Acupuncture reduces the postoperative pain in teeth 
with symptomatic apical periodontitis: a preliminary randomized placebo-controlled prospective clinical trial

Acupuncture reduces the postoperative pain in teeth 
with symptomatic apical periodontitis: a preliminary randomized placebo-controlled prospective clinical trial

MENA Dental Talents

25. November 2019

Hakan Arslan, Hany Mohamed Aly Ahmed, Ezgi Doğanay Yıldız, Eyup Candaş Gündoğdu, Fatih Seçkin, Sümeyye Arslan

Objective: Endodontic treatment generally results in a wide range of postoperative pain intensity. The aim of this study was to investigate the effect of preoperative acupuncture on postoperative pain in molar teeth with symptomatic apical periodontitis.

Method and Materials: Thirty patients having symptomatic apical periodontitis with a preoperative and percussion pain of visual analog scale (VAS) more than 60 were included in this study. The patients were randomly distributed into two groups; G1, real acupuncture; and G2, placebo (mock acupuncture). After 15 minutes of application, root canal treatment was performed. A logistic regression analysis was used to determine the variable(s) (group, age, gender, tooth number, preoperative pain, preoperative percussion pain, and radiographic status) that controls the postoperative pain significantly. Chi-square, Mann Whitney U, and independent t tests were performed to analyze the data, and the level of significance was set at .05 (P = .05).

Results: A regression analysis demonstrated that the group variable had the most significant effect on postoperative pain at day 1 (P = .003). Results showed that acupuncture reduced the preoperative and percussion pain levels significantly more than placebo group at all day intervals (P < .05). For postoperative pain at the 7-day follow-up, the pain ranged from “mild” to “no pain” in G1, compared with “moderate” to “minimal” in G2. Only one patient required postoperative analgesics in the acupuncture group compared to eight patients for placebo.

Conclusions: Preoperative acupuncture can be beneficial in reducing postoperative pain in teeth with symptomatic apical periodontitis. (Quintessence Int 2019;50:​–0; doi: 10.3290/j.qi.a42153)

Introduction

Endodontic treatment generally results in a postoperative pain intensity ranging from mild to moderate or severe, which varies according to a number of pre- and intraoperative factors.1-8 A recent prospective clinical study showed that the presence of preoperative pain is the variable that most influences the prevalence of postoperative pain.5 Another study found that complete endodontic debridement resulted in a significant reduction in postoperative pain only after 3 days compared with no endodontic debridement, and there was no significant difference in the need for escape (narcotic) medication between the two groups.9

Acupuncture is a nonpharmacologic approach for pain management. The literature demonstrates substantial evidence for acupuncture being effective in the treatment of acute pain.10 Acupuncture is frequently advocated as an effective treatment of dental pain. One study10 evaluated the effect of acupuncture on postoperative pain after surgical extraction of third molars; results showed that subjects treated with acupuncture reported longer pain-free duration times and experienced less pain intensity compared to those who received placebo acupuncture, consistent with results reported in a systematic review.12 Studies continue to show the effectiveness of acupuncture in reducing acute dental pain in patients waiting for emergency dental care,13 patients with temporomandibular and masticatory myofascial pain,14 as well as controlling gagging while taking impressions in patients with high gagging reflexes.15

The application of acupuncture in the field of endodontics was initially reported in 1976.16 Gross and Morse16 introduced the technique in 10 teeth with vital pulps scheduled for root canal treatment. Results showed that it was sufficiently effective to allow for pain-free pulp extirpation and instrumentation in only one case, six teeth required supplementary intra-pulpal injection, and no analgesia was observed in two cases. Recently, Jalali et al11 evaluated the effect of preoperative acupuncture on the success rate of inferior alveolar nerve blocks for mandibular molars with symptomatic irreversible pulpitis; results showed that the application of acupuncture before endodontic treatment increased the effectiveness of inferior alveolar nerve blocks. 

As per discussion above, it appears that literature supporting the application of acupuncture for pulp and periapical pain management is scarce. This study aimed to evaluate the effect of preoperative acupuncture on postoperative pain in molar teeth with symptomatic apical periodontitis. The null hypothesis was that there is no difference between the preoperative mock and real acupuncture in controlling the postoperative pain.

Method and materials 

Criteria for selection of the study samples

In total, 112 adult patients (at least 18 years of age) presenting with symptomatic apical periodontitis related to molar teeth were assessed for eligibility.

