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Efficacy of combining a buccal infiltration with an inferior alveolar nerve block for mandibular molars with irreversible pulpitis
Vol. 109 No. 3 March 2010
ENDODONTOLOGY
Editor: Larz S.W. Spångberg
Efficacy of combining a buccal infiltration with an inferior alveolar nerve block for mandibular molars with irreversible pulpitis Masoud Parirokh, DMD, MS,a Seyed Amir Satvati, DDS,b Rohollah Sharifi, DDS,b Ali Reza Rekabi, DDS,b Hedayat Gorjestani, DMD, MS,c Nozar Nakhaee, MD,a and Paul V. Abbott, DDS, MSc,d Kerman, Iran, and Perth, Australia KERMAN UNIVERSITY OF MEDICAL SCIENCES AND UNIVERSITY OF WESTERN AUSTRALIA
Objective. The aim of this study was to assess the efficacy of inferior alveolar nerve (IAN) block combined with buccal infiltration for mandibular molars with irreversible pulpitis. Methodology. Eighty-four patients were randomly assigned to 3 groups of 28 patients each. Lidocaine 2% with 1:80,000 epinephrine was used for all injections. Group I patients received an IAN block with 1.8 mL of anesthetic. Group II patients received an IAN block using 3.6 mL. Group III patients received 1.8 mL as an IAN block and 1.8 mL as a buccal infiltration. A visual analogue scale was used to rate pain before anesthesia and discomfort experienced before and during access cavity preparation. Data were analyzed by chi-square, ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Results. The success rates for groups I to III were 14.8%, 39.3%, and 65.4%, respectively. Group III had significantly better anesthesia compared with group I (P ⬍ .05). Conclusion. Combining an IAN block and a buccal infiltration injection provided more effective anesthesia in mandibular molars with irreversible pulpitis. However, some cases may still require further anesthesia to prevent pain during endodontic treatment. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:468-473)
Obtaining adequate anesthesia is a primary goal for dentists when performing endodontic procedures for patients.1 The use of an inferior alveolar nerve (IAN) block is a routine local anesthetic technique when treat-
This study was supported by the Neuroscience Research Center, Kerman University of Medical Sciences. a Professor of Endodontics, Neuroscience Research Center, Oral and Dental Research Center, Kerman University of Medical Sciences, Kerman, Iran. b Postgraduate student, Endodontic Department, School of Dentistry, Kerman University of Medical Sciences, Kerman, Iran. c Assistant Professor, Oral and Dental Diseases Research Center, Kerman University of Medical Sciences, Kerman, Iran. d Winthrop Professor of Clinical Dentistry, School of Dentistry, University of Western Australia, Perth, Australia. Received for publication Oct 8, 2009; returned for revision Nov 9, 2009; accepted for publication Nov 11, 2009. 1079-2104/$ - see front matter © 2010 Published by Mosby, Inc. doi:10.1016/j.tripleo.2009.11.016
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ing mandibular molar teeth.2,3 It has been generally accepted that mandibular molar teeth are difficult to anesthetize well with an IAN block even when the technique is used for teeth with healthy pulps.2-5 Numerous investigations have been performed to assess the success rate of anesthesia in mandibular molar teeth.2-12 Previous investigations have focused on increasing the volume of the anesthetic solution, the speed of injection of the anesthetic solution, the use of analgesics before administering anesthetic, adding supplements such as mepridine, and the use of various other techniques.2-13 Previous investigations have shown a higher rate of failure to achieve complete anesthesia for root canal therapy in teeth with irreversible pulpitis.12,14,15 It has been generally accepted that supplementary anesthesia and/or techniques are required when the initial injection is inadequate to allow root canal treatment to be done.16 Because of the high failure rate of IAN blocks in teeth
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with irreversible pulpitis, dentists should consider supplementary anesthesia in patients who report pain during access cavity preparation.11,14,15,16 Previous investigations have evaluated the efficacy of buccal infiltrations for teeth with normal pulps8,17-21 or as supplementary anesthesia to IAN blocks for teeth with either normal pulps or with irreversible pulpitis.4,5,22 Most of these investigations have focused on comparing lidocaine and articaine,4,5,17,18,21-23 or on achieving anesthesia in teeth with irreversible pulpitis, which is known to be more difficult.12,14,15 Because it is very important to perform endodontic procedures with no, or at least minimal, pain for the patient, the purpose of this study was to compare the success rate of using both an IAN block and a buccal infiltration with that obtained by using an IAN block alone for endodontic treatment of mandibular teeth with irreversible pulpitis. MATERIALS AND METHODS This study was approved by the Ethics Committee of Kerman University of Medical Sciences in Iran (No. EC/ KNRC/ 87-8). Sample size calculations required up to 28 patients in each group to detect a difference of 40% in the success rate of anesthesia. The following inclusion and exclusion criteria were used for this study: ●
●
Exclusion criteria: Presence of systemic disorder, sensitivity to lidocaine with 1:80,000 epinephrine, presence of periodontal ligament (PDL) widening or periapical radiolucency, or pregnancy. Inclusion criteria: Healthy patients having a first mandibular molar tooth with irreversible pulpitis and normal periapical radiographic appearance. Clinical diagnosis of irreversible pulpitis was confirmed by a positive response to an electric pulp test (The Element Diagnostic Unit, SybronEndo, Glendora, CA) and a prolonged response with moderate to severe pain to a cold test using Roeko Endo-Frost (Roeko, Langenau, Germany).
