- Email: [email protected]
Effect of Low-level Laser Therapy on Postoperative Pain after Root Canal Retreatment: A Preliminary Placebo-controlled, Triple-blind, Randomized Clinical Trial
CONSORT Randomized Clinical Trial
Effect of Low-level Laser Therapy on Postoperative Pain after Root Canal Retreatment: A Preliminary Placebo-controlled, Triple-blind, Randomized Clinical Trial Hakan Arslan, DDS, PhD,* Ezgi Do ganay, DDS, PhD,* Ertu grul Karatas¸, DDS, PhD,* € Mehmet Ali Unl€ u, DDS,* and Hany Mohamed Aly Ahmed, BDS, HDD (Endo), PhD† Abstract Introduction: Low-level laser therapy (LLLT) is a practical, nonpharmacologic technique for reducing pain. This study evaluated the effect of LLLT on postoperative pain after root canal retreatment (RCR). Methods: This study enrolled patients (N = 36) who required root canal retreatment (RCR) on mandibular molar teeth, presented with periapical lesions with periapical index scores of 2 or 3, and had a pain visual analog scale (VAS) <50 and a percussion pain VAS <50. The participants were divided into 2 groups: (1) patients scheduled for RCR followed by LLLT (n = 18) and (2) patients scheduled for RCR followed by a mock LLLT (placebo) (n = 18). Postoperative pain was assessed using the VAS. Data were collected and statistically analyzed with the chi-square test, the independent sample t test, and the Mann-Whitney U test (P = .05). Results: On the first 4 days, postoperative pain significantly reduced in the LLLT group compared with the placebo group (P < .05). However, no statistically significant differences in postoperative pain were found between the 2 groups after 5 and 7 days (P > .05). The number of patients who needed analgesics was lower in the LLLT group than in the placebo group (P < .05). No patient reported pain during LLLT application. Conclusions: LLLT may reduce postoperative pain after RCR of mandibular molars. (J Endod 2017;-:1–5)
Key Words Diode laser, endodontic retreatment, laser, low-level laser therapy, postoperative pain, retreatment, root canal retreatment
F
ailure of the initial root Significance canal treatment (RCT) There is an increasing body of evidence for the prompts the need for a application of LLLT in root canal treatment procednonsurgical root canal reures. This preliminary randomized clinical trial treatment (RCR). RCR is a examined a new potential application of LLLT for conservative method to reducing the postoperative pain after root canal reremove microorganisms, treatment. Results of this study show that the applithe main cause of RCT failcation of LLLT may reduce the postoperative pain ure, from the complex root after root canal retreatment procedures. canal system (1, 2). Conventional RCR provides favorable results with a success rate of 77% (3) and a survival rate of 89% (4). However, this treatment option is accompanied with posttreatment complications (5, 6). The incidence rate of flare-ups is significantly higher in RCR compared with initial RCT (7–9). The flare-up manifests as pain and/or swelling within a few hours or days after an endodontic treatment procedure, requiring an unscheduled clinical visit (10). Recently, the strategies recommended to manage endodontic postoperative pain have been categorized as pharmacologic or nonpharmacologic. Pharmacologic strategies aim to reduce postoperative pain via the prescription of acetaminophen (11), antihistamines (12), nonsteroidal anti-inflammatory drugs (13), steroidal anti-inflammatory drugs (14), salicylic acid (15), narcotic analgesics (16), a combination of 2 medications (17, 18), intracanal medication (19), or long-acting anesthesia (20). Nonpharmacologic strategies aim to reduce postoperative pain with the aid of preoperative relaxation approaches and explanations for patients (21), intracanal cryotherapy (22), the use of different kinematics during root canal treatment (23), intracanal laser irradiation (24), and low-level laser therapy (LLLT) (25, 26). LLLT, which has been used in dentistry since 1970, exerts neuron-regenerative and anti-inflammatory effects to provide pain control (27–30). Laser application with lowlevel parameters causes insignificant thermal changes and elicits biomodulatory effects (27, 29, 30). LLLT delays the initiation of pain and reduces the severity and duration of pain with limited side effects (27). A previous study (25) proved that LLLT reduces postoperative pain after endodontic surgery. Another study (26) found that LLLT reduces postoperative pain after RCT in mandibular molar teeth with symptomatic apical periodontitis. Despite favorable findings, the effect of LLLT on postoperative pain after RCR remains unknown. Therefore, we conducted a randomized controlled trial to evaluate
From the *Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey; and †Department of Restorative Dentistry, Faculty of Dentistry, University of Malaysia, Kuala Lumpur, Malaysia. Address requests for reprints to Dr Hakan Arslan, Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum 25240, Turkey. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2017 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2017.06.028
JOE — Volume -, Number -, - 2017
Effect of Low-level Laser Therapy on Postoperative Pain
1
CONSORT Randomized Clinical Trial the effect of LLLT on postoperative pain after RCR. The null hypothesis was that no difference in postoperative pain after RCR exists between the LLLT and placebo groups.
Materials and Methods Design This preliminary study was designed as a parallel-group, randomized, placebo-controlled trial with 2 arms. Subject Enrollment and Inclusion/Exclusion Criteria The study was approved by the ethics committee (number 742016), and informed consent was obtained from all patients. All study participants were taken from the pool of patients referred to the Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey, from April 2016 to January 2017.