Criteria for inclusion were limited to patients having symptomatic apical periodontitis (for both preoperative and percussion pain) with a visual analog scale (VAS) of more than 60. Percussion was applied by tapping on occlusal surfaces of the teeth with the back end of a mirror handle. It was first applied on a healthy contralateral tooth and the patient was informed that the feeling arising from that tapping on the tooth had to be marked as 0 on the VAS, and unbearable pain should be marked as 100. The percussion was then performed on the experimental tooth and the patient was asked to mark for percussion pain on the VAS. The patient was asked to mark for spontaneous pain similarly. Only patients with markings of 60 and above on VAS were included in this study. Patients with no previous experience of acupuncture were selected (in order not to identify the non-application of the needle).

Exclusion criteria included patients having systemic diseases or allergic reactions, patients under analgesics or antibiotic medication at least 3 days before the appointment, presence of a swelling, sinus tract, severe periodontal disease or a periodontal pocket more than 3 mm, previous root canal treatment, and periapical radiolucency related to the offending tooth with a diameter more than 3 mm. Periapical status was scored according to Ørstavik et al:17

  • Score 1: normal
  • Score 2: small changes in bone structure
  • Score 3: changes in bone structure with some mineral loss
  • Score 4: periodontitis with well-defined radiolucent area
  • Score 5: severe periodontitis with exacerbating features

All clinical and radiographic examinations were performed by the same investigator who was blinded to the procedures. Thirty patients met the criteria and were included in this preliminary study.

Approval for the study was obtained from the Research Ethics Committee (no: 07-2015) (clinical registration number: TCTR20160204002), and written informed consent was obtained from each participant.

Randomization and grouping

A web program (available at https://www.randomizer.org) was used for randomization. Thirty patients were divided into two groups (n = 15). Group 1 included the real acupuncture, and group 2 included the mock acupuncture. The acupuncture procedure was applied by one researcher and the patients were blinded to the procedure. The root canal treatment was performed by another researcher. 

Experimental procedures

Acupuncture

Root canal treatment procedures

The root canal treatment procedures were performed by a specialist in endodontics. Root canal treatment procedures were initiated 15 minutes after the acupuncture applications.

An inferior alveolar nerve block or buccal infiltration was performed in mandibular or maxillary molars, respectively, using one cartridge of 4% articaine with 1:100,000 epinephrine (Ultracaine DS forte; Aventis). One carpule of local anesthetic solution was sufficient in all patients.

After rubber dam isolation, the working length was determined using an electronic apex locator (Propex Pixi, Dentsply Maillefer) and confirmed by periapical radiograph. The root canals were instrumented using Reciproc instruments (VDW) and hand K-files up to size 25 to 80 depending on root canal size. The root canals were then dried with paper points and filled using single gutta-percha cones and 2 Seal sealer (VDW). The pulp chamber was filled with a flowable composite resin, and a microfilled hybrid composite resin (Gradia Direct, GC America) was used for coronal restoration (incremental technique and cured for 20 seconds using a LED light-curing unit (Valo Cordless, Ultradent) with an output of 1,000 mW/cm2. The patients were instructed to take 400 mg ibuprofen (Artril, Eczacıbaşı) if the postoperative pain cannot be tolerated. The patients recorded their pain experience on a customized form from the day 0 to day 7. The pain was further classified into six categories based on the mean VAS scores:

  • Unbearable (100)
  • Severe (≥ 75 to ≤ 99)
  • Moderate (≥ 50 to < 75)
  • Mild (≥ 25 to < 50)
  • Minimal (> 0 to < 25)
  • No pain (0)

Analgesic intake after the procedure (amount, time) was also recorded by the patients in a diary. The patients were recalled after 7 days and postoperative pain was recorded by the patients at that session.

Statistical analysis

Effect of the variables was analyzed using a logistic regression analysis. Normality and homogeneity tests were performed. Results for pre-, postoperative, and percussion pain values were not homogenous, therefore a nonparametric test was used. Chi-square test, Mann-Whitney U test, and independent samples t test were performed to analyze the data. The level of significance was set at .05 (P = .05). 

Results

Table 1 summarizes the demographic data. Patients’ demographics were similar for the groups (P > .05). Tables 2 and 3 summarize pulp and periapical status and other variables. The logistic regression analysis revealed that only one group had significant effect on postoperative pain (P = .003) (Table 4). 