Eighty-four patients were invited to participate in this prospective, randomized double-blind study. All patients were adults older than 18 years and were treated at the postgraduate clinic of the Endodontic Department of Kerman Dental School in Iran. The informed consent of all subjects who participated in this study was obtained after the nature of the procedure and possible discomforts and risks had been fully explained. The patients who agreed to participate were asked to rate their pain using a Heft-Parker visual analogue pain scale (VAS) before anesthetic solution was administered. The VAS scores were divided into 4 categories (Fig. 1). No pain corresponded to 0 mm. Mild pain was defined as greater than 0 mm and ⱕ 54 mm. Moderate pain was defined as greater than 54 mm
Parirokh et al. 469
Fig. 1. Heft-Parker VAS used for assessment of pain. The millimeter demarcations (numbers) were not shown on the VAS forms used by the patients.
and less than 114 mm. Severe pain was defined as 114 mm or more. The patients were randomly divided into 3 groups of 28 patients each. A side-loading cartridge syringe (Dena Instruments, Forgeman Instruments Co., Sialkot, Pakistan) was used for the injections. The syringe was equipped with a blood aspiration device and a thumb ring. A 27-gauge 38-mm needle (Carpule, Heraeus Kulzer GmbH, Hanau, Germany) was fitted to the syringe. A blood aspiration test was carried out before the IAN block was administered. In group I, following needle insertion and based on a standard IAN block method24 when bone contact was established, the needle was withdrawn 1 to 2 mm and aspiration was performed. If the aspiration was negative for blood, then the anesthetic solution (2% lidocaine with 1/80,000 epinephrine [Darupakhsh, Tehran, Iran]) was injected. Patients in group II received 3.6 mL of the same anesthetic solution; the same injection technique was used as in group I for the first cartridge. The second cartridge was then inserted in the syringe immediately after finishing the injection of the first cartridge without withdrawing the needle from the injection site. Thereafter, following further aspiration, the second cartridge was injected. Patients in group III had an IAN block administered in the same manner as group I and this was followed by injecting another cartridge of the same anesthetic solution in the buccal vestibule adjacent to the mandibular first molar. In summary, group I patients received 1.8 mL of anesthetic using a conventional IAN block, group II patients received 3.6 mL of anesthetic using a conventional IAN block, and the group III patients received 1.8 mL as a conventional IAN block and 1.8 mL as a buccal infiltration. Patients were randomly assigned to the groups by selecting a sealed opaque envelope with the group number concealed inside it. Two clinicians performed the clinical procedures: one of them administered the anesthetic solution and the other one prepared the endodontic access cavity 15 minutes following administration of the anesthetic. Only the clinician who administered the anesthetic solution was aware of the volume of solution and the type of anesthetic technique used. Fifteen minutes after administering anesthesia, the patients were retested with a cold pulp sensibility test
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Table I. Comparison of baseline characteristics between groups Characteristic
Group I (n ⫽ 27)
Group II (n ⫽ 28)
Group III (n ⫽ 27)
P value
Age, y Gender Male Female Education ⱕ Primary school Secondary school College Analgesic use Yes No Pain score before anesthesia
26.0 (⫾6.9)
28.4 (⫾8.1)
27.7 (⫾7.9)
.52*
10 (37.0%) 17 (63.0%)
8 (28.6%) 20 (71.4%)
7 (23.1%) 20 (76.9%)
2 (7.4%) 16 (59.3%) 9 (39.3%)
7 (25.0%) 12 (42.9%) 9 (32.1%)
6 (23.1%) 14 (53.8%) 6 (23.1%)
16 (59.3%) 11 (40.7%) 117.2 (⫾29.9)
22 (78.6%) 6 (21.4%) 119.2 (⫾22.8)
19 (73.1%) 7 (26.9%) 112.8 (⫾30.4)
.53†
.35†
.26† 0.69*
*Analysis of variance test. †Chi-square test.
Table II. Comparison of the overall success of anesthesia among the 3 groups End result Group I II III
Success (%)
Failure (%)
P value*
4 (14.80) 11 (39.3) 17 (65.4)
23 (85.2) 17 (64.3) 9 (34.6)
.001†
*Chi-square test pairwise. †There was significant difference only between groups I and III using pairwise comparisons with Bonferroni correction.
Fig. 2. The number of patients experiencing pain in the 3 groups 15 minutes after receiving the anesthetic injection, when penetrating dentin, when reaching the pulp chamber, and during canal instrumentation. The fifth bar in each group shows the number of patients without pain (success).
and they were asked to rate their pain using a HeftParker VAS. Then the teeth were isolated with rubber dam and endodontic access cavity preparation was begun. Access cavity preparation was started only in patients who reported lip numbness following administration of the anesthetic. The patients were instructed to rate any pain during each step of access cavity preparation including pain within dentin, when entering the pulp chamber, and when a file was being inserted into the root canals. If a patient reported sensitivity to the cold before starting the access cavity preparation or at any time during subsequent treatment, another method of anesthesia was then used in order to be able to continue with the treatment. Data were analyzed by chi-square, analysis of variance (ANOVA), KruskalWallis, and Mann-Whitney tests. The comparisons were considered significant if P was less than .05.
RESULTS Three patients from groups I and III were excluded from the study because they changed their mind after anesthesia administration or they were younger than 18. The remainder of the patients in groups I and II reported lip numbness following anesthesia, which traditionally would be clinically assumed as being 100% success rate for the IAN block technique. In group III patients, lip numbness could not be assumed as the sign of IAN success because the buccal injection may have masked the IAN block failure. Based on the Heft-Parker VAS, which was taken by the patients before anesthesia administration, patients in all 3 groups had the same level of preoperative pain. Table I shows no significant difference among the patients in all 3 groups for gender, age, taking analgesics before administering anesthesia, and the patient’s level of education. Success rates for groups I to III were 14.8%, 39.3%, and 65.4%, respectively. Overall 49 of the 81 patients did not have adequate anesthesia; among them, 17 patients reported responses to the cold pulp sensibility test 15 minutes after injection, and 32 patients had pain during access cavity preparation despite no response to the cold test 15 minutes after the injection (Fig. 2).
