Evaluation of root canal preparation with different tapers and apical diameters, the efficacy of new irrigation protocols, and the filling capacity of endodontic sealers: a micro-CT study with in-house prototyped teeth.

• Grant number: 24/21432-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2025
• End date: March 31, 2027
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Laila Gonzales Freire
• Grantee: Laila Gonzales Freire
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Elaine Yoshiko Matsubara
• Associated scholarship(s): 25/06652-7 - Evaluation of root canal preparation with different taper and apical diameters and the efficacy of new irrigation protocols: a microtomographic study with prototyped teeth in-house, BP.MS

Abstract

The integration of advanced technologies such as micro-computed tomography (micro-CT) and 3D printing offers a promising combination for endodontic research, given the anatomical complexity and inherent variability of natural teeth. This project aims to investigate, through two distinct experiments using micro-CT and rapid 3D prototyping: (i) the preparation of mesial canals in prototyped lower molars with different apical diameters and tapers, (ii) the removal of debris accumulated during preparation following different final cleaning protocols, and (iii) the filling capacity of the endodontic sealers AH Plus Jet®, Cimmo HP®, and Bio-C Sealer® in flattened canals of prototyped teeth filled using the single-cone technique. Three-dimensional models of lower molars obtained from micro-CT images will be produced and printed at Inovalab, part of the Interdisciplinary Center for Interactive Technologies at the University of São Paulo (CITI-USP). In the first experiment, mesial canals will be prepared using the VDW.Rotate system (VDW, Munich, Germany) sizes #15.04 and #20.05. The roots will then be divided into two groups according to the final taper of the preparation (n=30): Group 0.4 (#25.04, #30.04, and #35.04) and Group 0.6 (#25.06, #30.06, and #35.06). After canal preparation, the specimens will be divided into three experimental groups (n=10) according to the technique used for the final cleaning: Group IC - conventional irrigation without activation using the Irriflex® needle; Group IU - ultrasonic irrigation with the NiTiSonic® insert; and Group iVac - irrigation with the iVac® system. In the second experiment, 30 printed distal canals will be distributed into three groups according to the type of endodontic sealer used for obturation (n=10): Group AH - AH Plus Jet® sealer (Dentsply DeTrey); Group BC - Bio-C Sealer® (Angelus); and Group CM - Cimmo HP® sealer (Cimmo Soluções em Saúde). The endodontic sealers will be prepared according to each manufacturer's recommendations and applied with the single-cone technique. After restoration with temporary obturator (Coltosol; Coltene, Altstatten, Switzerland) and glass ionomer sealer (Riva Light Cure, SDI Limited Bayswater, Australia), samples will be immersed in 20 mL of phosphate-buffered saline (PBS) at 37°C for seven days. Quantitative 3D analysis of dentin, root canal, debris, and sealer material will be conducted using CTAn and CTvol software. Results will undergo statistical analysis with a significance level of 5%. (AU)