This study aimed to determine the effect of zinc ions and F concentration in a dentifrice on remineralization of early caries lesions in situ and on resistance to subsequent demineralization. This was a single-center, 6-period, 6-product, blinded (examiner, subject, analyst), randomized (n = 62), crossover study. Products (all NaF) were: 0, 250, 1,150 and 1,426 ppm F (dose-response controls), “Zn-A” (0.3% ZnCl2, 1,426 ppm F), and “Zn-B” (as Zn-A, with high-foaming surfactants) in a conventional silica base. Subjects wore palatal appliances holding partially demineralized bovine enamel specimens. They brushed their teeth with 1.5 g test dentifrice (25 s), then swished the slurry ensuring even exposure of specimens (95 s), expectorated, and rinsed (15 mL water, 10 s). After 4 h intraoral remineralization, specimens were removed and acid-challenged in vitro. Surface microhardness (SMH), measured pre-experimental, post-initial acid exposure, post-remineralization, and post-second acid exposure, was used to calculate recovery (SMHR), net acid resistance (NAR), and a new, specifically demineralization-focused calculation, “comparative acid resistance” (CAR). Enamel fluoride uptake (EFU) was also measured. For the F dose-response controls, all measures showed significant relationships with dentifrice F concentration (p < 0.0001). The presence of zinc counteracted the ability of F to promote remineralization in this model. Compared to the 1,426 ppm F control, the zinc formulations gave reduced SMHR, EFU, and NAR (all p < 0.0001); however, they showed evidence of increased CAR (Zn-A: p = 0.0040; Zn-B: p = 0.0846). Products were generally well tolerated. In this study, increasing dentifrice F concentration progressively increased in situ remineralization and demineralization resistance of early caries enamel lesions. Zinc ions reduced remineralization but could increase demineralization resistance.

Keywords:
Enamel caries, Tooth brushing, Toothpastes, Topical fluorides
1.
Barkvol P, Rolla G, Lagerlof F: Effect of sodium lauryl sulfate on the deposition of alkali-soluble fluoride on enamel in vitro. Caries Res 1988;22:139-144.
2.
Barlow AP, Sufi F, Mason SC: Evaluation of different fluoridated dentifrice formulations using an in situ erosion remineralization model. J Clin Dent 2009;20:192-198.
3.
Charles CH, Cronin MJ, Conforti NJ, Dembling WZ, Petrone DM, McGuire JA: Anticalculus efficacy of an antiseptic mouthrinse containing zinc chloride. J Am Dent Assoc 2001;132:94-98.
4.
Churchley D, Newby CS, Willson R, Haider A, Schemehorn B, Lynch RJ: Protection against enamel demineralisation using toothpastes containing o-cymen-5-ol, zinc chloride and sodium fluoride. Int Dent J 2011;61(suppl 3): 55-59.
5.
Corpron RE, Clark JW, Tsai A, More FG, Merrill DF, Kowalski CJ, Tice TR, Rowe CE: Intraoral effects of a fluoride-releasing device on acid-softened enamel. J Am Dent Assoc 1986;113:383-388.
6.
Creeth JE, Kelly SA, Martinez-Mier EA, Hara AT, Bosma ML, Butler A, Lynch RJM, Zero DT: Dose-response effect of fluoride dentifrice on remineralisation and further demineralisation of erosive lesions: a randomised in situ clinical study. J Dent 2015;43:823-831.
7.
Duckworth RM, Morgan SN: Oral fluoride retention after use of fluoride dentifrices. Caries Res 1991;25:123-129.
8.
Featherstone JD: Prevention and reversal of dental caries: role of low level fluoride. Community Dent Oral Epidemiol 1999;27:31-40.
9.
Featherstone JD: The continuum of dental caries - evidence for a dynamic disease process. J Dent Res 2004;83(spec No C):C39-C42.
10.
Featherstone JD: Caries prevention and reversal based on the caries balance. Pediatr Dent 2006;28:128-132.
11.
Featherstone JD: Dental caries: a dynamic disease process. Aust Dent J 2008;53:286-291.
12.
Gelhard TB, ten Cate JM, Arends J: Rehardening of artificial enamel lesions in vivo. Caries Res 1979;13:80-83.
13.
Kazmierczak M, Mather M, Ciancio S, Fischman S, Cancro L: Clinical evaluation of anticalculus dentifrices. Clin Prev Dent 1990;12:13-17.
14.
Kidd EA, Fejerskov O: The control of disease progression: non-operative treatment; in Fejerskov O, Kidd EA (eds): Dental Caries: The Disease and Its Clinical Management. Oxford, Blackwell Munksgaard, 2008, pp 251-254.
