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A Comparison of Different Volumes of Articaine for Inferior Alveolar Nerve Block for Molar Teeth with Symptomatic Irreversible Pulpitis
CONSORT Randomized Clinical Trial
A Comparison of Different Volumes of Articaine for Inferior Alveolar Nerve Block for Molar Teeth with Symptomatic Irreversible Pulpitis Ramin Abazarpoor, DMD,* Masoud Parirokh, DMD, MSc,† Nouzar Nakhaee, MD,‡ and Paul V. Abbott, MDS§ Abstract Introduction: Achieving anesthesia in mandibular molar teeth with irreversible pulpitis is very difficult. The aim of this study was to compare the efficacy of 1.8 mL and 3.6 mL articaine for an inferior alveolar nerve block (IANB) when treating molars with symptomatic irreversible pulpitis. Methods: In a randomized, double-blind clinical trial, 82 first mandibular molar teeth with symptomatic irreversible pulpitis randomly received conventional IANB injection either with 1 (1.8 mL) or 2 cartridges (3.6 mL) of 4% articaine with 1:100,000 epinephrine. The patients recorded their pain before and during access cavity preparation as well as during root canal instrumentation using a HeftParker visual analog scale. No or mild pain was considered as successful anesthesia. Data were analyzed by t and chi-square tests. Results: Eighty patients were eligible to participate in this study, which showed that 3.6 mL articaine provided a significantly higher success rate (77.5%) of IANBs compared with 1.8 mL of the same anesthetic solution (27.5%) although neither group had 100% successful anesthesia (P < .001). Conclusions: Increasing the volume of articaine provided a significantly higher success rate of IANBs in mandibular first molar teeth with symptomatic irreversible pulpitis, but it did not result in 100% anesthetic success. (J Endod 2015;-:1–4)
Key Words Anesthesia, articaine, inferior alveolar, irreversible pulpitis, mandibular molar, nerve block, symptomatic, volume
R
oot canal treatment is a procedure in which pulp tissue and bacteria are removed from the root canal system (1). A major concern for dentists during root canal treatment is to provide profound anesthesia during the procedure (2). Numerous studies have been performed to assess methods to overcome pain and discomfort during root canal treatment using various techniques, equipment, and anesthetic solutions (3–8). Teeth with irreversible pulpitis have shown greater difficulty in achieving anesthesia during endodontic treatment. In addition, achieving anesthesia in mandibular molar teeth with irreversible pulpitis is more difficult compared with other posterior teeth with the same condition (9). An inferior alveolar nerve block (IANB) is the most common anesthetic technique used to provide anesthesia for mandibular molars (10). Lidocaine is the mostly widely used anesthetic agent in dentistry (11, 12). Articaine is an anesthetic solution that was approved by the Food and Drug Administration for use in dentistry in the United States in 2000 (13). Articaine is claimed to provide faster onset and longer duration of pulp anesthesia compared with lidocaine (14). Several investigations have compared the anesthetic efficacy of articaine with other anesthetic agents (15–19). The results of these studies have shown no significant difference between articaine and lidocaine when used for IANB injections (15–18). It is a mistake if a dentist assumes that soft tissue anesthesia is a sign of successful pulp anesthesia. Soft tissue anesthesia after the administration of an IANB only indicates that the injection has been administered at the correct site, but it does not guarantee pulp anesthesia. Successful pulp anesthesia success is only achieved if no or minimal pain is reported by the patient during access cavity preparation and root canal instrumentation (9). One of the suggested methods to overcome the failure of anesthesia after the administration of an IANB is to increase the volume of the anesthetic solution (20–25). Most of the previous investigations have reported that increasing the volume has no significant effect on anesthesia success. However, these studies have only used lidocaine as the anesthetic solution (20–23, 25). The aim of this investigation was to compare the anesthetic success of IANBs with articaine in teeth with symptomatic irreversible pulpitis without spontaneous pain when either 1.8 mL or 3.6 mL was used.
Materials and Methods From the *Oral and Dental Diseases Research Center and † Endodontology Research Center, Kerman University of Medical Sciences, Kerman, Iran; ‡Neuroscience Research Center, Kerman, Iran; and §School of Dentistry, University of Western Australia, Perth, Australia. Address requests for reprints to Dr Masoud Parirokh, Endodontology Research Center, Kerman University of Medical Sciences, Kerman, Iran. E-mail address: masoudparirokh@gmail. com 0099-2399/$ - see front matter Copyright ª 2015 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2015.05.015
JOE — Volume -, Number -, - 2015
The protocol of this study and the informed consent document were approved by the Ethics Committee of Kerman University of Medical Sciences, Kerman, Iran (no. KA/ 92/476). The sample size calculation, which was based on a type I error of 0.05 and a power of 0.8, indicated that ideally a sample size of 30 in each group would be required to detect a 20% difference in the success rate of 2 test groups. The inclusion criteria were as follows: healthy adult patients 18–65 years old having a mandibular first molar tooth with symptomatic irreversible pulpitis and a normal periapical radiographic appearance. The teeth were tested with an electric pulp test (Parkell Inc, Farmingdale, NY) and a cold test (Roeko Endo Frost; Roeko, Hangenav, Germany) to determine pulp sensibility. The teeth were diagnosed as having symptomatic irreversible pulpitis if the patients had lingering pain and a prolonged response to the cold test (more than 10 seconds).
