Effect of daily use of fluoridated dentifrice and bleaching gels containing calcium, fluoride, or trimetaphosphate on enamel hardness: an in vitro study



This study evaluated the effects of calcium gluconate (CaGlu), sodium fluoride (NaF), sodium trimetaphosphate (TMP), and NaF/TMP added to a 35% hydrogen peroxide (HP) bleaching gel for the reduction in enamel demineralization in vitro, with and without the use of a fluoridated dentifrice.


Enamel blocks (n = 100) were obtained from bovine incisors (n = 200) after flattening and subjected to initial surface hardness (SH) analysis. The blocks were divided according to the bleaching gel (35% HP; 35% HP + 0.05% NaF; 35% HP + 0.25% TMP; 35% HP + 0.05% NaF + 0.25% TMP; 35% HP + 2% CaGlu) and were treated with ether non-fluoridated or fluoridated (1100 ppm) dentifrice. The bleaching gels were applied thrice (40 min/session) at the intervals of 7 days between each application. After 21 days, the final SH for the calculation of the percentage of SH loss (%SH) and cross-sectional hardness for the evaluation of the integrated hardness area (IH) were determined.


Bleaching containing HP + NaF + TMP presented lowest %SH (p < 0.001), regardless of the dentifrice used. HP + NaF + TMP bleaching gel led to lower subsurface enamel mineral loss (IH) compared to the other groups (p < 0.001), and these did not differ from each other (p > 0.05). Daily use of fluoride dentifrice led to higher IH values (p < 0.001), regardless of the bleaching gels.


The addition of NaF/TMP to a 35% HP bleaching gel remarkably reduced the mineral loss compared to the cases of the other bleaching gels, regardless of dentifrice.

Clinical relevance

The association of TMP/NaF can be used as a strategy for reducing mineral loss during the bleaching procedure, even without the daily use of fluoride dentifrice.

This is a preview of subscription content, log in to check access.

Fig. 1


  1. 1.

    Samorodnitzky-Naveh GR, Geiger SB, Levin L (2007) Patients’ satisfaction with dental esthetics. J Am Dent Assoc 138:805–808. https://doi.org/10.14219/jada.archive.2007.0269

    Article  PubMed  Google Scholar 

  2. 2.

    Kielbassa AM, Maier M, Gieren AK, Eliav E (2015) Tooth sensitivity during and after vital tooth bleaching: a systematic review on an unsolved problem. Quintessence Int 46:881–897. https://doi.org/10.3290/j.qi.a34700

    Article  PubMed  Google Scholar 

  3. 3.

    Carey CM (2014) Tooth whitening: what we now know. J Evid Based Dent Pract 14:70–76. https://doi.org/10.1016/j.jebdp.2014.02.006

    Article  PubMed  Google Scholar 

  4. 4.

    Auschill TM, Hellwig E, Schmidale S, Sculean A, Arweiler NB (2005) Efficacy, side-effects and patients’ acceptance of different bleaching techniques (OTC, in-office, at-home). Oper Dent 30:156–166. https://doi.org/10.1016/S0084-3717(08)70026-6

    Article  PubMed  Google Scholar 

  5. 5.

    Reis A, Tay L, Herrera D, Kossatz S, Loguercio AD (2011) Clinical effects of prolonged application time of an in-office bleaching gel. Oper Dent 36:590–596. https://doi.org/10.2341/10-173-C

    Article  PubMed  Google Scholar 

  6. 6.

    Magalhães JG, Marimoto ARK, Torres CRG, Pagani C, Teixeira SC, Barcellos DC (2012) Microhardness change of enamel due to bleaching with in-office bleaching gels of different acidity. Acta Odontol Scand 70:122–126. https://doi.org/10.3109/00016357.2011.600704

    Article  PubMed  Google Scholar 

  7. 7.

    Cintra LTA, Benetti F, Ferreira LL, Gomes-Filho JE, Ervolino E, Gallinari MO, Rahal V, Briso ALF (2016) Penetration capacity, color alteration and biological response of two in-office bleaching protocols. Braz Dent J 27:169–175. https://doi.org/10.1590/0103-6440201600329

    Article  PubMed  Google Scholar 

  8. 8.

    Zantner C, Beheim-Schwarzbach N, Neumann K, Kielbassa AM (2007) Surface microhardness of enamel after different home bleaching procedures. Dent Mater 23:243–250. https://doi.org/10.1016/j.dental.2006.06.044

    Article  PubMed  Google Scholar 

  9. 9.

    Eimar H, Siciliano R, Abdallah MN, Nader SA, Amin WM, Martinez PP, Celemin A, Cerruti M, Tamimi F (2012) Hydrogen peroxide whitens teeth by oxidizing the organic structure. J Dent 40:e25–e33. https://doi.org/10.1016/j.jdent.2012.08.008

    Article  PubMed  Google Scholar 

  10. 10.