Patients reported their preoperative pain and preoperative percussion pain on a 10-cm visual analog scale (VAS). Patients included in this study were scheduled for RCR on mandibular molars, presented with periapical lesions with scores 2 or 3 in accordance with the periapical index classification introduced by Ørstavik et al (31), and had a pain VAS <50 and a percussion pain VAS <50. All patients were in good health as determined by health history and verbal questioning. Exclusion criteria were periodontal probing greater than 3 mm, swelling or sinus tract, and palpation sensitivity.
Sample Size Calculation The sample size was calculated on the basis of the data obtained from a pilot study on 10 patients. Ten patients were randomly divided into 2 groups (n = 5). The randomization method is described later. The protocol of the pilot study was the same as that of the main study.
Figure 1. The Consolidated Standards of Reporting Trials 2010 flow diagram.
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Arslan et al.
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CONSORT Randomized Clinical Trial According to the data of the pilot study, 32 patients were found to be sufficient for 2 groups (power = 80%, significance level = 0.05, effect size = 0.91). Considering that some patients may not give feedback after 7 days, we decided to enroll 36 patients in our study, with an equal number of 18 patients in each group.
Randomization Method A randomization scheme was generated using a website (www. randomizer.org). The randomization was performed by a researcher (H.A.), and assignment was concealed from the clinician who performed the retreatment procedure (M.A.U.). Another clinician performed laser applications (E.D.). Data analysis and interpretation were performed by the 5 authors (H.A., E.D., E.K., M.A.U., and H.M.A.A.). Clinical Procedures All patients were scheduled for a 2-visit RCR. In the first appointment, the demographic data (age, sex, and tooth number) of the patients were recorded by the clinician, their preoperative pain values were recorded, and an inferior alveolar nerve block was given to all patients using 1.8 mL 4% articaine with 1:100,000 epinephrine (Ultracaine DS Forte; Aventis, Istanbul, Turkey). Rubber dam isolation was applied in all cases. After access cavity preparation, Reciproc nickeltitanium files (VDW, Munich, Germany) were used to remove the root canal filling with a torque-controlled motor (Silver Reciproc, VDW) in accordance with the program Reciproc ALL. No chemical solvent was used to remove the obturation material. R25 was initially inserted into the obturation material. After the coronal third of the root, an attempt was made to achieve the estimated working length using a size 15 K-file. If the file did not reach the working length, the preparation was continued using R25 to the middle third of the root. The working length was determined using an apex locator (Raypex, VDW) and confirmed with periapical radiographs. The canals were irrigated during instrumentation with 2 mL 1% sodium hypochlorite. An
appropriate size H-file was used to remove remnants of the obturation material on the canal walls. Root canal preparation was continued until no gutta-percha was observed on the instrument. The apical enlargement was performed up to R25, R40, R50, or bigger sizes of K-files. The last irrigation was accomplished using 5 mL 1% sodium hypochlorite, 2 mL 2% citric acid for 1 minute, and 5 mL distilled water. Canals were dried with paper points, and calcium hydroxide paste (Sultan Healthcare Inc, Englewood, NJ) was used as interappointment medication. The access cavity was sealed with a temporary restorative material (Cavit-G; 3M ESPE, St Paul, MN). Subsequently, real and mock laser applications were performed by another clinician (E.D.).
The LLLT Group Laser irradiation was performed using a diode laser (l = 970 15 nm, 14-W source power [SIROLaser Xtend; Sirona Dental Systems GmbH, Bensheim, Germany]). The mesial and distal root apexes were irradiated for 30 seconds at 0.5 W and 10 Hz (power density z 2.86 W/cm2). For the application, a 200-mm optical fiber and a bleaching application tip were used, and the tip was placed at a distance of approximately 10 mm to the tissue. The Placebo Group (Mock Laser Application) The diode laser tip was placed similarly to that in the LLLT group, but it was not activated. Each patient was scheduled for a second appointment a week after the initial appointment and was given a home questionnaire. Pain during operation and laser application was recorded on the VAS by the patient. The patients were given instructions to record postoperative pain levels on the 1st, 2nd, 3rd, 4th, 5th, 6th, and 7th days on the VAS and analgesic taken on the questionnaire. At the second appointment, postoperative pain on palpation and percussion were recorded. An unscheduled appointment, if needed, was also recorded. Root canals were then filled using the lateral compaction technique with gutta-percha cones and a Sealapex sealer
TABLE 1. Demographic Data Study details and pain levels N Demographic data Age Sex Men Women Tooth number #18 #19 #30 #31 Pain Preoperative pain Postoperative pain levels on 1st day Postoperative pain levels on 2nd day Postoperative pain levels on 3rd day Postoperative pain levels on 4th day Postoperative pain levels on 5th day Postoperative pain levels on 6th day Postoperative pain levels on 7th day Preoperative pain on percussion Postoperative pain on percussion Number of patients with preoperative pain on palpation Number of patients with postoperative pain on palpation Pain during operation Number of patients need analgesics Number of patients referred for an unscheduled appointment
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Placebo (mock laser application)
Low-level laser therapy
17
16
25.76 8.14
32.62 9.27
<.05
13 4
8 8
>.05
1 9 7 0
1 6 8 1
>.05
6.29 9.10 32.59 20.85 32.71 27.73 25.65 24.94 15.41 20.62 11.47 16.90 7.65 13.21 5.29 12.43 18.88 18.63 9.18 13.57 0 0 5.82 17.12 9 1
6.25 11.18 17.94 15.91 14.44 28.41 12.25 27.48 9.50 18.01 5.25 8.81 1.69 5.55 0.56 1.54 14.56 14.19 3.38 8.37 0 0 5.75 9.17 1 1
>.05 <.05 <.05 <.05 <.05 >.05 >.05 >.05 >.05 >.05
P value
>.05 >.05 <.05 >.05
Effect of Low-level Laser Therapy on Postoperative Pain
3
CONSORT Randomized Clinical Trial (Kerr Corporation, Orange, CA), and restoration was completed using resin composite (3M ESPE).