Anesthetic Efficacy of Different Volumes of Articaine
1
CONSORT Randomized Clinical Trial The exclusion criteria were as follows: a history of sensitivity to 4% articaine or epinephrine, systemic diseases, pregnancy, any type of medication that could potentially interact with the anesthetic solution, and spontaneous pain. Eighty-two patients were eligible to participate in this prospective, randomized double-blind study. All patients received treatment in the postgraduate clinic of the Endodontic Department of Kerman Dental School from September 2014 to May 2015. All patients signed an informed consent form. The patients were randomly divided into 2 groups of 40 patients each. To randomize the patients, odd and even numbers (1–80) were written on pieces of paper and kept in sealed envelopes. The first practitioner (M.P.) who performed the local anesthetic injection opened an envelope, and based on the number (group 1: odd number 1.8 mL articaine [Artinibsa; Inibsa, Barcelona, Spain] and group 2: even number 3.6 mL articaine), the patient was assigned to 1 of the groups. To provide a double-blind investigation, each patient received either 2 cartridges of the anesthetic solution or a cartridge of the anesthetic solution followed by a mock injection. Another practitioner (R.A.) performed the cold test and the rest of the treatment including access cavity preparation and root canal instrumentation. Hence, the second practitioner and the patients were not aware of the volume of anesthetic solution used. The patients were asked to rate their pain using a Heft-Parker visual analog pain scale (VAS) before administration of the anesthetic solution, after the cold test, and during the endodontic treatment (26). The VAS scores were divided into 4 categories: no pain corresponded to 0 mm, mild pain was defined as being >0 mm and #54 mm, moderate pain was >54 mm and <114 mm, and severe pain was $114 mm. A topical anesthetic gel (20% Benzocaine; Premier, Philadelphia, PA) was passively placed at the injection site with a cotton tip applicator for 1 minute before injection. Then, a conventional IANB was administered using an aspirating syringe with a side-loading cartridge system (Dena Instruments; Forgeman Instruments Co, Sialkot, Pakistan) and a 27-G 31-mm needle (C-K ject; CK Dental, Kor-Kyungji-do, Korea). All injections were given by 1 clinician (M.P.). Ten minutes after injection, the patients were asked whether they had lip numbness. Any patient without lip numbness at this stage was excluded from the study. Thereafter, the teeth were isolated with a rubber dam, and caries was removed followed by the preparation of an endodontic access cavity. Before starting the treatment, each patient received an explanation regarding the Heft-Parker VAS. The patients could stop the practitioner at any stage of treatment (ie, access cavity preparation, pulp chamber opening, or root canal instrumentation) if they felt more than mild pain by raising their hand. They were then given the VAS to rate the pain they felt during the procedure. At the end of each stage of treatment, the practitioner stopped work and asked the patients to rate their pain if they had not already raised their hand during treatment. No or mild discomfort (faint, weak, and mild pain) was considered as success, whereas moderate or severe pain was considered as failure of anesthesia. Fifteen minutes after the administration of the IANB, the teeth were re-evaluated with a cold test. If the patients reported sensitivity to the cold test before commencing caries removal and access cavity preparation or if higher than mild pain was recorded on the VAS at any stage of treatment, then supplemental anesthesia (intraperiodontal ligament or intrapulp injection) was used to provide patient comfort throughout the treatment. In each tooth, after establishing the working lengths, root canal instrumentation was completed with RaCe rotary instruments (FKG Dentaire, La Chaux-de-Fonds, Switzerland). Categorized data were analyzed using chi-square and t tests. P values <.05 were considered as significant. 2
Abazarpoor et al.
Results Two of the 82 patients who initially participated in the study were excluded because the patients were unwilling to continue the treatment procedure. No side effects, such as syncope, central nervous system reaction, cardiovascular reaction, methemoglobinemia, or allergic reactions, were reported by any of the patients. No significant difference was found between the age and sex of the patients in the 2 groups (P = .648 and P = 1.00, respectively). The total success rate of IANB anesthesia in group 2 was 77.5%, which was significantly higher (P < .001) than that in group 1 (27.5%). No significant difference was found between the groups either 15 minutes after the injection or during dentin penetration and root canal instrumentation (Table 1). However, the patients in group 1 reported significantly more pain compared with group 2 when the pulp was exposed during access cavity preparation (P < .001). Table 1 shows the success rate of anesthesia in each group during the various stages of treatment.
