Original Research Articles
Vol. 33 No. 1 (2026)
Antimicrobial effect of the photodynamic therapy on caries lesion: an in vitro study
Publisher's note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.
Published: 16 April 2026
111
Views
53
Downloads
Authors
The current evidence suggests that antimicrobial photodynamic therapy (aPDT) with the application of methylene blue as a photosensitizer and red laser activation is suitable for disinfecting carious tissue. However, since many dental practices lack access to lasers, a standard dental curing light could be an alternative light source. This study evaluated the use of fuchsin as a photosensitizer in aPDT and a blue light-emitting diode (LED) dental curing light for the disinfection of carious dentin. Sixty permanent third molars were selected, cut to obtain flat dentin surfaces, and subjected to a 15-day cariogenic challenge with Streptococcus mutans. The specimens were allocated into four groups (n=15): no disinfection; fuchsin; blue LED irradiation; and aPDT (fuchsin plus blue LED irradiation). S. mutans counts were obtained in the remaining carious dentin from all specimens across all groups. Results were analyzed by the Kruskal-Wallis test (Student-Newman-Keuls). The percentage reduction in microbial load was 96.07% for aPDT, 88.85% for LED alone, and 85.46% for fuchsin alone. SEM demonstrated a greater reduction in microbial burden after aPDT with fuchsin and blue LED light, with removal of the smear layer and exposure of dentin tubules. Fuchsin-mediated aPDT using blue LED irradiation significantly reduced microbial load and may represent a viable alternative for the disinfection of carious tissue, particularly in settings without access to laser devices.
Downloads
Download data is not yet available.
Citations
1. Abinaya R, Nagar P, Urs P, et al. Comparing the efficacy of three minimally invasive techniques on demineralized dentin in primary teeth and evaluating its residual dentin and microhardness levels: an in vitro study. Int J Clin Pediatr Dent 2020;13:585-9. DOI: https://doi.org/10.5005/jp-journals-10005-1815
2. Frencken JE, Holmgren CJ. Caries management through the atraumatic restorative treatment (ART) approach and glass-ionomers: update 2013. Braz Oral Res 2014;28:5-8.
3. Tanner AC, Kent RL Jr, Holgerson PL, et al. Microbiota of severe early childhood caries before and after therapy. J Dent Res 2011;90:1298-305. DOI: https://doi.org/10.1177/0022034511421201
4. Spatafora G, Li Y, He X, et al. The evolving microbiome of dental caries. Microorganisms 2024;12:121. DOI: https://doi.org/10.3390/microorganisms12010121
5. Ng M, Ho YC, Wycoff S, et al. Short-wavelength infrared imaging of infected and affected dentin. Diagnostics (Basel) 2024;14:744. DOI: https://doi.org/10.3390/diagnostics14070744
6. Bjørndal L, Larsen T, Thylstrup A. A clinical and microbiological study of deep carious lesions during stepwise excavation using long treatment intervals. Caries Res 1997;31:411-7. DOI: https://doi.org/10.1159/000262431
7. Schwendicke F. Contemporary concepts in carious tissue removal: a review. J Esthet Restor Dent 2017;29:403-8. DOI: https://doi.org/10.1111/jerd.12338
8. Li T, Zhai X, Song F, Zhu H. Selective versus non-selective removal for dental caries: a systematic review and meta-analysis. Acta Odontol Scand 2018;76:135-40. DOI: https://doi.org/10.1080/00016357.2017.1392602
9. Desai H, Stewart CA, Finer Y. Minimally invasive therapies for the management of dental caries-a literature review. Dent J (Basel) 2021;9:147. DOI: https://doi.org/10.3390/dj9120147
10. Kwiatkowski S, Knap B, Przystupski D, et al. Photodynamic therapy - mechanisms, photosensitizers and combinations. Biomed Pharmacother 2018;106:1098-107. DOI: https://doi.org/10.1016/j.biopha.2018.07.049
11. Moro GG, Massat NC, Grandizoli DRP, et al. Effect of cetrimide 2% with and without photodynamic therapy to reduce Streptococcus mutans burden in dentinal carious lesions. Lasers Med Sci 2021;36:1935-40. DOI: https://doi.org/10.1007/s10103-021-03300-6
12. Fernandes FGL, de Moraes FB, De Cezare JA, et al. In vitro evaluation of EDTA combined with photodynamic therapy to reduce Streptococcus mutans in carious dentin. Photodiagnosis Photodyn Ther 2022;37:102718. DOI: https://doi.org/10.1016/j.pdpdt.2022.102718
13. Entezari S, Moezzimoghadam N, Lawaf S, Azizi A. In vitro effect of photodynamic therapy with curcumin and methylene blue photosensitizers on Staphylococcus aureus. J Dent (Shiraz) 2022;23:387-92.