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More discomfort after having retested the teeth with the cold sensibility test 15 minutes after injection was reported by patients in group I, whereas patients in group II felt more discomfort when the pulp chamber was entered (Fig. 2). There were significant differences between groups I and II (P ⬍ .01) and groups I and III (P ⬍ .05) based on the post hoc Mann-Whitney test for pain scores at 15 minutes after anesthetic injection. Patients who received 1 IAN block and 1 buccal infiltration injection (group III) showed significantly better anesthesia when compared with patients in group I (P ⬍ .001) at the end of the study (Table II). Despite better anesthesia scores in group III, there was no significant difference between groups II and III (Table II) at the end of investigation. Also, despite better scores in group II, there was no significant difference between groups I and II (P ⬎ .05). DISCUSSION The results of this study showed significantly better anesthesia was obtained when a combination of conventional IAN block and buccal infiltration were administered in comparison with using conventional IAN with 1.8 mL of 2% lidocaine with 1/80,000 epinephrine in mandibular molar teeth with irreversible pulpitis. In this study, the patients’ gender, age, whether taking analgesics before administering anesthesia, and pain score before anesthesia were not significantly different (Table I). Therefore, it can be assumed that the potential effects of these parameters had minimal influence on the results of the study and hence the effectiveness of the 3 groups can be directly compared. Two methods have been used to assess the efficacy of local anesthetic injections in previous studies. Some investigators have used pulp sensibility tests such as electric pulp tests (EPT) or the cold test,5,9,17,20 whereas others have used the Heft-Parker visual analogue scale.6,9,10,25 In the current study, the Heft-Parker visual analogue pain scale was used to assess patient discomfort before and after injection. It has been shown that in teeth with irreversible pulpitis, no response to pulp sensibility tests (cold test and EPT) after local anesthetic injection may not guarantee complete pulp anesthesia.14,16 The results of this study agreed with previous investigations regarding invalid negative responses of cold tests following IAN block anesthesia.14,16 Overall, 64 patients from all 3 groups showed minimal or no response to cold testing 15 minutes after anesthetic injection, whereas 50% of them had pain during access cavity preparation. In the current study, 2% lidocaine with 1:80,000 epinephrine was used as the anesthetic solution because previous investigations have compared this anesthetic
Parirokh et al. 471
solution with other anesthetic solutions and it has been used to evaluate various injection techniques for mandibular teeth.2,4,6,9,10,12,19,23 Feeling no pain at the start of the treatment procedure is very important for both the dentist and the patient. In the present study, 15 minutes following injection of the anesthetic solution and before starting access cavity preparation, significant differences were found in pain levels with the cold test between groups III and I (P ⬍ .01) and between groups II and I (P ⬍ .05). The overall success rate for the combination of an IAN block and buccal infiltration was 65.4%, which was higher than the IAN block alone with both 1.8 mL and 3.6 mL of the same anesthetic solution (14.80% and 39.3% success rate, respectively). The difference was significant when buccal infiltration and IAN block were administered (group III) compared with the IAN block used alone. In contrast, Foster et al.19 reported that the success rates of an IAN block and the IAN plus buccal infiltration were 53% and 57%, respectively, for normal healthy mandibular first molar teeth. Their study showed no significant difference when buccal infiltration was used as a supplementary injection to the IAN block. In the present study, only teeth with irreversible pulpitis were included, whereas Foster et al.19 evaluated anesthesia efficacy on teeth with normal, healthy pulps. Previous investigations have confirmed that pulp anesthesia with an IAN block technique is more difficult to achieve in teeth with irreversible pulpitis.12,14,15 Successful anesthesia in mandibular molars with irreversible pulpitis following administration of an IAN block has been reported in 19% to 56% of patients.6,10,14,26,27 In this study, more effective anesthesia was achieved when an IAN block was combined with buccal infiltration (65.4%) compared with previous investigations. Comparing the 3 groups in the current study showed that most failures in group I occurred when the teeth were retested with cold sensibility tests 15 minutes after injection, whereas in group II most failures occurred when the pulp chamber was entered. This finding is in contrast with Bigby et al.,6 who reported greater than mild discomfort in most of their patients during access cavity preparation when the dentin was penetrated. In this study, different amounts of the anesthetic solutions were administered. Patients in group I received 1.8 mL, whereas patients in group II received 3.6 mL of the same anesthetic solution. Successful anesthesia was achieved in 14.8% and 39.3% in groups I and II, respectively. There was no significant difference between groups I and II despite more effective anesthesia for the latter group. Although the amount of anesthetic solution was greater in group II than in group
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I and this could possibly explain the better results, previous investigations have reported that the amount of anesthetic solution has no significant effect on efficacy of IAN block anesthesia.28,29 Despite using 2% lidocaine with 1:80,000 epinephrine, the success rate in the current investigation after administrating a combination of buccal infiltration and IAN block (65.4%) was higher in comparison with the results of the studies by Jung et al.20 and Matthews et al.22 (54% and 58%, respectively) who used articaine for the buccal injection and a combination of buccal injection with IAN block, respectively. A recent investigation20 of mandibular first molars with normal pulps compared buccal infiltration with conventional IAN block. Their results showed no statistically significant difference in the effectiveness of anesthesia between the 2 techniques despite more success when the buccal infiltration injection was used. In the present study on mandibular first molars with irreversible pulpitis, the combination of buccal infiltration with conventional IAN block resulted in significantly better anesthesia. The different pulp status between the 2 studies and the use of the buccal infiltration injection in combination with an IAN block in the present study may explain the conflicting results. Rood30 reported that a supplementary buccal infiltration following IAN block failure produced a higher success rate during various dental procedures. This is in agreement with the results of the current study and is also comparable with an investigation22 that used articaine as the supplementary anesthesia in posterior mandibular molar teeth with irreversible pulpitis. Currently, dentists typically begin treatment on their patients within 10 to 15 minutes following anesthetic injection. If a patient feels pain, then a supplementary technique should be used.16 Intraosseous injection is often the first choice because of its higher success rate,16 although it can be time consuming and may have side effects such as pain and discomfort postoperatively. The higher success rate obtained by using a supplementary buccal injection, as in the current study, can help dentists provide more predictable anesthesia for their patients and decrease the need for other supplementary anesthetic techniques. A dentist cannot be entirely sure about the success of the IAN block if a buccal injection is given immediately following the IAN block, but lower lip numbness is generally a good indicator that the IAN block has worked. The results of the current study showed that despite this drawback, a supplementary buccal injection provides more predictable anesthesia than a conventional IAN block used alone. Therefore, administering a buccal injection immediately following the IAN block injection can save time and improve pain control for the patient.