Statistical Analysis All statistical analyses were performed using SPSS version 20 software (IBM SPSS Inc, Chicago, IL) at a 95% confidence level (P = .05) by an examiner blinded to the groups (H.A.). After homogeneity and normality tests, the independent sample t test (for homogeneous results) and Mann-Whitney U test (for nonhomogenous results) were performed. For nominal data, the chi-square test was performed.
Results One patient from the placebo group and 2 patients from the LLLT group did not attend the follow-up (Fig. 1). Demographic data and postoperative pain progress are listed in Table 1. Aside from age, no statistically significant differences were detected between the groups in terms of other demographic data (sex and tooth number) (P > .05). Preoperative pain and pain on percussion were similar within groups (P > .05). The patients in the LLLT group reported less pain compared with those in the placebo group in the first 4 days (P < .05). However, no statistically significant differences were found between the groups after 5 and 7 days (P > .05). In addition, no significant differences in terms of postoperative pain on percussion were found between the groups (P > .05). The number of patients who needed analgesics was lower in the LLLT group than in the placebo group (P < .05). The number of patients who referred for an unscheduled appointment was similar between the 2 groups (P > .05). Postoperative swelling, sinus tract, and palpation pain were not observed in both groups. No patient reported pain during LLLT application.
Discussion The primary goals of RCR are to focus canal preparation on obtaining and maintaining access to the apical infection, achieve sufficient canal shaping to its terminus for adequate decontamination, and then provide a well-condensed root filling extending to the canal system terminus (3). Nonsurgical RCR achieves high success and survival rates as long as access to the apical infection can be reestablished (3, 4); however, varying levels of pain and discomfort may persist even after removal of the inflammation source by cleaning and shaping retreatment procedures (5–9). This justifies why RCR is challenging given that reasons for failure of the initial RCT are diverse and could affect postoperative pain progression, especially in molars that are technically more difficult to manage. In addition, the extrusion of debris has been reported during RCR procedures using rotary or reciprocating file systems (32), which may cause postoperative pain. The application of LLLT in endodontics has been the subject of several studies (25, 26, 33–37). LLLT effectively reduces postoperative pain after single-visit RCT (33, 34). Similar findings were achieved when LLLT was used after endodontic surgery (25, 35), but a different outcome was obtained in another study (36). In the present study, LLLT significantly reduced postoperative pain after RCR. In addition, the number of patients who needed analgesics was lower in the LLLT group than in the placebo group. In consideration of these results, the null hypothesis was rejected. LLLT affects both local microcirculation and cellular metabolism and exerts regenerative effects (38, 39). LLLT increases the amount of prostaglandins, such as prostaglandin I2 that exhibits antiinflammatory effects, immunoglobulins and lymphokines that play a role in the immune system, and beta-endorphins that are involved in analgesia (40). LLLT inhibits the synthesis of inflammatory factors 4
Arslan et al.
and pain-related neurotransmitters (41). Furthermore, LLLT increases the removal of pain-inducing substances, including substance P, histamine, and dopamine, and inhibits cyclooxygenase-2 (42, 43). Moreover, LLLT doubles lymphatic drainage (40). LLLT can also affect the permeability of the cell membrane to calcium, sodium, and potassium ions. This permeability change causes the degradation of bradykinin (44), induces the production of endorphins by increasing the activity of cellular receptors (45), decreases the activity of C fibers, and increases the action potential of neurons (44). All of these biological activities could explain the favorable results presented in this study. To date, the literature lacks evidence on the effect of tissue penetration depths for LLLT applications in endodontics. The penetration depth depends mainly on the laser wavelength. Notably, the laser wavelength used in this study (970 15 nm) penetrates 1 mm into the tissues (46, 47). The literature shows conflicting results with regard to the effect of age on postoperative pain. Although some studies concluded that age affects postoperative pain (7, 48), some studies concluded that it does not have a significant effect (9, 49). The simple randomization technique used in the present study resulted in an unequal distribution of age among the groups (50), and the difference was statistically significant. However, the mean age of the patients in the 2 groups was 25.76 and 32.62 years; this range usually is categorized in a single group (7, 48). This age difference does not have a clinical significance. In the present study, a placebo-controlled, randomized, 2-armed, parallel-designed controlled trial was performed. The RCR procedures were performed on blinded patients by 1 operator, the LLLT was performed by a different operator, and the statistical analysis was performed by a researcher blinded to the results of the experimental groups. Blinding strengthens the credibility of randomized controlled trials by minimizing bias (51). The sample size of this preliminary study was determined from the data provided from 10 patients divided into 2 groups. The application on a larger sample would substantiate results obtained from the present study (51). The influence of LLLT on postoperative pain related to RCR and surgical RCT of different tooth types in the mandible and maxilla on different ethnic groups remains to be investigated further.