14. Anvekar MP, Virupaxi SG, Yavagal C, et al. Evaluating the efficacy of cavity disinfection using methylene blue dye with 660-nm diode laser on primary molars: an in vivo study. J Indian Soc Pedod Prev Dent 2024;42:280-5. DOI: https://doi.org/10.4103/jisppd.jisppd_258_24
15. Pinheiro SL, Schenka AA, Neto AA, et al. Photodynamic therapy in endodontic treatment of deciduous teeth. Lasers Med Sci 2009;24:521-6. DOI: https://doi.org/10.1007/s10103-008-0562-2
16. Cieplik F, Buchalla W, Hellwig E, et al. Antimicrobial photodynamic therapy as an adjunct for treatment of deep carious lesions - a systematic review. Photodiagnosis Photodyn Ther 2017;18:54-62. DOI: https://doi.org/10.1016/j.pdpdt.2017.01.005
17. Trindade AC, De Figueiredo JA, Steier L, Weber JB. Photodynamic therapy in endodontics: a literature review. Photomed Laser Surg 2015;33:175-82. DOI: https://doi.org/10.1089/pho.2014.3776
18. Moghissi K, Dixon K, Gibbins S. Does PDT have potential in the treatment of COVID 19 patients? Photodiagnosis Photodyn Ther 2020;31:101889. DOI: https://doi.org/10.1016/j.pdpdt.2020.101889
19. Pourhajibagher M, Keshavarz Valian N, Bahador A. Theranostic nanoplatforms of emodin-chitosan with blue laser light on enhancing the anti-biofilm activity of photodynamic therapy against Streptococcus mutans biofilms on the enamel surface. BMC Microbiol 2022;22:68. DOI: https://doi.org/10.1186/s12866-022-02481-6
20. Contaldo M, Di Stasio D, Romano A, et al. Oral candidiasis and novel therapeutic strategies: antifungals, phytotherapy, probiotics, and photodynamic therapy. Curr Drug Deliv 2023;20:441-56. DOI: https://doi.org/10.2174/1567201819666220418104042
21. Godoy RCL, Bueno CEDS, De Martin AS, et al. Ex vivo evaluation of the efficacy of photodynamic therapy in eliminating Enterococcus faecalis from dentinal tubules by confocal laser scanning microscopy. J Endod 2023;49:889-93. DOI: https://doi.org/10.1016/j.joen.2023.05.007
22. Gholami L, Shahabi S, Jazaeri M, et al. Clinical applications of antimicrobial photodynamic therapy in dentistry. Front Microbiol 2023;13:1020995. DOI: https://doi.org/10.3389/fmicb.2022.1020995
23. Baghani Z, Karrabi M, Assarzadeh H. Dentition type as a determinant of microbial load reduction by antimicrobial photodynamic therapy in deep dentin caries: a systematic review and meta-analysis. J Dent (Shiraz) 2024;25:296-308.
