Assessment of Postoperative Pain after Single-Visit Root Canal Treatment using Wave One® and One Shape® Single File System: A Clinical Study.

BACKGROUND: Wave One® (WO) and One Shape® (OS) are among the common endodontic file systems having rotary and reciprocating movement of instrument, respectively. The study evaluated the postoperative pain after single-visit root canal treatment using single file rotary and reciprocating system.
MATERIALS AND METHODS: The present study was conducted in the department of conservative dentistry and endodontics on 68 teeth of patients aged between 20 and 45 years. Sixty-eight teeth were divided into two study groups. In Group A, instrumentation with OS file systems (n = 34) was done with subgroup A1 having patients without periapical lesion (n = 17) and subgroup A2 having patients with periapical lesion (n = 17). In Group B, instrumentation with WO file systems (n = 34) was done with subgroup B1 having patients without periapical lesion (n = 17) and subgroup B2 having patients with periapical lesion (n = 17). The root canal shaping procedures were performed according to the manufacturer's instructions for each instrument system. Presence of postobturation pain was accessed by visual analog scale (VAS) scale (0-10), where 0 showed no pain, 1-3 mild pain, 4-6 moderate pain, 7-9 severe pain, and 10 worst possible pain.
RESULTS: The intensity of pain was measured with VAS score in patients without periapical lesions and with periapical lesions using WO and OS file system on the 1st, 2nd, 3rd, and 7th day. VAS score was found to be nonsignificant on the 1st, 2nd, 3rd, and 7th day in both groups (P > 0.05). Intergroup comparison of VAS score was found to be nonsignificant (P > 0.05).
CONCLUSION: Both systems were found to have similar effect with respect to postoperative pain. However, WO single file system presented less pain as compared to OS system in cases with periapical lesion. Large sample studies are required to substantiate the result obtained in this study. Copyright:

INTRODUCTION

The basic principles of endodontic therapy are the removal of irritants of root canal, root canal system obturation, and maintenance of natural dentition.[1] Despite revolutionary modifications in root canal treatment (RCT), literature showed that there is variation in intensity and frequency of pain after endodontic treatment.[2] Postobturation pain prevalence which is although of short duration is thwarting both for patient and for a dental surgeon and is infuriating, especially if there was no symptom in tooth previous to treatment.[3]

There is a myth among general population that single-visit endodontic treatment induces more postoperative pain, discomfort, and flare-up. Several studies revealed that single-visit RCT performed in vital pulp cases had reproduced good outcome.[4] There are more chances of flare-up, discomfort, and postoperative pain with single-visit endodontic treatment as compared to multiple visit endodontic treatment.[56]

Common method of instrumentation in bio-mechanical preparation of the root canal is in “rotary motion,” but a method of “reciprocating” motion is developed to reduce the risks associated with rotary movement of instruments. Reciprocating method uses clockwise and counterclockwise motion of the files minimizing manual instrumentation, hence reducing the risk of file breakage in the canal.[7]

Recently, various single file systems with the capability to prepare root canals with only one instrument have been introduced. Wave One (WO) and One Shape (OS) are one among the common systems having rotary and reciprocating movement of instrument, respectively.[8] The OS file (Micro Mega) is used in continuous clockwise rotation. WO by Dentsply is another single file system using reciprocating kinematics. The reciprocating motion of these instruments varies in clockwise and counterclockwise rotations.[9] Hence, the purpose of this study was to evaluate the postoperative pain after single-visit RCT using single file rotary and reciprocating system.

MATERIALS AND METHODS

The present study was conducted in the department of conservative dentistry and endodontics. The study protocol was approved by the institutional ethics committee. This study was conducted on 68 teeth. Inclusion criteria were single-rooted teeth requiring RCT, asymptomatic teeth, patient aged between 20 and 45 years. Exclusion criteria comprised patients with hypoplastic teeth, deciduous teeth, single root having more than one canal, opposing prosthesis, periapical lesion >2 mm, and teeth with calcified canals.

Sixty-eight teeth were divided into two study groups as follows:

Group A - Instrumentation with OS file systems (n = 34)

Subgroup A1 = Patients without periapical lesion (n = 17)

Subgroup A2 = Patients with periapical lesion (n = 17).

Group B - Instrumentation with WO file systems (n = 34)

Subgroup B1 = Patients without periapical lesion (n = 17)

Subgroup B2 = Patients with periapical lesion (n = 17).