15.
Landis JR, Koch GG: The measurement of observer agreement for categorical data. Biometrics 1977;33:159-174.
16.
Lippert F: Dose-response effects of zinc and fluoride on caries lesion remineralization. Caries Res 2012;46:62-68.
17.
Lynch RJ, Churchley D, Butler A, Kearns S, Thomas GV, Badrock TC, Cooper L, Higham SM: Effects of zinc and fluoride on the remineralisation of artificial carious lesions under simulated plaque fluid conditions. Caries Res 2011;45:313-322.
18.
Margolis HC, Moreno EC: Physiochemical perspectives on the cariostatic mechanism of systemic and topical fluorides. J Dent Res 1990;69(spec):606-613.
19.
Melsen B, Rolla G: Reduced clinical effect of monofluorophosphate in the presence of lauryl sulphate. Caries Res 1983;17:549-553.
20.
Mohammed NR, Mneimne M, Hill RG, Al-Jawad M, Lynch RJ, Anderson P: Physical chemical effects of zinc on in vitro enamel demineralization. J Dent 2014;42:1096-1104.
21.
Newby EE, Martinez-Mier EA, Hara A, Lippert F, Kelly SA, Fleming N, Butler A, Bosma ML, Zero DT: A randomised clinical study to evaluate experimental children's toothpastes in an in-situ palatal caries model in children aged 11-14 years. Int Dent J 2013;63(suppl 2): 31-38.
22.
Richter R, Jogun S, Won B, Zhang YP, Miller S: Long-lasting efficacy of an experimental 1,450 ppm fluoride/zinc-based dentifrice as measured by calcium buildup using an in situ intra-oral device after 12 h: a randomized clinical trial. J Clin Dent 2015;26:91-95.
23.
Ripa LW, Leske GS, Triol CW, Volpe AR: Clinical study of the anticaries efficacy of three fluoride dentifrices containing anticalculus ingredients: three-year (final) results. J Clin Dent 1990;2:29-33.
24.
Robinson C, Strafford S, Rees G, Brookes SJ, Kirkham J, Shore RC, Watson PS, Wood S: Plaque biofilms: the effect of chemical environment on natural human plaque biofilm architecture. Arch Oral Biol 2006;51:1006-1014.
25.
Sakkab NY, Cilley WA, Haberman JP: Fluoride in deciduous teeth from an anti-caries clinical study. J Dent Res 1984;63:1201-1205.
26.
Stephen KW, Creanor SL, Russell JI, Burchell CK, Huntington E, Downie CF: A 3-year oral health dose-response study of sodium monofluorophosphate dentifrices with and without zinc citrate: anti-caries results. Community Dent Oral Epidemiol 1988;16:321-325.
27.
ten Cate JM: The caries preventive effect of a fluoride dentifrice containing triclosan and zinc citrate, a compilation of in vitro and in situ studies. Int Dent J 1993;43:407-413.
28.
ten Cate JM: Contemporary perspective on the use of fluoride products in caries prevention. Br Dent J 2013;214:161-167.
29.
Vogel GL, Schumacher GE, Chow LC, Tenuta LMA: Oral fluoride levels 1 h after use of a sodium fluoride rinse: effect of sodium lauryl sulfate. Caries Res 2015;49:291-296.
30.
Walsh T, Worthington HV, Glenny AM, Appelbe P, Marinho VC, Shi X: Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents. Cochrane Database Syst Rev 2010;1:CD007868.
31.
Zero DT: In situ caries models. Adv Dent Res 1995;9:214-230.
32.
Zero DT: Dentifrices, mouthwashes, and remineralization/caries arrestment strategies. BMC Oral Health 2006;6(suppl 1):S9.
33.
Zero DT, Creeth JE, Bosma ML, Butler A, Guibert RG, Karwal R, Lynch RJ, Martinez-Mier EA, Gonzalez-Cabezas C, Kelly SA: The effect of brushing time and dentifrice quantity on fluoride delivery in vivo and enamel surface microhardness in situ. Caries Res 2010;44:90-100.
34.
Zero DT, Fu J, Anne KM, Cassata S, McCormack SM, Gwinner LM: An improved intra-oral enamel demineralization test model for the study of dental caries. J Dent Res 1992;71(spec No):871-878.
35.
Zero DT, Zhang JZ, Harper DS, Wu M, Kelly S, Waskow J, Hoffman M: The remineralizing effect of an essential oil fluoride mouthrinse in an intraoral caries test. J Am Dent Assoc 2004;135:231-237.
© 2018 S. Karger AG, Basel
2018
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.