In conclusion, the combination of an IAN block and buccal infiltration significantly increased the effectiveness of local anesthesia in mandibular molar teeth with irreversible pulpitis compared with an IAN block alone. However, some cases may still require further anesthesia to prevent pain during endodontic treatment. REFERENCES 1. Walton RE, Reader A, Nusstein JM. Local anesthesia. In: Torabinejad M, Walton RE, editors. Endodontics, Principles and Practice. 4th ed. St. Louis MO: Saunders Elsevier; 2008. p. 129-47. 2. McLean C, Reader A, Beck M, Meryers WJ. An evaluation of 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. J Endod 1993;19:146-50. 3. Yared GM, Dagher FB. Evaluation of lidocaine in human inferior alveolar nerve block. J Endod 1997;23:575-8. 4. Robertson D, Nusstein J, Reader A, Beck M, McCartney M. The anesthetic efficacy of articaine in buccal infiltration of mandibular posterior teeth. J Am Dent Assoc 2007;138:1104-12. 5. Haase A, Reader A, Nusstein J, Beck M, Drum M. Comparing anesthetic efficacy of articaine versus lidocaine as a supplemental buccal infiltration of the mandibular first molar after an inferior alveolar nerve block. J Am Dent Assoc 2008;139: 1228-35. 6. Bigby J, Reader A, Nusstein J, Beck M. Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks in patients with irreversible pulpitis. J Endod 2007;33:7-10. 7. Ianiro SR, Jeansonne BG, McNeal SF, Eleazer PD. The effect of preoperative acetaminophen or a combination of acetaminophen and Ibuprofen on the success of inferior alveolar nerve block for teeth with irreversible pulpitis. J Endod 2007;33:11-4. 8. Corbett IP, Kanaa MD, Whitworth JM, Meechan JG. Articaine infiltration for anesthesia of mandibular first molars. J Endod 2008;34:514-8. 9. Mikesell P, Nusstein J, Reader A, Beck M, Weaver J. A comparison of articaine and lidocaine for inferior alveolar nerve blocks. J Endod 2005;31:265-70. 10. Claffey E, Reader A, Nusstein J, Beck M, Weaver J. Anesthetic efficacy of articaine for inferior alveolar nerve blocks in patients with irreversible pulpitis. J Endod 2004;30:568-71. 11. Reitz J, Reader A, Nist R, Beck M, Meyers WJ. Anesthetic efficacy of the intraosseous injection of 0.9 mL of 2% lidocaine (1:100,000 epinephrine) to augment an inferior alveolar nerve block. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86:516-23. 12. Tortamano IP, Siviero M, Costa CG, Buscariolo IA, Armonia PL. A comparison of the anesthetic efficacy of articaine and lidocaine in patients with irreversible pulpitis. J Endod 2009;35: 165-8. 13. Goodman A, Reader A, Nusstein J, Beck M, Weaver J. Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks. Anesth Prog 2006;53:131-9. 14. Reisman D, Reader A, Nist R, Beck M, Weaver J. Anesthetic efficacy of the supplemental intraosseous injection of 3% mepivacaine in irreversible pulpitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:676-82. 15. Hargreaves KM, Keiser K. Local anesthetic failure in endodontics: mechanisms and management (a review). Endod Topics 2002;1:26-39. 16. Reader A, Nusstein, Hargreaves KM. Local anesthesia in endodontics. In: Cohen S, Hargreaves KM, editors. Pathways of the pulp. 9th ed. St. Louis, MO: Mosby Elsevier; 2006. p. 691-723.
OOOOE Volume 109, Number 3 17. Kanaa MD, Whitworth JM, Corbett IP, Meechan JG. Articaine buccal infiltration enhances the effectiveness of lidocaine inferior alveolar nerve block. Int Endod J 2009;42:238-46. 18. Kanaa MD, Whitworth JM, Corbett IP, Meechan JG. Articaine and lidocaine mandibular buccal infiltration anesthesia: a prospective randomized double-blind cross-over study. J Endod 2006;32:296-8. 19. Foster W, Drum M, Reader A, Beck M. Anesthetic efficacy of buccal and lingual infiltrations of lidocaine following an inferior alveolar nerve block in mandibular posterior teeth. Anesth Prog 2007;54:163-9. 20. Jung IY, Kim JH, Kim ES, Lee CY, Lee SJ. An evaluation of buccal infiltrations and inferior alveolar nerve blocks in pulpal anesthesia for mandibular first molars. J Endod 2008;34: 11-3. 21. Meechan JG, Kanaa MD, Corbett IP, Steen IN, Whitworth JM. Pulpal anaesthesia for mandibular permanent first molar teeth: a double-blind randomized cross-over trial comparing buccal and buccal plus lingual infiltration injections in volunteers. Int Endod J 2006;39:764-9. 22. Matthews R, Drum M, Reader A, Nusstein J, Beck M. Articaine for supplemental buccal mandibular infiltration anesthesia in patients with irreversible pulpitis when the inferior alveolar nerve block fails. J Endod 2009;35:343-6. 23. Rosenberg PA, Amin KG, Zibari Y, Lin LM. Comparison of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine when used as a supplemental anesthetic. J Endod 2007;33:403-5.
Parirokh et al. 473 24. Malamed SF. Handbook of local anesthesia. 5th ed. St. Louis, MO: Mosby; 2004. p. 227-54. 25. McCartney M, Reader A, Beck M. Injection pain of the inferior alveolar nerve block in patients with irreversible pulpitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:571-5. 26. Cohen HP, Cha BY, Spångberg LS. Endodontic anesthesia in mandibular molars: a clinical study. J Endod 1993;19:370-3. 27. Kennedy S, Reader A, Nusstein J, Beck M, Weaver J. The significance of needle deflection in success of the inferior alveolar nerve block in patients with irreversible pulpitis. J Endod 2003;29:630-3. 28. Nusstein J, Reader A, Beck M. Anesthetic efficacy of different volumes of lidocaine with epinephrine for inferior alveolar nerve blocks. Gen Dent 2002;50:372-5. 29. Vreeland DL, Reader A, Beck M, Meyers W, Weaver J. An evaluation of volumes and concentrations of lidocaine in human inferior alveolar nerve block. J Endod 1989;15:6-12. 30. Rood JP. The analgesia and innervations of mandibular teeth. Br Dent J 1976;140:237-9.
