Comparison of Postoperative Pain Using Endo-Activator Vs. Conventional Irrigation in Symptomatic Periapical Periodontitis: A Randomised Controlled Trial

By Soha Pirzado, Syed Yawar Ali Abidi, Maham Muneeb Lone, Samira Adnan, Isma Sajjad, Jamshed Ahmed

Affiliations

1. Department of Operative Dentistry and Endodontics, Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University, Karachi, Pakistan

doi: 10.29271/jcpsp.2025.07.830

ABSTRACT
Objective: To compare the frequency of pain after using endo-activator and conventional irrigation in patients presenting with symptomatic periapical periodontitis following endodontic treatment by means of a visual analogue scale (VAS).
Study Design: Randomised clinical trial.
Place and Duration of the Study: Department of Operative Dentistry and Endodontics, Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University, Karachi, Pakistan, from September 2023 to March 2024.
Methodology: Sixty patients with symptomatic teeth requiring endodontic treatment were recruited by probability random sampling into two groups based on irrigation protocols used during endodontic treatment: Conventional needle and endo-activator irrigation system. The difference between intensity of pain in the two groups at various time intervals was assessed by Mann-Whitney U test. The postoperative pain of patients was recorded via a telephone call at 6 hours, 24 hours, and at 7^th day on the visual analogue scale (VAS).
Results: Pain was higher in the conventional group as compared to the endo-activator group at 6 hours, 24 hours as well as at the 7^th day (p <0.001).
Conclusion: The intensity and severity of postoperative pain occurring in patients presenting with symptomatic periapical periodontitis was significantly reduced by the use of endo-activator when used with 2.5% NaOCl seven days after single-visit endodontic treatment.

Key Words: Conventional irrigation, Endo-activator, Postoperative pain, Symptomatic periapical periodontitis, Visual analogue scale.

INTRODUCTION

Adequate debridement and removal of root canal space from the infected pulp tissues including necrotic tissues and microorganisms, along with complete sealing of the root canal system is key to successful endodontic treatment.^1-4 Clinical evaluation of success is gauged through several factors including the absence of sinus tract, swelling, pain, and discomfort and is radiographically evident by means of a gradual decrease in the periapical radiolucency by size and normal periodontal ligament space during follow-up periods.^1,3 The degree of unpleasant pain sensation that can occur after root canal treatment is defined as postoperative pain and its occurrence varies between 3 and 58%.^2,5-7

The postoperative pain may be due to dentin debris extrusion, microorganisms, pulp tissue, or irritants into periradicular tissues resulting in swelling and persistent inflammation of the periapex.^1,6,8 Apical periodontitis is reported to be present in 16-86% of cases with an increase in its presence with age.³ Pain perception is variable and a subjective experience dependent on a varied number of physical as well as psychological factors. The measure of pain intensity can be done by means of a visual analogue scale (VAS) because of its simplicity of use and wide acceptance in clinical research. It has two extreme points ranging from no pain to worst pain along the 100-mm length line.¹

Manual irrigation through a syringe and needle is generally the acceptable means of irrigation during endodontic canal preparation, however, areas such as fins and isthmus in the apical third are unreachable by this approach.^6,9-11 The use of various irrigation agitation methods have been introduced to improve the potency of irrigating solutions within canal spaces. Using sonic instruments is one of these agitation approaches.^2,10,11 The method to improve the potency and flow of irrigants in unreachable areas of canals by means of mechanical or other energy forms is defined as activated irrigation.^7,10,12-14 Improved cleaning of the root canal space can be a cause of reduced postoperative pain after an endodontic procedure.

This study was conducted in order to determine an irrigation technique which will help to reduce postoperative pain in patients following endodontic treatment, initially presenting with symptomatic periapical periodontitis. The results of this study will help to recommend the irrigation technique that significantly reduces postoperative pain in patients following endodontic treatment.

