{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T20:52:52Z","timestamp":1781643172903,"version":"3.54.5"},"reference-count":31,"publisher":"Springer Science and Business Media LLC","issue":"4","license":[{"start":{"date-parts":[[2026,3,14]],"date-time":"2026-03-14T00:00:00Z","timestamp":1773446400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,3,14]],"date-time":"2026-03-14T00:00:00Z","timestamp":1773446400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100001794","name":"The University of Queensland","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100001794","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Clin Oral Invest"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To compare stress-controlled torsional fatigue resistance of TruNatomy (TN), ProTaper Next (PTN), and ProTaper Ultimate (PTUL) instruments of comparable sizes at both room and body temperature.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods<\/jats:title>\n                    <jats:p>Torsional strength and related twist angles were determined at both temperatures in a torque testing fixture. Stress-controlled torsional fatigue resistance (TFR) was determined by cycling instruments in a custom fixture to pre-set twist angles corresponding to 90% torsional strength until fracture. Data were analyzed using two-way ANOVA and Tukey post-hoc tests with the significance level set at 0.05.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Overall, mean (\u00b1\u2009standard deviation) TFR ranged from 192 (\u00b1\u200966) to 841 (\u00b1\u2009201) cycles; PTUL had the highest TFR and TN the lowest; the differences among the three instruments were statistically significant. At 37\u00a0\u00b0C compared to room temperature, PTUL had a similar TFR, while PTN had a higher and TN a lower one. Applying customized stress-controlled conditions resulted in differences in TFR among the 3 instrument types. Different environmental temperatures had varying effects on the tested instruments manufactured from differently heat-treated nickel-titanium (NiTi) alloy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Understanding TFR is relevant for clinical use of NiTi instruments for continuous rotation and reciprocation, specifically for motor settings. Within the limitations and specific testing parameters of this study, stress-controlled TFR varied among the three tested instruments. Different environmental temperatures had varying effects on the tested instruments manufactured from differently heat-treated nickel-titanium (NiTi) alloy. Variations in instrument design and the NiTi alloy type used may account for different torsional fatigue performance and suggest specific clinical usage parameters.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Clinical Significance<\/jats:title>\n                    <jats:p>During canal preparation, instruments are stressed under cyclic load, a condition which is replicated in this experiment. The data is relevant for motor presets for continuous rotation and reciprocating motion as well as handling of contemporary heat-treated Nickel-titanium instruments.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s00784-026-06811-0","type":"journal-article","created":{"date-parts":[[2026,3,14]],"date-time":"2026-03-14T00:42:55Z","timestamp":1773448975000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Stress-Controlled Torsional Fatigue Assessment of Selected Contemporary Endodontic Instruments"],"prefix":"10.1007","volume":"30","author":[{"given":"Kushagra","family":"Ohri","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8902-0272","authenticated-orcid":false,"given":"Philip Yuan-Ho","family":"Chien","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5222-8718","authenticated-orcid":false,"given":"Ove A.","family":"Peters","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,3,14]]},"reference":[{"key":"6811_CR1","doi-asserted-by":"publisher","first-page":"1517","DOI":"10.1111\/iej.13982","volume":"56","author":"MC Cheung","year":"2023","unstructured":"Cheung MC, Peters OA, Parashos P (2023) Global survey of endodontic practice and adoption of newer technologies. 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Drs. Ohri and Chien have no conflicts of interest to disclose.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing Interests"}}],"article-number":"124"}}