Periradicular repair after single- and two-visit root canal treatments using ultrasonic irrigant activation and calcium hydroxide dressing of teeth with apical periodontitis: study protocol for randomized controlled trials

Abstract Background Traditionally, root canal treatment in teeth with apical periodontitis is performed in multiple-visits, with the use of intracanal dressing between visits, aiming to reduce microorganisms and their by-products of the root canal system prior to filling. However, in recent years, discussions have been growing about the real need for the use of intracanal dressing in these cases. The use of ultrasonic activation of the auxiliary chemical substance has increased the potential for decontamination promoted during the chemomechanical preparation of the root canal. Thus, this study is designed to explore whether the use of intracanal dressing between visits during endodontic treatment favors periradicular repair in teeth with apical periodontitis. Methods This is a randomized, prospective, double-blinded, controlled clinical trial designed to evaluate 3 distinct clinical approaches used during endodontic therapy. Group 1- Root canal treatment in a single-visit (RCT-SV); Group 2- Root canal treatment in two-visits with intracanal dressing (RCT-TVWD); Group 3- Root canal treatment in two-visits without intracanal dressing (RCT-TVWOD). A total of 150 adult patients ages 18 to 60, with at least one tooth diagnosed with asymptomatic apical periodontitis and periradicular lesion will be randomized and will undergo one of the types of clinical approaches during endodontic therapy. Patients' postoperative pain levels will also be recorded in periods of 24, 48, 72 hours and 7 days. Subsequently, clinical findings and long-term follow-up evaluations, with periradicular repair will be performed by periapical radiograph and cone beam computed tomography (CBCT) at 6, 12 and 24 months. Discussion This study will evaluate the periradicular repair of mandibular molar teeth with apical periodontitis, providing information about the efficacy, benefits and safety of performing endodontic treatment in a single- and two-visit, with and without the use of calcium hydroxide dressing. All endodontic therapy procedures will be performed under a dental operating microscope and using ultrasonic activation of auxiliary chemical substances. These results may contribute to changes in the clinical approaches adopted during endodontic therapy of teeth with apical periodontitis and reveal the potential of complementary approaches that aim to enhance the decontamination of the root canal system during the preparation stage. Trial registration: ClinicalTrials.gov NCT05256667. Registered on 24 February 2022