):413-420. 11. Bennett CR. Monheim’s Local Anesthesia and Pain Control in Dental Practice. 3rd ed. St. Louis: Mosby; 1983:76-82. 12. Nevin HR. Simplifying the infraorbital injection. Modern Dent 1952;19(1):14-19. 13. Allen GD. Dental Anesthesia and Analgesia: Local and General. 2nd ed. Baltimore: Williams & Wilkins; 1979:104-106.
February 2010
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