{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T16:00:46Z","timestamp":1785427246707,"version":"3.56.0"},"reference-count":39,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T00:00:00Z","timestamp":1782259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"King Saud University in Riyadh","award":["ORF-2026-1419"],"award-info":[{"award-number":["ORF-2026-1419"]}]},{"award":["ORF-2026-1419"],"award-info":[{"award-number":["ORF-2026-1419"]}],"id":[{"id":"https:\/\/ror.org\/02f81g417","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Background: This study assessed the effect of solvent aging on Vickers microhardness (VHN) and fracture toughness (KIC) of four resin composites: two high-strength flowable materials indicated for all cavity classes (GUF and CBF), a packable nanohybrid composite (XTE), and its flowable counterpart (XTEF). Methods: Disk specimens (n = 6 per group) were photocured and stored at 37 \u00b0C in distilled water or in a 75%\/25% ethanol\/water solution for 1 or 30 days. Vickers microhardness was recorded with a 300 g load applied for 15 s. Single-edge-notched beam (SENB) specimens (32 \u00d7 6 \u00d7 3 mm; n = 6 per group) were loaded in three-point bending for KIC determination after 1 and 30 days of storage in water or ethanol\/water. Data were analyzed by three-way ANOVA followed by Tukey\u2019s post hoc test (\u03b1 = 0.05). Results: At 1 day, the four composites separated into distinct VHN groups in the order XTE &gt; GUF &gt; CBF &gt; XTEF (p \u2264 0.05). After 30 d, VHN decreased in all materials, with larger reductions in ethanol\/water (17\u201330% relative to the 1 d water value) than in water alone (5\u201311%). At 1 day, KIC values for XTE, GUF and CBF formed a single statistical group, all significantly higher than XTEF (p \u2264 0.05). Thirty-day water storage did not affect KIC for any material (p &gt; 0.05), whereas ethanol\/water storage reduced KIC by 21\u201326% in all four composites and produced four distinct material groups (p \u2264 0.05). Conclusions: The high-strength flowable composites showed greater hardness and toughness than a conventional flowable composite but did not match the mechanical performance of the highly filled packable composite. Ethanol\/water aging markedly softened the composite surfaces and reduced fracture toughness, whereas prolonged water storage had a smaller effect on hardness and no measurable effect on KIC.<\/jats:p>","DOI":"10.3390\/bioengineering13070726","type":"journal-article","created":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T15:02:56Z","timestamp":1783436576000},"page":"726","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Influence of Solvent Challenge on the Hardness and Toughness of Viscosity-Modified Composites"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8890-8707","authenticated-orcid":false,"given":"Abdulrahman","family":"Alshabib","sequence":"first","affiliation":[{"name":"Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hamad","family":"Algamaiah","sequence":"additional","affiliation":[{"name":"Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Silvia","family":"Rojas-Rueda","sequence":"additional","affiliation":[{"name":"School of Dental Medicine, Ponce Health Sciences University, Ponce, PR 00732, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlos A.","family":"Jurado","sequence":"additional","affiliation":[{"name":"School of Dental Medicine, Ponce Health Sciences University, Ponce, PR 00732, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6052-5237","authenticated-orcid":false,"given":"Abdullah","family":"Almansour","sequence":"additional","affiliation":[{"name":"College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj 16245, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0636-9266","authenticated-orcid":false,"given":"Saad","family":"AlOtaibi","sequence":"additional","affiliation":[{"name":"Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1194","DOI":"10.1016\/j.dental.2019.05.017","article-title":"Hardness and fracture toughness of resin-composite materials with and without fibers","volume":"35","author":"Alshabib","year":"2019","journal-title":"Dent. 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