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.

BACKGROUND: In certain clinical situations, 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); and group 3-root canal treatment in two visits without intracanal dressing (RCT-TVWOD). A total of 150 adult patients aged 18 to 60, with at least one tooth diagnosed with asymptomatic apical periodontitis and periradicular lesion (confirmed with a cone beam computed tomography (CBCT)), 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, and 72 h and 7 days. Subsequently, clinical findings and long-term follow-up evaluations, with periradicular repair, will be performed at 6 and 12 months by intraoral periapical radiograph (IOPAR) and CBCT at the 24-month follow-up. 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 the endodontic treatment in a single and two visits, 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.

Solubility and dimensional change after setting of root canal sealers: a proposal for smaller dimensions of test samples.

This study proposed smaller dimensions for samples used in solubility and dimensional change tests of root filling materials on the basis of American National Standard Institute/American Dental Association (ANSI/ADA) Specification No. 57. The volume, mass, and density of the test samples were determined, and 6 different samples of smaller dimensions were proposed for each test. Endofill and AH Plus sealers were used in the tests. For the solubility test, 2 samples were weighted, stored in distilled and dionized water for 24 hours, dried, and weighed again. Solubility was calculated by using samples' weight loss (%). For dimensional change analysis, the samples' heights were measured before and after immersion in dionized water for 30 days. For both tests, correlation between data of the different groups was observed. Kruskal-Wallis test showed that Endofill sealer presented higher solubility values than AH Plus (P < .05). The Endofill sealer presented 0.56% of shrinkage and AH Plus 0.62% expansion. Smaller dimensions for test samples used in solubility and dimensional change tests are a viable alternative, decreasing the amount of filling material necessary for executing these tests.