METHODOLOGY

This single-blind, randomised control trial was registered with Reg. No: NCT06668662 according to Preferred Reporting Items for Randomised Trials in Endodontics (PRIRATE) 2020 guidelines. Ethical approval from the Ethical Review Board of Jinnah Sindh Medical University, Karachi, Pakistan, was taken before the commencement of the study. Patients were recruited from those who presented to the Department of Operative Dentistry and Endodontics, Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University, Karachi, Pakistan, from September 2023 to March 2024. The sample size was calculated by using the WHO sample size calculator, assuming a pain proportion of 80% in Group 1 (conventional irrigation) and 40% in Group 2 (endo-activator) with a power of test 90% and a level of significance 5%. The calculated sample size was 60 (30 in each group).

After consideration of criteria, the detailed history was taken. This randomised control trial included individuals aged older than 18 years, presenting to the dental OPD with complaints of pain in the maxillary or mandibular single-rooted teeth requiring root canal treatment. Patients not taking any sedative or analgesic medication 48 hours prior to presenting to the dental clinic were included in the study. The teeth that were included were tender to percussion and palpation but had a sound periodontium and no inflammatory exudate or pus drainage. Patients with any systemic diseases, retreatment cases, or teeth with calcified canals were excluded. Before commencing treatment, all steps of the procedure were explained in detail and written informed consent was obtained from the patients. The primary outcome of the study i.e. degree of postoperative pain, was recorded by inquiring the patients regarding their pain on a VAS that consisted of a 10 cm line anchored by 1 denoting mild and 10 being most severe. This was recorded by the principal investigator at 6 hours, 24 hours, and at 7^th-day post-endodontic treatment via a telephone call.

Patients were divided into 2 groups by probability simple random sampling – the allocation of patients to each group was done by means of choosing an envelope. The randomisation process was done by keeping two opaque, sealed envelopes containing inserts of Group 1 or Group 2 in them. When a patient was deemed eligible to be a part of the study and gave their informed consent, they were asked to pick and choose one of the envelopes. The envelope was opened before root canal treatment to determine the group they will be in. The group allocation and intervention were not revealed to the patient, thereby the patient did not know which group they were in. This random allocation and enrolment of participants for the assigned intervention group was done by a dental assistant who was not a part of the research investigation. Figure 1 shows the study flow chart. Conventional irrigation was used in Group 1, and endo-activator irrigation system in Group 2.¹⁵ All other steps of endodontic treatment remained the same in both groups and were carried out by the principal investigator. Local anaesthesia was obtained was by administering 1.8 mL, 2% lidocaine with 1: 100,000 epinephrine (Septodont, UK), and isolation was ensured by placing a rubber dam. The Endo Z bur and long shank bur #2 (Mani, Japan) attached to the high- speed handpiece were used for access cavity preparation. A barbed broach was used for complete extirpation of the pulp. Working length (WL) was measured by Root ZX apex locator and then further confirmation was done by digital radiograph using #20 K-file (Mani, Japan). The shaping and finishing files (SX – F3) of the ProTaper Universal rotary system (DENTSPLY, Switzerland) were used for canal preparation in the recommended sequence. All canals were irrigated with 4 mL of 2.5% NaOCl between the preparation procedures. Two ml of 17% EDTA solution was employed for the final flushing of the canals for one minute. In Group I, by placing the needle 2 mm short of the desired working length, 4 mL of 2.5% NaOCl was placed into each canal for 40 seconds with an approximate flow rate of 0.1 mL/s. In Group 2, 4 mL of 2.5% NaOCl was delivered into pulp chamber with a conventional endodontic needle and then an endo-activator tip (size #15.02) (DENTSPLY/ Tulsa Dental, OK) was placed loosely 2 mm short of working length, and activated at 20000 Hz in each canal, moving in a constant in and out motion. The NaOCl was agitated for one minute with approximately 2-3 mm vertical strokes. All canals were then dried with paper points, the entire irrigation protocols were repeated in the two groups and the canals were finally dried again with F3 paper points. Obturation was done with F3 gutta percha using Kerr Seal apex root canal sealer followed by core build-up at the same appointment. The patients were contacted via telephone after 6 hours, 24 hours, and at the 7^th day, to record their postoperative pain. The patients' responses at these times were recorded by the investigator via telephone on the VAS as previously described. Clinical effect was labelled as positive (0-l on VAS) when there was no pain and as negative (2- 10 on VAS) when there was pain based on the symptoms described by the patient.

