{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T11:37:54Z","timestamp":1785411474624,"version":"3.56.0"},"reference-count":33,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T00:00:00Z","timestamp":1783900800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"\u201cVictor Babe\u0219\u201d University of Medicine and Pharmacy"},{"id":[{"id":"https:\/\/ror.org\/00afdp487","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dentistry Journal"],"abstract":"<jats:p>Background and Objectives: In-office bleaching is one of the most requested aesthetic procedures, but its biomechanical aftermath on enamel\u2014particularly the recovery trajectory of microhardness, surface roughness, and erosive vulnerability\u2014remains incompletely characterised. The present study quantified the 28-day mechanical recovery profile of enamel after three commonly used chairside bleaching protocols and examined inter-relationships between mechanical, topographic and erosive endpoints. Methods: Forty-two human molars and premolars (27 molars, 15 premolars) extracted for clinical reasons and previously catalogued in the institutional biobank were sectioned along the cervical\u2013occlusal axis to obtain matched control and experimental halves. The experimental halves were assigned (n = 14 per group) to Opalescence Quick (45% carbamide peroxide, no light), Opalescence Boost (40% hydrogen peroxide, chemically activated), or BlancOne Ultra+ (35% hydrogen peroxide with light activation). Vickers microhardness (VHN), profilometric roughness (Ra), and erosive wear after a standardised citric-acid challenge were measured at baseline, immediately post-bleaching, and at 24 h, 7 d, 14 d, and 28 d in artificial saliva. Wilcoxon signed-rank, Kruskal\u2013Wallis with Dunn\u2013Bonferroni post hoc, linear mixed-effects models, multiple linear regression, ROC analysis, and Spearman correlations were used (\u03b1 = 0.05). Results: Immediate VHN drops were \u221213.2 \u00b1 3.9%, \u221222.6 \u00b1 3.6%, and \u221229.6 \u00b1 4.7% for Opalescence Quick, Opalescence Boost, and BlancOne Ultra+, respectively. By 28 days, recovery reached 97.4 \u00b1 2.2%, 96.0 \u00b1 2.9%, and 91.6 \u00b1 2.3% of baseline (p &lt; 0.001). Exponential rate constants were 0.137, 0.075, and 0.092 d\u22121. Erosive wear after acid challenge was 2.1\u00d7, 2.8\u00d7, and 3.8\u00d7 control values. ROC analysis identified \u0394-immediate Ra as the strongest predictor of incomplete recovery (AUC = 0.859). Conclusions: Higher-aggression protocols delayed mechanical recovery and amplified erosive susceptibility, with light-activated systems carrying the greatest residual risk. These in vitro findings provide an evidence base for the design of future clinical studies on post-bleaching enamel recovery and remineralisation.<\/jats:p>","DOI":"10.3390\/dj14070434","type":"journal-article","created":{"date-parts":[[2026,7,14]],"date-time":"2026-07-14T00:55:21Z","timestamp":1783990521000},"page":"434","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Microhardness Recovery Kinetics, Surface Roughness Trajectories, and Erosive Wear Susceptibility of Enamel After Three In-Office Bleaching Protocols: A 28-Day In Vitro Investigation"],"prefix":"10.3390","volume":"14","author":[{"given":"Berivan Laura Rebeca","family":"Buzatu","sequence":"first","affiliation":[{"name":"Faculty of Dental Medicine, Doctoral School, \u201cVictor Babe\u0219\u201d University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania"},{"name":"Translational and Experimental Clinical Research Centre in Oral Health, Department of Preventive, Community Dentistry and Oral Health, \u201cVictor Babe\u0219\u201d University of Medicine and Pharmacy, 300041 Timisoara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Magda Mihaela","family":"Luca","sequence":"additional","affiliation":[{"name":"Pediatric Dentistry Research Center (Pedo-Research), Department of Pediatric Dentistry, Faculty of Dental Medicine, \u201cVictor Babes\u201d University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0653-0996","authenticated-orcid":false,"given":"Roxana","family":"Buzatu","sequence":"additional","affiliation":[{"name":"Department of Dental Aesthetics, Faculty of Dental Medicine, \u201cVictor Babes\u201d University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1016\/j.jdent.2006.02.002","article-title":"The bleaching of teeth: A review of the literature","volume":"34","author":"Joiner","year":"2006","journal-title":"J. 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