Discussion The results of the present study have shown that increasing the volume of articaine improved anesthesia success after IANB injection (P < .001) for mandibular first molar teeth with symptomatic irreversible pulpitis. Conflicting results regarding IANB anesthesia success have been reported after the use of different volumes of anesthetic agents (20– 25, 27). Most investigations have reported no significant difference in the success rate of IANB anesthesia with higher volumes of lidocaine (20–23, 25). In contrast, 2 studies have reported significantly higher success rates when the volume of lidocaine was increased for IANB injections (24, 27). Some of the previous studies regarding different volumes of anesthetic solutions for IANBs have evaluated teeth with healthy pulps (20, 21, 23, 27), whereas some others have tested different volumes of lidocaine in teeth with irreversible pulpitis (22, 24, 25). The present study was in accordance with a previous investigation that showed a significant positive effect of increasing the volume of anesthetic agents for mandibular molar teeth with irreversible pulpitis (24), but it was in contrast to 2 other studies (22, 25). It has been generally accepted that pain management in teeth with spontaneous pain and symptomatic irreversible pulpitis is very difficult during endodontic procedures, including access cavity preparation and root canal instrumentation (9). Previous investigations have evaluated different volumes of anesthetic in teeth with spontaneous pain and conditions requiring emergency treatment (24, 25), whereas the present study only included teeth with symptomatic irreversible pulpitis diagnosed by lingering pain after a cold test without spontaneous pain. Hence, it can be assumed that the degree of inflammation in these teeth was less than in the other studies. Patients with spontaneous pain might expect some pain during treatment
TABLE 1. Number of Cases and Percentage of Failure of Anesthesia during Access Cavity Preparation and Root Canal Instrumentation Failure number (%) Stage of procedure 15 minutes Dentin Pulp Instrumentation Final success
1.8 mL
3.6 mL
P value
0 2 (5.0) 23 (57.5) 4 (10.0) 11 (27.5)
0 0 7 (17.5) 2 (5.0) 31 (77.5)
1.00 .494 <.001 .08 <.001
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CONSORT Randomized Clinical Trial compared with patients who have not had spontaneous pain before treatment. Hence, in the present study, only patients with symptomatic irreversible pulpitis in first mandibular teeth were included. Several different reasons could possibly be attributed to the higher success rate when 3.6 mL articaine was used for an IANB in this study. First, some researchers believe that a sufficient length of an axon should be exposed to the anesthetic solution to achieve nerve impulse blockade (28). A higher volume of anesthetic agent can significantly improve anesthesia success during an IANB because it may provide a higher concentration of the anesthetic agent in the pterygomandibular space. In addition, a greater length of the inferior alveolar nerve would be exposed to the anesthetic solution (25). Second, a recently published article that used data from previous investigations by the same group of researchers reported that the administration of 2 cartridges of anesthetic agent helps to achieve a higher success rate of anesthesia because of the concern of possibly missing the inferior alveolar nerve when only 1 cartridge of anesthetic solution is used (29). In the present study, all patients reported lip numbness after having received either 1.8 or 3.6 mL articaine. However, 27.5% and 77.5% of the patients who received 1.8 mL and 3.6 mL, respectively, of articaine had no to minimal pain during endodontic procedures. Aggarwal et al (24) achieved a similar rate of success in their study on teeth with symptomatic irreversible pulpitis; they reported 26% and 54% success rates when 1.8 and 3.6 mL lidocaine was used for IANBs, respectively. In the present study, 77.5% of the patients had a successful IANB after receiving 3.6 mL articaine. It is very close to the results of Tortamano et al (17) who obtained 65% successful IANBs in mandibular posterior teeth with symptomatic irreversible pulpitis using the same volume of articaine. In contrast, Claffey et al (15) used 2.2 mL articaine for IANBs in their study, and they reported a 24% success rate for mandibular posterior teeth with irreversible pulpitis, which is comparable with the results of the present study when the patients received only 1.8 mL articaine (27.5%). Another investigation that used 1.8 mL articaine reported a 76% success rate, which is the highest success rate of IANBs when only 1 cartridge of articaine was used for posterior teeth with irreversible pulpitis (30). During laboratory studies, it has been shown that anesthetic agents have had an effective dose, which means that increasing the anesthetic agent more than that provides no significant beneficial effect in blocking nerve impulses. The effective dose for lidocaine is about 2 mL, but no study has evaluated the effective dose of articaine; this may be another reason why there was a significantly higher success rate with higher volumes of the anesthetic agent (28). No to minimal pain during caries excavation and root canal instrumentation was assumed as a sign of successful anesthesia, whereas more than mild pain based on the Heft-Parker VAS was a sign of failure during the endodontic procedure. In this study, most patients who had inadequate anesthesia felt more than minimal pain when the pulp was exposed, and for that reason the number of failures at that stage of treatment is higher compared with when dentin was penetrated (Table 1). Despite a different route of injection, higher volumes of articaine for mandibular buccal injections in young adults also provided a significant improvement in pulp anesthesia of molar teeth with normal pulps (31). Several side effects after the injection of articaine in dentistry have been described including paresthesia and methemoglobinemia (32, 33). However, a retrospective investigation conducted by Sambrook et al (33) in Australia showed that bupivacaine and prilocaine had higher incidences of side effects compared with articaine, whereas lidocaine was the safest anesthetic agent. In the present study, none of the patients reported any adverse side effects after treatment. JOE — Volume -, Number -, - 2015
Previous investigations have shown that different tooth types had different success rates of anesthesia after an IANB (16, 20). Therefore, only mandibular first molar teeth were included in the present study to reduce the number of experimental variables. A recent investigation on the incidence of missed IANBs in subjects with both asymptomatic vital teeth and patients with symptomatic irreversible pulpitis concluded that an injection of 3.6 mL lidocaine was significantly better than 1.8 mL of the same anesthetic solution (29). In the present study, none of the patients in either group reported a missed IANB. In conclusion, the present study showed that 3.6 mL articaine for IANB injection provided a significantly higher success rate of anesthesia compared with 1.8 mL of the same solution. However, complete pain control was not achieved in all of the teeth, indicating that supplemental anesthetic techniques are still required for many cases.