In all patients, thorough case history was taken and intraoral examination was done. Patients requiring RCT were screened with digital radiographs to confirm the presence of only one root canal and periapical lesion. Access cavity preparation was done using round diamond abrasive point # ISO BR 41 and nonend cutting tapered fissure bur #EX24. Patency of root canal was checked by introducing # 10 file into the canal. Working length was measured.

The root canal shaping procedures were performed according to the manufacturer's instructions for each instrument system. In OS Endodontic File System, file #25/0.06 was used in a slow in and out pecking motion at 350–450 rpm and torque 2.4 N. Ethylenediaminetetraacetic acid (EDTA) gel was used as a lubricant. The flutes were cleaned after every 3 pecks. The instrument was worked till the working length until the apical portion of the root was cleaned adequately. Canals were irrigated with 5% NaOCl after each instrumentation. Final flush with 17% EDTA followed by normal saline was done.

For WO Endodontic File System, the primary file (#25/0.08) in the WO file system was used. The file was used at a speed of 250 rpm and torque 2 N in and out pecking motion.

Master cone was selected and confirmed with intraoral periapical radiograph. Lateral condensation technique was followed, and again, digital radiograph was taken to confirm good quality obturation without voids. Temporary restoration with Cavit (3M ESPE) was placed in access cavity. Postoperative instructions were given. A questionnaire was given to patient to be filled with respect to postobturation pain on the 1st, 2nd, 3rd, and 7th day. Presence of postobturation pain was accessed by visual analog scale (VAS) scale (0–10), where 0 showed no pain, 1–3 mild pain, 4–6 moderate pain, 7–9 severe pain, and 10 worst possible pain. The results were statistically analyzed by using “Mann–Whitney U-test” and “Freidman's test.”

RESULTS

The intensity of pain was measured with VAS score in patients without periapical lesions using rotary single file system on the 1st, 2nd, 3rd, and 7th day. The present study revealed that the number of patients with no pain in Group A1 without periapical lesions was 10 and in Group B1 was 11. Worst pain was seen in 1 in Group A and 2 in Group B on 1st day. Both the groups showed decrease in number of patients with worst pain, severe pain, and moderate pain on the 2nd, 3rd, and 7th day. Group A had 14 patients and Group B had 13 patients with no pain on the 7th day. Postoperative pain using VAS score was found to be nonsignificant on the 1st, 2nd, 3rd, and 7th day in both groups (P > 0.05) [Tables 1–3 and Graphs 1–4].

Table 1

Intragroup comparison of pain in teeth with and without periapical lesions using One Shape® single file system (Group A1/A2)

Day	Intragroup A1/A2	Intensity of pain in patients with and without periapical lesions
		No pain patients, n (%)	Mild pain patients, n (%)	Moderate pain patients, n (%)	Severe pain patients, n (%)	Worst pain patients, n (%)
1st day	A1	10 (58.8)	2 (11.7)	2 (11.7)	2 (11.7)	1 (5.9)
	A2	3 (17.6)	2 (11.7)	2 (11.7)	4 (23.5)	6 (35.2)
2nd day	A1	12 (70.6)	3 (17.6)	1 (5.9)	1 (5.9)	0
	A2	3 (17.6)	3 (17.6)	4 (23.5)	3 (17.6)	4 (23.5)
3rd day	A1	14 (82.3)	2 (11.7)	1 (5.9)	0	0
	A2	4 (23.5)	4 (23.5)	5 (29.4)	2 (11.7)	2 (11.7)
7th day	A1	15 (88.2)	2 (11.7)	0	0	0
	A2	6 (35.2)	7 (41.1)	4 (23.5)	0	0

Table 3

Intergroup comparison of pain in teeth without periapical lesions in Group A1 and Group B1

