Effect of CO2 laser (10.6 μm) and Remin Pro on microhardness of enamel white spot lesions


This study investigated the combined effect of CO2 laser irradiation and Remin Pro paste on microhardness of enamel white spot lesions (WSLs). Seventy-eight intact premolars were randomly assigned into six groups and then stored in a demineralizing solution to create WSLs. Afterwards, the teeth in group 6 (negative control) remained untreated, while groups 1 and 4 were exposed to CO2 laser irradiation (20 Hz, 1 W, 30 s) and Remin Pro paste, respectively. In groups 2 and 3, the teeth were exposed to laser either before (group 2) or after (group 3) Remin Pro application. The teeth in groups 1 to 5 were then immersed in artificial saliva for 90 days while subjected to fluoride mouthwash and weekly brushing. Finally, the teeth were sectioned, and Vickers microhardness was measured at the enamel surface and at 50, 100, and 150 μm from the surface. One sample of each group was also examined with scanning electron microscope (SEM). Data were analyzed by two-way analysis of variance (ANOVA) and Tukey’s test. The significance was set at 0.05. Laser irradiation followed by Remin Pro application (group 2) caused a significant increase in total WSLs’ microhardness compared with laser alone (group 1) and control groups (P < 0.05). Microhardness at depths of 100 and 150 μm was also significantly greater in group 2 compared with those of group 3 and control groups (P < 0.05). Combined application of CO2 laser with Remin Pro paste, when laser is irradiated before the paste, is suggested for re-hardening of WSLs in deep layers of enamel.

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  1. 1.

    Årtun J, Brobakken BO (1986) Prevalence of carious white spots after orthodontic treatment with multibonded appliances. The European Journal of Orthodontics 8(4):229–234

    Article  Google Scholar 

  2. 2.

    Mann AB, Dickinson ME. Nanomechanics, chemistry and structure at the enamel surface. The teeth and their environment. 19: Karger Publishers; 2006. p. 105–31

  3. 3.

    Lone E, Utreja A, Singh S, Jena A (2015) Effect of multibracket orthodontic appliance on frequency and severity of enamel demineralization-a prospective study. Journal of Dental Specialities 3(1):36–39

    Google Scholar 

  4. 4.

    Paula ABP, Fernandes AR, Coelho AS, Marto CM, Ferreira MM, Caramelo F, et. al.. Therapies for white spot lesions—a systematic review. Journal of Evidence Based Dental Practice 2017;17(1):23–38

  5. 5.

    Cochrane N, Cai F, Huq N, Burrow M, Reynolds E (2010) New approaches to enhanced remineralization of tooth enamel. J Dent Res 89(11):1187–1197

    CAS  Article  Google Scholar 

  6. 6.

    Sudjalim T, Woods M, Manton D (2006) Prevention of white spot lesions in orthodontic practice: a contemporary review. Aust Dent J 51(4):284–289

    CAS  Article  Google Scholar 

  7. 7.

    Øgaard B, Rolla G, Øgaard BJOMS, Clinical Aspects. Stuttgart T. Oral microbiological changes, long-term enamel alterations due to decalcification, and caries prophylactic aspects. 2001:123–42

  8. 8.

    Azrak B, Callaway A, Knözinger S, Willershausen B. Reduction of the pH-values of whole saliva after the intake of apple juice containing beverages in children and adults. Oral health & preventive dentistry. 2003;1(3)

  9. 9.

    Susan A-K, Forsberg C-M, de Jong EdJ, Angmar-Månsson B. A longitudinal laser fluorescence study of white spot lesions in orthodontic patients. Am J Orthod Dentofac Orthop 1998;113(6):595–602

  10. 10.

    Shungin D, Olsson AI, Persson M. Orthodontic treatment-related white spot lesions: a 14-year prospective quantitative follow-up, including bonding material assessment American Journal of Orthodontics and Dentofacial Orthopedics. 2010;138(2):136. e1-. e8

  11. 11.

