This research was conducted with the approval of the Institutional Review Committee (IRC number 077/19) in the duration from April 2019 to December 2019.
One hundred and sixty patients requiring endodontic treatment for single tooth were included in the study. Endodontic treatment was performed in single or multiple visits of either vital or non-vital tooth and anterior or posterior tooth. Each patient was explained about the aims and design of the study, and written consent were obtained before their inclusion. The exclusion criteria were: complex cases such as pulp canal obliteration, procedural accidents, variable anatomy where maintaining patency is difficult, retreatment cases, teeth with periapical radiolucency, pregnancy patients who are medically compromised and patients under analgesic medication within last 3 days.
The sample size calculation for each group was 36.8 with level of significance of 0.05, a power of 0.9, an effect size of 0.8 and standard deviation of 1.2 (14). One hundred sixty subjects were included in the study after careful screening of patients reporting to Department of Conservative Dentistry and Endodontics, Universal College of Medical Sciences, Bhairahawa, Nepal.
The preoperative radiographic examination and clinical records were collected from all the patients, like preoperative pain, pulpal status, and group of the teeth (anterior or posterior teeth). The pulpal status was checked with electric pulp tester (Digitest™ Parkell Inc., USA) and Endofrost (Coltene/Whaledent GmbH and Co.KG). This was later reconfirmed upon access opening i.e presence of bleeding and on sensibility tests positive response implied for vital tooth similarly for non-vital tooth absence of bleeding and negative response on sensibility tests. The preoperative pain scores were also recorded and noted for both groups (patency/non-patency group) in Numeric pain rating scale.
The eligible patients were randomly allocated to one of the two groups: patency (Group A) and non-patency (Group B). An equal proportion of randomization allocation ratio for the two groups was done by shuffled deck of cards with number assigned from 1 to 160 (i.e. even number for patency group and odd number for non-patency group). Number of visits were allocated by another set of equal proportion of envelopes containing concealed assignment codes. Single blinding was done where patients were unaware of nature of treatment administered throughout the investigation. Endodontic treatments were performed by one endodontist in single visits and multiple visits.
Group A: Patency group ( n = 80)
Sub-division A1V: Vital teeth (n = 20)
Division A1Va: Anterior teeth (n = 10)
Division A1Vp: Posterior teeth (n = 10)
Sub-division A1NV: Non-vital teeth (n = 20)
Division A1NVa: Anterior teeth (n = 10)
Division A1NVp: Posterior teeth (n = 10)
Sub-division A2V: Vital teeth (n = 20)
Division A2Va: Anterior teeth (n = 10)
Division A2Vp: Posterior teeth (n = 10)
Sub-division A2NV: Non-vital teeth (n = 20)
Division A2NVa: Anterior teeth (n = 10)
Division A2NVp: Posterior teeth (n = 10)
Group B: Non-patency group ( n = 80)
Sub-division B1V: Vital teeth (n = 20)
Division B1Va: Anterior teeth (n = 10)
Division B1Vp: Posterior teeth (n = 10)
Sub-division B1NV: Non-vital teeth (n = 20)
Division B1NVa: Anterior teeth (n = 10)
Division B1NVp: Posterior teeth (n = 10)
Sub-division B2V: Vital teeth (n = 20)
Division B2Va: Anterior teeth (n = 10)
Division B2Vp: Posterior teeth (n = 10)
Sub-division B2NV: Non-vital teeth (n = 20)
Division B2NVa: Anterior teeth (n = 10)
Division B2NVp: Posterior teeth (n = 10)
Local anesthesia (2% lidocaine hydrochloride and epinephrine 1:200,000; Neon laboratories Ltd., India) using conventional nerve block techniques was given to patients. Root canal procedure was started under rubber dam isolation. The access cavity preparation was done using round bur (SS White, USA) and Endo Z bur (Dentsply Maillefer, Switzerland) with highspeed handpiece. Number 10 Kfile (Dentsply Maillefer, Switzerland) was used to negotiate the canals with the help of Glyde (Dentsply Maillefer, Switzerland). WL was confirmed using Propex II apex locator (Dentsply Maillefer, Switzerland) and then confirmed radiographically. If there is disagreement between radiographic and electronic working length measurements, the apex locator was selected.
Filing was done cautiously to prevent surpassing of patency file beyond the working length for non-apical patency group (i.e. Group B) at all times during treatment for both single visit and multiple visits, vital and non-vital, anterior and posterior teeth. Likewise, for patency group (i.e. Group A), a size 10 K-file was passed 1 mm beyond the working length between each instrument change. Irrigation was performed with saline, 5 ml of 5% sodium hypochlorite (NaOCl) solution (Dentpro, India), and 2% chlorhexidine (Dentochlore, Ammdent, India) after each instrumentation. Cleaning and shaping was done with hand K-files (Dentsply Maillefer, Switzerland) using step-back technique. For multiple visit (Group A2 and B2), canal was medicated with calcium hydroxide (RC CAL Prime Dental products ltd,India), temporarily sealed with cavit (3M ESPE) and recalled after a week for follow-up. In single visit (Group A1 and B1) and asymptomatic multiple visit (Group A2 and B2) the obturation was done in following steps: The master cone radiograph was taken to re-confirm the length. Canals were dried using paper points. AH Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) was applied on the walls of the canal. After that, obturation was done with lateral condensation technique and access cavity was restored using direct composite resin. Postoperative pain scores were recorded on Numeric pain rating scale forms by the patients on 1st, 2nd and 7th day.
Normality of the data was tested using Kolmogorov Smironov test. The data were not distributed normally hence, non-parametric test i.e Mann-Whitney U test was used. The relation between pre-operative pain and post-operative pain was evaluated by Spearman correlation test.