Conclusion Within the limitations of the present study, LLLT may reduce postoperative pain after RCR of mandibular molars.
Acknowledgments The authors deny any conflict of interest related to this study.
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CONSORT Randomized Clinical Trial 7. Torabinejad M, Kettering JD, McGraw JC, et al. Factors associated with endodontic interappointment emergencies of teeth with necrotic pulps. J Endod 1988;14: 261–6. 8. Trope M. Flare-up rate of single-visit endodontics. Int Endod J 1991;24:24–7. 9. Imura N, Zuolo M. Factors associated with endodontic flare-ups: a prospective study. Int Endod J 1995;28:261–5. 10. Walton R, Fouad A. Endodontic interappointment flare-ups: a prospective study of incidence and related factors. J Endod 1992;18:172–7. 11. Torabinejad M, Dorn SO, Eleazer PD, et al. Effectiveness of various medications on postoperative pain following root canal obturation. J Endod 1994;20:427–31. 12. Arslan H, G€undogdu EC, S€umb€ull€u M. The effect of preoperative administration of antihistamine, analgesic and placebo on postoperative pain in teeth with symptomatic apical periodontitis: a randomized controlled trial. Eur Endod J 2016;1:2–6. 13. Attar S, Bowles WR, Baisden MK, et al. Evaluation of pretreatment analgesia and endodontic treatment for postoperative endodontic pain. J Endod 2008;34:652–5. 14. Gallatin E, Reader A, Nist R, Beck M. Pain reduction in untreated irreversible pulpitis using an intraosseous injection of Depo-Medrol. J Endod 2000;26:633–8. 15. Rowe NH, Shekter MA, Turner JL, et al. Control of pain resulting from endodontic therapy: a double-blind, placebo-controlled study. Oral Surg Oral Med Oral Pathol 1980;50:257–63. 16. Ryan JL, Jureidini B, Hodges JS, et al. Gender differences in analgesia for endodontic pain. J Endod 2008;34:552–6. 17. Menhinick KA, Gutmann JL, Regan JD, et al. The efficacy of pain control following nonsurgical root canal treatment using ibuprofen or a combination of ibuprofen and acetaminophen in a randomized, double-blind, placebo-controlled study. Int Endod J 2004;37:531–41. 18. Morse DR, Esposito JV, Furst ML. Comparison of prophylactic and on-demand diflunisal for pain management of patients having one-visit endodontic therapy. Oral Surg Oral Med Oral Pathol 1990;69:729–36. 19. Singh RD, Khatter R, Bal RK, Bal CS. Intracanal medications versus placebo in reducing postoperative endodontic pain–a double-blind randomized clinical trial. Braz Dent J 2013;24:25–9. 20. Crout RJ, Koraido G, Moore PA. A clinical trial of long-acting local anesthetics for periodontal surgery. Anesth Prog 1990;37:194–8. 21. Gatchel RJ. Managing anxiety and pain during dental treatment. J Am Dent Assoc 1992;123:37–41. 22. Keskin C, Ozdemir O, Uzun I, Guler B. Effect of intracanal cryotherapy on pain after single-visit root canal treatment. Aust Endod J 2016 Oct 4; http://dx.doi.org/ 10.1111/aej.12175 [Epub ahead of print]. 23. Arslan H, Khalilov R, Doganay E, Karatas E. The effect of various kinematics on postoperative pain after instrumentation: a prospective, randomized clinical study. J Appl Oral Sci 2016;24:503–8. 24. Koba K, Kimura Y, Matsumoto K, et al. A clinical study on the effects of pulsed Nd:YAG laser irradiation at root canals immediately after pulpectomy and shaping. J Clin Laser Med Surg 1999;17:53–6. 25. Kreisler MB, Haj HA, Noroozi N, Willershausen B. Efficacy of low level laser therapy in reducing postoperative pain after endodontic surgery–a randomized double blind clinical study. Int J Oral Maxillofac Surg 2004;33:38–41. 26. Doganay E, Arslan H. Effect of low level laser therapy and intracanal diode laser application on postoperative pain in mandibular molar teeth with symptomatic apical periodontitis: placebo-controlled prospective clinical trial (PhD thesis). Erzurum, Turkey: University of Ataturk; 2016. 27. He WL, Li CJ, Liu ZP, et al. Efficacy of low-level laser therapy in the management of orthodontic pain: a systematic review and meta-analysis. Lasers Med Sci 2013;28: 1581–9. 28. Kim WT, Bayome M, Park JB, et al. Effect of frequent laser irradiation on orthodontic pain. A single-blind randomized clinical trial. Angle Orthod 2013;83: 611–6.