Table 1 Demographic data (independent-samples t test and chi-square test were used to analyze the data):

Characteristic Placebo Acupuncture P value
Age, y (mean ± SD) 34.33 ± 11.29 29.20 ± 10.03 0.119
Gender (n) Female 9 8 0.713
Male 6 7
Tooth number (FDI) (n) Tooth 16 2 0 0.402
Tooth 17 0 1
Tooth 26 1 1
Tooth 27 2 4
Tooth 36 2 4
Tooth 37 3 1
Tooth 38 1 0
Tooth 46 3 1
Tooth 47 1 3

Table 2 Pulp and periapical status of teeth according to the groups (chi-square test was used to analyze the data)

Characteristic Placebo Acupuncture Pvalue
Pulp status* Vital 15 15 NA
Non-vital 0 0
Periapical status† Score 1 15 12 0.112
Score 2 0 3
Score 3 0 0
Score 4 0 0
Score 5 0 0
NA, not applicable. *Pulp vitality was confirmed according to the presence of bleeding in the pulp chamber. †Periapical status was scored according to Ørstavik et al.17 Score 1, normal; Score 2, small changes in bone structure; Score 3, changes in bone structure with some mineral loss; Score 4, periodontitis with well-defined radiolucent area; Score 5, severe periodontitis with exacerbating features.

Table 3 Preoperative and postoperative status of some variables (chi-square test was used to analyze the data)

Variable Placebo Acupuncture Pvalue
Patients with preoperative palpation sensitivity (n) 0 0 NA
Patients with preoperative swelling (n) 0 0 NA
Patients with preoperative sinus tract (n) 0 0 NA
Patients with intake of preoperative drugs (n) 0 0 NA
Patients who needed analgesics postoperatively (n) 8 1 0.007
Patients with postoperative palpation sensitivity (n) 0 0 NA
Patients with postoperative swelling (n) 0 0 NA
Patients with postoperative sinus tract (n) 0 0 NA
Patients referred for an unscheduled appointment (n) 0 0 NA
NA, not applicable.

Table 4 Logistic regression model of pain at postoperative pain at day 1, as a function of group, age, gender, tooth number, pulp status, preoperative pain and preoperative percussion

*Coefficient (β) represents the mathematical weighting of each variable in the model. The positivity/negativity indicates the direction of the effect: positive indicates an increased risk of failure; negative indicates a decreased risk of failure.

Variable Coefficient (β)* Standard error Pvalue
Group 38.092 11.255 0.003
Age −0.558 0.556 0.326
Gender 6.039 12.512 0.634
Tooth number −0.196 0.579 0.738
Preoperative pain −0.589 0.665 0.386
Preoperative percussion 0.555 0.439 0.219
Radiological status 7.468 17.108 0.667
*Coefficient (β) represents the mathematical weighting of each variable in the model. The positivity/negativity indicates the direction of the effect: positive indicates an increased risk of failure; negative indicates a decreased risk of failure.

Preoperative pain levels (P = .103) and percussion pain levels (P = .296) were statistically similar between the groups. Unscheduled appointments related to severe symptoms were not evident for any patient. The frequency of postoperative need of analgesic use was higher in the placebo group (8 patients) compared to the acupuncture group (one patient) (P < .05).

Figure 2 shows the postoperative pain levels according to the groups. Acupuncture resulted in a significant reduction of pain levels compared to placebo group at all time intervals (P < .05). In addition, acupuncture significantly reduced the postoperative percussion pain levels compared to placebo (P < .05) (Fig 3). For the postoperative pain at 7 days’ follow up, the pain ranged from “mild” to “no pain” in the real acupuncture group, compared with “moderate” to “minimal” in the mock acupuncture (Fig 4).

Fig 2 The postoperative pain levels according to the groups (descriptive analysis using mean and standard deviation [SD]). 
Acupuncture resulted in lower pain levels (VAS, visual analog scale) than placebo group at all time periods (day 1, 3, 5, and 7) (P < .05). *Significantly different using Mann Whitney test (median and interquartile range [IQR]).
Fig 3 Acupuncture resulted in lower postoperative percussion pain levels (VAS, visual analog scale) than placebo (descriptive 
analysis using mean and SD). *Significantly different using Mann Whitney test (median and IQR).

 

Fig 4 Classification of postoperative pain progress for both groups on visual analog scale (VAS): unbearable (100), severe 
(≥ 75 to ≤ 99), moderate (≥ 50 to < 75), 
mild (≥ 25 to < 50), minimal (> 0 to < 25), 
no pain (0).

Discussion

Alleviating pain is of prime importance for the clinician while treating apprehensive dental patients. A number of factors contribute to increased pain perception such as psychologic factors, previous history of traumatic dental experience, and anxiety.18 Symptomatic apical periodontitis is a common cause of dental pain, and arises from an inflamed or necrotic dental pulp.19 The present study aimed to evaluate the effect of preoperative acupuncture on postoperative pain in molar teeth with symptomatic apical periodontitis.