Time and intensity of pain using VAS	Group A1, value (%)		Group B1, value (%)		P
1st day (24 h)
No pain	10	58.8	11	64.7	0.21
Mild pain	2	11.7	1	5.9
Moderate pain	2	11.7	2	11.7
Severe pain	2	11.7	1	5.9
Worst pain	1	5.9	2	11.7
2nd day (48 h)
No pain	12	70.6	13	76.4	0.13
Mild pain	3	17.6	1	5.9
Moderate pain	1	5.9	1	5.9
Severe pain	1	5.9	2	11.7
Worst pain	0	0	0	0
3rd day (72 h)
No pain	14	82.3	13	76.4	0.52
Mild pain	2	11.7	2	11.7
Moderate pain	1	5.9	2	11.7
Severe pain	0	0	0	0
Worst pain	0	0	0	0
7th day
No pain	15	76.4	14	82.3	0.14
Mild pain	2	11.7	3	17.6
Moderate pain	0	0	0	0
Severe pain	0	0	0	0
Worst pain	0	0	0	0

VAS: Visual analog scale

Graph 1

Intergroup comparison of postoperative pain in Group A1 and B1 on 1st day

Graph 4

Intergroup comparison of postoperative pain in Group A1 and B1 on 7th day

Intergroup comparison of postoperative pain in Group A1 and B1 on 2nd day

Intergroup comparison of postoperative pain in Group A1 and B1 on 3rd day

We found that three patients in Group A and 5 in Group B had no pain and six patients each had worst pain in both groups on the 1st day. The number of patients with worst pain reduced to 4 in Group A and 5 in Group B on the 2nd day which further reduced to 2 in Group A and 3 in Group B on the 3rd day. On the 7th day, no patient had worst pain in both groups. Four patients each had moderate pain in both groups, while 7 and 6 patients had mild pain in Group A and B, respectively. Six patients in Group A and 7 patients in Group B had no pain. Intergroup comparison of VAS score was found to be nonsignificant (P > 0.05) Table 4 and Graphs 5–8].

Table 4

Intergroup comparison of pain in teeth with periapical lesions in Group A2 and Group B2

Time and intensity of pain using VAS	Group A2, value (%)		Group B2, value (%)		P
1st day (24 h)
No pain	3	17.6	5	29.4	0.51
Mild pain	2	11.7	1	5.9
Moderate pain	2	11.7	3	17.6
Severe pain	4	23.5	2	11.7
Worst pain	6	35.2	6	35.2
2nd day (48 h)
No pain	3	17.6	5	29.4	0.23
Mild pain	3	17.6	2	11.7
Moderate pain	4	23.5	2	11.7
Severe pain	3	17.6	3	17.6
Worst pain	4	23.5	5	29.4
3rd day (72 h)
No pain	4	23.5	6	35.2	0.14
Mild pain	4	23.5	5	29.4
Moderate pain	5	29.4	2	11.7
Severe pain	2	11.7	1	5.9
Worst pain	2	11.7	3	17.6
7th day
No pain	6	35.2	7	41.1	0.52
Mild pain	7	41.1	6	35.2
Moderate pain	4	23.5	4	23.5
Severe pain	0	0	0	0
Worst pain	0	0	0	0

VAS: Visual analog scale

Graph 5

Intergroup comparison of postoperative pain in Group A2 and B2 on 1st day

Graph 8

Intergroup comparison of postoperative pain in Group A2 and B2 on 7th day

Intergroup comparison of postoperative pain in Group A2 and B2 on 2nd day

Intergroup comparison of postoperative pain in Group A2 and B2 on 3rd day

DISCUSSION

RCT or endodontic therapy is a common treatment option in many cases for eradication of pain. The RCT significantly reduces the severity of pain. In few instances, there is variation in severity of pain immediate after treatment. The severity of pain immediately following treatment may show higher level as compared to pain level before the treatment. This results from penetration of pulpal tissues, dentinal debris, microorganisms, and irrigants to the periapical tissues during RCT, leading to periradicular inflammation.[10]

Any injury to the periapical tissue during RCT promotes more intensive secretion of inflammatory mediators, such as prostaglandins, serotonin, leukotrienes, histamine, and bradykinin, which are considered to be mediators of pain.[11]

The endodontic treatment may be multiple visits or single visit. There are certain criteria to be followed for performing single-visit endodontics. There has been debate for many years regarding rationale of single-visit and multiple visit endodontics. One opinion for less postoperative pain in single-visit endodontics is due to immediate obturation after root canal preparation and hence preventing penetration of medications, irrigants, and repeated instrumentation which is considered precipitating factors for postoperative pain.[12]

In the present study, we evaluated and compared postoperative pain in single-visit RCT using OS (rotary) and WO (reciprocating) single file systems. Many techniques such as visual analog, verbal, functional, colored analog, numerical, finger-reach rating scales, cortical-evoked potentials, and calibrated questionnaires have been used to assess pain intensity.[13] In the present study for pain assessment, a modified VAS was used in both groups.