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29. Tortamano A, Lenzi DC, Haddad AC, et al. Low-level laser therapy for pain caused by placement of the first orthodontic archwire: a randomized clinical trial. Am J Orthod Dentofacial Orthop 2009;136:662–7. 30. Turhani D, Scheriau M, Kapral D, et al. Pain relief by single low-level laser irradiation in orthodontic patients undergoing fixed appliance therapy. Am J Orthod Dentofacial Orthop 2006;130:371–7. 31. Ørstavik D, Kerekes K, Eriksen HM. The periapical index: a scoring system for radiographic assessment of apical periodontitis. Dent Traumatol 1986;2:20–34. 32. Plotino G, Ahmed HM, Grande NM, et al. Current assessment of reciprocation in endodontic preparation: a comprehensive review–part II: properties and effectiveness. J Endod 2015;41:1939–50. 33. Asnaashari M, Mohebi S, Paymanpour P. Pain reduction using low level laser irradiation in single-visit endodontic treatment. J Lasers Med Sci 2011;2:5. 34. Pawar S, Pujar M, Makandar S, Khaiser M. Postendodontic treatment pain management with low-level laser therapy. J Dent Lasers 2014;8:60–3. 35. Escalante-Macıas L, Mendez-Gonzalez V, Davila-Perez C, et al. Clinical efficacy of low level laser therapy in reducing pain and swelling after periapical surgery. A preliminary report. J Oral Res 2015;4:183–8. 36. Payer M, Jakse N, Pertl C, et al. The clinical effect of LLLT in endodontic surgery: a prospective study on 72 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;100:375–9. 37. Asnaashari M, Safavi N. Application of low level lasers in dentistry (endodontic). J Lasers Med Sci 2013;4:57–66. 38. Silveira PC, Silva LA, Freitas TP, et al. Effects of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing. Lasers Med Sci 2011;26:125–31. 39. AlGhamdi KM, Kumar A, Moussa NA. Low-level laser therapy: a useful technique for enhancing the proliferation of various cultured cells. Lasers Med Sci 2012;27: 237–49. 40. Gama SK, Habib FA, Monteiro JS, et al. Tooth movement after infrared laser phototherapy: clinical study in rodents. Photomed Laser Surg 2010;28(Suppl 2):S79–83. 41. Pallotta RC, Bjordal JM, Frigo L, et al. Infrared (810-nm) low-level laser therapy on rat experimental knee inflammation. Lasers Med Sci 2012;27:71–8. 42. Sakurai Y, Yamaguchi M, Abiko Y. Inhibitory effect of low-level laser irradiation on LPS-stimulated prostaglandin E2 production and cyclooxygenase-2 in human gingival fibroblasts. Eur J Oral Sci 2000;108:29–34. 43. Pires D, Xavier M, Araujo T, et al. Low-level laser therapy (LLLT; 780 nm) acts differently on mRNA expression of anti- and pro-inflammatory mediators in an experimental model of collagenase-induced tendinitis in rat. Lasers Med Sci 2011;26: 85–94. 44. Pozza DH, Fregapani PW, Weber JB, et al. Analgesic action of laser therapy (LLLT) in an animal model. Med Oral Patol Oral Cir Bucal 2008;13:E648–52. 45. Hagiwara S, Iwasaka H, Okuda K, Noguchi T. GaAlAs (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats. Lasers Surg Med 2007;39: 797–802. 46. Barolet D. Light-emitting diodes (LEDs) in dermatology. Semin Cutan Med Surg 2008;27:227–38. 47. Avci P, Gupta A, Sadasivam M, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Semin Cutan Med Surg 2013;32:41–52. 48. Ali SG, Mulay S, Palekar A, et al. Prevalence of and factors affecting post-obturation pain following single visit root canal treatment in Indian population: a prospective, randomized clinical trial. Contemp Clin Dent 2012;3:459–63. 49. Ng YL, Glennon JP, Setchell DJ, Gulabivala K. Prevalence of and factors affecting postobturation pain in patients undergoing root canal treatment. Int Endod J 2004;37: 381–91. 50. Suresh KP. An overview of randomization techniques: an unbiased assessment of outcome in clinical research. J Hum Reprod Sci 2011;4:8–11. 51. Miller LE, Stewart ME. The blind leading the blind: use and misuse of blinding in randomized controlled trials. Contemp Clin Trials 2011;32:240–3.