SPSS version 23.0 was used for data entry and analysis. For quantitative variables, such as age, duration of symptoms, and pain score, mean ± SD was calculated for normal data and median (IQR) was used for skewed data. Shapiro-Wilk’s test was used to assess normality. Qualitative variables such as gender, tooth type, and presence of pain were presented as frequency and percentage. Difference between the intensity of pain in the two groups at various time intervals was assessed by the Mann-Whitney U test. Difference between frequencies of pain among groups at various time intervals was assessed by the Chi-square test. All effect modifiers such as age, duration of symptoms, gender, and tooth type were controlled through stratification. A p-value of <0.05 was kept as significant.

RESULTS

A total of 60 patients were divided into two groups (n = 30 per group) by probability random sampling and their pain score was recorded at 6 hours, 24 hours, and 7 days postoperatively.

There were 24 (40%) males and 36 (60%) females included in the study. The mean age of the patients was 36.42 ± 9.011 years with an age range of the participants from 22-59 years. The type of teeth treated in the study included central incisors (n = 25, 41.7%), lateral incisors (n = 24, 40%), and canines (n = 11, 18.3%).

Shapiro-Wilk’s test was applied on the quantitative outcome variable (pain scores recorded on VAS) to assess the normality of data. As the p-value was <0.001, it was determined that data were not normally distributed.

Out of a total of 60 patients, 48 (80.0%) patients reported post- operative pain at 6 hours, while 21 (35.0%) patients reported pain at 7 days postoperatively. The mean pain score of the 60 participants as recorded by the VAS at 6 hours was 4.82 ± 2.690, while at 24 hours was 3.13 ± 2.626 and reduced significantly at 7 days at 1.55 ± 1.789.

Figure 1: Study flowchart.¹⁵

Table I: Intensity of postoperative pain at different time intervals in between the two experimental groups.

Postoperative time	Group 1 (n = 30) Endoactivator		Group 2 (n = 30) Conventional irrigation		p-value*
	Median	IQR	Median	IQR
6 hours	2.00	4	7.00	2	<0.001*
24 hours	1.00	1	5.00	1	<0.001*
Mann-Whitney U test applied. A p-value of <0.05 was considered as statistically significant.

Table II: Frequency of postoperative pain (recorded on the VAS) at different time intervals among two experimental groups.

Postoperative time	Group 1 (n = 30) Endoactivator		Group 2 (n = 30) Conventional irrigation		p-value*
	Pain		Pain
	Yes n, (%)	No n, (%)	Yes n, (%)	No n, (%)
6 hours	18 (60.0)	12 (40.0)	30 (100.0)	0 (0.0)	<0.001*
24 hours	1 (3.3)	29 (96.7)	30 (100.0)	0 (0.0)	<0.001*
7days	0 (0.0)	30 (100.0)	21 (70.0)	9 (30.0)	<0.001*
*Chi-square test / Fisher’s exact test applied. A p-value of <0.05 was considered as statistically significant.

Table III: Stratification of postoperative pain with respect to age.

Postoperative time	20-40 years		41-60 years		p-value*
	Pain		Pain
	Yes n, (%)	No n, (%)	Yes n, (%)	No n, (%)
6 hours	38 (84.4)	7 (15.6)	10 (66.7)	5 (33.3)	0.153
2 4hours	23 (51.1)	22 (48.9)	8 (53.3)	7 (46.7)	0.99
7 days	15 (33.3)	30 (66.7)	6 (40.0)	9 (60.0)	0.757
*Chi-square test/ Fisher’s exact test was applied. A p-value of <0.05 was considered as statistically significant. n=number of patients.

