Lasers in Medical Science

, Volume 29, Issue 6, pp 1785–1791 | Cite as

Prevention of dentine caries using silver diamine fluoride application followed by Er:YAG laser irradiation: an in vitro study

  • May L. Mei
  • Leticia Ito
  • C. H. Chu
  • Edward C. M. Lo
  • C. F. Zhang
Original Article


To evaluate the preventive effect of Er:YAG laser (EYL) irradiation followed by silver diamine fluoride (SDF) application on dentine with cariogenic biofilm challenge. Twenty-four dentine slices were prepared from extracted sound human third molars. Each slice was cut into four parts for SDF application, followed by EYL irradiation (group SL), SDF application (group S), EYL irradiation (group L) and water (group W). The specimens were subjected to cariogenic biofilm challenge for 12 h, followed by immersion in a buffered remineralising solution containing calcium chloride and sodium hypophosphate for 12 h at 37 °C. Surface morphological changes in the specimens were examined using scanning electronic microscopy. Elemental analysis was performed using energy-dispersive X-ray spectrometry. Micro-mechanical properties were investigated by nano-indentation. The specimen surfaces of groups SL and L showed laser melting contours with narrowed dentinal orifices. Group S showed a partial tubular occlusion. A porous surface was observed in group W, indicating demineralisation. The mean (SD) fluoride weight percentages were 3.93 (0.91), 3.10 (0.61), 0.17 (0.09) and 0.32 (0.07) in groups SL, S, L and W, respectively, (p < 0.001; SL, S > L, W). The mean (SD) micro-hardness values in GPa were 1.84 (0.22), 0.49 (0.13), 0.41 (0.11) and 0.30 (0.06) in groups SL, S, L and W, respectively, (p < 0.001; SL > S > L, W). The mean (SD) elastic moduli in GPa were 75.1 (7.2), 20.0 (1.3), 24.3 (5.2) and 20.2 (2.8) in groups SL, S, L and W, respectively, (p < 0.001; SL > S, L, W). SDF application followed by EYL irradiation on a dentine surface increased its resistance to cariogenic biofilm challenge.


Laser Preventive Silver diamine fluoride Caries Nano-indentation Micro-hardness 



This study was supported by the HKU seed funding programme for basic research (Grant no. HKU#201111159079).


