{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,6]],"date-time":"2026-09-06T02:10:54Z","timestamp":1788660654539,"version":"build-2803163510"},"reference-count":35,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T00:00:00Z","timestamp":1788566400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T00:00:00Z","timestamp":1788566400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100002352","name":"Ain Shams University","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100002352","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Oral Health"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Restoration of endodontically treated teeth (ETT) with significant coronal loss poses a challenge in clinical dentistry. Advances in CAD\/CAM technology and biomimetic materials have introduced minimally invasive approaches, such as endocrowns and overlays, which can replace traditional post-core and crown approach.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Aim<\/jats:title>\n                    <jats:p>The aim of this in-vitro study was to comparatively assess the mechanical behaviour of two restorative designs (endocrowns and overlays) fabricated from two CAD\/CAM materials in endodontically treated mandibular molars.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and methods<\/jats:title>\n                    <jats:p>\n                      Thirty-six endodontically treated lower molars (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200936) were split into two main groups based on restoration type (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200918): endocrowns and overlays. Each group was further subdivided into two subgroups based on the CAD\/CAM material (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u20099): lithium disilicate (Tessera) and indirect composite (Crios). Restorations were fabricated and bonded to their respective specimens following a strict bonding protocol with an adhesive resin cement (Bisco self-adhesive). Thermo-mechanical aging (Chewing Simulator CS-4, SD Mechatronic) was conducted to simulate oral conditions, followed by a universal testing machine's evaluation of fracture resistance. The test was stopped after fracture. Fractured parts were analysed to determine mode of failure. Data were analyzed using two-way ANOVA followed by Tukey\u2019s honestly significant difference (HSD) test for pairwise comparisons (\u03b1\u2009=\u20090.05).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      All specimens survived the 5,000 chewing cycles, simulating early intraoral service. Fracture resistance test showed significantly higher fracture resistance for overlays (2048.46\u2009\u00b1\u2009664.63 N) than endocrowns (1234.54\u2009\u00b1\u2009338.50 N) (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.002). Crios overlays exhibited the highest fracture resistance (2384.60\u2009\u00b1\u2009631.10 N), significantly outperforming Tessera overlays (1712.33\u2009\u00b1\u2009559.59 N) (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.043) and endocrowns (1354.20\u2009\u00b1\u2009346.88 N) (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.004). No substantial material change was seen in endocrown restorations (\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.445).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Overlay restorations and indirect composite material (Crios) provide superior resistance to fracture compared to lithium disilicate overlays and endocrowns and may represent a reliable restorative option for endodontically treated molars.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12903-026-07835-4","type":"journal-article","created":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T13:53:55Z","timestamp":1788616435000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mechanical behavior of endodontically treated molars restored using two restorative approaches and two CAD\/CAM materials: an in-vitro study"],"prefix":"10.1186","volume":"26","author":[{"given":"Ahmed Adel Naguib","family":"Khater","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ahmad Khaled Abo El","family":"Fadl","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ingy","family":"Nouh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,9,5]]},"reference":[{"issue":"4","key":"7835_CR1","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1016\/j.prosdent.2005.07.003","volume":"94","author":"E Asmussen","year":"2005","unstructured":"Asmussen E, Peutzfeldt A, Sahafi A. 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No human participants were directly involved, and no identifiable personal data were used. The Research Ethics Committee of the Faculty of Dentistry, Ain Shams University (FDASU-Rec: EM122231) waived the requirement for written informed consent due to the retrospective nature of the study and the use of anonymized extracted teeth.","order":1,"name":"Ethics","label":"Ethics approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Not applicable.","order":2,"name":"Ethics","label":"Consent for publication","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"1671"}}