Reprint requests: Masoud Parirokh, DMD, MS Neurosciences Research Center Tahmasbabad Cross Road Kerman, Iran [email protected]
ENDODONTOLOGY
Editor: Larz S.W. Spångberg
Efficacy of combining a buccal infiltration with an inferior alveolar nerve block for mandibular molars with irreversible pulpitis Masoud Parirokh, DMD, MS,a Seyed Amir Satvati, DDS,b Rohollah Sharifi, DDS,b Ali Reza Rekabi, DDS,b Hedayat Gorjestani, DMD, MS,c Nozar Nakhaee, MD,a and Paul V. Abbott, DDS, MSc,d Kerman, Iran, and Perth, Australia KERMAN UNIVERSITY OF MEDICAL SCIENCES AND UNIVERSITY OF WESTERN AUSTRALIA
Objective. The aim of this study was to assess the efficacy of inferior alveolar nerve (IAN) block combined with buccal infiltration for mandibular molars with irreversible pulpitis. Methodology. Eighty-four patients were randomly assigned to 3 groups of 28 patients each. Lidocaine 2% with 1:80,000 epinephrine was used for all injections. Group I patients received an IAN block with 1.8 mL of anesthetic. Group II patients received an IAN block using 3.6 mL. Group III patients received 1.8 mL as an IAN block and 1.8 mL as a buccal infiltration. A visual analogue scale was used to rate pain before anesthesia and discomfort experienced before and during access cavity preparation. Data were analyzed by chi-square, ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Results. The success rates for groups I to III were 14.8%, 39.3%, and 65.4%, respectively. Group III had significantly better anesthesia compared with group I (P ⬍ .05). Conclusion. Combining an IAN block and a buccal infiltration injection provided more effective anesthesia in mandibular molars with irreversible pulpitis. However, some cases may still require further anesthesia to prevent pain during endodontic treatment. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:468-473)
Obtaining adequate anesthesia is a primary goal for dentists when performing endodontic procedures for patients.1 The use of an inferior alveolar nerve (IAN) block is a routine local anesthetic technique when treat-
This study was supported by the Neuroscience Research Center, Kerman University of Medical Sciences. a Professor of Endodontics, Neuroscience Research Center, Oral and Dental Research Center, Kerman University of Medical Sciences, Kerman, Iran. b Postgraduate student, Endodontic Department, School of Dentistry, Kerman University of Medical Sciences, Kerman, Iran. c Assistant Professor, Oral and Dental Diseases Research Center, Kerman University of Medical Sciences, Kerman, Iran. d Winthrop Professor of Clinical Dentistry, School of Dentistry, University of Western Australia, Perth, Australia. Received for publication Oct 8, 2009; returned for revision Nov 9, 2009; accepted for publication Nov 11, 2009. 1079-2104/$ - see front matter © 2010 Published by Mosby, Inc. doi:10.1016/j.tripleo.2009.11.016
468
ing mandibular molar teeth.2,3 It has been generally accepted that mandibular molar teeth are difficult to anesthetize well with an IAN block even when the technique is used for teeth with healthy pulps.2-5 Numerous investigations have been performed to assess the success rate of anesthesia in mandibular molar teeth.2-12 Previous investigations have focused on increasing the volume of the anesthetic solution, the speed of injection of the anesthetic solution, the use of analgesics before administering anesthetic, adding supplements such as mepridine, and the use of various other techniques.2-13 Previous investigations have shown a higher rate of failure to achieve complete anesthesia for root canal therapy in teeth with irreversible pulpitis.12,14,15 It has been generally accepted that supplementary anesthesia and/or techniques are required when the initial injection is inadequate to allow root canal treatment to be done.16 Because of the high failure rate of IAN blocks in teeth
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with irreversible pulpitis, dentists should consider supplementary anesthesia in patients who report pain during access cavity preparation.11,14,15,16 Previous investigations have evaluated the efficacy of buccal infiltrations for teeth with normal pulps8,17-21 or as supplementary anesthesia to IAN blocks for teeth with either normal pulps or with irreversible pulpitis.4,5,22 Most of these investigations have focused on comparing lidocaine and articaine,4,5,17,18,21-23 or on achieving anesthesia in teeth with irreversible pulpitis, which is known to be more difficult.12,14,15 Because it is very important to perform endodontic procedures with no, or at least minimal, pain for the patient, the purpose of this study was to compare the success rate of using both an IAN block and a buccal infiltration with that obtained by using an IAN block alone for endodontic treatment of mandibular teeth with irreversible pulpitis. MATERIALS AND METHODS This study was approved by the Ethics Committee of Kerman University of Medical Sciences in Iran (No. EC/ KNRC/ 87-8). Sample size calculations required up to 28 patients in each group to detect a difference of 40% in the success rate of anesthesia. The following inclusion and exclusion criteria were used for this study: ●
●
Exclusion criteria: Presence of systemic disorder, sensitivity to lidocaine with 1:80,000 epinephrine, presence of periodontal ligament (PDL) widening or periapical radiolucency, or pregnancy. Inclusion criteria: Healthy patients having a first mandibular molar tooth with irreversible pulpitis and normal periapical radiographic appearance. Clinical diagnosis of irreversible pulpitis was confirmed by a positive response to an electric pulp test (The Element Diagnostic Unit, SybronEndo, Glendora, CA) and a prolonged response with moderate to severe pain to a cold test using Roeko Endo-Frost (Roeko, Langenau, Germany).