Effect of Low-level Laser Therapy on Postoperative Pain
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Effect of Low-level Laser Therapy on Postoperative Pain after Root Canal Retreatment: A Preliminary Placebo-controlled, Triple-blind, Randomized Clinical Trial Hakan Arslan, DDS, PhD,* Ezgi Do ganay, DDS, PhD,* Ertu grul Karatas¸, DDS, PhD,* € Mehmet Ali Unl€ u, DDS,* and Hany Mohamed Aly Ahmed, BDS, HDD (Endo), PhD† Abstract Introduction: Low-level laser therapy (LLLT) is a practical, nonpharmacologic technique for reducing pain. This study evaluated the effect of LLLT on postoperative pain after root canal retreatment (RCR). Methods: This study enrolled patients (N = 36) who required root canal retreatment (RCR) on mandibular molar teeth, presented with periapical lesions with periapical index scores of 2 or 3, and had a pain visual analog scale (VAS) <50 and a percussion pain VAS <50. The participants were divided into 2 groups: (1) patients scheduled for RCR followed by LLLT (n = 18) and (2) patients scheduled for RCR followed by a mock LLLT (placebo) (n = 18). Postoperative pain was assessed using the VAS. Data were collected and statistically analyzed with the chi-square test, the independent sample t test, and the Mann-Whitney U test (P = .05). Results: On the first 4 days, postoperative pain significantly reduced in the LLLT group compared with the placebo group (P < .05). However, no statistically significant differences in postoperative pain were found between the 2 groups after 5 and 7 days (P > .05). The number of patients who needed analgesics was lower in the LLLT group than in the placebo group (P < .05). No patient reported pain during LLLT application. Conclusions: LLLT may reduce postoperative pain after RCR of mandibular molars. (J Endod 2017;-:1–5)
Key Words Diode laser, endodontic retreatment, laser, low-level laser therapy, postoperative pain, retreatment, root canal retreatment
F
ailure of the initial root Significance canal treatment (RCT) There is an increasing body of evidence for the prompts the need for a application of LLLT in root canal treatment procednonsurgical root canal reures. This preliminary randomized clinical trial treatment (RCR). RCR is a examined a new potential application of LLLT for conservative method to reducing the postoperative pain after root canal reremove microorganisms, treatment. Results of this study show that the applithe main cause of RCT failcation of LLLT may reduce the postoperative pain ure, from the complex root after root canal retreatment procedures. canal system (1, 2). Conventional RCR provides favorable results with a success rate of 77% (3) and a survival rate of 89% (4). However, this treatment option is accompanied with posttreatment complications (5, 6). The incidence rate of flare-ups is significantly higher in RCR compared with initial RCT (7–9). The flare-up manifests as pain and/or swelling within a few hours or days after an endodontic treatment procedure, requiring an unscheduled clinical visit (10). Recently, the strategies recommended to manage endodontic postoperative pain have been categorized as pharmacologic or nonpharmacologic. Pharmacologic strategies aim to reduce postoperative pain via the prescription of acetaminophen (11), antihistamines (12), nonsteroidal anti-inflammatory drugs (13), steroidal anti-inflammatory drugs (14), salicylic acid (15), narcotic analgesics (16), a combination of 2 medications (17, 18), intracanal medication (19), or long-acting anesthesia (20). Nonpharmacologic strategies aim to reduce postoperative pain with the aid of preoperative relaxation approaches and explanations for patients (21), intracanal cryotherapy (22), the use of different kinematics during root canal treatment (23), intracanal laser irradiation (24), and low-level laser therapy (LLLT) (25, 26). LLLT, which has been used in dentistry since 1970, exerts neuron-regenerative and anti-inflammatory effects to provide pain control (27–30). Laser application with lowlevel parameters causes insignificant thermal changes and elicits biomodulatory effects (27, 29, 30). LLLT delays the initiation of pain and reduces the severity and duration of pain with limited side effects (27). A previous study (25) proved that LLLT reduces postoperative pain after endodontic surgery. Another study (26) found that LLLT reduces postoperative pain after RCT in mandibular molar teeth with symptomatic apical periodontitis. Despite favorable findings, the effect of LLLT on postoperative pain after RCR remains unknown. Therefore, we conducted a randomized controlled trial to evaluate
From the *Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey; and †Department of Restorative Dentistry, Faculty of Dentistry, University of Malaysia, Kuala Lumpur, Malaysia. Address requests for reprints to Dr Hakan Arslan, Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum 25240, Turkey. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2017 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2017.06.028
JOE — Volume -, Number -, - 2017
Effect of Low-level Laser Therapy on Postoperative Pain
1
CONSORT Randomized Clinical Trial the effect of LLLT on postoperative pain after RCR. The null hypothesis was that no difference in postoperative pain after RCR exists between the LLLT and placebo groups.
Materials and Methods Design This preliminary study was designed as a parallel-group, randomized, placebo-controlled trial with 2 arms. Subject Enrollment and Inclusion/Exclusion Criteria The study was approved by the ethics committee (number 742016), and informed consent was obtained from all patients. All study participants were taken from the pool of patients referred to the Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey, from April 2016 to January 2017.
Patients reported their preoperative pain and preoperative percussion pain on a 10-cm visual analog scale (VAS). Patients included in this study were scheduled for RCR on mandibular molars, presented with periapical lesions with scores 2 or 3 in accordance with the periapical index classification introduced by Ørstavik et al (31), and had a pain VAS <50 and a percussion pain VAS <50. All patients were in good health as determined by health history and verbal questioning. Exclusion criteria were periodontal probing greater than 3 mm, swelling or sinus tract, and palpation sensitivity.
Sample Size Calculation The sample size was calculated on the basis of the data obtained from a pilot study on 10 patients. Ten patients were randomly divided into 2 groups (n = 5). The randomization method is described later. The protocol of the pilot study was the same as that of the main study.
