Postoperative Pain and Healing of Molar Root Canal Teeth Using GentleWave vs. EndoActivator
Phase: NA
Conditions: Symptomatic Irreversible Pulpitis, Apical Periodontitis
Sponsor: St. Louis University

 
Postoperative Pain and Healing in Teeth 
Treated With GentleWave or 
EndoActivator 
 
 
NCT# 04552132 
 
 
May 2, 2022 
 
 

Pain Assessment Protocol 
This study protocol was approved by the Institutional Review Board of Saint Louis 
University, Saint Louis, MO (Protocol Number 31359).  Patients were recruited for this study 
from the patients seen at the Center for Advanced Dental Education at Saint Louis University 
from September 2020 through March 2022. Informed consent was obtained from each patient 
for participation in this study.  The following inclusion criteria were utilized for participation in 
the study: adults fully able to provide informed consent, with restorable, symptomatic molar 
teeth (reporting ≥20mm on the VAS during the previous 24 hours) seeking endodontic therapy. 
Patients where both Ibuprofen and Acetaminophen were contraindicated, patients with chronic 
pain issues for which they regularly need to consume analgesics, and patients having taken 
analgesics or antibiotics within the previous 6 hours were excluded from this study. 
The first patient treated in the study was randomized by coin toss, followed by an 
alternating pattern thereafter for the 2 groups: GentleWave (GWS) (n=16) or EndoActivator 
(EA) (n=17). Prior to their clinical evaluation, the patients marked on: 1) a 100mm VAS 
instrument where they felt best represented their degree of pain experienced at that moment, 
and 2) a 2nd 100mm VAS instrument their maximum level of pain during the previous 24 hours. 
Clinical evaluation of the patient included percussion and palpation testing, periodontal probing 
measurements, thermal pulp sensibility testing using a cold source (Endo Ice), and an 
evaluation of tooth mobility. Radiographic examination (XDR Radiology, Los Angeles, CA) 
included bitewing, straight-on periapical, angled periapical, and 4X4 cm high-resolution limited 
field of view cone beam computed tomography (CBCT) (Carestream 9600-Carestream Dental, 
Atlanta, GA) imaging. 

Following the administration of topical anesthetic (20% Benzocaine), the same high-
level of anesthetic was administered to all patients, in order to standardize the number of 
injections received by the participants. If supplemental anesthesia was required, intrapulpal 
injections were performed for vital teeth and periodontal ligament injections were performed 
for necrotic teeth. 
Rubber dam isolation and the surgical operating microscope were used throughout the 
treatment procedure. All deficient existing restorations and caries were removed. If inadequate 
isolation existed to perform the root canal treatment within an isolated environment, 
SoundSeal (Sonendo Inc., Laguna Hills, CA), a light-cured composite resin, was used to facilitate 
proper isolation1. 
Canal patency was achieved, and working length (WL) was determined using a #10 C-file 
and Root ZX II electronic apex locator (EAL) (J. Morita USA, Irvine, CA). WL was defined as being 
1mm short of full tone on the EAL for patients in the GWS group (per the recommended 
Sonendo protocol)2 and 0.5mm short of full tone on the EAL for the EA group. All canals were 
instrumented to a size #20/.06 Vortex Blue nickel titanium rotary file (DENTSPLY Tulsa Dental 
Specialties, Tulsa, OK).  5.25% sodium hypochlorite (NaOCl) was administered using a 30-gauge, 
side-vented needle (ProRinse Probes-DENTSPLY Tulsa Dental Specialties, Tulsa, OK) with each 
successive file placed into the canal.   
For the GWS group, 70% isopropyl alcohol placed on a dry cotton pellet was used to 
clean and dry the tooth. After having created a suitable platform using SoundSeal, the choice of 

GWS cycle was determined according to the clinical situation and the corresponding 
manufacturer-recommended protocol 3 (Fig 1).   
Fig 1. GentleWave System Cycles 
Case Type 
3% NaOCl 
Distilled Water 
8% EDTA 
Distilled Water 
Necrotic 
4 Minutes 
30 Seconds 
1.5 Minutes 
15 Seconds 
Vital 
5 Minutes 
30 Seconds 
2 Minutes 
15 Seconds 
Extended 
5 Minutes 
30 Seconds 
2 Minutes 
15 Seconds 
Low 
0.5% NaOCl 
Distilled Water 
8% EDTA 
Distilled Water 
8 Minutes 
30 Seconds 
2 Minutes 
15 Seconds 
Settings were chosen based off of the proximity of root apices to vital structures such as the 
inferior alveolar nerve or maxillary sinus: ‘Extended’>2mm, ‘Necrotic’ or ‘Vital’ 1-2mm, 
‘Low’<1mm 
 