The difference in pain scores among the two experimental groups at various postoperative time intervals is shown in Table I. Pain was higher in the conventional group compared to the endo-activator group at 6 hours, 24 hours as well as 7 days. Man-Whitney U test was applied; a statistically significant difference at all observation times was seen between the study groups (p <0.001).

The presence and absence of postoperative pain in two experimental groups (endo-activator / conventional irrigation system) are shown in Table II. A fewer patients reported pain at 6 hours (60%) in the endo-activator group when compared to pain at 6 hours (100%) in the conventional irrigation group. There was a statistically significant difference in the presence of pain at all-time intervals among the study groups (p <0.001). No statistically significant difference was found in the postoperative pain when compared on the basis of age as shown in Table III.

DISCUSSION

Adequate cleaning of the root canal system, along with complete eradication of infected, necrotic pulp remnants, persistent microorganisms, and complete sealing of the root canal space is key to successful root canal treatment.^1,3,4 Activated irrigation is a method that is used to agitate and increase efficacy of irrigant flow to irregularities of the root canal spaces as lateral canals and isthmus by chemo-mechanical or various other energy forms. It is one of the irrigation methods used in this study. It has been shown that the Endo-Activator^TM system produces effective irrigation in all spaces of the root canal including lateral canals and isthmuses, and the chances of extrusion of irrigant is less than that compared by means of conventional irrigation methods.¹⁶ Thirty seconds use of activated irrigation solution appeared to be more effective in disinfecting root canals compared with a standard irrigation regimen.¹⁷ The most relevant preferred method of activating the irrigant is by using a non-cutting oscillating ultrasonic tip.¹⁸

NaOCl is the widely used irrigation solution during chemo-mechanical instrumentation as it has a broad range of antibacterial effects and a high capacity of organic tissue dissolution. It has a dissolution capacity when used in concentrations as low as 2.5%, resulting in decreased antibiofilm effect and removal of organic part of smear layer. Similarly, the use of EDTA during the preparation removes the organic part of smear layer resulting in exposure of dentinal tubule and better penetration of NaOCl for dis-infection.¹ The same protocol and irrigation techniques were followed in the present study to maximise the benefit of NaOCl and EDTA during endodontic treatment.

Multiple studies^1,2,4 have examined the effects of various irrigation methods in relation to endodontic procedures on postoperative pain that corroborate with the results of this current study. In this study, working length was determined by the use of an apex locator i.e. electronic measurement device for root canal length which was then confirmed by a digital radiograph. This protocol was followed to ensure that preparation was confined within root canal space and prevent chances of over-instru­mentation that is considered to be one of those major leading causes of postoperative pain.¹

The endo-activator system results in minimal extrusion of irritants and irrigates simulated lateral canals at 4.5 and 2 mm from the desired working length as compared with the conventional methods resulting in better irrigation and decreased postoperative pain among different variables.¹⁹ The highest values of postoperative pain were recorded after 6 hours of treatment that potentially decreased in the follow-up periods until almost disappeared after the time interval of one week. In studies evaluation regarding the duration of postoperative pain after root canal treatment was noted in regard with above-mentioned aggrement.³

Studies by Gondim et al.,²⁰ and Topcuoglu et al.,² also reported lower values of pain in the Endovac group com­pared to conventional needle irrigation, showing sig­nificantly marked results after 6 hours followed by 48 hours time intervals. The chances of extrusion of debris apically was greater resulting in increased level of pain with conventional needle-syringe irrigation due to the positive pressure of conventional irrigation.^1,3

A study concluded that postoperative pain in patients when irrigation was done by means of endo-activator significantly reduced from 6 hours (35.7 ± 17.2) to 7 days (4.8 ± 7.4).⁴ Topcuoglu et al. concluded that after 24 hours, pain in the conventional irrigation group was higher 3.96 ± 1.95 while endo-activator caused mild pain 2.36 ± 1.32.⁹ Gundogar concluded that postoperative pain at 48 hours in conventional irrigation group was 0.23 ± 0.63 while that in the endo-activator group was 0.07 ± 0.37.⁵ Similarly, in the present study canals irrigated by means of endo-activator reported less postoperative pain as compared to canals irrigated with conventional irrigation.