    Benjamin S, Roshni PS, Nainan MT (2012) Seal that heals. World J Dent 3(3):243–246

    Article  Google Scholar 

  12. 12.

    VOCO. Instructions for use of Remin Pro. 2010. Aug 1 Jan 6, 2012 [Available from: https://www.voco.dental/in/portaldata/1/resources/products/folders/gb/remin-pro-forte_fol_gb.pdf

  13. 13.

    Poosti M, Ahrari F, Moosavi H, Najjaran H (2014) The effect of fractional CO2 laser irradiation on remineralization of enamel white spot lesions. Lasers Med Sci 29(4):1349–1355

    Article  Google Scholar 

  14. 14.

    Castellan CS, Luiz AC, Bezinelli LM, Lopes RM, Mendes FM, Eduardo CDP, et. al.. In vitro evaluation of enamel demineralization after Er: YAG and Nd: YAG laser irradiation on primary teeth. Photomed Laser Surg 2007;25(2):85–90

  15. 15.

    Pogrel M, Muff D, Marshall G (1993) Structural changes in dental enamel induced by high energy continuous wave carbon dioxide laser. Lasers Surg Med 13(1):89–96

    CAS  Article  Google Scholar 

  16. 16.

    Heravi F, Ahrari F, Mahdavi M, Basafa S (2014) Comparative evaluation of the effect of Er: YAG laser and low level laser irradiation combined with CPP-ACPF cream on treatment of enamel caries. J Clin Exp Dent 6(2):e121

    Article  Google Scholar 

  17. 17.

    Kumar V, Itthagarun A, King N (2008) The effect of casein phosphopeptide-amorphous calcium phosphate on remineralization of artificial caries-like lesions: an in vitro study. Aust Dent J 53(1):34–40

    CAS  Article  Google Scholar 

  18. 18.

    Lata S, Varghese N, Varughese JM (2010) Remineralization potential of fluoride and amorphous calcium phosphate-casein phospho peptide on enamel lesions: an in vitro comparative evaluation. Journal of conservative dentistry: JCD 13(1):42

    CAS  Article  Google Scholar 

  19. 19.

    Derks A, Katsaros C, Frencken J, Van’t Hof M, Kuijpers-Jagtman AJCr. Caries-inhibiting effect of preventive measures during orthodontic treatment with fixed appliances 2004;38(5):413–420

  20. 20.

    Heymann HO, Swift Jr EJ, Ritter AV. Sturdevant’s art & science of operative dentistry-E-Book: Elsevier Health Sciences; 2014

  21. 21.

    Davidson C, Hoekstra I, Arends JJCr. Microhardness of sound, decalcified and etched tooth enamel related to the calcium content 1974;8(2):135–144

  22. 22.

    Kodaka T, Debari K, Yamada M, Kuroiwa MJCr. Correlation between microhardness and mineral content in sound human enamel 1992;26(2):139–141

  23. 23.

    González-Rodríguez A, de Dios López-González J, Del Castillo JdDL, Villalba-Moreno J. Comparison of effects of diode laser and CO2 laser on human teeth and their usefulness in topical fluoridation. Lasers Med Sci 2011;26(3):317–324

  24. 24.

    Hsu J, Fox J, Wang Z, Powell G, Otsuka M, Higuchi W (1998) Combined effects of laser irradiation/solution fluoride ion on enamel demineralization. J Clin Laser Med Surg 16(2):93–105

    CAS  Article  Google Scholar 

  25. 25.

    Knoop F, Peters CG, Emerson WBJJoRotNBos. A sensitive pyramidal-diamond tool for indentation measurements 1939;23(1):39

  26. 26.

    Marsillac MdWSd, Delbem ACB, Vieira RdSJBJoOS. Effect of time in hardness test on artificially demineralized human dental enamel 2008:1507–1511

  27. 27.