After completion of the preprogrammed GWS cycle, the canals were flushed with saline. 
For obturation, gutta-percha cones were selected that would extend 0.5mm beyond the end 
point of mechanical instrumentation, in order to facilitate obturation 0.5mm short of full tone 
on the EAL. The canals were dried using sterile paper points. Hi Flo BC Sealer (Brasseler USA, 
Savannah, Georgia) was expressed directly into the canal. Cones were placed, and seared off at 
the opening of each canal orifice using a heated System B unit (SybronEndo, Glendora, CA). The 
chamber was cleaned of excess sealer using a cotton pellet moistened with water, then rinsed 
and air dried with an air/water syringe. A sterile sponge was placed on the chamber floor, and 
the access opening was temporized with Cavit (3M ESPE, Neuss, Germany). Straight-on and 
angled periapical radiographs were exposed postoperatively.      
For the EA group, instrumentation was performed as described above, but to 0.5mm 
short of full tone on the EAL, and the canals and chambers were flooded with 5.25% NaOCl. The 

small EA tip (ISO 15/.02) was placed 2mm short of WL and activated vertically, in 2-3mm 
strokes for 30 seconds within each canal, as per the manufacturer’s directions 4. The canals 
were subsequently flushed with fresh 5.25% NaOCl and then the irrigant was reactivated with 
the EndoActivator for an additional 30 seconds within each canal. Fresh sodium hypochlorite 
was again applied, and then removed by retracting the plunger on the syringe. A total of five 
milliliters of 5.25% NaOCl was used to irrigate each tooth during each procedure for patients 
within the EA Group. All canals were then irrigated with 3 milliliters of 17% EDTA using a 30-
gauge, side-vented needle for a total of 1 minute. Canals and chamber were once again 
evacuated by retracting the plunger on the syringe and then a final flush with 3mL of saline was 
delivered using a 30-gauge side-vented needle. Canals were then dried with sterile paper 
points. The same single-cone obturation technique was used as for the GWS group.  
Prior to leaving the clinic, the patient was provided an 8.5X11 inch, pre-stamped 
envelope containing 4 blank VAS forms to be filled out by the patient at 24 hours, 48 hours, 72 
hours, and 96 hours postoperatively, as well as 4-days’ worth of Ibuprofen (600mg Ibuprofen X 
16 tablets) (Ascend Laboratories, LLC, Parsippany, NJ) and Acetaminophen (650mg 
Acetaminophen X 16 tablets) (Perrigo, Allegan, MI). The printed patient instructions were to 
take 1 tablet of Ibuprofen every 6 hours as needed for pain. If the Ibuprofen did not provide 
adequate pain relief, then the patient was instructed to also take 1 tablet of Acetaminophen 
every 6 hours as needed for pain. If the patient maximized the Ibuprofen and Acetaminophen 
intake and still required additional pain relief, then patient was instructed to call the clinic and a 
prescription would be provided for Tramadol 50mg X 12 tabs, to be taken every 6 hours as 
needed for pain. The patients were provided with a Pain Pill Log to record what analgesics were 

taken at what times. After ninety-six hours postoperatively, patients were instructed to mail, or 
physically return, back to the clinic the large envelope with the 4 completed VAS forms, the 
Pain Pill Log, as well as any unused analgesics. Patients who properly returned all of the 
requested paperwork were compensated with a $75 Visa gift card. 
Pain Assessment Statistical Analysis 
Data was compiled and analyzed by a biostatistician at two different time periods. 
Therefore, participants that were seen between 09/2020-06/2021 were analyzed separately 
from those seen between 07/2021-03/2022. Data points for pain assessment and analgesic 
intake were plotted for visualization. A Shapiro-Wilk test of normality indicated a non-normal 
distribution of the pain data. Due to the skewness observed, a non-parametric analysis was 
utilized. 
The level of pain recorded from each postoperative VAS was compared to the patient’s 
preoperative VAS score to determine if their pain level had increased or decreased. A two-sided 
Fischer’s Exact Test for Count Data was then used to determine whether postoperative pain 
decreased relative to preoperative pain scores more often in one group as compared to the 
other group. 
Results were considered significant if the p≤.05. 
CBCT Healing Assessment and statistical analysis 
 
Patients (GWS=12, EA=14), were recalled at 12 months postoperative, and the 
same imaging and clinical endodontic testing was done as had been performed preoperatively. 
A 3-D volumetric analysis using ITK Snap software (ITK SNAP, Philadelphia, PA) was completed 

to measure the volume of pre-and-post-operative periapical findings in mm3. Each individual 
root was then assigned a 3Droot classification of either healed (normal PDL around the root at 
recall), healing (reduced size of finding), or diseased (same or larger size finding). Pearson’s Chi 
squared test was used to evaluate if there was any difference in 3Droot healing outcomes 
between the GWS and EA groups. Results were considered significant if the p≤.05. 
Clinical tooth healing classification based on clinical examination and patient report (Ctooth)  
Teeth were classified as being clinically successful if the patient had no symptoms other than 
mild tenderness to percussion. Teeth were not considered as failures due to mild percussion 
sensitivity alone, as long as the patient reported no pain when chewing.  
Pearson’s Chi squared test was used to evaluate if there was any difference in Ctooth 
healing outcomes between the GWS and EA groups. Results were considered significant if the 
p≤.05. 
 
 
 
 
 
 

References 
1. 
Grigsby Jr D, Ordinola-Zapata R, McClanahan SB, Fok A. Postoperative pain after 
treatment using the GentleWave system: a randomized controlled trial. Journal of 
endodontics 2020;46(8):1017-1022. 
 
2. 
Inc. S. The GentleWave System Training Manual. 2020. 
 
3. 
Inc. S. The GentleWave System Console IFU. In. Laguna Hills, CA; 2019. p. 52. 
 
4. 
Sirona D. ENDOACTIVATOR Directions for Use. In.; 2019. p. 8.