    White DJ, Kozak KM, Zoladz JR, Duschner H, Götz H (2002) Peroxide interactions with hard tissues: effects on surface hardness and surface/subsurface ultrastructural properties. Compend Contin Educ Dent 23:42–48

  11. 11.

    Sasaki RT, Arcanjo AJ, Flório FM, Basting RT (2009) Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide. J Appl Oral Sci 17:611–616. https://doi.org/10.1590/S1678-77572009000600014

    Article  PubMed  PubMed Central  Google Scholar 

  12. 12.

    Basting R, Amaral F, França F, Flório F (2012) Clinical comparative study of the effectiveness of and tooth sensitivity to 10% and 20% carbamide peroxide home-use and 35% and 38% hydrogen peroxide in-office bleaching materials containing desensitizing agents. Oper Dent 37:464–473. https://doi.org/10.2341/11-337-C

    Article  PubMed  Google Scholar 

  13. 13.

    Wiegand A, Schreier M, Attin T (2007) Effect of different fluoridation regimes on the microhardness of bleached enamel. Oper Dent 32:610–615. https://doi.org/10.2341/06-171

    Article  PubMed  Google Scholar 

  14. 14.

    Chen HP, Chang CH, Liu JK, Chuang SF, Yang JY (2008) Effect of fluoride containing bleaching agents on enamel surface properties. J Dent 36:718–725. https://doi.org/10.1016/j.jdent.2008.05.003

    Article  PubMed  Google Scholar 

  15. 15.

    Cavalli V, Rodrigues LK, Paes-Leme AF, Brancalion ML, Arruda MA, Berger SBGM (2010) Effects of bleaching agents containing fluoride and calcium on human enamel. Quintessence Int 41:157–165

    Google Scholar 

  16. 16.

    da Costa Soares MUS, Araújo NC, Borges BCD, Sales WS, Sobral APV (2013) Impact of remineralizing agents on enamel microhardness recovery after in-office tooth bleaching therapies. Acta Odontol Scand 71:343–348. https://doi.org/10.3109/00016357.2012.681119

    Article  PubMed  Google Scholar 

  17. 17.

    Alexandrino L, Gomes Y, Alves E, Costi H, Rogez H, Silva C (2014) Effects of a bleaching agent with calcium on bovine enamel. Eur J Dent 08:320–325. https://doi.org/10.4103/1305-7456.137634

    Article  Google Scholar 

  18. 18.

    Basting RT, Antunes EV, Turssi CP, do Amaral FL, Franca FM, Florio FM (2015) In vitro evaluation of calcium and phosphorus concentrations in enamel submitted to an in-office bleaching gel treatment containing calcium. Gen Dent 63:52–56

  19. 19.

    Furlan IS, Bridi EC, Amaral FLBD, França FMG, Turssi CP, Basting RT (2017) Effect of high- or low-concentration bleaching agents containing calcium and/or fluoride on enamel microhardness. Gen Dent 65:66–70

  20. 20.

    Cavalli V, Rosa DAD, Silva DPD et al (2018) Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels. J Appl Oral Sci 26:26. https://doi.org/10.1590/1678-7757-2017-0589

    Article  Google Scholar 

  21. 21.

    Vieira-Junior W, Lima D, Tabchoury C, Ambrosano GMB, Aguiar FHB, Lovadino JR (2016) Effect of toothpaste application prior to dental bleaching on whitening effectiveness and enamel properties. Oper Dent 41:E29–E38. https://doi.org/10.2341/15-042-L

    Article  PubMed  Google Scholar 

  22. 22.

    Tschoppe P, Neumann K, Mueller J, Kielbassa AM (2009) Effect of fluoridated bleaching gels on the remineralization of predemineralized bovine enamel in vitro. J Dent 37:156–162. https://doi.org/10.1016/j.jdent.2008.11.001

    Article  PubMed  Google Scholar 

  23. 23.

    Cruz NVS, Pessan JP, Manarelli MM, Souza MDB, Delbem ACB (2015) In vitro effect of low-fluoride toothpastes containing sodium trimetaphosphate on enamel erosion. Arch Oral Biol 60:1231–1236. https://doi.org/10.1016/j.archoralbio.2015.05.010

    Article  PubMed  Google Scholar 

  24. 24.

    Missel EMC, Cunha RF, Vieira AEM, Cruz NVS, Castilho FCN, Delbem ACB (2016) Sodium trimetaphosphate enhances the effect of 250 p.p.m. fluoride toothpaste against enamel demineralization in vitro. Eur J Oral Sci 124:343–348. https://doi.org/10.1111/eos.12277

    Article  PubMed  Google Scholar 

  25. 25.