    Purdell-Lewis DJ, Groeneveld A, Arends J (1976) Microhardness and densitometric measurements of the effect of 4% SnF2 solution on artificial white spot lesions. Caries Res 10(3):216–226

    CAS  Article  Google Scholar 

  28. 28.

    Paes Leme AF, Tabchoury CP, Zero DT, Cury JA (2003) Effect of fluoridated dentifrice and acidulated phosphate fluoride application on early artificial carious lesions. Am J Dent 16(2):91–95

    PubMed  Google Scholar 

  29. 29.

    Delbem AC, Cury JA (2002) Effect of application time of APF and NaF gels on microhardness and fluoride uptake of in vitro enamel caries. Am J Dent 15(3):169–172

    PubMed  Google Scholar 

  30. 30.

    Ana P, Bachmann L (2006) Zezell DJLp. Lasers effects on enamel for caries prevention 16(5):865

    CAS  Google Scholar 

  31. 31.

    Steiner-Oliveira C, Rodrigues LK, Soares LE, Martin AA, Zezell DM, Nobre-Dos-Santos MJDmj. Chemical, morphological and thermal effects of 10.6-μm CO2 laser on the inhibition of enamel demineralization. 2006;25(3):455–62

  32. 32.

    Seino PY, Freitas PM, Marques MM, de Souza Almeida FC, Botta SB, Moreira MS (2015) Influence of CO2 (10.6 mum) and Nd:YAG laser irradiation on the prevention of enamel caries around orthodontic brackets. Lasers Med Sci 30(2):611–616

    Article  Google Scholar 

  33. 33.

    Souza-Gabriel A, Colucci V, Turssi C, Serra M, Corona S (2010) Microhardness and SEM after CO2 laser irradiation or fluoride treatment in human and bovine enamel. Microsc Res Tech 73(11):1030–1035

    CAS  Article  Google Scholar 

  34. 34.

    Fried D, Ragadio JN, Akrivou M, Featherstone JD, Murray MW, Dickenson KMJJobo. Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at lambda= 9.6 and 10.6 um. 2001;6(2):231–9

  35. 35.

    Fox J, Yu D, Otsuka M, Higuchi W, Wong J, Powell GJCr. Combined effects of laser irradiation and chemical inhibitors on the dissolution of dental enamel 1992;26(5):333–339

  36. 36.

    Tagomori S, Morioka T (1989) Combined effects of laser and fluoride on acid resistance of human dental enamel. Caries Res 23(4):225–231

    CAS  Article  Google Scholar 

  37. 37.

    Meurman JH, Hemmerle J, Voegel JC, Rauhamaa-Makinen R, Luomanen M (1997) Transformation of hydroxyapatite to fluorapatite by irradiation with high-energy CO2 laser. Caries Res 31(5):397–400

    CAS  Article  Google Scholar 

  38. 38.

    Chen C-C, Huang S-TJP, surgery l. The effects of lasers and fluoride on the acid resistance of decalcified human enamel 2009;27(3):447–452

  39. 39.

    Esteves-Oliveira M, Pasaporti C, Heussen N, Eduardo C, Lampert F, Apel C (2011) Rehardening of acid-softened enamel and prevention of enamel softening through CO 2 laser irradiation. J Dent 39(6):414–421

    CAS  Article  Google Scholar 

  40. 40.

    Kawasaki K, Tanaka Y, Takagi OJAoob. Crystallographic analysis of demineralized human enamel treated by laser-irradiation or remineralization 2000;45(9):797–804

  41. 41.

    Kamath U, Sheth H, Mullur D, Soubhagya M (2013) The effect of Remin Pro® on bleached enamel hardness: an in-vitro study. Indian J Dent Res 24(6):690

    Article  Google Scholar 

  42. 42.

    Heravi F, Ahrari F, Tanbakuchi B (2018) Effectiveness of MI paste plus and Remin Pro on remineralization and color improvement of postorthodontic white spot lesions. Dental research journal 15(2):95

    Article  Google Scholar 

  43. 43.