24. Oda DF, Duarte MAH, Andrade FB, et al. Antimicrobial action of photodynamic therapy in root canals using LED curing light, curcumin and carbopol gel. Int Endod J 2019;52:1010-9. DOI: https://doi.org/10.1111/iej.13092
25. Ravazzi TPQ, de Jesus IM, de Oliveira Santos GP, et al. The effects of antimicrobial photodynamic therapy (aPDT) with nanotechnology-applied curcumin and 450nm blue led irradiation on multi-species biofilms in root canals. Lasers Med Sci 2023;38:254. DOI: https://doi.org/10.1007/s10103-023-03925-9
26. Hirose M, Yoshida Y, Horii K, et al. Efficacy of antimicrobial photodynamic therapy with Rose Bengal and blue light against cariogenic bacteria. Arch Oral Biol 2021;122:105024. DOI: https://doi.org/10.1016/j.archoralbio.2020.105024
27. Li Y, Sun G, Xie J, et al. Antimicrobial photodynamic therapy against oral biofilm: influencing factors, mechanisms, and combined actions with other strategies. Front Microbiol 2023;14:1192955. DOI: https://doi.org/10.3389/fmicb.2023.1192955
28. Şahin ÖH, Korucu H, Aydin ZU. Evaluation of the effects of different photosensitizers used in antimicrobial photodynamic therapy on tooth discoloration: spectrophotometric analysis. Lasers Med Sci 2024;39:133. DOI: https://doi.org/10.1007/s10103-024-04085-0
29. Abedin F, Ye Q, Spencer P. Hydrophilic dyes as photosensitizers for photopolymerization of dental adhesives. J Dent 2020;99:103405. DOI: https://doi.org/10.1016/j.jdent.2020.103405
30. Oliveira LM, Pazinatto J, Zanatta FB. Are oral hygiene instructions with aid of plaque-disclosing methods effective in improving self-performed dental plaque control? A systematic review of randomized controlled trials. Int J Dent Hyg 2021;19:239-54. DOI: https://doi.org/10.1111/idh.12491
31. Le Goff A, Bunetel L, Mouton C, Bonnaure-Mallet M. Evaluation of root canal bacteria and their antimicrobial susceptibility in teeth with necrotic pulp. Oral Microbiol Immunol 1997;12:318-22. DOI: https://doi.org/10.1111/j.1399-302X.1997.tb00397.x
32. Lima LM, Motisuki C, Spolidorio DM, Santos-Pinto L. In vitro evaluation of probiotics microorganisms adhesion to an artificial caries model. Eur J Clin Nutr 2005;59:884-6. DOI: https://doi.org/10.1038/sj.ejcn.1602158
33. de Carvalho FG, de Fucio SB, Sinhoreti MA, et al. Confocal laser scanning microscopic analysis of the depth of dentin caries-like lesions in primary and permanent teeth. Braz Dent J 2008;19:139-44. DOI: https://doi.org/10.1590/S0103-64402008000200010
34. Santin GC, Oliveira DS, Galo R, et al. Antimicrobial photodynamic therapy and dental plaque: a systematic review of the literature. ScientificWorldJournal 2014;2014:824538. DOI: https://doi.org/10.1155/2014/824538
35. Carti Dörterler Ö, Yilmaz F, Halici SE, et al. Does the use of different remineralisation agents in a 14-day demineralisation/remineralisation cycle affect the bond strength to artificial carious enamel surfaces? Oral Health Prev Dent 2025;23:241-51.
36. Salam AEA, Ismail HS, Hamama H. Evaluation methods of artificial demineralization protocols for coronal dentin: a systematic review of laboratory studies. BMC Oral Health 2025;25:621. DOI: https://doi.org/10.1186/s12903-025-05885-8
37. Bowen WH, Koo H. Biology of Streptococcus mutans-derived glucosyltransferases: role in extracellular matrix formation of cariogenic biofilms. Caries Res 2011;45:69-86. DOI: https://doi.org/10.1159/000324598
38. Orhan AI, Oz FT, Ozcelik B, Orhan K. A clinical and microbiological comparative study of deep carious lesion treatment in deciduous and young permanent molars. Clin Oral Investig 2008;12:369-78. DOI: https://doi.org/10.1007/s00784-008-0208-6
39. Guglielmi C de A, Simionato MR, Ramalho KM, et al. Clinical use of photodynamic antimicrobial chemotherapy for the treatment of deep carious lesions. J Biomed Opt 2011;16:088003. DOI: https://doi.org/10.1117/1.3611009
40. Almeida A, Faustino MAF, Neves MGPMS. Antimicrobial photodynamic therapy in the control of COVID-19. Antibiotics (Basel) 2020;9:320. DOI: https://doi.org/10.3390/antibiotics9060320
