{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T08:49:38Z","timestamp":1785919778150,"version":"3.56.0"},"reference-count":27,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T00:00:00Z","timestamp":1785888000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Background: Ultra-fast high-irradiance curing shortens exposure time, but its effects on conversion and polymer-network integrity may vary among bulk-fill resin composites. This in vitro study was designed as a materials-level investigation of irradiated-surface polymerization behavior. It evaluated irradiated-surface degree of conversion and polymer-network quality while deliberately excluding assessment of depth of cure or polymerization throughout the 4 mm bulk increment. Methods: Eighty disk specimens (6 mm \u00d7 4 mm) of Filtek One Bulk Fill, SDR Plus, Beautifil Bulk Flowable, and Beautifil Bulk Restorative (n = 10\/material\/protocol) were cured with a polywave LED at 1200 mW\/cm2 for 10 s or 3000 mW\/cm2 for 3 s. Degree of conversion (DC) was measured by ATR-FTIR on the irradiated (top) surface only. Ethanol-induced softening (ES%, Knoop-hardness reduction at the irradiated surface after 24 h ethanol immersion) served as an inverse, indirect indicator of polymer-network quality (cross-link density). Data were analyzed by two-way ANOVA and Tukey tests (\u03b1 = 0.05); the DC\u2013ES% relationship was examined by Pearson correlation at the individual-specimen level (n = 80). Results: Ultra-fast curing yielded higher pooled DC (66.30 \u00b1 10.06%) than conventional curing (59.37 \u00b1 7.96%; p &lt; 0.001), but the effect was material-dependent: DC increased significantly for Filtek One Bulk Fill (p &lt; 0.001) and Beautifil Bulk Flowable (p = 0.035), but not for SDR Plus or Beautifil Bulk Restorative. ES% was influenced mainly by material (p &lt; 0.001) and less by curing protocol (p = 0.009). At the specimen level (n = 80), DC and ES% showed a weak but statistically significant negative correlation (r = \u22120.31, p = 0.006). Conclusions: Within the conditions of this study, irradiated-surface polymerization behavior under ultra-fast curing depended primarily on composite formulation, underscoring the need to evaluate both conversion efficiency and polymer-network quality when optimizing dental restorative materials. Because conversion was assessed only at the irradiated surface, these findings describe irradiated-surface behavior and do not provide evidence of adequate cure at the bottom of the 4 mm increment.<\/jats:p>","DOI":"10.3390\/ma19153323","type":"journal-article","created":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T08:14:46Z","timestamp":1785917686000},"page":"3323","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of Ultra-Fast Light Curing on the Irradiated-Surface Degree of Conversion and Polymer-Network Quality of Bioactive and Conventional Bulk-Fill Resin Composites: An In Vitro Study"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-7642-3825","authenticated-orcid":false,"given":"Sarah Fahad","family":"Alsenani","sequence":"first","affiliation":[{"name":"Department of Restorative Dentistry, College of Medicine and Dentistry, Riyadh Elm University, Riyadh 12734, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6273-0357","authenticated-orcid":false,"given":"Sultan","family":"Binalrimal","sequence":"additional","affiliation":[{"name":"Department of Restorative Dentistry, College of Medicine and Dentistry, Riyadh Elm University, Riyadh 12734, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.dental.2010.10.020","article-title":"Resin composite\u2014State of the art","volume":"27","author":"Ferracane","year":"2011","journal-title":"Dent. 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Dentistry\u2014Polymer-Based Restorative Materials (Standard No. ISO 4049)."}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/19\/15\/3323\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,5]],"date-time":"2026-08-05T08:21:01Z","timestamp":1785918061000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/19\/15\/3323"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,5]]},"references-count":27,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["ma19153323"],"URL":"https:\/\/doi.org\/10.3390\/ma19153323","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,5]]}}}