Eighty-four patients were invited to participate in this prospective, randomized double-blind study. All patients were adults older than 18 years and were treated at the postgraduate clinic of the Endodontic Department of Kerman Dental School in Iran. The informed consent of all subjects who participated in this study was obtained after the nature of the procedure and possible discomforts and risks had been fully explained. The patients who agreed to participate were asked to rate their pain using a Heft-Parker visual analogue pain scale (VAS) before anesthetic solution was administered. The VAS scores were divided into 4 categories (Fig. 1). No pain corresponded to 0 mm. Mild pain was defined as greater than 0 mm and ⱕ 54 mm. Moderate pain was defined as greater than 54 mm
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Fig. 1. Heft-Parker VAS used for assessment of pain. The millimeter demarcations (numbers) were not shown on the VAS forms used by the patients.
and less than 114 mm. Severe pain was defined as 114 mm or more. The patients were randomly divided into 3 groups of 28 patients each. A side-loading cartridge syringe (Dena Instruments, Forgeman Instruments Co., Sialkot, Pakistan) was used for the injections. The syringe was equipped with a blood aspiration device and a thumb ring. A 27-gauge 38-mm needle (Carpule, Heraeus Kulzer GmbH, Hanau, Germany) was fitted to the syringe. A blood aspiration test was carried out before the IAN block was administered. In group I, following needle insertion and based on a standard IAN block method24 when bone contact was established, the needle was withdrawn 1 to 2 mm and aspiration was performed. If the aspiration was negative for blood, then the anesthetic solution (2% lidocaine with 1/80,000 epinephrine [Darupakhsh, Tehran, Iran]) was injected. Patients in group II received 3.6 mL of the same anesthetic solution; the same injection technique was used as in group I for the first cartridge. The second cartridge was then inserted in the syringe immediately after finishing the injection of the first cartridge without withdrawing the needle from the injection site. Thereafter, following further aspiration, the second cartridge was injected. Patients in group III had an IAN block administered in the same manner as group I and this was followed by injecting another cartridge of the same anesthetic solution in the buccal vestibule adjacent to the mandibular first molar. In summary, group I patients received 1.8 mL of anesthetic using a conventional IAN block, group II patients received 3.6 mL of anesthetic using a conventional IAN block, and the group III patients received 1.8 mL as a conventional IAN block and 1.8 mL as a buccal infiltration. Patients were randomly assigned to the groups by selecting a sealed opaque envelope with the group number concealed inside it. Two clinicians performed the clinical procedures: one of them administered the anesthetic solution and the other one prepared the endodontic access cavity 15 minutes following administration of the anesthetic. Only the clinician who administered the anesthetic solution was aware of the volume of solution and the type of anesthetic technique used. Fifteen minutes after administering anesthesia, the patients were retested with a cold pulp sensibility test
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Table I. Comparison of baseline characteristics between groups Characteristic
Group I (n ⫽ 27)
Group II (n ⫽ 28)
Group III (n ⫽ 27)
P value
Age, y Gender Male Female Education ⱕ Primary school Secondary school College Analgesic use Yes No Pain score before anesthesia
26.0 (⫾6.9)
28.4 (⫾8.1)
27.7 (⫾7.9)
.52*
10 (37.0%) 17 (63.0%)
8 (28.6%) 20 (71.4%)
7 (23.1%) 20 (76.9%)
2 (7.4%) 16 (59.3%) 9 (39.3%)
7 (25.0%) 12 (42.9%) 9 (32.1%)
6 (23.1%) 14 (53.8%) 6 (23.1%)
16 (59.3%) 11 (40.7%) 117.2 (⫾29.9)
22 (78.6%) 6 (21.4%) 119.2 (⫾22.8)
19 (73.1%) 7 (26.9%) 112.8 (⫾30.4)
.53†
.35†
.26† 0.69*
*Analysis of variance test. †Chi-square test.
Table II. Comparison of the overall success of anesthesia among the 3 groups End result Group I II III
Success (%)
Failure (%)
P value*
4 (14.80) 11 (39.3) 17 (65.4)
23 (85.2) 17 (64.3) 9 (34.6)
.001†
*Chi-square test pairwise. †There was significant difference only between groups I and III using pairwise comparisons with Bonferroni correction.
Fig. 2. The number of patients experiencing pain in the 3 groups 15 minutes after receiving the anesthetic injection, when penetrating dentin, when reaching the pulp chamber, and during canal instrumentation. The fifth bar in each group shows the number of patients without pain (success).
and they were asked to rate their pain using a HeftParker VAS. Then the teeth were isolated with rubber dam and endodontic access cavity preparation was begun. Access cavity preparation was started only in patients who reported lip numbness following administration of the anesthetic. The patients were instructed to rate any pain during each step of access cavity preparation including pain within dentin, when entering the pulp chamber, and when a file was being inserted into the root canals. If a patient reported sensitivity to the cold before starting the access cavity preparation or at any time during subsequent treatment, another method of anesthesia was then used in order to be able to continue with the treatment. Data were analyzed by chi-square, analysis of variance (ANOVA), KruskalWallis, and Mann-Whitney tests. The comparisons were considered significant if P was less than .05.
RESULTS Three patients from groups I and III were excluded from the study because they changed their mind after anesthesia administration or they were younger than 18. The remainder of the patients in groups I and II reported lip numbness following anesthesia, which traditionally would be clinically assumed as being 100% success rate for the IAN block technique. In group III patients, lip numbness could not be assumed as the sign of IAN success because the buccal injection may have masked the IAN block failure. Based on the Heft-Parker VAS, which was taken by the patients before anesthesia administration, patients in all 3 groups had the same level of preoperative pain. Table I shows no significant difference among the patients in all 3 groups for gender, age, taking analgesics before administering anesthesia, and the patient’s level of education. Success rates for groups I to III were 14.8%, 39.3%, and 65.4%, respectively. Overall 49 of the 81 patients did not have adequate anesthesia; among them, 17 patients reported responses to the cold pulp sensibility test 15 minutes after injection, and 32 patients had pain during access cavity preparation despite no response to the cold test 15 minutes after the injection (Fig. 2).