41. Pereira LM, Estevam LR, da Silva MF, Pinheiro SL. Polyacrylic acid with methylene blue dye as a sensitizing agent for photodynamic therapy to reduce Streptococcus mutans in dentinal caries. Photobiomodul Photomed Laser Surg 2020;38:687-93. DOI: https://doi.org/10.1089/photob.2019.4736
42. Manphibool C, Matangkasombut O, Chantarangsu S, Chantarawaratit PO. Effects of blue-light LED toothbrush on reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances: a crossover randomized controlled trial. BMC Oral Health 2023;23:293. DOI: https://doi.org/10.1186/s12903-023-02977-1
43. Sato Y, Fusayama T. Removal of dentin by fuchsin staining. J Dent Res 1976;55:678-83. DOI: https://doi.org/10.1177/00220345760550042301
44. Yip HK, Stevenson AG, Beeley JA. The specificity of caries detector dyes in cavity preparation. Br Dent J 1994;176:417-21. DOI: https://doi.org/10.1038/sj.bdj.4808470
45. Calori IR, Pellosi DS, Vanzin D, et al. Distribution of xanthene dyes in DPPC vesicles: rationally accounting for drug partitioning using a membrane model. J Braz Chem Soc 2016;27:1938-48. DOI: https://doi.org/10.5935/0103-5053.20160079
46. Galdino DYT, da Rocha Leódido G, Pavani C, et al. Photodynamic optimization by combination of xanthene dyes on different forms of Streptococcus mutans: an in vitro study. Photodiagnosis Photodyn Ther 2021;33:102191. DOI: https://doi.org/10.1016/j.pdpdt.2021.102191
47. Kitanaka Y, Takeuchi Y, Hiratsuka K, et al. The effect of antimicrobial photodynamic therapy using yellow-green LED and rose bengal on Porphyromonas gingivalis. Photodiagnosis Photodyn Ther 2020;32:102033. DOI: https://doi.org/10.1016/j.pdpdt.2020.102033
48. Gonçalves MLL, Santos EM, Renno ACM, et al. Erythrosine as a photosensitizer for antimicrobial photodynamic therapy with blue light-emitting diodes - an in vitro study. Photodiagnosis Photodyn Ther 2021;35:102445. DOI: https://doi.org/10.1016/j.pdpdt.2021.102445
Ethics Approval
All procedures were performed in compliance with relevant laws and institutional guidelines and with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments. The study was approved by the Ethics Committee of Pontifícia Universidade Católica de Campinas (PUC-Campinas; Certificate of Submission for Ethical Appraisal: 5066322.1.0000.5481) on November 25, 2022. Each patient gave written informed consent to the study protocol prior to donating their teeth for research.CRediT authorship contribution
Ana Clara Miarelli Fortuna, José Roberto Rodini Caldari, Maria Fernanda Marchi, Maria Olivia Marcondes Pinto: data curation, investigation, methodology, project administration, resources, visualization, writing – original draft preparation, writing – review & editing; Carlos Eduardo Fontana: investigation, methodology, supervision, visualization, writing – original draft preparation, writing – review & editing; Victor Elias Arana-Chavez: investigation, methodology, visualization, writing – original draft preparation, writing – review & editing; Sérgio Luiz Pinheiro: conceptualization, data curation, formal analysis, investigation, methodology, project administration, resources, supervision, validation, visualization, writing – original draft preparation, writing – review & editing. All authors read and approved the final version of the manuscript and agreed to be accountable for all aspects of the work.
Supporting Agencies
This study was supported by undergraduate research scholarships from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundo de Apoio à Iniciação Científica/Reitoria PUC-Campinas (Brazil), which were essential for enabling student participation in scientific research, as well as for supporting the execution of laboratory procedures and data collection, thereby contributing to the advancement of knowledge in this field.Data Availability Statement
All data generated or analyzed during this study are included in this published article.
How to Cite
Miarelli Fortuna, A. C., Rodini Caldari, J. R., Marchi, M. F., Marcondes Pinto, M. O., Fontana, C. E., Arana-Chavez, V. E., & Pinheiro, S. L. (2026). Antimicrobial effect of the photodynamic therapy on caries lesion: an in vitro study. Laser Therapy, 33(1). https://doi.org/10.4081/ltj.2026.436
Copyright (c) 2026 the Author(s)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.