{"title":"Dynamic Photoelastic Analysis of Stress Distribution in Simulated Canals Using Rotary Instruments with Varied Tip and Taper Sizes: A Quasi-3D Approach","authors":"","doi":"10.1016/j.joen.2024.05.008","DOIUrl":null,"url":null,"abstract":"<div><h3>Introduction</h3><p>To compare the stress produced on the walls of simulated canals by rotary instruments with varied tip and taper sizes.</p></div><div><h3>Methods</h3><p>Ninety isotropic transparent blocks, each containing a 60-degree curved canal, were distributed into 18 groups (<em>n</em><span> = 5) based on the instrument tip (sizes 10, 15, 20, 25, 30, and 35) and taper (sizes 0.02, 0.04, and 0.06). The blocks were fixed in a circular polariscope setup for dark field analysis. A digital camera was employed to capture the real-time birefringence<span> patterns generated by each instrument. Digital image frames, corresponding to the instrument reaching the end of each canal third, were extracted and evaluated by 2 independent observers for the stress generation on canal walls. The data analysis employed a semi-quantitative scale ranging from 0 to 5. Cohen's Kappa coefficient test was used to determine the inter-observer agreement while the results were compared using Kruskal–Wallis test followed by an all-pairwise posthoc procedure (α = 5%).</span></span></p></div><div><h3>Results</h3><p>Inter-observer agreement was 0.95. A significant influence of the tip size on stress was observed across the coronal (<em>P</em> = .011), middle (<em>P</em> = .006), and apical (<em>P</em> = .026) thirds. In contrast, taper size did not affect the stress induced at the coronal (<em>P</em> = .509), middle (<em>P</em> = .958), or apical (<em>P</em> = .493) thirds. The variations in tip and taper sizes did not result in a significant stress differences among the thirds (<em>P</em> = .181).</p></div><div><h3>Conclusions</h3><p>The stress significantly increased across all canal thirds with larger tip sizes of rotary instruments, whereas the taper sizes did not influence the stress when compared to the canal thirds.</p></div>","PeriodicalId":15703,"journal":{"name":"Journal of endodontics","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of endodontics","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0099239924003030","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"DENTISTRY, ORAL SURGERY & MEDICINE","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction
To compare the stress produced on the walls of simulated canals by rotary instruments with varied tip and taper sizes.
Methods
Ninety isotropic transparent blocks, each containing a 60-degree curved canal, were distributed into 18 groups (n = 5) based on the instrument tip (sizes 10, 15, 20, 25, 30, and 35) and taper (sizes 0.02, 0.04, and 0.06). The blocks were fixed in a circular polariscope setup for dark field analysis. A digital camera was employed to capture the real-time birefringence patterns generated by each instrument. Digital image frames, corresponding to the instrument reaching the end of each canal third, were extracted and evaluated by 2 independent observers for the stress generation on canal walls. The data analysis employed a semi-quantitative scale ranging from 0 to 5. Cohen's Kappa coefficient test was used to determine the inter-observer agreement while the results were compared using Kruskal–Wallis test followed by an all-pairwise posthoc procedure (α = 5%).
Results
Inter-observer agreement was 0.95. A significant influence of the tip size on stress was observed across the coronal (P = .011), middle (P = .006), and apical (P = .026) thirds. In contrast, taper size did not affect the stress induced at the coronal (P = .509), middle (P = .958), or apical (P = .493) thirds. The variations in tip and taper sizes did not result in a significant stress differences among the thirds (P = .181).
Conclusions
The stress significantly increased across all canal thirds with larger tip sizes of rotary instruments, whereas the taper sizes did not influence the stress when compared to the canal thirds.
期刊介绍:
The Journal of Endodontics, the official journal of the American Association of Endodontists, publishes scientific articles, case reports and comparison studies evaluating materials and methods of pulp conservation and endodontic treatment. Endodontists and general dentists can learn about new concepts in root canal treatment and the latest advances in techniques and instrumentation in the one journal that helps them keep pace with rapid changes in this field.