Postoperative pain and quality of life after sonic irrigation with Waterpik dental flosser home care device: a randomized clinical trial

Abstract

Purpose:

This study aimed to evaluate the effect of irrigation agitation on postoperative pain (PP) and oral health-related quality of life (OHQoL) in patients undergoing single-visit root canal therapy (RCT).

Materials and methods:

The study was a double-blind randomized clinical trial where a single-visit RCT was performed on forty patients diagnosed with symptomatic irreversible pulpitis in molars. The study participants were divided into two groups (n=20) based on the final irrigation protocol. Group 1- No agitation (NA), Group 2: Sonic agitation (SA). The pain scores were recorded using the Visual Analogue Rating scale (VAS) preoperatively and postoperative at 6, 12, 24, 48 and 72 hours. The OHQoL scores were recorded before and 72 hours after the treatment using the oral health impact profile (OHIP-14). Statistical analysis was performed for inter- and intra-group comparisons using Mann-Whitney U test and the Wilcoxon Signed Rank Test.

Results:

Lower pain scores were observed in the sonic agitation group at 12 hours (p=0.03),24 hours(p=0.02),48 hours (p=0.02),72 hours (p=0.04) after RCT. The patient's OHQoL was improved postoperatively (p=0.278), but there was no significant difference between sonic agitation and the control groups.

Conclusion:

Endodontic treatment improved patients’ quality of life, and sonic irrigation agitation using a Waterpik device reduced postoperative pain in patients with symptomatic irreversible pulpitis.

Introduction

Endodontic treatment is performed either to treat or to prevent apical periodontitis (1). Irreversible pulpitis is defined as a clinical condition in which the vital inflamed pulp is incapable of healing and requires Root Canal Treatment (RCT). A root canal treatment is a dental procedure to remove inflamed or infected pulp on the inside of the tooth which is then carefully cleaned and disinfected, then filled and sealed. Root canal treatment is designed to eliminate bacteria from the infected root canal, prevent reinfection of the tooth and save the natural tooth (2). However, the reported literature suggested that the incidence of postoperative pain (PP) after RCT ranges from 3-58%. Although alleviation of pain is not the solely parameter but an important criterion for successful endodontic treatment which is determined by absence of pain and infection, normal tooth function, and evidence of radiographic healing or health over time (3).

One factor that could immensely influence the complete debridement is the irrigation protocol. In the intricate areas where mechanical instrumentation is not quite easy, the irrigating solutions fulfill the job of efficient disinfection, which further enhances the success of RCT. Despite various irrigation protocols, agitation of the irrigating solutions was proven to be effective in the isthmus as well as the apical area compared to the conventional techniques (4). Since then, various agitation techniques such as manual dynamic agitation, sonic agitation, passive ultrasonic irrigation, lasers and pressure alteration devices, have been introduced to effectively clear off the debris and the smear layer by enhancing the efficacy of the irrigating solution (5, 6).

A systematic review and meta-analysis by Govula et al. (7) had concluded that there is a reduction in the PP, especially in the first 24 and 48 hours, which were crucial for the anxious patients, when the irrigant activation was done by Endoactivator compared with the conventional needle irrigation. An in vitro study by Hemalatha et al. (8) demonstrated a sonic device (Waterpik WD 100, Water Pik, Inc., Colorado, USA) designed for interdental cleaning significantly enhanced irrigant penetration when used as a irrigant agitation in root canals. Oral-health-related quality of life (OHRQoL) is a concept that measures how oral health influences overall well-being, encompassing functional limitations, pain, psychological discomfort, and social and emotional impacts (9). The endodontic therapy helps to encounter these factors especially the physical pain and the functional limitations. The success of the endodontic therapy is not only by the dentist’s perception of clinical and the radiographic evaluation but also under the patient centered outcomes (10).

The oral health impact profile (OHIP) is an accepted instrument for measuring the OHRQoL. There is a reported consensus that the quality of life of the patients has been improved after non-surgical endodontic therapy (11). So far, no clinical studies have evaluated the effectiveness of the modified Waterpik device on PP and OHQoL. This study was therefore conducted to determine and compare the effectiveness of the modified Waterpik device on the PP and quality of life of the patients after a single-visit RCT with the conventional irrigation technique. The null hypothesis of the study states that the agitation of the irrigating solutions has no postoperative effect on the patient's pain and oral health quality.

