The aim was to validate a novel protocol to measure the cariostatic efficacies of demineralization inhibitors by repeating previous SMR (scanning microradiography) studies investigating the dose response of Zn2+ and F– on demineralization kinetics in vitro using real-time Ca2+ ion selective electrodes (ISEs). In this study, Ca2+ release was used as a proxy for the extent of demineralization. Forty-eight hydroxyapatite (HAP) discs were allocated into 16 groups (n = 3) and adding either increasing [Zn2+], or [F–], similar to those used in the previous SMR studies. Each HAP disc was immersed in 50 mL, pH 4.0, buffered acetic acid for 1 h, and real-time ISE methodology was used to monitor the rate of increase in [Ca2+] in the demineralization solution. Next, either zinc acetate or sodium fluoride was added into each demineralization solution accordingly. Then after each [Zn2+] or [F–] addition, the HAP disc was further demineralized for 1 h, and ISE measurements were continued. The percentage reduction in the rate of calcium loss from hydroxyapatite (PRCLHAP) at each [Zn2+] or [F–] was calculated from the decrease in Ca2+ release rate, similar to that used in the previous SMR studies. A log-linear relationship between mean PRCLHAP and inhibitor concentration was found for both Zn2+ and F–, similar to that reported for each ion in the previous SMR studies. In conclusion, real-time Ca2+ ISE systems can be used to measure the cariostatic efficacies of demineralization inhibitors.

Keywords:
Demineralization, Dental caries, Inhibitors, Ion selective electrodes, Real-time method
1.
Arends J, Jongebloed W, Ogaard B, Rolla G: SEM and microradiographic investigation of initial enamel caries. Scand J Dent Res 1987; 95: 193–201.
2.
Berkovitz BKB: Master Dentistry, ed 3. Edinburgh, Churchill Livingstone, 2011, vol 3: Oral Biology.
3.
Bjorvatn K, Morch T: The calcium selective electrode – a possible tool in dental research. Acta Odontol Scand 1979; 37: 259–265.
4.
Bollet-Quivogne FR, Anderson P, Dowker SE, Elliott JC: Scanning microradiographic study on the influence of diffusion in the external liquid on the rate of demineralization in hydroxyapatite aggregates. Eur J Oral Sci 2005; 113: 53–59.
5.
Carey CM, Vogel GL: Measurement of calcium activity in oral fluids by ion selective electrode: method evaluation and simplified calculation of ion activity products. J Res Natl Inst Standards Technol 2000; 105, 267–273.
6.
Chan WD, Yang L, Wan W, Rizkalla AS: Fluoride release from dental cements and composites: a mechanistic study. Dent Mater 2006; 22: 366–73.
7.
Chumbimuni-Torres KY, Bakker E, Wang J: Real-time probing of the growth dynamics of nanoparticles using potentiometric ion-selective electrodes. Electrochem Commun 2009; 11: 1964–1967.
8.
Covington KA: Ion-Selective Electrode Methodology. Boca Raton, CRC Press, 1979.
9.
Do Amaral JG, Delbem AC, Pessan JP, Manarelli MM, Barbour ME: Effects of polyphosphates and fluoride on hydroxyapatite dissolution: a pH-stat investigation. Arch Oral Biol 2016; 63: 40–46.
10.
Elliott JC, Anderson P, Gao XJ, Wong FSL, Davis GR, Dowker SEP: Application of scanning microradiography and X-ray microtomography to studies of bones and teeth. J X-Ray Sci Technol 1994; 4: 102–117.
11.
Itota T, Al-Naimi OT, Carrick TE, Yoshiyama M, Mccabe JF: Fluoride release from aged resin composites containing fluoridated glass filler. Dent Mater 2005; 21: 1033–1038.
12.
Jeffcoat MK: Osteoporosis: a possible modifying factor in oral bone loss. Ann Periodontol 1998; 3: 312–321.
13.
Kim H-J, Hummel JW, Birrell SJ, Sudduth KA: Evaluation of phosphate ion-selective membranes for real-time soil nutrient sensing. ASAE Meeting Presentation, 2005, paper No 051033.
14.
Kosoric J, Hector MP, Anderson P: The influence of proteins on demineralization kinetics of hydroxyapatite aggregates. J Biomed Mater Res A 2010; 94: 972–977.
15.
Kumar P, Vinitha B, Fathima G: Bone grafts in dentistry. J Pharm Bioallied Sci 2013; 5:S125–S127.
16.
Marsh PD: Oral Microbiology. London, Elsevier, 2009.
17.
Mohammed NR, Lynch RJ, Anderson P: Effects of fluoride concentration on enamel demineralization kinetics in vitro. J Dent 2014; 42: 613–618.
18.
Mohammed NR, Lynch RJ, Anderson P: Inhibitory effects of zinc ions on enamel demineralisation kinetics in vitro. Caries Res 2015; 49: 600–605.
19.
Robinson CPD, Kirkham J, Shore R: Dental Enamel: Formation to Destruction. Boca Raton, CRC Press, 1995.
20.
Rundle CC: A Beginner’s Guide to Ion-Selective Electrode Measurements. London, Nico2000 Ltd, 2000.
21.
Selwitz RH, Ismail AI, Pitts NB: Dental caries. Lancet 2007; 369: 51–59.
22.
Shah S, Kosoric J, Hector MP, Anderson P: An in vitro scanning microradiography study of the reduction in hydroxyapatite demineralization rate by statherin-like peptides as a function of increasing N-terminal length. Eur J Oral Sci 2011; 119(suppl 1): 13–18.
23.
Shellis RP, Barbour ME, Jones SB, Addy M: Effects of pH and acid concentration on erosive dissolution of enamel, dentine, and compressed hydroxyapatite. Eur J Oral Sci 2010; 118: 475–482.
24.
Tezel H, Atalayin C, Erturk O, Karasulu E: Susceptibility of enamel treated with bleaching agents to mineral loss after cariogenic challenge. Int J Dent 2011; 2011: 953835.
25.
West NX, Joiner A: Enamel mineral loss. J Dent 2014; 42(suppl 1):S2–S11.
26.
Wiegand A, Buchalla W, Attin T: Review on fluoride-releasing restorative materials – fluoride release and uptake characteristics, antibacterial activity and influence on caries formation. Dent Mater 2007; 23: 343–362.
27.
Xu X, Ling L, Wang R, Burgess JO: Formulation and characterization of a novel fluoride-releasing dental composite. Dent Mater 2006; 22: 1014–1023.
28.
Zeitchek AM: All Solid-State-Ion-Selective Electrodes for Real-Time Measurement of Relevant Physiological Phenomena; dissertation, Purdue University, 2013.
© 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.