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More discomfort after having retested the teeth with the cold sensibility test 15 minutes after injection was reported by patients in group I, whereas patients in group II felt more discomfort when the pulp chamber was entered (Fig. 2). There were significant differences between groups I and II (P ⬍ .01) and groups I and III (P ⬍ .05) based on the post hoc Mann-Whitney test for pain scores at 15 minutes after anesthetic injection. Patients who received 1 IAN block and 1 buccal infiltration injection (group III) showed significantly better anesthesia when compared with patients in group I (P ⬍ .001) at the end of the study (Table II). Despite better anesthesia scores in group III, there was no significant difference between groups II and III (Table II) at the end of investigation. Also, despite better scores in group II, there was no significant difference between groups I and II (P ⬎ .05). DISCUSSION The results of this study showed significantly better anesthesia was obtained when a combination of conventional IAN block and buccal infiltration were administered in comparison with using conventional IAN with 1.8 mL of 2% lidocaine with 1/80,000 epinephrine in mandibular molar teeth with irreversible pulpitis. In this study, the patients’ gender, age, whether taking analgesics before administering anesthesia, and pain score before anesthesia were not significantly different (Table I). Therefore, it can be assumed that the potential effects of these parameters had minimal influence on the results of the study and hence the effectiveness of the 3 groups can be directly compared. Two methods have been used to assess the efficacy of local anesthetic injections in previous studies. Some investigators have used pulp sensibility tests such as electric pulp tests (EPT) or the cold test,5,9,17,20 whereas others have used the Heft-Parker visual analogue scale.6,9,10,25 In the current study, the Heft-Parker visual analogue pain scale was used to assess patient discomfort before and after injection. It has been shown that in teeth with irreversible pulpitis, no response to pulp sensibility tests (cold test and EPT) after local anesthetic injection may not guarantee complete pulp anesthesia.14,16 The results of this study agreed with previous investigations regarding invalid negative responses of cold tests following IAN block anesthesia.14,16 Overall, 64 patients from all 3 groups showed minimal or no response to cold testing 15 minutes after anesthetic injection, whereas 50% of them had pain during access cavity preparation. In the current study, 2% lidocaine with 1:80,000 epinephrine was used as the anesthetic solution because previous investigations have compared this anesthetic
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solution with other anesthetic solutions and it has been used to evaluate various injection techniques for mandibular teeth.2,4,6,9,10,12,19,23 Feeling no pain at the start of the treatment procedure is very important for both the dentist and the patient. In the present study, 15 minutes following injection of the anesthetic solution and before starting access cavity preparation, significant differences were found in pain levels with the cold test between groups III and I (P ⬍ .01) and between groups II and I (P ⬍ .05). The overall success rate for the combination of an IAN block and buccal infiltration was 65.4%, which was higher than the IAN block alone with both 1.8 mL and 3.6 mL of the same anesthetic solution (14.80% and 39.3% success rate, respectively). The difference was significant when buccal infiltration and IAN block were administered (group III) compared with the IAN block used alone. In contrast, Foster et al.19 reported that the success rates of an IAN block and the IAN plus buccal infiltration were 53% and 57%, respectively, for normal healthy mandibular first molar teeth. Their study showed no significant difference when buccal infiltration was used as a supplementary injection to the IAN block. In the present study, only teeth with irreversible pulpitis were included, whereas Foster et al.19 evaluated anesthesia efficacy on teeth with normal, healthy pulps. Previous investigations have confirmed that pulp anesthesia with an IAN block technique is more difficult to achieve in teeth with irreversible pulpitis.12,14,15 Successful anesthesia in mandibular molars with irreversible pulpitis following administration of an IAN block has been reported in 19% to 56% of patients.6,10,14,26,27 In this study, more effective anesthesia was achieved when an IAN block was combined with buccal infiltration (65.4%) compared with previous investigations. Comparing the 3 groups in the current study showed that most failures in group I occurred when the teeth were retested with cold sensibility tests 15 minutes after injection, whereas in group II most failures occurred when the pulp chamber was entered. This finding is in contrast with Bigby et al.,6 who reported greater than mild discomfort in most of their patients during access cavity preparation when the dentin was penetrated. In this study, different amounts of the anesthetic solutions were administered. Patients in group I received 1.8 mL, whereas patients in group II received 3.6 mL of the same anesthetic solution. Successful anesthesia was achieved in 14.8% and 39.3% in groups I and II, respectively. There was no significant difference between groups I and II despite more effective anesthesia for the latter group. Although the amount of anesthetic solution was greater in group II than in group
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I and this could possibly explain the better results, previous investigations have reported that the amount of anesthetic solution has no significant effect on efficacy of IAN block anesthesia.28,29 Despite using 2% lidocaine with 1:80,000 epinephrine, the success rate in the current investigation after administrating a combination of buccal infiltration and IAN block (65.4%) was higher in comparison with the results of the studies by Jung et al.20 and Matthews et al.22 (54% and 58%, respectively) who used articaine for the buccal injection and a combination of buccal injection with IAN block, respectively. A recent investigation20 of mandibular first molars with normal pulps compared buccal infiltration with conventional IAN block. Their results showed no statistically significant difference in the effectiveness of anesthesia between the 2 techniques despite more success when the buccal infiltration injection was used. In the present study on mandibular first molars with irreversible pulpitis, the combination of buccal infiltration with conventional IAN block resulted in significantly better anesthesia. The different pulp status between the 2 studies and the use of the buccal infiltration injection in combination with an IAN block in the present study may explain the conflicting results. Rood30 reported that a supplementary buccal infiltration following IAN block failure produced a higher success rate during various dental procedures. This is in agreement with the results of the current study and is also comparable with an investigation22 that used articaine as the supplementary anesthesia in posterior mandibular molar teeth with irreversible pulpitis. Currently, dentists typically begin treatment on their patients within 10 to 15 minutes following anesthetic injection. If a patient feels pain, then a supplementary technique should be used.16 Intraosseous injection is often the first choice because of its higher success rate,16 although it can be time consuming and may have side effects such as pain and discomfort postoperatively. The higher success rate obtained by using a supplementary buccal injection, as in the current study, can help dentists provide more predictable anesthesia for their patients and decrease the need for other supplementary anesthetic techniques. A dentist cannot be entirely sure about the success of the IAN block if a buccal injection is given immediately following the IAN block, but lower lip numbness is generally a good indicator that the IAN block has worked. The results of the current study showed that despite this drawback, a supplementary buccal injection provides more predictable anesthesia than a conventional IAN block used alone. Therefore, administering a buccal injection immediately following the IAN block injection can save time and improve pain control for the patient.
