Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching

Tooth bleaching is a widely used esthetic treatment; however, bleaching agents can temporarily alter the surface morphology of enamel, increasing surface roughness and porosity, which may lead to increased susceptibility to discoloration. This in vitro study investigated the effectiveness of fluorid...

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Main Authors: Ryotaro Yago, Chiharu Kawamoto, Rafiqul Islam, Hirofumi Kaneko, Monica Yamauti, Masayuki Otsuki, Hidehiko Sano, Atsushi Tomokiyo
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Journal of Functional Biomaterials
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Online Access:https://www.mdpi.com/2079-4983/16/7/245
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author Ryotaro Yago
Chiharu Kawamoto
Rafiqul Islam
Hirofumi Kaneko
Monica Yamauti
Masayuki Otsuki
Hidehiko Sano
Atsushi Tomokiyo
author_facet Ryotaro Yago
Chiharu Kawamoto
Rafiqul Islam
Hirofumi Kaneko
Monica Yamauti
Masayuki Otsuki
Hidehiko Sano
Atsushi Tomokiyo
author_sort Ryotaro Yago
collection DOAJ
description Tooth bleaching is a widely used esthetic treatment; however, bleaching agents can temporarily alter the surface morphology of enamel, increasing surface roughness and porosity, which may lead to increased susceptibility to discoloration. This in vitro study investigated the effectiveness of fluoride varnish in preventing immediate discoloration of bovine incisors after bleaching. Specimens were bleached with 35% hydrogen peroxide and treated with either Clinpro White Varnish (CW) or Enamelast Fluoride Varnish (EN), whereas control specimens received no treatment after bleaching. The samples were immersed in coffee for 24 h, and the color difference (Δ<i>E</i><sub>00</sub>) was calculated using the CIEDE2000 formula. The surface morphology of enamel was examined using SEM. The fluoride varnish groups showed significantly lower color difference values than the control group (<i>p</i> < 0.05), with Δ<i>E</i><sub>00</sub> reduced by approximately two-thirds in both the CW and EN groups. SEM observations showed that the enamel surfaces in the varnish-treated groups exhibited reduced surface irregularities compared to the untreated group, suggesting remineralization. These results suggest that the immediate application of fluoride varnish after bleaching can effectively reduce short-term discoloration by providing physical protection and promoting remineralization. Fluoride varnish may serve as a simple and effective strategy to maintain whitening outcomes and minimize early discoloration.
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spelling doaj-art-1279fa0ed39541e4aa76cd8576cf78d02025-08-20T02:45:38ZengMDPI AGJournal of Functional Biomaterials2079-49832025-07-0116724510.3390/jfb16070245Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After BleachingRyotaro Yago0Chiharu Kawamoto1Rafiqul Islam2Hirofumi Kaneko3Monica Yamauti4Masayuki Otsuki5Hidehiko Sano6Atsushi Tomokiyo7Department of Restorative Dentistry, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanDepartment of Restorative Dentistry, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanDepartment of Restorative Dentistry, Faculty of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanDepartment of Restorative Dentistry, Faculty of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanDepartment of Biomedical and Applied Science, Indiana University School of Dentistry, 1121 W. Michigan Street, Indianapolis, IN 46202, USACariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, JapanDepartment of Restorative Dentistry, Faculty of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanDepartment of Restorative Dentistry, Faculty of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586, JapanTooth bleaching is a widely used esthetic treatment; however, bleaching agents can temporarily alter the surface morphology of enamel, increasing surface roughness and porosity, which may lead to increased susceptibility to discoloration. This in vitro study investigated the effectiveness of fluoride varnish in preventing immediate discoloration of bovine incisors after bleaching. Specimens were bleached with 35% hydrogen peroxide and treated with either Clinpro White Varnish (CW) or Enamelast Fluoride Varnish (EN), whereas control specimens received no treatment after bleaching. The samples were immersed in coffee for 24 h, and the color difference (Δ<i>E</i><sub>00</sub>) was calculated using the CIEDE2000 formula. The surface morphology of enamel was examined using SEM. The fluoride varnish groups showed significantly lower color difference values than the control group (<i>p</i> < 0.05), with Δ<i>E</i><sub>00</sub> reduced by approximately two-thirds in both the CW and EN groups. SEM observations showed that the enamel surfaces in the varnish-treated groups exhibited reduced surface irregularities compared to the untreated group, suggesting remineralization. These results suggest that the immediate application of fluoride varnish after bleaching can effectively reduce short-term discoloration by providing physical protection and promoting remineralization. Fluoride varnish may serve as a simple and effective strategy to maintain whitening outcomes and minimize early discoloration.https://www.mdpi.com/2079-4983/16/7/245bovine toothfluoride varnishrestorative dentistrytooth bleachingtooth discoloration
spellingShingle Ryotaro Yago
Chiharu Kawamoto
Rafiqul Islam
Hirofumi Kaneko
Monica Yamauti
Masayuki Otsuki
Hidehiko Sano
Atsushi Tomokiyo
Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
Journal of Functional Biomaterials
bovine tooth
fluoride varnish
restorative dentistry
tooth bleaching
tooth discoloration
title Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
title_full Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
title_fullStr Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
title_full_unstemmed Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
title_short Prevention of Tooth Discoloration Using Fluoride Varnish Immediately After Bleaching
title_sort prevention of tooth discoloration using fluoride varnish immediately after bleaching
topic bovine tooth
fluoride varnish
restorative dentistry
tooth bleaching
tooth discoloration
url https://www.mdpi.com/2079-4983/16/7/245
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