We observed that in Group A (OS single file system) subgroup A1 (i.e. without periapical lesion) patients on the 1st day, 10 (58.8%) patients out of 17 had no pain which became 15 (82.3%) on the 7th day. There was no patient of moderate, severe, and worst pain on the 7th day.

Similarly, in Group A (OS single file system) subgroup A2 (i.e. with periapical lesion), we assessed postoperative pain on the 1st, 2nd, 3rd, and 7th day. There were 3 (17.6%) patients with no pain and 6 (35.2%) patients with worst pain on 1st day. On the 7th day, the number of patients with no pain increased to 6 (35.2%) and there was no patient with worst pain. However, there were more patients who had postoperative pain in this subgroup as compared to A1 subgroup. This shows that OS (rotary) single file system is effective in controlling pain in Group A patients with no periapical lesions. Our results are in agreement with Neelakantan et al.[3] In their study, there were 507 patients treated with RECIPROC system and 462 treated with OS. Both systems offered statistical significant difference in terms of incidence of postoperative pain. This can be postulated by the concept that teeth with periapical lesions have more pain as compared to teeth without lesions due to release of pain mediators such as bradykinin and leukotrienes.[14]

In Group B (WO single file system) subgroup B1 (i.e. without periapical lesion), teeth were instrumented with WO (reciprocating) single file system. It was observed that on 1st day, 11 (64.7%) patients had no pain and only 2 (11.7%) patients had worst pain. With the progression of days, the number of patients with worst pain, severe pain, and moderate pain decreased significantly, and on the 7th day, 14 (82.3%) patients had no pain. Our results are in agreement with Ramazani et al.[15]

In subgroup B2 (i.e. with periapical lesion), WO (reciprocating) single file system was used to instrument root canal. There was significant difference of VAS scale on different days on comparison between Group A patients with Group B, i.e. teeth with no periapical lesions and teeth with periapical lesions in both groups. This shows that OS (rotary) single file system is effective in controlling pain in Group A patients with no periapical lesions. Our results are in agreement with Kherlakian et al.[16] This shows that reciprocating system is better in terms of controlling pain as compared to single rotary file system. However, De Melo Ribeiro et al.[17] in their study found that self-adjusting file system in the apical third, created cleaner inner canal walls when compared to a rotary system. The results of this study demonstrated similar pain values in both the reciprocating and rotary instrumentation groups.

The flexibility of OS instrument insures a perfect follow of curvature and canal path. It has cross-sections which is capable of showing its cutting ability in three zones of the canal.[18] WO nickel-titanium file system works in a reciprocating motion. There is rotation of the instrument initially is in a counterclockwise direction resulting in penetration and cutting of the dentin.[19] The resultant debris is not pushed periapically but removed through the root canal, thus reducing postoperative pain.

CONCLUSION

Both systems were found to be effective in controlling postoperative pain. However, WO single file system had less pain as compared to OS system. Large sample studies are required to substantiate the results obtained in this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Table 2

Intragroup comparison of pain in teeth with and without periapical lesions using Wave One® (reciprocating) single file system (Group B1/B2)

Day	Intragroup B1/B2	Intensity of pain in patients with and without periapical lesions
		No pain patients, n (%)	Mild pain patients, n (%)	Moderate pain patients, n (%)	Severe pain patients, n (%)	Worst pain patients, n (%)
1st day	B1	11 (64.7)	1 (5.9)	2 (11.7)	1 (5.9)	2 (11.7)
	B2	5 (29.4)	1 (5.9)	3 (17.6)	2 (11.7)	6 (35.2)
2nd day	B1	13 (76.5)	1 (5.9)	1 (5.9)	2 (11.7)	0
	B2	5 (29.4)	2 (11.7)	2 (11.7)	3 (17.6)	5 (29.4)
3rd day	B1	13 (76.5)	2 (11.7)	2 (11.7)	0	0
	B2	6 (35.2)	5 (29.4)	2 (11.7)	1 (5.9)	3 (17.6)
7th day	B1	14 (82.3)	3 (17.6)	0	0	0
	B2	7 (41.1)	6 (35.2)	4 (23.5)	0	0