Effectiveness of five instruments when removing calcium hydroxide paste from simulated internal root resorption cavities in extracted maxillary central incisors

• Published in: International endodontic journal 2020-03, Vol.53 (3), p.366-375
• Main Authors: Marques‐da‐Silva, B., Alberton, C. S., Tomazinho, F. S. F., Gabardo, M. C. L., Duarte, M. A. H., Vivan, R. R., Baratto‐Filho, F.
• Format: Article
• Language: English
• Subjects: Acids; Calcium Hydroxide; Cavities; Demineralization; Dental Caries; Dental Pulp Cavity; Dental restorative materials; Dental roots; Dentistry; Electron microscopes; Endodontics; Humans; Incisor; Incisors; internal root resorption; Irrigation; Lavage; Light microscopy; Maxilla; Nitric acid; Root Canal Irrigants; Root Canal Preparation; Root canals; Root Resorption; Scanning electron microscopy; Therapeutic Irrigation
• ISSN: 0143-2885; 1365-2591
• DOI: 10.1111/iej.13223

Aim To evaluate the effectiveness of five instruments used for irrigant agitation during the removal of calcium hydroxide [Ca(OH)2] paste in simulated internal root resorption (IRR) cavities created in extracted maxillary central incisors. Methodology Seventy maxillary central incisors with a single canal were selected. The canals were accessed and instrumented with Reciproc R50, then the roots were split in the bucco‐lingual direction and the halves separated. Simulated IRR cavities were created, in both halves of the roots, 5 mm from the apex with a spherical bur. The specimens were reconstructed with cyanoacrylate glue and allocated into seven groups: negative control – no treatment; positive control – filled with Ca(OH)2 without performing any irrigation protocol; the other groups were divided according to the instrument used for irrigant agitation, namely: Ultrasonic, EndoActivator®, EDDY®, XP‐endo® Finisher and XP‐endo® Shaper. The specimens were cleaved and analysed using optical microscopy and scanning electron microscopy, to compare the Ca(OH)2 remnants between them. Then, the IRR cavities created by the burs were cleaned and subjected to a protocol of demineralization with 20% nitric acid, the roots reconstructed, and the irrigant agitation methods, as well as the microscopic analysis was repeated. Analysis of the images of Ca(OH)2 remaining in the simulated IRR cavities after irrigation was performed by two calibrated examiners based on a previously established scoring system. The data were statistically compared by Kruskal–Wallis test, Mann–Whitney U‐test and Wilcoxon tests, with the significance level set at 5%. Results There was a significant difference in the effectiveness of the instruments in relation to the cavity creation method (bur vs. bur/acid) and evaluation method (optical microscopy and scanning electron microscopy) (P