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Impacts of Contracted Endodontic Cavities on Instrumentation Efficacy and Biomechanical Responses in Maxillary Molars.
- Source :
-
Journal of endodontics [J Endod] 2016 Dec; Vol. 42 (12), pp. 1779-1783. - Publication Year :
- 2016
-
Abstract
- Introduction: Recently, we reported that in mandibular molars contracted endodontic cavities (CECs) improved fracture strength compared with traditional endodontic cavities (TECs) but compromised instrumentation efficacy in distal canals. This study assessed the impacts of CECs on instrumentation efficacy and axial strain responses in maxillary molars.<br />Methods: Eighteen extracted intact maxillary molars were imaged with micro-computed tomographic imaging (12-μm voxel), assigned to CEC or TEC groups (n = 9/group), and accessed accordingly. Canals were instrumented (V-Taper2H; SSWhite Dental, Lakewood, NJ) with 2.5% sodium hypochlorite irrigation, reimaged, and the proportion of the modified canal wall determined. Cavities were restored with bonded composite resin (TPH-Spectra-LV; Dentsply International, York, PA). Another 28 similar molars (n = 14/group) with linear strain gauges (Showa Measuring Instruments, Tokyo, Japan) attached to mesiobuccal and palatal roots were subjected to load cycles (50-150 N) in the Instron Universal Testing machine (Instron, Canton, MA), and the axial microstrain was recorded before access and after restoration. These 28 molars and additional 11 intact molars (control) were cyclically fatigued (1 million cycles, 5-50 N, 15 Hz) and subsequently loaded to failure. Data were analyzed by the Wilcoxon rank sum and Kruskal-Wallis tests (α = 0.05).<br />Results: The overall mean proportion of the modified canal wall did not differ significantly between CECs (49.7% ± 12.0%) and TECs (44.7% ± 9.0%). Relative changes in axial microstrain responses to load varied in both groups. The mean load at failure for CECs (1703 ± 558 N) did not differ significantly from TECs (1384 ± 377 N) and was significantly lower (P < .005) for both groups compared with intact molars (2457 ± 941 N).<br />Conclusions: In maxillary molars tested in vitro, CECs did not impact instrumentation efficacy and biomechanical responses compared with TECs.<br /> (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)
- Subjects :
- Biomechanical Phenomena
Composite Resins
Dental Cavity Preparation instrumentation
Dental Restoration, Permanent methods
Dental Stress Analysis
Humans
Materials Testing
Maxilla
Root Canal Irrigants therapeutic use
Root Canal Preparation adverse effects
Root Canal Preparation instrumentation
Sodium Hypochlorite therapeutic use
Tooth Apex anatomy & histology
Tooth Crown anatomy & histology
Tooth Root injuries
X-Ray Microtomography methods
Dental Cavity Preparation methods
Dental Pulp Cavity
Molar anatomy & histology
Root Canal Preparation methods
Stress, Mechanical
Tooth Fractures etiology
Subjects
Details
- Language :
- English
- ISSN :
- 1878-3554
- Volume :
- 42
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Journal of endodontics
- Publication Type :
- Academic Journal
- Accession number :
- 27871481
- Full Text :
- https://doi.org/10.1016/j.joen.2016.08.028