Acupuncture (from the Latin acus meaning needle and “puncture” meaning insertion) originated in China more than 5,000 years ago, and is a well-known complementary and alternative therapy.20 It involves the stimulation of certain points on or near the surface of the human body through any technique of point stimulation with or without the insertion of needles; these include the use of electrical, magnetic, light and sound energy, cupping, and moxibustion (the burning of selected herbs on or over the skin), to normalize physiologic functions, to treat various conditions of the human body, or to obtain regional analgesia.16,20

Results of the present preliminary study showed that acupuncture reduced the postoperative pain level significantly more than placebo at all time intervals, thus rejecting the null hypothesis. These findings are consistent with two studies.11,16 Gross and Morse16 introduced the application of acupuncture in patients with vital pulps indicated for root canal treatment. In six out of 10 cases, the operator was able to achieve painless removal of the pulp chamber roof but intra-pulpal injection was indicated for pulp extirpation. A pain-free pulpectomy was achieved in only one case. Another study11 showed that the application of acupuncture before endodontic treatment increased the effectiveness of inferior alveolar nerve block (IANB) for mandibular molars with symptomatic irreversible pulpitis. Notably, the investigators16 reported that at least 25 minutes (or 15 minutes before IANB) is required for acupuncture to have an effect, which may be considered not practical in routine endodontic practice. However, this is not a concern if acupuncture is used for controlling postoperative pain, as demonstrated in the current study.

Although the mechanism of action of acupuncture has not yet been fully established, several mechanisms have been suggested. It is generally accepted that insertion of a needle in an acupuncture point will create a limited inflammatory response with the release of neurotransmitters such as bradykinin, histamine, and subsequent stimulation of Aδ fibers located in the skin and muscle. The Aδ fibers terminate in the second layer of the dorsal horn, and inhibit the incoming painful sensations by release of enkephalin. This mechanism probably accounts for the pain-relieving effect of acupuncture in most cases.21 In addition, acupuncture is responsible for increased levels of endorphin and adrenocorticotropic hormone (ACTH; responsible for the increase of cortisol level), thus controlling stress and anxiety.21 Other mechanisms related to the modulating effects of acupuncture on the pain processing areas in the brain have been documented.22

In the present study, the Hegu acupoint was used, and this is frequently selected to control dentofacial pain.11,13 In addition, its location on the hand does not interfere with the dental procedure.11 Of note, the needles were inserted on the same side of the offending teeth; reports showed that ipsilateral acupuncture injection sites exhibit stronger effects on sensory thresholds compared to needle insertion at contralateral sites.23

Acupuncture is a natural, low-cost, safe procedure. Considering the well-documented adverse effects of most of anti-inflammatory drugs, acupuncture has the potential to be used as a supplemental technique to control postoperative pain in endodontics.11 However, the literature reports some adverse effects of acupuncture, such as fatigue, pain, drowsiness, and bleeding,24,25 in addition to more serious complications such as endocarditis and hepatitis; most of these result from ignorance of basic anatomy and/or lack of aseptic protocols.21 When proper precautions are followed, acupuncture proves to be a very safe technique in the hands of a properly trained practitioner.21 In the present study, no patient displayed adverse reactions during or after the treatment, similar to a recent study.11

The present study is a preliminary study that evaluates the effect of acupuncture on the postoperative pain in teeth with symptomatic apical periodontitis. Preliminary studies may have small sample sizes,26-28 and this is considered a limitation of the present study. Despite favorable findings demonstrated in this preliminary study, further investigations are needed with larger sample sizes to prove the effectiveness of acupuncture in controlling the postoperative pain in other symptomatic diseases related to the pulp and periapical tissues, such as acute pulpitis and acute periapical abscess. 

Conclusion

Within the limitations of the present study, it can be concluded that preoperative acupuncture can be beneficial in reducing postoperative pain in teeth with symptomatic apical periodontitis.

References

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Hakan Arslan
Hakan Arslan
Associate Professor Dr

Department of Endodontics, Health Sciences University, Üsküdar, İstanbul, 34688, Turkey.

Hany Mohamed Aly Ahmed

Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.

Ezgi Doğanay Yıldız
Assistant Professor

Department of End- odontics, Faculty of Dentistry, Kırıkkale University, Kırıkkale, Turkey

Eyup Candaş Gündoğdu
Research Assistant

Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Ataturk Univer- sity, Erzurum, Turkey.

Fatih Seçkin

Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey.

Sümeyye Arslan

Department of Physical Therapy and Rehabilitation, Faculty of Medicine, Ataturk University, Erzurum, Turkey.