Impact of several NiTi‐thermally treated instrumentation systems on biomechanical preparation of curved root canals in extracted mandibular molars

• Published in: International endodontic journal 2022-01, Vol.55 (1), p.124-136
• Main Authors: Carvalho, Kleber Kildare Teodoro, Petean, Igor Bassi Ferreira, Silva‐Sousa, Alice Corrêa, Camargo, Rafael Verardino, Mazzi‐Chaves, Jardel Francisco, Silva‐Sousa, Yara Teresinha Corrêa, Sousa‐Neto, Manoel Damião
• Format: Article
• Language: English
• Subjects: Computed tomography; curvature; danger zone; Dental Pulp Cavity - diagnostic imaging; Dental roots; dentine thickness; Endodontics; Equipment Design; Humans; Kinematics; Mandible; micro‐CT; Molar - diagnostic imaging; Molar - surgery; Molars; Nickel; root canal preparation; Root Canal Preparation - instrumentation; Root canals; Sodium hypochlorite; Surface area; Teeth; Titanium; X-Ray Microtomography
• ISSN: 0143-2885; 1365-2591
• DOI: 10.1111/iej.13649

Aim To evaluate the shaping ability of several heat‐treated nickel–titanium systems used to prepare root canals with moderate and severe curvature, in extracted mandibular molars, by micro‐computed tomography, considering their variation in kinematics and design. Methodology Curved‐mesial roots of mandibular molars were randomly selected and assigned into 4 balanced experimental groups (n = 10), established by determining homogeneous 3D parameters of volume and surface area: R‐Motion (RM) size 30, 0.04 taper (RM; FKG Dentaire), Reciproc Blue (RCB) size 25, 0.08 taper (RCB; VDW GmbH), HyFlex CM (HFX) size 30, 0.04 taper (HFX; Coltène Whaledent) and XP‐endo Shaper size (XPS) 30, 0.01 taper (XPS; FKG Dentaire). The volume of irrigation was established at 10 ml of 2.5% NaOCl. Throughout the entire root canal preparation procedures, the samples were fixed in a vice submerged in a container with water monitored at 37°C. Dimensional cross‐sectional measures of area, perimeter, roundness, major/minor diameters and 3‐dimensional (volume, surface area, structure model index – SMI) parameters as well as the smallest dentine thickness along the cervical and middle root thirds were evaluated by micro‐CT. Data were analysed using analysis of variance and post hoc Tukey tests (α = 5%). Results Reciproc Blue and XPS had significantly greater mean increases in cross‐sectional area measurements, only in the middle third, when compared with RM and HFX (p  .05), and HFX had significantly lower mean increases in perimeter values only when compared with XPS (p