Materials and methods

Ethical consideration and reporting guidelines

This parallel randomized, double-blinded clinical trial study was conducted in strict compliance with the Consolidated Standards of Reporting Trials guidelines (CONSORT 2010) after obtaining approval from the Institutional Ethical Committee (IEC/NDCH/2023/NOV/P-101). The trial was conducted in accordance with the World Medical Association Declaration of Helsinki and registered under the Clinical Trial Registry of India with the number CTRI/2024/01/062145.

Selection of subjects

The trial was carried out for a period of 6 months (from January 2024 to June 2024) in the Outpatient Department of Conservative Dentistry and Endodontics on the individuals who met the criteria for non-surgical endodontic therapy.

Sample size determination

Forty participants were enrolled based on a sample size calculation performed using the G*Power software (version 3.1.9.7). A previous study (12) was used as a reference, and a two-sample t-test power analysis was conducted with an alpha error of 0.05, 80% power, a significance level of 0.05, and an effect size of 0.5, resulting in a required sample size of 20 (n=20) per group. The participants were randomly allocated using a computer-based simple randomization method (www.random.org).

Inclusion and exclusion criteria

All participants were selected according to the following inclusion and exclusion criteria. Systemically healthy individuals classified as ASA I, aged 18–50 years, and diagnosed with moderate to severe symptomatic irreversible pulpitis in mature maxillary or mandibular molars were included. Teeth presenting with spontaneous pain but no tenderness on percussion, a positive cold test with lingering pain lasting longer than 30 seconds, radiolucency confined to the pulp without periapical changes, and molars with mild to moderate curvature (5°–20° according to Schneider’s method) were eligible. Patients who could understand the Visual Analogue Scale and were willing to participate were also included. Patients classified as ASA III or above, those unable to provide informed consent, individuals allergic to local anesthetics or prescribed medications, those who had taken analgesics within the previous 12 hours, and pregnant or lactating women were excluded. Teeth were excluded if they exhibited malposition, lacked an opposing tooth, had developmental anomalies, extra roots, fractures, C-shaped or S-shaped canals, root curvatures greater than 20°, open apices, calcified canals, apical periodontitis, or any previous endodontic treatment confirmed by periapical radiographs.

Subject allocation and randomization

A computer-generated randomization was done, and allocation concealment was ensured by asking the patients to pick up a sealed envelope containing the group information, and the allocation ratio was set at 1:1.

Pre-treatment procedure

The preoperative pain level was assessed using a visual analogue rating scale (VAS), which is a 10-point rating scale (SS). It ranges from 0- No discomfort, 1–3: Mild (recognizable, not discomforting), 4–7: Moderate (discomforting, but bearable, 8–10: Severe (considerable discomfort, difficult to bear) (13). Patients having a VAS score greater than 4 at baseline and diagnosed with symptomatic irreversible pulpitis were included based on subjective symptoms and radiograph findings, which were confirmed by performing the cold test with the ethyl chloride spray (Endo frost, Coltene, Germany). Before the start of the treatment, informed consent was obtained from all the participants

The preoperative quality of life was evaluated using the OHIP-14 questionnaire with a 5-point Likert score ranging from 0 - Never, 1- Hardly ever, 2 -Occasionally, 3- Fairly often, and 4 - Very often (14). The Figure 1 represents the seven domains and fourteen questions of OHIP-14 questionnaire (SS).

Figure 1.

Oral Health Impact Profile – 14 (OHIP-14) questionnaires.

After completing this preoperative protocol, all root canal procedures were performed in a single visit (NKL), started by administrating the local anesthesia with 3 ml of 2% lignocaine with 1:80000 adrenaline (Lignox 2%, Indoco Remedies Ltd., Mumbai, India). All the carious lesions were removed and previous restorations were replaced, when necessary, under proper isolation with rubber-dam. The access cavity was prepared using an endo access bur and an endo Z bur (Dentsply Sirona, Ballaigues, Switzerland), after which, the canal patency was established with a 10 K-file (Mani Inc., Tochigi, Japan). The working length set at 1mm short of the radiograph apex using an electronic apex locator (Root ZX Mini Apex Locator, Morita Corporation, Kyoto, Japan) and confirmed radiographically. The biomechanical preparation of the canal walls was performed using a Protaper gold rotary file system (DentsplyMaillefer, Ballaigues, Switzerland) with a crown-down technique using an Endo motor (X-Smart Plus, Densply Sirona, Ballaigues, Switzerland) with an adjusted torque of 3.10 Ncm and speed of 300 rpm according to the manufacturer's instructions. Master apical file size was determined based on the canal width (i.e., F3 size for distal and palatal canals whereas F2 for others). In between the instrumentation, root canals were irrigated with 5 ml of 3% sodium hypochlorite (NaOCl) (Prime Dental Product Private Ltd, Mumbai, India) solution with 31-gauge side vented needles (EndoRinse) for about 1 minute after placing each file 1mm short of the working length.