In the present study, the pain score at 6 hours was 4.82 ± 2.690, while at 24 hours was 3.13 ± 2.62 and reduced significantly at 7^th day to 1.55 ± 1.789.

The study aimed to evaluate the comparison related to postoperative pain after use of endo-activator and conventional irrigation during endodontic treatment in symptomatic periapical periodontitis. The VAS scale is a common acceptable method for measuring postoperative pain in research related to dentistry. This scale was described in detail to the patient before recording their pain intensity on the VAS scale so as to reduce significant chances of errors that patients could make while describing their pain intensity. Therefore, patients were made familiar with the VAS and were assisted accordingly in recording their preoperative and postoperative pain conditions.²¹

A recent systematic review by Romualdo et al. stated that apical extrusion of irrigant was considerably less when using apical negative pressure compared to positive pressure techniques.²² The conclusive findings elaborated that the negative apical pressure decreases the chances of apical extrusion. In the present study, less pain scores were seen in group of endo-activator as compared to those in the conventional irrigation group in the first 6 hours. These results may be related to the fact that chances of extrusion are less in the endo-activator group in comparison to the conventional irrigation group. Tang et al. in their study also compared the level of post-endodontic pain after single-visit root canal treatment after 24 hours and after a one-week time interval.²³ However, the level of pain was markedly lower in ultrasonic groups compared to the conventional irrigation group at 24 hours and one week after the procedure.

In the first 6 hours after treatment, the greatest postoperative pain scores were seen in both groups, while subsequent observation time points at 24 hours and 7 days showed significant reduction in pain levels in both the study groups. Studies that have evaluated postoperative pain after endodontic treatment have reported similar results.^1,4 Nivedhitha in a systematical review concluded that the prevalence of pain diminished from 40% at 24 hours post-endodontic treatment to 11% at the 7^th postoperative day.⁴

One of the strengths of this study was random allocation of patients to groups to minimise confounders. A single operator carrying out all the procedures helped to avoid technical errors and standardise the endodontic procedure. Standard protocols for root canal treatment were adhered to in both the study groups for effective root canal treatment to ensure that the postoperative pain could be attributed only to the difference in irrigation protocols.

Despite certain strengths, the present study focused primarily on vital pulp of single-rooted teeth with fully formed apices, treated in a single visit. Therefore, these results may not directly apply to the cases involving multi-rooted teeth or immature apices. Moreover, pain is often difficult to measure and can be attributed to multiple variables, so pinning only one specific cause of pain is quite difficult. In future, studies can be carried out on multirooted teeth with necrotic pulp, treated in multiple visits, to evaluate the effect of endo-activator irrigation or other sonic irrigation methods to assess their effect on post-endodontic pain incidence.

CONCLUSION

This study found that the intensity and severity of postopera-tive pain occurring in patients presenting with symptomatic periapical periodontitis were significantly reduced by the use of endoactivator when used with 2.5% NaOCl 7 days after single-visit endodontic treatment.

ETHICAL APPROVAL:
All procedures were performed in accordance with local regulations after ethical approval from the Ethical Review Board of Jinnah Sindh Medical University, taken before the commencement of the study (Ref. No: JSMU/IRB/2023/714).

PATIENTS' CONSENT:
All steps of the procedure were explained in detail and written informed consent was obtained from the patients.

COMPETING INTEREST:
The authors declared no conflict of interest.

AUTHORS’ CONTRIBUTION:
SP: Conception, design of the work, acquisition, analysis, interpretation of data for the work, drafting of the work, and revising the manuscript critically for important intellectual content.
SYAA, MML: Contributions to the conception, design of the work, acquisition, analysis, and interpretation of data for the work.
SA: Contributions to the conception, design of the work, acquisition, and analysis.
IS: Substantial contributions to the conception, design of the work, and acquisition.
JA: Contributions to the conception and design of the work.
All authors approved the final version of the manuscript to be published.
 

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