Acknowledgments The authors wish to thank the Oral and Dental Diseases Research Center for their financial support of this project. The authors deny any conflicts of interest related to this study.
References 1. Nabeshima CK, Caballero-Flores H, Cai S, et al. Bacterial removal promoted by 2 single-file systems: Wave One and One Shape. J Endod 2014;40:1995–8. 2. Pak JG, White SN. Pain prevalence and severity before, during, and after root canal treatment: a systematic review. J Endod 2011;37:429–38. 3. Shahi S, Mokhtari H, Rahimi S, et al. Effect of premedication with ibuprofen and dexamethasone on success rate of inferior alveolar nerve block for teeth with asymptomatic irreversible pulpitis: a randomized clinical trial. J Endod 2013;39: 160–2. €_I, Alac¸am T. Efficacy of single buccal infiltrations for maxillary first 4. Atasoy Ulusoy O molars in patients with irreversible pulpitis: a randomized controlled clinical trial. Int Endod J 2014;47:222–7. 5. Schellenberg J, Drum M, Reader A, et al. Effect of buffered 4% lidocaine on the success of the inferior alveolar nerve block in patients with symptomatic irreversible pulpitis: a prospective, randomized, double-blind study. J Endod 2015;41:791–6. 6. Parirokh M, Sadr S, Nakhaee N, et al. Efficacy of supplementary buccal infiltrations and intraligamentary injections to inferior alveolar nerve blocks in mandibular first molars with asymptomatic irreversible pulpitis: a randomized controlled trial. Int Endod J 2014;47:926–33. 7. Click V, Drum M, Reader A, et al. Evaluation of the Gow-Gates and Vazirani-Akinosi techniques in patients with symptomatic irreversible pulpitis: a prospective randomized study. J Endod 2015;41:16–21. 8. Saatchi M, Khademi A, Baghaei B, Noormohammadi H. Effect of sodium bicarbonate-buffered lidocaine on the success of inferior alveolar nerve block for teeth with symptomatic irreversible pulpitis: a prospective, randomized double-blind study. J Endod 2015;41:33–5. 9. Parirokh M, V Abbott P. Various strategies for pain-free root canal treatment. Iran Endod J 2014;9:1–14. 10. Ogle OE, Mahjoubi G. Local anesthesia: agents, techniques, and complications. Dent Clin North Am 2012;56:133–48. 11. Corbett IP, Ramacciato JC, Groppo FC, Meechan JG. A survey of local anaesthetic use among general dental practitioners in the UK attending postgraduate courses on pain control. Br Dent J 2005;199:784–7. 12. Gaffen AS, Haas DA. Survey of local anesthetic use by Ontario dentists. J Can Dent Assoc 2009;75:649. 13. Paxton K, Thome DE. Efficacy of articaine formulations: quantitative reviews. Dent Clin North Am 2010;54:643–53. 14. Tortamano IP, Siviero M, Lee S, et al. Onset and duration period of pulpal anesthesia of articaine and lidocaine in inferior alveolar nerve block. Braz Dent J 2013;24: 371–4. 15. Claffey E, Reader A, Nusstein J, et al. Anesthetic efficacy of articaine for inferior alveolar nerve blocks in patients with irreversible pulpitis. J Endod 2004;30:568–71. 16. Mikesell P, Nusstein J, Reader A, et al. A comparison of articaine and lidocaine for inferior alveolar nerve blocks. J Endod 2005;31:265–70. 17. Tortamano IP, Siviero M, Costa CG, et al. A comparison of the anesthetic efficacy of articaine and lidocaine in patients with irreversible pulpitis. J Endod 2009;35: 165–8.