  1. 1.
    Llodra JC, Rodriguez A, Ferrer B, Menardia V, Ramos T, Morato M (2005) Efficacy of silver diamine fluoride for caries reduction in primary teeth and first permanent molars of schoolchildren: 36-month clinical trial. J Dent Res 84:721–724PubMedCrossRefGoogle Scholar
  2. 2.
    Chu CH, Lo EC, Lin HC (2002) Effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting dentin caries in Chinese pre-school children. J Dent Res 81:767–770PubMedCrossRefGoogle Scholar
  3. 3.
    Tan HP, Lo EC, Dyson JE, Luo Y, Corbet EF (2010) A randomised trial on root caries prevention in elders. J Dent Res 89:1086–1090PubMedCrossRefGoogle Scholar
  4. 4.
    Chu CH, Mei L, Seneviratne CJ, Lo EC (2012) Effects of silver diamine fluoride on dentine carious lesions induced by Streptococcus mutans and Actinomyces naeslundii biofilms. Int J Paediatr Dent 22(1):2–10PubMedCrossRefGoogle Scholar
  5. 5.
    Mei ML, Li QL, Chu CH, Yiu CK, Lo EC (2012) The inhibitory effects of silver diamine fluoride at different concentrations on matrix metalloproteinases. Dent Mater 28:903–908PubMedCrossRefGoogle Scholar
  6. 6.
    Chu CH, Lo EC (2008) Micro-hardness of dentine in primary teeth after topical fluoride applications. J Dent 36:387–391PubMedCrossRefGoogle Scholar
  7. 7.
    Rosenblatt A, Stamford TC, Niederman R (2009) Silver diamine fluoride: a caries ‘silver-fluoride bullet’. J Dent Res 88:116–125PubMedCrossRefGoogle Scholar
  8. 8.
    Zhang CF (1996) The effects of pulsed Nd:YAG laser irradiation with fluoride on root surface. J Clin Laser Med Sur 14:399–403Google Scholar
  9. 9.
    Gao XL, Pan JS, Hsu CY (2006) Laser–fluoride effect on root demineralization. J Dent Res 85:919–923PubMedCrossRefGoogle Scholar
  10. 10.
    Hsu CY, Gao XL, Pan JS, Wefel JS (2004) Effects of CO2 laser on fluoride uptake in enamel. J Dent 32:161–167CrossRefGoogle Scholar
  11. 11.
    Liu Y, Hsu CY, Teo CM, Teoh SH (2013) Potential mechanism for the laser–fluoride effect on enamel demineralization. J Dent Res 92:71–75PubMedCrossRefGoogle Scholar
  12. 12.
    Ana PA, Tabchoury CP, Cury JA, Zezell DM (2012) Effect of Er, Cr:YSGG laser and professional fluoride application on enamel demineralization and on fluoride retention. Caries Res 46:441–451PubMedCrossRefGoogle Scholar
  13. 13.
    Zhang C, Kimura Y, Matsumoto K, Harashima T, Zhou H (1998) Effects of pulsed Nd:YAG laser irradiation on root canal wall dentin with different laser initiators. J Endodont 24:352–355CrossRefGoogle Scholar
  14. 14.
    Aoki A, Ando Y, Watanabe H, Ishikawa I (1994) In vitro studies on laser scaling of sub gingival calculus with an erbium:YAG laser. J Periodontol 65:1097–1106PubMedCrossRefGoogle Scholar
  15. 15.
    Matsumoto K, Wang X, Zhang C, Kinoshita J (2007) Effect of a novel Er:YAG laser in caries removal and cavity preparation: a clinical observation. Photomed Laser Surg 25:8–13PubMedCrossRefGoogle Scholar
  16. 16.
    Grossenbacher R (1992) Laser surgery in the oral cavity. J Clin Laser Med Sur 10:19–21Google Scholar
  17. 17.
    Zhang C, Kimura Y, Matsumoto K (1996) The effects of pulsed Nd:YAG laser irradiation with fluoride on root surface. J Clin Laser Med Sur 14:399–403Google Scholar
  18. 18.
    de Melo JB, Hanashiro FS, Steagall Jr. W, Turbino ML, Nobre-Dos-Santos M, Youssef MN, de Souza-Zaroni WC (2013) Effect of CO(2) laser on root caries inhibition around composite restorations: an in vitro study. Lasers Med Sci. Jan 5 [Epub ahead of print]Google Scholar
  19. 19.
    Marquezan M, Correa FN, Sanabe ME, Rodrigues Filho LE, Hebling J, Guedes-Pinto AC, Mendes FM (2009) Artificial methods of dentine caries induction: a hardness and morphological comparative study. Arch Oral Biol 54:1111–1117PubMedCrossRefGoogle Scholar
  20. 20.
    Xu Z, Neoh KG, Amaechi B, Kishen A (2010) Monitoring bacterial-demineralization of human dentine by electrochemical impedance spectroscopy. J Dent 38:138–148PubMedCrossRefGoogle Scholar
  21. 21.
    Bader C, Krejci I (2006) Indications and limitations of Er:YAG laser applications in dentistry. Am J Dent 19:178–186PubMedGoogle Scholar
  22. 22.
    Hossain M, Nakamura Y, Kimura Y, Yamada Y, Ito M, Matsumoto K (2000) Caries-preventive effect of Er:YAG laser irradiation with or without water mist. J Clin Laser Med Sur 18:61–65Google Scholar
  23. 23.
    Ceballos L, Toledano M, Osorio R, Garcia-Godoy F, Flaitz C, Hicks J (2001) ER:YAG laser pre-treatment effect on in vitro secondary caries formation around composite restorations. Am J Dent 14:46–49PubMedGoogle Scholar
  24. 24.
    Celik EU, Ergucu Z, Turkun LS, Turkun M (2008) Effect of different laser devices on the composition and micro-hardness of dentin. Oper Dent 33:496–501PubMedCrossRefGoogle Scholar
  25. 25.
    Hossain M, Nakamura Y, Tamaki Y, Yamada Y, Murakami Y, Matsumoto K (2003) Atomic analysis and Knoop hardness measurement of the cavity floor prepared by Er, Cr:YSGG laser irradiation in vitro. J Oral Rehabil 30:515–521PubMedCrossRefGoogle Scholar
  26. 26.
    Nelson DG, Wefel JS, Jongebloed WL, Featherstone JD (1987) Morphology, histology and crystallography of human dental enamel treated with pulsed low-energy infrared laser radiation. Caries Res 21:411–426PubMedCrossRefGoogle Scholar
  27. 27.
    Takeuchi Y, Guggenheim B, Filieri A, Baehni P (2007) Effect of chlorhexidine/thymol and fluoride varnishes on dental biofilm formation in vitro. Eur J Oral Sci 115:468–472PubMedCrossRefGoogle Scholar
  28. 28.
    Chan YL, Ngan AH, King NM (2011) Nano-scale structure and mechanical properties of the human dentine–enamel junction. J Mech Behav Biomed Mater 4:785–795PubMedCrossRefGoogle Scholar
  29. 29.
    He LH, Fujisawa N, Swain MV (2006) Elastic modulus and stress–strain response of human enamel by nano-indentation. Biomaterials 27:4388–4398PubMedCrossRefGoogle Scholar
  30. 30.
    Sauro S, Osorio R, Watson TF, Toledano M (2012) Assessment of the quality of resin–dentin bonded interfaces: an AFM nano-indentation, muTBS and confocal ultra morphology study. Dent Mater 28:622–631PubMedCrossRefGoogle Scholar
  31. 31.
    Cheng YT, Cheng CM (1998) Relationships between hardness, elastic modulus and the work of indentation. Appl Phys Lett 73:614–616CrossRefGoogle Scholar
  32. 32.
    Darvell BW (2009) Mechanical testing. In: Darvell BW (ed) Materials Science for Dentistry, 9th edn. Woodhead Publishing, UK, pp 1–28CrossRefGoogle Scholar
  33. 33.
    Chu CH, Mei ML, Lo EC (2010) Use of fluorides in dental caries management. Gen Dent 58:37–43, quiz 44–35, 79–80PubMedGoogle Scholar

Copyright information

© Springer-Verlag London 2013

Authors and Affiliations

  • May L. Mei
    • 1
  • Leticia Ito
    • 1
  • C. H. Chu
    • 1
  • Edward C. M. Lo
    • 1
  • C. F. Zhang
    • 1
  1. 1.Faculty of DentistryThe University of Hong KongHong KongChina

Personalised recommendations