No agitation group (NA)

Final irrigation was performed with 5 mL 3% NaOCl with 31-G single-sided vented needle 1mm short of the working length for 1 minute, no agitation was performed. Root canals were irrigated, 2 mL 17% Ethylene Diamine Tetraacetic Acid (EDTA) (Premier Dental Product Co., King of Prussia, PA, USA) irrigation for 1 minute in each canal was done.

Sonic agitation group (SA)

Final irrigation was performed with 5 mL of 3% NaOCl delivered using a 31-G single-sided vented needle positioned 1 mm short of the working length for 1 minute. The needle was attached to the tip of the Waterpik device (Figure 2) and used to agitate the irrigant within the canals. The device was operated in continuous mode, with the needle inserted 1 mm short of the working length and activated for 1 minute. Subsequently, 2 mL of 17% EDTA was introduced into each canal, and the device was again activated in same mode for 1 minute. Recapitulation of the canal was finally perfomed about 2-3 times, with 20 size hand K files up to the complete working length.

Figure 2.

31 gauge single-side vented needle was connected to the tip of the Waterpik device.

The final irrigation was completed in both groups by flushing 5 mL of normal saline using a syringe and a 31-gauge side-vented needle. The obturation was performed in the same visit using single cone gutta-percha points with Zinc Oxide Eugenol-based sealer (Prime Dental Products Pvt Ltd, India) in all groups. A postoperative radiograph was taken to ensure that root canals were adequately filled up to the working length, with no over- or under extensions of the filling material. A barrier of restorative GIC (GC Corporation, Tokyo, Japan) followed by the adhesive composite resin (Tetric N-Ceram, IvoclarVivadent, Liechtenstein) as the post-endodontic restoration. The patient was informed about the possibility of PP and analgesics of ibuprofen 400mg were prescribed with an advised to be taken only in the event of significant pain.

Postoperative evaluation

All the participants were made familiar with the VAS and were instructed to note down the pain scores at 6, 12, 24, 48 and 72-hour time intervals after completion of the RCT. During the follow-up visit which was three days after the completion of the treatment, the pain score data were collected from the patient, and quality of life was assessed using the OHIP-14 questionnaire on the same visit (SS).

Statistical analysis

The collected data was statistically analyzed using the SPSS software (SPSS version 22, IBM Corporation, Armonk, NY, USA), with a 5% level of significance. The descriptive statistics were conducted for demographic variables and the normality distribution was assessed using Kolmogorov-Smirnov test. Inter-group comparisons for the pain level at different time intervals and quality of life before and after the treatment were made using the Mann-Whitney U test, whereas the intra-group comparisons for both outcomes were made using the Wilcoxon signed-rank test.

Results

The CONSORT 2010 diagram for randomized trials in Endodontics is represented in the flow diagram in Figure 3.

Figure 3.

The Consolidated Standards of Reporting Trials 2010 flow diagram.

There were 40 participants in total, 16 males and 24 females, equally distributed among both groups. The mean age of the patients in group 1 is 35.7±9.63, whereas 32.9±8.44 in group 2. On evaluating the demographic data, no significant difference was noticed between the two groups concerning the age (p=0.334) and gender (p=1.000) of the participants included in the study.

During the intragroup comparison, a significant reduction in the pain scores was observed in both groups after the completion of the treatment. The intergroup comparison found no significant difference between the two groups at preoperative pain levels (p=0.68). The mean pain scores were less in the sonic agitation group, at all the time intervals, but a significant difference at 12h (p=0.03), at 24h (p=0.02) at 48h (p=0.02) and (p=0.04) at 72h was noted and presented in Table 1. The mean pain score reduction for both groups with time intervals is depicted in Figure 4.

Table 1.

Inter-group comparison of pain scores at different time intervals (NA: No Agitation, SA: Sonic Agitation, SD: standard deviation, Pre-op: preoperative).