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CONSORT Randomized Clinical Trial 18. Ashraf H, Kazem M, Dianat O, Noghrehkar F. Efficacy of articaine versus lidocaine in block and infiltration anesthesia administered in teeth with irreversible pulpitis: a prospective, randomized, double-blind study. J Endod 2013;39:6–10. 19. Monteiro MR, Groppo FC, Haiter-Neto F, et al. 4% articaine buccal infiltration versus 2% lidocaine inferior alveolar nerve block for emergency root canal treatment in mandibular molars with irreversible pulpits: a randomized clinical study. Int Endod J 2015;48:145–52. 20. Vreeland DL, Reader A, Beck M, et al. An evaluation of volumes and concentrations of lidocaine in human inferior alveolar nerve block. J Endod 1989;15: 6–12. 21. Nusstein J, Reader A, Beck FM. Anesthetic efficacy of different volumes of lidocaine with epinephrine for inferior alveolar nerve blocks. Gen Dent 2002;50:372–5. 22. Parirokh M, Satvati SA, Sharifi R, et al. Efficacy of combining a buccal infiltration with an inferior alveolar nerve block for mandibular molars with irreversible pulpitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109: 468–73. 23. Wali M, Drum M, Reader A, Nusstein J. Prospective, randomized single-blind study of the anesthetic efficacy of 1.8 and 3.6 milliliters of 2% lidocaine with 1:50,000 epinephrine for inferior alveolar nerve block. J Endod 2010;36:1459–62. 24. Aggarwal V, Singla M, Miglani S, et al. Comparative evaluation of 1.8 mL and 3.6 mL of 2% lidocaine with 1:200,000 epinephrine for inferior alveolar nerve block in patients with irreversible pulpitis: a prospective, randomized single-blind study. J Endod 2012;38:753–6.
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25. Fowler S, Reader A. Is a volume of 3.6 mL better than 1.8 mL for inferior alveolar nerve blocks in patients with symptomatic irreversible pulpitis? J Endod 2013;39: 970–2. 26. Heft MW, Parker SR. An experimental basis for revising the graphic rating scale for pain. Pain 1984;19:153–61. 27. Yared GM, Dagher FB. Evaluation of lidocaine in human inferior alveolar nerve block. J Endod 1997;23:575–8. 28. Potocnik I, Bajrovic F. Failure of inferior alveolar nerve block in endodontics. Endod Dent Traumatol 1999;15:247–51. 29. Fowler S, Reader A, Beck M. Incidence of missed inferior alveolar nerve blocks in vital asymptomatic subjects and in patients with symptomatic irreversible pulpitis. J Endod 2015;41:637–9. 30. Sood R, Hans MK, Shetty S. Comparison of anesthetic efficacy of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:80,000 epinephrine for inferior alveolar nerve block in patients with irreversible pulpitis. J Clin Exp Dent 2014;6: e520–3. 31. Martin M, Nusstein J, Drum M, et al. Anesthetic efficacy of 1.8 mL versus 3.6 mL of 4% articaine with 1:100,000 epinephrine as a primary buccal infiltration of the mandibular first molar. J Endod 2011;37:588–92. 32. Becker DE, Reed KL. Local anesthetics: review of pharmacological considerations. Anesth Prog 2012;59:90–101. 33. Sambrook PJ, Smith W, Elijah J, Goss AN. Severe adverse reactions to dental local anaesthetics: systemic reactions. Aust Dent J 2011;56:148–53.