Figure 1. The Consolidated Standards of Reporting Trials 2010 flow diagram.
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CONSORT Randomized Clinical Trial According to the data of the pilot study, 32 patients were found to be sufficient for 2 groups (power = 80%, significance level = 0.05, effect size = 0.91). Considering that some patients may not give feedback after 7 days, we decided to enroll 36 patients in our study, with an equal number of 18 patients in each group.
Randomization Method A randomization scheme was generated using a website (www. randomizer.org). The randomization was performed by a researcher (H.A.), and assignment was concealed from the clinician who performed the retreatment procedure (M.A.U.). Another clinician performed laser applications (E.D.). Data analysis and interpretation were performed by the 5 authors (H.A., E.D., E.K., M.A.U., and H.M.A.A.). Clinical Procedures All patients were scheduled for a 2-visit RCR. In the first appointment, the demographic data (age, sex, and tooth number) of the patients were recorded by the clinician, their preoperative pain values were recorded, and an inferior alveolar nerve block was given to all patients using 1.8 mL 4% articaine with 1:100,000 epinephrine (Ultracaine DS Forte; Aventis, Istanbul, Turkey). Rubber dam isolation was applied in all cases. After access cavity preparation, Reciproc nickeltitanium files (VDW, Munich, Germany) were used to remove the root canal filling with a torque-controlled motor (Silver Reciproc, VDW) in accordance with the program Reciproc ALL. No chemical solvent was used to remove the obturation material. R25 was initially inserted into the obturation material. After the coronal third of the root, an attempt was made to achieve the estimated working length using a size 15 K-file. If the file did not reach the working length, the preparation was continued using R25 to the middle third of the root. The working length was determined using an apex locator (Raypex, VDW) and confirmed with periapical radiographs. The canals were irrigated during instrumentation with 2 mL 1% sodium hypochlorite. An
appropriate size H-file was used to remove remnants of the obturation material on the canal walls. Root canal preparation was continued until no gutta-percha was observed on the instrument. The apical enlargement was performed up to R25, R40, R50, or bigger sizes of K-files. The last irrigation was accomplished using 5 mL 1% sodium hypochlorite, 2 mL 2% citric acid for 1 minute, and 5 mL distilled water. Canals were dried with paper points, and calcium hydroxide paste (Sultan Healthcare Inc, Englewood, NJ) was used as interappointment medication. The access cavity was sealed with a temporary restorative material (Cavit-G; 3M ESPE, St Paul, MN). Subsequently, real and mock laser applications were performed by another clinician (E.D.).
The LLLT Group Laser irradiation was performed using a diode laser (l = 970 15 nm, 14-W source power [SIROLaser Xtend; Sirona Dental Systems GmbH, Bensheim, Germany]). The mesial and distal root apexes were irradiated for 30 seconds at 0.5 W and 10 Hz (power density z 2.86 W/cm2). For the application, a 200-mm optical fiber and a bleaching application tip were used, and the tip was placed at a distance of approximately 10 mm to the tissue. The Placebo Group (Mock Laser Application) The diode laser tip was placed similarly to that in the LLLT group, but it was not activated. Each patient was scheduled for a second appointment a week after the initial appointment and was given a home questionnaire. Pain during operation and laser application was recorded on the VAS by the patient. The patients were given instructions to record postoperative pain levels on the 1st, 2nd, 3rd, 4th, 5th, 6th, and 7th days on the VAS and analgesic taken on the questionnaire. At the second appointment, postoperative pain on palpation and percussion were recorded. An unscheduled appointment, if needed, was also recorded. Root canals were then filled using the lateral compaction technique with gutta-percha cones and a Sealapex sealer
TABLE 1. Demographic Data Study details and pain levels N Demographic data Age Sex Men Women Tooth number #18 #19 #30 #31 Pain Preoperative pain Postoperative pain levels on 1st day Postoperative pain levels on 2nd day Postoperative pain levels on 3rd day Postoperative pain levels on 4th day Postoperative pain levels on 5th day Postoperative pain levels on 6th day Postoperative pain levels on 7th day Preoperative pain on percussion Postoperative pain on percussion Number of patients with preoperative pain on palpation Number of patients with postoperative pain on palpation Pain during operation Number of patients need analgesics Number of patients referred for an unscheduled appointment
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Placebo (mock laser application)
Low-level laser therapy
17
16
25.76 8.14
32.62 9.27
<.05
13 4
8 8
>.05
1 9 7 0
1 6 8 1
>.05
6.29 9.10 32.59 20.85 32.71 27.73 25.65 24.94 15.41 20.62 11.47 16.90 7.65 13.21 5.29 12.43 18.88 18.63 9.18 13.57 0 0 5.82 17.12 9 1
6.25 11.18 17.94 15.91 14.44 28.41 12.25 27.48 9.50 18.01 5.25 8.81 1.69 5.55 0.56 1.54 14.56 14.19 3.38 8.37 0 0 5.75 9.17 1 1
>.05 <.05 <.05 <.05 <.05 >.05 >.05 >.05 >.05 >.05
P value
>.05 >.05 <.05 >.05
Effect of Low-level Laser Therapy on Postoperative Pain
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CONSORT Randomized Clinical Trial (Kerr Corporation, Orange, CA), and restoration was completed using resin composite (3M ESPE).
