Sumita Bhagwat et al 48 Preliminary in vivo Investigation into the Relationship between Canal Preparation Protocol and Incidence of Postoperative Pain in Single-visit and Two-visit Endodontic Therapy: A Randomized Controlled Clinical Trial 1 Sumita Bhagwat, 2 Nehal Sheth, 3 Leena Padhye ABSTRACT Introduction: Postoperative pain is a major concern for patients undergoing root canal treatment. Much research has gone into the alteration of several variables to determine the elusive technique that will result in no postoperative pain. Aim: The aim of our study was to investigate the incidence, severity, and duration of postoperative pain in relation to tech- nique of root canal preparation and compare the difference in incidence, severity, and duration of postoperative pain in single- and two-sitting root canal therapy when different instru- mentation techniques are used. Materials and methods: Sixty adult patients requiring root canal therapy were selected and divided into six groups. Single- sitting root canal treatment was carried out in three groups, with three different canal preparation methods (group I – Conventional hand fles, group II – hand ProTaper fles, and group III – rotary ProTaper fles). Two-sitting root canal treatment was carried out in three groups, with the same canal prepara- tion methods (group IV – conventional hand fles, group V – hand ProTaper fles, and group VI – rotary ProTaper fles). Postoperatively, the subjects were instructed to fll out a series of self-report questionnaires for pain incidence after 1 day, 2 days, 3 days, 1 week, and 2 weeks. After 2 weeks, the patients were recalled and their responses were duly noted. Results: Results were tabulated and statistically analyzed using Mann–Whitney U test. Conclusion: There was a signifcant difference in incidence, character, and duration of postoperative pain in rotary-prepared canals as compared with hand-prepared canals in both single- and two-sitting endodontics. Clinical signifcance: The purpose of this study was to search for a predictability in incidence, duration, and character of postoperative pain in canals instrumented with hand and rotary 1 Professor and Postgraduate Guide, 2 Ex-resident, 3 Professor and Head 1-3 Department of Conservative Dentistry and Endodontics, DY Patil University School of Dentistry, Navi Mumbai, Maharashtra India Corresponding Author: Sumita Bhagwat, Professor and Postgraduate Guide, Department of Conservative Dentistry and Endodontics, DY Patil University School of Dentistry, Navi Mumbai, Maharashtra, India, Phone: +912221713763, e-mail: sumita1572@gmail.com JCD RESEARCH ARTICLE 10.5005/jp-journals-10031-1184 instruments. Knowing this will enable clinicians to make more prudent choices in instruments, techniques, and protocols for root canal therapy. Keywords: Manual preparation, Pain duration, Postendodontic pain, Postoperative pain, Rotary preparation. How to cite this article: Bhagwat S, Sheth N, Padhye L. Preliminary in vivo Investigation into the Relationship between Canal Preparation Protocol and Incidence of Postoperative Pain in Single-visit and Two-visit Endodontic Therapy: A Random- ized Controlled Clinical Trial. J Contemp Dent 2017;7(1):48-52. Source of support: Nil Confict of interest: None INTRODUCTION In the past decade, the shift from manual canal prepa- ration to rotary canal preparation during endodontic therapy has been noteworthy. But even with the use of rotary methods, postoperative pain continues to appear with high frequency. 1,2 Much research has gone into the alteration of variables like interappointment time span 3 and number of sittings to reduce postoperative pain. Till date, there is very little research that com- pares postoperative pain following hand vs rotary canal preparation techniques. Our study aimed at testing the hypothesis that there is a definite relationship between occurrence of postoperative pain and the technique used for canal preparation. This clinical study has compared the incidence, duration, and character of postoperative endodontic pain in canals prepared with hand instru- ments (2% and hand ProTaper™) and those prepared with rotary instrumentation (ProTaper™) in both single- and two-sitting endodontics. MATERIALS AND METHODS Sixty adult patients aged between 16 and 65 years, requiring root canal therapy in anterior and single- rooted premolar teeth were selected from the Depart- ment of Conservative Dentistry and Endodontics for this study.