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A Comparison of Different Volumes of Articaine for Inferior Alveolar Nerve Block for Molar Teeth with Symptomatic Irreversible Pulpitis Ramin Abazarpoor, DMD,* Masoud Parirokh, DMD, MSc,† Nouzar Nakhaee, MD,‡ and Paul V. Abbott, MDS§ Abstract Introduction: Achieving anesthesia in mandibular molar teeth with irreversible pulpitis is very difficult. The aim of this study was to compare the efficacy of 1.8 mL and 3.6 mL articaine for an inferior alveolar nerve block (IANB) when treating molars with symptomatic irreversible pulpitis. Methods: In a randomized, double-blind clinical trial, 82 first mandibular molar teeth with symptomatic irreversible pulpitis randomly received conventional IANB injection either with 1 (1.8 mL) or 2 cartridges (3.6 mL) of 4% articaine with 1:100,000 epinephrine. The patients recorded their pain before and during access cavity preparation as well as during root canal instrumentation using a HeftParker visual analog scale. No or mild pain was considered as successful anesthesia. Data were analyzed by t and chi-square tests. Results: Eighty patients were eligible to participate in this study, which showed that 3.6 mL articaine provided a significantly higher success rate (77.5%) of IANBs compared with 1.8 mL of the same anesthetic solution (27.5%) although neither group had 100% successful anesthesia (P < .001). Conclusions: Increasing the volume of articaine provided a significantly higher success rate of IANBs in mandibular first molar teeth with symptomatic irreversible pulpitis, but it did not result in 100% anesthetic success. (J Endod 2015;-:1–4)
Key Words Anesthesia, articaine, inferior alveolar, irreversible pulpitis, mandibular molar, nerve block, symptomatic, volume
R
oot canal treatment is a procedure in which pulp tissue and bacteria are removed from the root canal system (1). A major concern for dentists during root canal treatment is to provide profound anesthesia during the procedure (2). Numerous studies have been performed to assess methods to overcome pain and discomfort during root canal treatment using various techniques, equipment, and anesthetic solutions (3–8). Teeth with irreversible pulpitis have shown greater difficulty in achieving anesthesia during endodontic treatment. In addition, achieving anesthesia in mandibular molar teeth with irreversible pulpitis is more difficult compared with other posterior teeth with the same condition (9). An inferior alveolar nerve block (IANB) is the most common anesthetic technique used to provide anesthesia for mandibular molars (10). Lidocaine is the mostly widely used anesthetic agent in dentistry (11, 12). Articaine is an anesthetic solution that was approved by the Food and Drug Administration for use in dentistry in the United States in 2000 (13). Articaine is claimed to provide faster onset and longer duration of pulp anesthesia compared with lidocaine (14). Several investigations have compared the anesthetic efficacy of articaine with other anesthetic agents (15–19). The results of these studies have shown no significant difference between articaine and lidocaine when used for IANB injections (15–18). It is a mistake if a dentist assumes that soft tissue anesthesia is a sign of successful pulp anesthesia. Soft tissue anesthesia after the administration of an IANB only indicates that the injection has been administered at the correct site, but it does not guarantee pulp anesthesia. Successful pulp anesthesia success is only achieved if no or minimal pain is reported by the patient during access cavity preparation and root canal instrumentation (9). One of the suggested methods to overcome the failure of anesthesia after the administration of an IANB is to increase the volume of the anesthetic solution (20–25). Most of the previous investigations have reported that increasing the volume has no significant effect on anesthesia success. However, these studies have only used lidocaine as the anesthetic solution (20–23, 25). The aim of this investigation was to compare the anesthetic success of IANBs with articaine in teeth with symptomatic irreversible pulpitis without spontaneous pain when either 1.8 mL or 3.6 mL was used.
Materials and Methods From the *Oral and Dental Diseases Research Center and † Endodontology Research Center, Kerman University of Medical Sciences, Kerman, Iran; ‡Neuroscience Research Center, Kerman, Iran; and §School of Dentistry, University of Western Australia, Perth, Australia. Address requests for reprints to Dr Masoud Parirokh, Endodontology Research Center, Kerman University of Medical Sciences, Kerman, Iran. E-mail address: masoudparirokh@gmail. com 0099-2399/$ - see front matter Copyright ª 2015 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2015.05.015
JOE — Volume -, Number -, - 2015
The protocol of this study and the informed consent document were approved by the Ethics Committee of Kerman University of Medical Sciences, Kerman, Iran (no. KA/ 92/476). The sample size calculation, which was based on a type I error of 0.05 and a power of 0.8, indicated that ideally a sample size of 30 in each group would be required to detect a 20% difference in the success rate of 2 test groups. The inclusion criteria were as follows: healthy adult patients 18–65 years old having a mandibular first molar tooth with symptomatic irreversible pulpitis and a normal periapical radiographic appearance. The teeth were tested with an electric pulp test (Parkell Inc, Farmingdale, NY) and a cold test (Roeko Endo Frost; Roeko, Hangenav, Germany) to determine pulp sensibility. The teeth were diagnosed as having symptomatic irreversible pulpitis if the patients had lingering pain and a prolonged response to the cold test (more than 10 seconds).
