Please cite this article in press as: Sayed M, et al. Effect of silver-containing agents on the ultra-structural morphology of dentinal collagen. Dent Mater (2020), https://doi.org/10.1016/j.dental.2020.04.028 ARTICLE IN PRESS DENTAL-3564; No. of Pages 9 d e n t a l m a t e r i a l s x x x ( 2 0 2 0 ) xxx–xxx Available online at www.sciencedirect.com ScienceDirect jo ur nal home p ag e: www.intl.elsevierhealth.com/journals/dema Effect of silver-containing agents on the ultra-structural morphology of dentinal collagen Mahmoud Sayed a,* , Noriko Hiraishi b,* , Khairul Matin c,d , Ahmed Abdou a , Michael F. Burrow e , Junji Tagami c a Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan b Research Fellow of Japan Society for the Promotion of Science, Tokyo Medical and Dental University, Tokyo, Japan c Cariology and Operative Dentistry Department, Tokyo Medical and Dental University, Tokyo, Japan d Endowed Department of International Oral Health Science, Tsurumi University, 2-1-3, Tsurumi, Tsurumi-ku, Kanagawa 230-0063, Japan e University of Hong Kong, Faculty of Dentistry, Hong Kong, China a r t i c l e i n f o Article history: Received 2 January 2020 Received in revised form 15 April 2020 Accepted 30 April 2020 Available online xxx Keywords: SDF Silver Daimmine Fluoride Nano-silver Collagen Dentin Remineralization Biomimetics a b s t r a c t Objective. This study investigated the effect of silver diammine fluoride (SDF), nano-silver (AgNPs) and nano-silver/potassium fluoride (AgNPs/KF) on the morphology of dentin col- lagen and color staining on the dentin. Also, we investigated the anti-caries properties in terms of anti-bacterial effects and potentiality of dentin remineralization at collagen level. Methods. Dentin specimens obtained from bovine tooth roots were finished with #2000 SiC and sonicated for 5 min. Specimens were divided into two main groups: sound and dem- ineralized dentin. Each group was subdivided into five subgroups according to treatment solution: control (no treatment), SDF, nano-silver (AgNPs), AgNPs/KF and KF. Specimens were analyzed using transmission electron microscope (TEM), spectrophotometer, scanning electron microscope (SEM) and antibacterial test. Repeated Measures ANOVA was used for statistical analysis of color change while one-way ANOVA was used for CFU analysis. Results. Regarding color change, SDF showed the highest values while the other groups exhib- ited insignificant changes. SDF showed alteration in the collagen fibrils while the other groups showed normal intact fibrils. Regarding antibacterial activity, SDF and AgNPs/KF showed the greatest antibacterial effect. Significance. SDF altered the dentin collagen morphology and inferior ethetics, but still pro- viding intrafibrillar remineralization. Nano-silver fluoride preparations (AgNPs/KF) can be an alternative material for SDF as it can preserve the dentin collagen, showing no color change overtime, and provide a high anti-caries property including intrafibrillar remineralization with a significant anti-bacterial effect. © 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved. ∗ Corresponding authors at: Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. E-mail addresses: DrmahmoudMacklad@gmail.com (M. Sayed), hiraope@tmd.ac.jp (N. Hiraishi). https://doi.org/10.1016/j.dental.2020.04.028 0109-5641/© 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.