    Manarelli MM, Moretto MJ, Sassaki KT, Martinhon CC, Pessan JP, Delbem AC (2013) Effect of fluoride varnish supplemented with sodium trimetaphosphate on enamel erosion and abrasion. Am J Dent 26:307–312

    PubMed  Google Scholar 

  26. 26.

    Pancote LP, Manarelli MM, Danelon M, Delbem ACB (2014) Effect of fluoride gels supplemented with sodium trimetaphosphate on enamel erosion and abrasion: in vitro study. Arch Oral Biol 59:336–340. https://doi.org/10.1016/j.archoralbio.2013.12.007

    Article  PubMed  Google Scholar 

  27. 27.

    Burgmaier GM, Schulze IM, Attin T (2002) Fluoride uptake and development of artificial erosions in bleached and fluoridated enamel in vitro. J Oral Rehabil 29:799–804. https://doi.org/10.1046/j.1365-2842.2002.00966.x

    Article  PubMed  Google Scholar 

  28. 28.

    Basting RT, Rodrigues AL, Serra MC (2003) The effects of seven carbamide peroxide bleaching agents on enamel microhardness over time. J Am Dent Assoc 134:1335–1342. https://doi.org/10.14219/jada.archive.2003.0047

    Article  PubMed  Google Scholar 

  29. 29.

    Vieira AEM, Danelon M, Camara DMD et al (2017) In vitro effect of amorphous calcium phosphate paste applied for extended periods of time on enamel remineralization. J Appl Oral Sci 25:596–603. https://doi.org/10.1590/1678-7757-2016-0513

    Article  PubMed  PubMed Central  Google Scholar 

  30. 30.

    Amaral JG, Pessan JP, Souza JAS, Moraes JCS, Delbem ACB (2018) Cyclotriphosphate associated to fluoride increases hydroxyapatite resistance to acid attack. J Biomed Mater Res B Appl Biomater 106:2553–2564. https://doi.org/10.1002/jbm.b.34072

    Article  PubMed  Google Scholar 

  31. 31.

    Featherstone JDB, ten Cate JM, Shariati M, Arends J (1983) Comparison of artificial caries-like lesions by quantitative microradiography and microhardness profiles. Caries Res 17:385–391. https://doi.org/10.1159/000260692

    Article  PubMed  Google Scholar 

  32. 32.

    Kielbassa AM, Wrbas KT, Schulte-Mönting J, Hellwig E (1999) Correlation of transversal microradiography and microhardness on in situ-induced demineralization in irradiated and nonirradiated human dental enamel. Arch Oral Biol 44:243–251. https://doi.org/10.1016/S0003-9969(98)00123-X

    Article  PubMed  Google Scholar 

  33. 33.

    Dalpasquale G, Delbem ACB, Pessan JP, Nunes GP, Gorup LF, Neto FNS, de Camargo ER, Danelon M (2017) Effect of the addition of nano-sized sodium hexametaphosphate to fluoride toothpastes on tooth demineralization: an in vitro study. Clin Oral Investig 21:1821–1827. https://doi.org/10.1007/s00784-017-2093-3

    Article  PubMed  Google Scholar 

  34. 34.

    Danelon M, Garcia LG, Pessan JP, Passarinho A, Camargo ER, Delbem ACB (2019) Effect of fluoride toothpaste containing nano-sized sodium hexametaphosphate on enamel remineralization: an in situ study. Caries Res 53:260–267. https://doi.org/10.1159/000491555

    Article  PubMed  Google Scholar 

  35. 35.

    Delbem ACB, Souza JAS, Zaze ACSF, Takeshita EM, Sassaki KT, Moraes JCS (2014) Effect of trimetaphosphate and fluoride association on hydroxyapatite dissolution and precipitation in vitro. Braz Dent J 25:479–484. https://doi.org/10.1590/0103-6440201300174

    Article  PubMed  Google Scholar 

Download references


This study was supported by FAPESP (The State of São Paulo Research Foundation, grant 2016/26132-9).

Author information



Corresponding author

Correspondence to Alberto Carlos Botazzo Delbem.

Ethics declarations

Conflict of interest

The authors Alberto Carlos Botazzo Delbem and Mirela Sanae Shinohara and hold a patent request for a product used in the study, by the National Institute of Industrial Property—INPI/SP, on 11 Nov. 2014 under number BR 102013 006761-0 A2.

Ethical approval

This paper does not contain any studies with human subjects, so that no ethical approval was required.

Informed consent

Same as above.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Júnior, R.A.T.P., Danelon, M., Pessan, J.P. et al. Effect of daily use of fluoridated dentifrice and bleaching gels containing calcium, fluoride, or trimetaphosphate on enamel hardness: an in vitro study. Clin Oral Invest (2020). https://doi.org/10.1007/s00784-020-03375-5

Download citation


  • Tooth demineralization
  • Dental enamel
  • Phosphates
  • Fluorides
  • Dental bleaching