Anesthetic Efficacy of Different Volumes of Articaine
1
CONSORT Randomized Clinical Trial The exclusion criteria were as follows: a history of sensitivity to 4% articaine or epinephrine, systemic diseases, pregnancy, any type of medication that could potentially interact with the anesthetic solution, and spontaneous pain. Eighty-two patients were eligible to participate in this prospective, randomized double-blind study. All patients received treatment in the postgraduate clinic of the Endodontic Department of Kerman Dental School from September 2014 to May 2015. All patients signed an informed consent form. The patients were randomly divided into 2 groups of 40 patients each. To randomize the patients, odd and even numbers (1–80) were written on pieces of paper and kept in sealed envelopes. The first practitioner (M.P.) who performed the local anesthetic injection opened an envelope, and based on the number (group 1: odd number 1.8 mL articaine [Artinibsa; Inibsa, Barcelona, Spain] and group 2: even number 3.6 mL articaine), the patient was assigned to 1 of the groups. To provide a double-blind investigation, each patient received either 2 cartridges of the anesthetic solution or a cartridge of the anesthetic solution followed by a mock injection. Another practitioner (R.A.) performed the cold test and the rest of the treatment including access cavity preparation and root canal instrumentation. Hence, the second practitioner and the patients were not aware of the volume of anesthetic solution used. The patients were asked to rate their pain using a Heft-Parker visual analog pain scale (VAS) before administration of the anesthetic solution, after the cold test, and during the endodontic treatment (26). The VAS scores were divided into 4 categories: no pain corresponded to 0 mm, mild pain was defined as being >0 mm and #54 mm, moderate pain was >54 mm and <114 mm, and severe pain was $114 mm. A topical anesthetic gel (20% Benzocaine; Premier, Philadelphia, PA) was passively placed at the injection site with a cotton tip applicator for 1 minute before injection. Then, a conventional IANB was administered using an aspirating syringe with a side-loading cartridge system (Dena Instruments; Forgeman Instruments Co, Sialkot, Pakistan) and a 27-G 31-mm needle (C-K ject; CK Dental, Kor-Kyungji-do, Korea). All injections were given by 1 clinician (M.P.). Ten minutes after injection, the patients were asked whether they had lip numbness. Any patient without lip numbness at this stage was excluded from the study. Thereafter, the teeth were isolated with a rubber dam, and caries was removed followed by the preparation of an endodontic access cavity. Before starting the treatment, each patient received an explanation regarding the Heft-Parker VAS. The patients could stop the practitioner at any stage of treatment (ie, access cavity preparation, pulp chamber opening, or root canal instrumentation) if they felt more than mild pain by raising their hand. They were then given the VAS to rate the pain they felt during the procedure. At the end of each stage of treatment, the practitioner stopped work and asked the patients to rate their pain if they had not already raised their hand during treatment. No or mild discomfort (faint, weak, and mild pain) was considered as success, whereas moderate or severe pain was considered as failure of anesthesia. Fifteen minutes after the administration of the IANB, the teeth were re-evaluated with a cold test. If the patients reported sensitivity to the cold test before commencing caries removal and access cavity preparation or if higher than mild pain was recorded on the VAS at any stage of treatment, then supplemental anesthesia (intraperiodontal ligament or intrapulp injection) was used to provide patient comfort throughout the treatment. In each tooth, after establishing the working lengths, root canal instrumentation was completed with RaCe rotary instruments (FKG Dentaire, La Chaux-de-Fonds, Switzerland). Categorized data were analyzed using chi-square and t tests. P values <.05 were considered as significant. 2
Abazarpoor et al.
Results Two of the 82 patients who initially participated in the study were excluded because the patients were unwilling to continue the treatment procedure. No side effects, such as syncope, central nervous system reaction, cardiovascular reaction, methemoglobinemia, or allergic reactions, were reported by any of the patients. No significant difference was found between the age and sex of the patients in the 2 groups (P = .648 and P = 1.00, respectively). The total success rate of IANB anesthesia in group 2 was 77.5%, which was significantly higher (P < .001) than that in group 1 (27.5%). No significant difference was found between the groups either 15 minutes after the injection or during dentin penetration and root canal instrumentation (Table 1). However, the patients in group 1 reported significantly more pain compared with group 2 when the pulp was exposed during access cavity preparation (P < .001). Table 1 shows the success rate of anesthesia in each group during the various stages of treatment.
Discussion The results of the present study have shown that increasing the volume of articaine improved anesthesia success after IANB injection (P < .001) for mandibular first molar teeth with symptomatic irreversible pulpitis. Conflicting results regarding IANB anesthesia success have been reported after the use of different volumes of anesthetic agents (20– 25, 27). Most investigations have reported no significant difference in the success rate of IANB anesthesia with higher volumes of lidocaine (20–23, 25). In contrast, 2 studies have reported significantly higher success rates when the volume of lidocaine was increased for IANB injections (24, 27). Some of the previous studies regarding different volumes of anesthetic solutions for IANBs have evaluated teeth with healthy pulps (20, 21, 23, 27), whereas some others have tested different volumes of lidocaine in teeth with irreversible pulpitis (22, 24, 25). The present study was in accordance with a previous investigation that showed a significant positive effect of increasing the volume of anesthetic agents for mandibular molar teeth with irreversible pulpitis (24), but it was in contrast to 2 other studies (22, 25). It has been generally accepted that pain management in teeth with spontaneous pain and symptomatic irreversible pulpitis is very difficult during endodontic procedures, including access cavity preparation and root canal instrumentation (9). Previous investigations have evaluated different volumes of anesthetic in teeth with spontaneous pain and conditions requiring emergency treatment (24, 25), whereas the present study only included teeth with symptomatic irreversible pulpitis diagnosed by lingering pain after a cold test without spontaneous pain. Hence, it can be assumed that the degree of inflammation in these teeth was less than in the other studies. Patients with spontaneous pain might expect some pain during treatment