Statistical Analysis All statistical analyses were performed using SPSS version 20 software (IBM SPSS Inc, Chicago, IL) at a 95% confidence level (P = .05) by an examiner blinded to the groups (H.A.). After homogeneity and normality tests, the independent sample t test (for homogeneous results) and Mann-Whitney U test (for nonhomogenous results) were performed. For nominal data, the chi-square test was performed.
Results One patient from the placebo group and 2 patients from the LLLT group did not attend the follow-up (Fig. 1). Demographic data and postoperative pain progress are listed in Table 1. Aside from age, no statistically significant differences were detected between the groups in terms of other demographic data (sex and tooth number) (P > .05). Preoperative pain and pain on percussion were similar within groups (P > .05). The patients in the LLLT group reported less pain compared with those in the placebo group in the first 4 days (P < .05). However, no statistically significant differences were found between the groups after 5 and 7 days (P > .05). In addition, no significant differences in terms of postoperative pain on percussion were found between the groups (P > .05). The number of patients who needed analgesics was lower in the LLLT group than in the placebo group (P < .05). The number of patients who referred for an unscheduled appointment was similar between the 2 groups (P > .05). Postoperative swelling, sinus tract, and palpation pain were not observed in both groups. No patient reported pain during LLLT application.
Discussion The primary goals of RCR are to focus canal preparation on obtaining and maintaining access to the apical infection, achieve sufficient canal shaping to its terminus for adequate decontamination, and then provide a well-condensed root filling extending to the canal system terminus (3). Nonsurgical RCR achieves high success and survival rates as long as access to the apical infection can be reestablished (3, 4); however, varying levels of pain and discomfort may persist even after removal of the inflammation source by cleaning and shaping retreatment procedures (5–9). This justifies why RCR is challenging given that reasons for failure of the initial RCT are diverse and could affect postoperative pain progression, especially in molars that are technically more difficult to manage. In addition, the extrusion of debris has been reported during RCR procedures using rotary or reciprocating file systems (32), which may cause postoperative pain. The application of LLLT in endodontics has been the subject of several studies (25, 26, 33–37). LLLT effectively reduces postoperative pain after single-visit RCT (33, 34). Similar findings were achieved when LLLT was used after endodontic surgery (25, 35), but a different outcome was obtained in another study (36). In the present study, LLLT significantly reduced postoperative pain after RCR. In addition, the number of patients who needed analgesics was lower in the LLLT group than in the placebo group. In consideration of these results, the null hypothesis was rejected. LLLT affects both local microcirculation and cellular metabolism and exerts regenerative effects (38, 39). LLLT increases the amount of prostaglandins, such as prostaglandin I2 that exhibits antiinflammatory effects, immunoglobulins and lymphokines that play a role in the immune system, and beta-endorphins that are involved in analgesia (40). LLLT inhibits the synthesis of inflammatory factors 4
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and pain-related neurotransmitters (41). Furthermore, LLLT increases the removal of pain-inducing substances, including substance P, histamine, and dopamine, and inhibits cyclooxygenase-2 (42, 43). Moreover, LLLT doubles lymphatic drainage (40). LLLT can also affect the permeability of the cell membrane to calcium, sodium, and potassium ions. This permeability change causes the degradation of bradykinin (44), induces the production of endorphins by increasing the activity of cellular receptors (45), decreases the activity of C fibers, and increases the action potential of neurons (44). All of these biological activities could explain the favorable results presented in this study. To date, the literature lacks evidence on the effect of tissue penetration depths for LLLT applications in endodontics. The penetration depth depends mainly on the laser wavelength. Notably, the laser wavelength used in this study (970 15 nm) penetrates 1 mm into the tissues (46, 47). The literature shows conflicting results with regard to the effect of age on postoperative pain. Although some studies concluded that age affects postoperative pain (7, 48), some studies concluded that it does not have a significant effect (9, 49). The simple randomization technique used in the present study resulted in an unequal distribution of age among the groups (50), and the difference was statistically significant. However, the mean age of the patients in the 2 groups was 25.76 and 32.62 years; this range usually is categorized in a single group (7, 48). This age difference does not have a clinical significance. In the present study, a placebo-controlled, randomized, 2-armed, parallel-designed controlled trial was performed. The RCR procedures were performed on blinded patients by 1 operator, the LLLT was performed by a different operator, and the statistical analysis was performed by a researcher blinded to the results of the experimental groups. Blinding strengthens the credibility of randomized controlled trials by minimizing bias (51). The sample size of this preliminary study was determined from the data provided from 10 patients divided into 2 groups. The application on a larger sample would substantiate results obtained from the present study (51). The influence of LLLT on postoperative pain related to RCR and surgical RCT of different tooth types in the mandible and maxilla on different ethnic groups remains to be investigated further.
Conclusion Within the limitations of the present study, LLLT may reduce postoperative pain after RCR of mandibular molars.
Acknowledgments The authors deny any conflict of interest related to this study.
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