{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T11:11:39Z","timestamp":1782990699853,"version":"3.54.5"},"reference-count":25,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,12]],"date-time":"2025-08-12T00:00:00Z","timestamp":1754956800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JFB"],"abstract":"<jats:p>The mechanical behavior of dental composites depends on the sample size and stress configuration. This makes it difficult to extrapolate laboratory data to clinical restorations with significant variations in size and geometry. Intrinsic parameters, such as fracture toughness, are therefore of great importance, even if they are less common and more difficult to measure. The aim of this study was to apply principles of fractography and fracture mechanics to exploit the results obtained from a three-point bending test. The objectives include calculating a material-specific constant, validating the experimental findings, and establishing a correlation with fracture toughness. Forty representative composites with wide variation in filler quantity (65\u201383% by weight and 46.4\u201364% by volume), type (compact glasses and pre-polymerized), and composition were examined. Fracture toughness\/KIc was evaluated in a notchless triangular prism test. Fracture type, origin, and mirror size were determined on 280 flexural fracture specimens (n = 20). The amount of filler strongly influences all measured parameters, with the effect strength varying in the sequence: mechanical work (\u03b7P2 = 0.995), modulus of elasticity (\u03b7P2 = 0.991), flexural strength (\u03b7P2 = 0.988), fracture toughness (\u03b7P2 = 0.979), and mirror constant (\u03b7P2 = 0.965). Fracture surfaces allowed the delineation of the fracture mirror and the application of fracture mechanics approaches. The mirror constant was derived from the radius of the fracture mirror, measured in the direction of constant stress, using Orr\u2019s equation, and correlates well with KIc (0.81). Larger confidence intervals were observed for the mirror constant data, while for 5 of 14 materials, the mirror constant was overestimated compared to KIc. The overestimation was attributed to the lower refractive index of the urethane methacrylate composition.<\/jats:p>","DOI":"10.3390\/jfb16080290","type":"journal-article","created":{"date-parts":[[2025,8,12]],"date-time":"2025-08-12T16:30:36Z","timestamp":1755016236000},"page":"290","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Relationship Between Fracture Toughness and Fracture Mirror in Modern Polymer-Based Dental Composites"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6003-9199","authenticated-orcid":false,"given":"Nicoleta","family":"Ilie","sequence":"first","affiliation":[{"name":"Department of Conservative Dentistry, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1111\/adj.12487","article-title":"Comparison between published clinical success of direct resin composite restorations in vital posterior teeth in 1995\u20132005 and 2006\u20132016 periods","volume":"62","author":"Alvanforoush","year":"2017","journal-title":"Aust. 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