In conclusion, the combination of an IAN block and buccal infiltration significantly increased the effectiveness of local anesthesia in mandibular molar teeth with irreversible pulpitis compared with an IAN block alone. However, some cases may still require further anesthesia to prevent pain during endodontic treatment. REFERENCES 1. Walton RE, Reader A, Nusstein JM. Local anesthesia. In: Torabinejad M, Walton RE, editors. Endodontics, Principles and Practice. 4th ed. St. Louis MO: Saunders Elsevier; 2008. p. 129-47. 2. McLean C, Reader A, Beck M, Meryers WJ. An evaluation of 4% prilocaine and 3% mepivacaine compared with 2% lidocaine (1:100,000 epinephrine) for inferior alveolar nerve block. J Endod 1993;19:146-50. 3. Yared GM, Dagher FB. Evaluation of lidocaine in human inferior alveolar nerve block. J Endod 1997;23:575-8. 4. Robertson D, Nusstein J, Reader A, Beck M, McCartney M. The anesthetic efficacy of articaine in buccal infiltration of mandibular posterior teeth. J Am Dent Assoc 2007;138:1104-12. 5. Haase A, Reader A, Nusstein J, Beck M, Drum M. Comparing anesthetic efficacy of articaine versus lidocaine as a supplemental buccal infiltration of the mandibular first molar after an inferior alveolar nerve block. J Am Dent Assoc 2008;139: 1228-35. 6. Bigby J, Reader A, Nusstein J, Beck M. Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks in patients with irreversible pulpitis. J Endod 2007;33:7-10. 7. Ianiro SR, Jeansonne BG, McNeal SF, Eleazer PD. The effect of preoperative acetaminophen or a combination of acetaminophen and Ibuprofen on the success of inferior alveolar nerve block for teeth with irreversible pulpitis. J Endod 2007;33:11-4. 8. Corbett IP, Kanaa MD, Whitworth JM, Meechan JG. Articaine infiltration for anesthesia of mandibular first molars. J Endod 2008;34:514-8. 9. Mikesell P, Nusstein J, Reader A, Beck M, Weaver J. A comparison of articaine and lidocaine for inferior alveolar nerve blocks. J Endod 2005;31:265-70. 10. Claffey E, Reader A, Nusstein J, Beck M, Weaver J. Anesthetic efficacy of articaine for inferior alveolar nerve blocks in patients with irreversible pulpitis. J Endod 2004;30:568-71. 11. Reitz J, Reader A, Nist R, Beck M, Meyers WJ. Anesthetic efficacy of the intraosseous injection of 0.9 mL of 2% lidocaine (1:100,000 epinephrine) to augment an inferior alveolar nerve block. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86:516-23. 12. Tortamano IP, Siviero M, Costa CG, Buscariolo IA, Armonia PL. A comparison of the anesthetic efficacy of articaine and lidocaine in patients with irreversible pulpitis. J Endod 2009;35: 165-8. 13. Goodman A, Reader A, Nusstein J, Beck M, Weaver J. Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks. Anesth Prog 2006;53:131-9. 14. Reisman D, Reader A, Nist R, Beck M, Weaver J. Anesthetic efficacy of the supplemental intraosseous injection of 3% mepivacaine in irreversible pulpitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:676-82. 15. Hargreaves KM, Keiser K. Local anesthetic failure in endodontics: mechanisms and management (a review). Endod Topics 2002;1:26-39. 16. Reader A, Nusstein, Hargreaves KM. Local anesthesia in endodontics. In: Cohen S, Hargreaves KM, editors. Pathways of the pulp. 9th ed. St. Louis, MO: Mosby Elsevier; 2006. p. 691-723.
OOOOE Volume 109, Number 3 17. Kanaa MD, Whitworth JM, Corbett IP, Meechan JG. Articaine buccal infiltration enhances the effectiveness of lidocaine inferior alveolar nerve block. Int Endod J 2009;42:238-46. 18. Kanaa MD, Whitworth JM, Corbett IP, Meechan JG. Articaine and lidocaine mandibular buccal infiltration anesthesia: a prospective randomized double-blind cross-over study. J Endod 2006;32:296-8. 19. Foster W, Drum M, Reader A, Beck M. Anesthetic efficacy of buccal and lingual infiltrations of lidocaine following an inferior alveolar nerve block in mandibular posterior teeth. Anesth Prog 2007;54:163-9. 20. Jung IY, Kim JH, Kim ES, Lee CY, Lee SJ. An evaluation of buccal infiltrations and inferior alveolar nerve blocks in pulpal anesthesia for mandibular first molars. J Endod 2008;34: 11-3. 21. Meechan JG, Kanaa MD, Corbett IP, Steen IN, Whitworth JM. Pulpal anaesthesia for mandibular permanent first molar teeth: a double-blind randomized cross-over trial comparing buccal and buccal plus lingual infiltration injections in volunteers. Int Endod J 2006;39:764-9. 22. Matthews R, Drum M, Reader A, Nusstein J, Beck M. Articaine for supplemental buccal mandibular infiltration anesthesia in patients with irreversible pulpitis when the inferior alveolar nerve block fails. J Endod 2009;35:343-6. 23. Rosenberg PA, Amin KG, Zibari Y, Lin LM. Comparison of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine when used as a supplemental anesthetic. J Endod 2007;33:403-5.
Parirokh et al. 473 24. Malamed SF. Handbook of local anesthesia. 5th ed. St. Louis, MO: Mosby; 2004. p. 227-54. 25. McCartney M, Reader A, Beck M. Injection pain of the inferior alveolar nerve block in patients with irreversible pulpitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:571-5. 26. Cohen HP, Cha BY, Spångberg LS. Endodontic anesthesia in mandibular molars: a clinical study. J Endod 1993;19:370-3. 27. Kennedy S, Reader A, Nusstein J, Beck M, Weaver J. The significance of needle deflection in success of the inferior alveolar nerve block in patients with irreversible pulpitis. J Endod 2003;29:630-3. 28. Nusstein J, Reader A, Beck M. Anesthetic efficacy of different volumes of lidocaine with epinephrine for inferior alveolar nerve blocks. Gen Dent 2002;50:372-5. 29. Vreeland DL, Reader A, Beck M, Meyers W, Weaver J. An evaluation of volumes and concentrations of lidocaine in human inferior alveolar nerve block. J Endod 1989;15:6-12. 30. Rood JP. The analgesia and innervations of mandibular teeth. Br Dent J 1976;140:237-9.
Reprint requests: Masoud Parirokh, DMD, MS Neurosciences Research Center Tahmasbabad Cross Road Kerman, Iran [email protected]