    Tepper SA, Zehnder M, Pajarola GF, Schmidlin PR (2004) Increased fluoride uptake and acid resistance by CO2 laser-irradiation through topically applied fluoride on human enamel in vitro. J Dent 32(8):635–641

    CAS  Article  Google Scholar 

  44. 44.

    Schmidlin PR, Döriga I, Lussi A, Roos M, Imfeld TJOh, dentistry p. CO 2 laser-irradiation through topically applied fluoride increases acid resistance of demineralised human enamel in vitro. 2007;5(3)

  45. 45.

    Mohan AG, Ebenezar AR, Ghani MF, Martina L, Narayanan A, Mony BJEjod. Surface and mineral changes of enamel with different remineralizing agents in conjunction with carbon-dioxide laser 2014;8(1):118

  46. 46.

    Hossain MM, Hossain M, Kimura Y, Kinoshita J, Yamada Y, Matsumoto K (2002) Acquired acid resistance of enamel and dentin by CO2 laser irradiation with sodium fluoride solution. J Clin Laser Med Surg 20(2):77–82

    Article  Google Scholar 

  47. 47.

    Fox J, Yu D, Otsuka M, Higuchi W, Wong J, Powell GJJodr. Initial dissolution rate studies on dental enamel after CO2 laser irradiation. 1992;71(7):1389–98

  48. 48.

    Delbem ACB, Cury J, Nakassima C, Gouveia V, Theodoro LHJJoclm, surgery. Effect of Er: YAG laser on CaF2 formation and its anti-cariogenic action on human enamel: an in vitro study. 2003;21(4):197–201

  49. 49.

    Oho T, Morioka TJCr. A possible mechanism of acquired acid resistance of human dental enamel by laser irradiation 1990;24(2):86–92

  50. 50.

    Ahrari F, Mohammadipour HS, Hajimomenian L, Fallah-Rastegar A (2018) The effect of diode laser irradiation associated with photoabsorbing agents containing remineralizing materials on microhardness, morphology and chemical structure of early enamel caries. J Clin Exp Dent 10(10):e955–ee62

    PubMed  PubMed Central  Google Scholar 

  51. 51.

    Wu CC, Roan RT, Chen JHJLiS, Medicine MTOJotASfL, Surgery. Sintering mechanism of the CaF2 on hydroxyapatite by a 10.6-lμm CO2 laser. 2002;31(5):333–8

  52. 52.

    Hsu CY, Jordan TH, Dederich DN, Wefel JS (2001) Laser-matrix-fluoride effects on enamel demineralization. J Dent Res 80(9):1797–1801

    CAS  Article  Google Scholar 

  53. 53.

    Kantorowitz Z, Featherstone JD, Fried D. Caries prevention by CO2 laser treatment: dependency on the number of pulses used. Journal of the American Dental Association (1939). 1998;129(5):585–91

  54. 54.

    McCormack S, Fried D, Featherstone J, Glena R, Seka WJJodr. Scanning electron microscope observations of CO2 laser effects on dental enamel. 1995;74(10):1702–8

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The authors gratefully acknowledge that this report is based on a thesis which was submitted to the School of Dentistry, Shahid Sadoughi University of Medical Sciences, in partial fulfillment of the requirement for the DDS degree (#886).


This study supported and approved by Vice Chancellor for Research at Shahid Sadoughi University of Medical Science, Yazd, Iran.

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Correspondence to Pooya Fadaei Tehrani.

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The ethics committee of the university approved the study (IR.SSU.REC.1396.188) before the sampling took place.

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Rafiei, E., Fadaei Tehrani, P., Yassaei, S. et al. Effect of CO2 laser (10.6 μm) and Remin Pro on microhardness of enamel white spot lesions. Lasers Med Sci 35, 1193–1203 (2020). https://doi.org/10.1007/s10103-020-02970-y

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  • CO2 laser
  • Tooth remineralization
  • White spots