Groups	Pre-op	6h	12h	24h	48h	72h
	Mean±SD	Mean±SD	Mean±SD	Mean±SD	Mean±SD	Mean±SD
NA	6±1.58	2.4±2.79	2.8±2.85	2.5±2.58	2.2±2.50	1.5±2.03
SA	5.8±1.57	0.9±1.51	0.9±1.372	0.7±1.17	0.5±0.88	0.73
P	0.68	0.08	0.03	0.02	0.02	0.04

Figure 4.

Inter-group comparison of pain scores at different time intervals.

On intragroup comparison of pre and postoperative OHIP scores, a reduction of the values is noted in both groups, which represents the improvement in the patient's quality of life after the completion of the endodontic treatment. In the intergroup comparison, no statistically significant difference (p=0.27) was found between the “no agitation” and “sonic agitation” presented in Table 2.

Table 2.

Inter and intra group comparison of the overall OHIP scores (OHIP:Oral Health Impact Profile ,NA: No Agitation ,SA: Sonic Agitation ,SD: standard deviation ,Pre-op: preoperative, Post-op: postoperative).

Pre-op	Post-op	P
	Mean± SD	Mean± SD
NA	20.20±8.93	5.10±5.42	0.000
SA	18.20±4.07	2.60±2.21	0.000
P	0.515	0.278

With respect to domains in the OHIP-14, a significant difference was found between the 2 groups. Pre-operatively, it was observed in domain 3, i.e., psychological discomfort, whereas post-operatively, the difference was noted in domains 4 and 7, i.e., physical disability and handicap. No statistically significant difference was found in the other domains, either pre or postoperatively. None of the study participants had taken the analgesics (Table 3).

Table 3.

Inter and Intra group comparisons of OHIP scores for all the domains (OHIP:Oral Health Impact Profile , NA:NoAgitation , SA: Sonic agitation Pre-op: Pre operative ,Post-op: Post operative ,SD: Standard Deviation).

Domains	Groups	Pre-op		Post-op		Intragroup	Inter group
		Mean±SD		Mean±SD		P values	Pre-op	Post-op
							Pvalues	P values
Functional limitation	NA	0.7±1.30182		0.15±0.67082		0.078	0.735	0.317
	SA	0.35±0.74516		0±0		0.034
Physical pain	NA	6.15±1.53125		2.3±2.69698		0.000	0.904	0.678
	SA	6.3±0.8645		1.5±1.50438		0.000
Psychological discomfort	NA	3.9±1.71372		0.8±1.19649		0.000	0.02	0.702
	SA	2.4±1.63514		0.55±0.88704		0.000
Physical disability	NA	2.95±2.37254		0.3±0.92338		0.001	0.121	0.002
	SA	3.45±1.35627		0.5±0.88852		0.47
Psychological disability	NA	2.55±2.37254		0.4±0.99472		0.001	0.369	0.429
	SA	1.75±1.48235		0		0.01
Social disability	NA	1.85±1.69442		0.2±0.69585		0.001	0.57	0.15
	SA	1.5±1.23544		0±0		0.01
Handicap	NA	2.1±1.48324		0.95±1.2763		0.02	0.000	0.046
	SA	2.45±1.39454		0.05±0.22361		0.000

Discussion

PP is still a common consequence impacting between 2.5% to 60% of individual’s undergone endodontic treatment. The presence of chronic PP heightened the burden on patients, leading in tooth extraction (15). Post operative pain can be decreased by the usage of the irrigating solutions with the agitation, like manual dynamic agitation, sonic and ultrasonic devices, lasers, etc. (16, 17). In the current study, NaOCl, recognized as the gold standard irrigating solution, was utilized alongside EDTA (18). The modified Waterpik device was used to perform the sonic agitation of the irrigants, sonic frequency affects the irrigant penetration in the root canal system through acoustic streaming, producing rapid oscillations that cause strong, circular fluid movement, better contact of irrigant and deeper penetration into the dentinal tubules. The higher sonic frequencies improve the mechanical flushing action and effectively decontaminating the root canal. The amplitude of sonic devices is often associated with minimum oscillation, i.e. node and maximum oscillation, i.e. antinodes. The three-dimensional root canal systems constrict the side-to-side oscillations, resulting in more longitudinal oscillation of the instrument, which results in effective root canal debridement (8).