TABLE 1. Number of Cases and Percentage of Failure of Anesthesia during Access Cavity Preparation and Root Canal Instrumentation Failure number (%) Stage of procedure 15 minutes Dentin Pulp Instrumentation Final success
1.8 mL
3.6 mL
P value
0 2 (5.0) 23 (57.5) 4 (10.0) 11 (27.5)
0 0 7 (17.5) 2 (5.0) 31 (77.5)
1.00 .494 <.001 .08 <.001
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CONSORT Randomized Clinical Trial compared with patients who have not had spontaneous pain before treatment. Hence, in the present study, only patients with symptomatic irreversible pulpitis in first mandibular teeth were included. Several different reasons could possibly be attributed to the higher success rate when 3.6 mL articaine was used for an IANB in this study. First, some researchers believe that a sufficient length of an axon should be exposed to the anesthetic solution to achieve nerve impulse blockade (28). A higher volume of anesthetic agent can significantly improve anesthesia success during an IANB because it may provide a higher concentration of the anesthetic agent in the pterygomandibular space. In addition, a greater length of the inferior alveolar nerve would be exposed to the anesthetic solution (25). Second, a recently published article that used data from previous investigations by the same group of researchers reported that the administration of 2 cartridges of anesthetic agent helps to achieve a higher success rate of anesthesia because of the concern of possibly missing the inferior alveolar nerve when only 1 cartridge of anesthetic solution is used (29). In the present study, all patients reported lip numbness after having received either 1.8 or 3.6 mL articaine. However, 27.5% and 77.5% of the patients who received 1.8 mL and 3.6 mL, respectively, of articaine had no to minimal pain during endodontic procedures. Aggarwal et al (24) achieved a similar rate of success in their study on teeth with symptomatic irreversible pulpitis; they reported 26% and 54% success rates when 1.8 and 3.6 mL lidocaine was used for IANBs, respectively. In the present study, 77.5% of the patients had a successful IANB after receiving 3.6 mL articaine. It is very close to the results of Tortamano et al (17) who obtained 65% successful IANBs in mandibular posterior teeth with symptomatic irreversible pulpitis using the same volume of articaine. In contrast, Claffey et al (15) used 2.2 mL articaine for IANBs in their study, and they reported a 24% success rate for mandibular posterior teeth with irreversible pulpitis, which is comparable with the results of the present study when the patients received only 1.8 mL articaine (27.5%). Another investigation that used 1.8 mL articaine reported a 76% success rate, which is the highest success rate of IANBs when only 1 cartridge of articaine was used for posterior teeth with irreversible pulpitis (30). During laboratory studies, it has been shown that anesthetic agents have had an effective dose, which means that increasing the anesthetic agent more than that provides no significant beneficial effect in blocking nerve impulses. The effective dose for lidocaine is about 2 mL, but no study has evaluated the effective dose of articaine; this may be another reason why there was a significantly higher success rate with higher volumes of the anesthetic agent (28). No to minimal pain during caries excavation and root canal instrumentation was assumed as a sign of successful anesthesia, whereas more than mild pain based on the Heft-Parker VAS was a sign of failure during the endodontic procedure. In this study, most patients who had inadequate anesthesia felt more than minimal pain when the pulp was exposed, and for that reason the number of failures at that stage of treatment is higher compared with when dentin was penetrated (Table 1). Despite a different route of injection, higher volumes of articaine for mandibular buccal injections in young adults also provided a significant improvement in pulp anesthesia of molar teeth with normal pulps (31). Several side effects after the injection of articaine in dentistry have been described including paresthesia and methemoglobinemia (32, 33). However, a retrospective investigation conducted by Sambrook et al (33) in Australia showed that bupivacaine and prilocaine had higher incidences of side effects compared with articaine, whereas lidocaine was the safest anesthetic agent. In the present study, none of the patients reported any adverse side effects after treatment. JOE — Volume -, Number -, - 2015
Previous investigations have shown that different tooth types had different success rates of anesthesia after an IANB (16, 20). Therefore, only mandibular first molar teeth were included in the present study to reduce the number of experimental variables. A recent investigation on the incidence of missed IANBs in subjects with both asymptomatic vital teeth and patients with symptomatic irreversible pulpitis concluded that an injection of 3.6 mL lidocaine was significantly better than 1.8 mL of the same anesthetic solution (29). In the present study, none of the patients in either group reported a missed IANB. In conclusion, the present study showed that 3.6 mL articaine for IANB injection provided a significantly higher success rate of anesthesia compared with 1.8 mL of the same solution. However, complete pain control was not achieved in all of the teeth, indicating that supplemental anesthetic techniques are still required for many cases.
Acknowledgments The authors wish to thank the Oral and Dental Diseases Research Center for their financial support of this project. The authors deny any conflicts of interest related to this study.
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