The patient and the secondary investigator who was in charge of randomization and the outcome assessment were blinded and the clinician who performed the treatment was not blinded because of the nature of the intervention. Single-visit RCT was preferred as it does not affect postoperative pain; however, it improves quality of life by saving time, preventing missed appointments, and supporting tooth survival by reducing the risk of inter-appointment fractures (19). In the current study the patients who did not take medication in the past 12 hours were selected, as this could have an impact on the pain perception after the treatment.

In the present study, except for the final irrigation technique, both groups underwent the same treatment protocol during RCT, which helped to achieve standardization and minimize the impact of variables on the studies. In some studies, variables such as age, sex, and preoperative pain were considered to play an essential role in the incidence of PP (20). However, the current study showed no significant differences between the groups related to the demographic variables and preoperative pain scores. Therefore, the effects of these variables were nullified. Several in vitro studies detailed the efficacy of this Waterpik device as an irrigant agitation device due to its irrigant penetration (8) and smear layer removal capacity. This is the first registered clinical trial using the modified Waterpik device for agitation, and aimed to assess its effect PP and OHQoL.

Data analysis revealed that the intervention with RCT reduced the pain in both groups. Significant reduction of the pain was more evident in SA group compared to NA especially at 12, 24, 48, 72-hour time intervals after the treatment. This is the first study to show that the sonic agitation by Waterpik device has reduced the post operative pain significantly compared. The results are contradicting with a previous report where no difference in PP was detected when sonic irrigation agitation, was compared to no agitation (21, 22) The reduced pain scores in SA groupin the current study were likely due to the efficient improved irrigant penetration and removal of debris smear layer facilitated by the modified Waterpik device (8). The primary mechanism behind the modified Waterpik device is sonic agitation, attributing a water pressure of 7kgf/cm3 and frequency of 1-6 kHz with 1800 pulsations per minute,creatingvibrations or oscillations,thereby enhancing the efficacy of the irrigating solutions in the removal of debris(8).The study by Ala Mohammed et al.(23) compared the Waterpik device, Endoactivator, and manual dynamic agitation and concluded that the Waterpik device performed better significantly in removing the smear layer, especially at the apical third. The author stated that it is not completely clear why WaterPik performed better in the apical third, could be attributed to the frequency power and oscillation amplitude of WaterPik. Shenoy et al. (24) in a study concluded that fewer colony-forming units were evident when agitation was done with the modification of Waterpik Power Flosser system (Waterpik Inc. Fort Collins, Colorado) with a Profile tip. Another invitro study by Bhargavi Dhamaraju et al. (25) used a custom-made Waterpik Power Flosser system as an irrigant activating device proven to be effective in the removal of smear layer both in the dentinal tubules as well as on its surface. The null hypothesis was partly rejected as agitation with the Waterpik device significantly reduced postoperative pain. Based on this result theWaterpik device can be suggested to be used for irrigation agitation during RCT. Given that advanced versions of this device are also available, which are cordless and can be modified and used more easily, it can be a practical add to clinical use toreduce PP.

Current randomized clinical trial was the first to test the effect of agitation of the irrigating solution on patients’ quality of life and demonstrated no effect.The statistical analysis had shown that patient's quality of life improved following endodontic treatment, which is compatiblewiththeliterature (11, 26); however, it was not effected by agitation similar to rotary file systems which yielded comparable results with each other in terms of OHIP scores (27).On theotherhand, on intergroup comparisons significant difference was found with the domains 4 and 7, i.e., Physical disability, and handicap domains, which suggests an improvement in the intake of a satisfactory diet with no interruption, and the patient was able to function after the completion of treatment. The irrigation activation with the modified Waterpik had decreased the postoperative pain and, so the null hypothesis is rejected.

The primary limitation of this study was non inclusivity of the post operative pain observations on the seventh day following the non-surgical endodontic treatment. The other limitations are clogging of the debris is evident while using the Waterpik device, which requires repeated recapitulation. The needle tip can't be placed to the working length mentioned in the narrow and curved canals protocol. Various studies with more comparisons of similar or advanced agitation techniques are recommended to improve the standard for its clinical use.

Conclusion

Endodontic treatment improved patients’ quality of life, sonic agitation with the Waterpik device reduced the incidence of postoperative pain. Given its low cost, the Waterpik device may serve as a practical alternative for irrigation agitation.