Assessment of the effect of photodynamic therapy on the reduction of bacteria in deep dental caries lesions of primary teeth

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Materials and Methods: The study group consisted of 36 children with deep carious lesions in primary teeth. A LAD FotoSan®630 diode lamp was used for the therapy. Participants were randomly assigned to two groups: in the first group, antibacterial photodynamic therapy (aPDT) was performed using a 0.1% toluidine blue gel photosensitizer (FotoSan Agent® High, CMS Dental, Roslev, Denmark); in the second group, curcumin QroxB2® (CMS Dental, Roslev, Denmark) was used as the photosensitizer. Thirty-six carious lesions were selectively excavated. Dentin samples were collected twice—after caries removal and after aPDT application. Samples were cultured on Columbia Agar with sheep blood PLUS to assess microbial viability and the total number of microorganisms. Strain identification was performed using the VITEK® MS system (bioMérieux SSC, France). Diluted samples were then inoculated onto selective media: Mitis Salivarius Agar supplemented with sucrose for total streptococci, Mitis Salivarius Agar with bacitracin for Streptococcus mutans , Rogosa SL Agar for Lactobacilli , and Sabouraud Dextrose Agar for fungi. Results: A statistically significant reduction in the total number of microorganisms was noted after therapy. A decrease in bacterial counts was also observed on selective media for total Streptococci and Streptococcus mutans . The degree of microbial reduction did not significantly differ depending on the photosensitizer used. Follow-up examinations were performed at 3, 6, and 12 months. No pain symptoms or signs of treatment failure were observed. Conclusions: Photodynamic therapy appears to be highly effective in reducing bacteria in deep carious lesions of primary teeth. Clinical Significance: Photodynamic therapy may be successfully used as an adjunct in selective caries excavation. photodynamic therapy primary teeth dental caries FotoSan Figures Figure 1 Figure 2 Background Dental caries remains one of the most common chronic diseases affecting humans [ 1 ]. Minimally invasive dentistry (MID) is a modern concept of preventive and therapeutic treatment. The idea behind this concept is to perform minimally invasive medical procedures in order to preserve as much of the mineralized tooth tissue as possible. The treatment of deep caries lesion remains a challenge for dentists due to the high risk of tooth pulp exposure during the removal of caries. Selective caries excavation, while preserving the internal demineralized layer of dentin helps avoid the need for endodontic treatment, which is particularly important in pediatric dentistry, due to the varying emotional state of children often hindering conventional treatment [ 2 , 3 ]. The reduction of caries bacteria that remain in the cavity may pose a challenge. There are publications indicating that photodynamic therapy (aPTD) may be a promising method for eliminating bacteria that remain in the dentin after partial or even complete cavity preparation [ 1 ]. This increases the chance of dentin remineralization and promotes positive treatment outcomes. Photodynamic therapy involves the destruction of target cells by reactive oxygen forms generated as a result of the interaction of a photosensitizer, light, and oxygen. Photosensitizers have a cationic charge and quickly bind to bacterial cells, exhibiting a high degree of selective destruction of microorganisms without damaging the host cells. [ 3 ] Aim The aim of our study was to evaluate the effect of photodynamic therapy on the reduction of bacteria in deep caries lesions of deciduous teeth using the FotoSan® lamp (CMS Dental, Roslev, Denmark). Materials and method Research group and clinical procedure The study was conducted on patients visiting the Pediatric Dentistry Clinic of the Medical University of Białystok between January 2023 and June 2024. The experiment was approved by the Bioethics Committee of the Medical University of Białystok (number APK.002.5.2023). The parents/guardians of the patients gave their voluntary, informed, written consent to participate in the study, and the children themselves also consented to the treatment. The study group consisted of 36 children aged 5 to 8 years (average age 6.4), 22 boys and 14 girls. The following inclusion criteria were applied: generally healthy children who had not taken antibiotics in the three months prior, and who had at least one deciduous molar with deep caries on the occlusal surface, covering at least ½ of the inner layer of dentin (ICDAS II 5,6). Exclusion criteria: uncooperative behavior, systemic diseases, antibiotic use within the last three months, teeth presenting pain symptoms indicative of irreversible pulpitis, or radiographic evidence of periapical inflammation. Participants were randomly assigned to two groups: — in the first group the treatment consisted of an antibacterial photodynamic therapy (aPTD) with a photosensitizer of 0.1% toluidine blue gel — FotoSan Agent® High (CMS Dental, Roslev, Denmark) — the second group also underwent antibacterial photodynamic therapy, with the photosensitizer being curcumin QroxB2® (CMS Dental, Roslev, Denmark). The therapy used a LAD FotoSan®630 diode lamp emitting red light with a wavelength of 630 nm. A bunt tip with a diameter of approximately 4 mm was used. The estimated power of the lamp was approximately 3500–4000 mW/cm2. Clinical procedure: All clinical procedures were performed by a single operator. Treatments were conducted under isolation of the operating field. Thirty-six deep carious lesions were selectively excavated according to the principles of minimally invasive dentistry. Carious tissue was completely removed from the lateral walls, while on the pulpal wall a layer of demineralized, moderately hard dentin was intentionally preserved. The photosensitizer—either toluidine blue or curcumin, depending on group allocation—was applied directly into the cavity from a syringe. After a 1-minute pre-incubation, the cavity was irradiated with the FotoSan®630 lamp for 30 seconds. The photosensitizer was then rinsed with distilled water, and the cavity was dried.Dentin samples were collected twice: after caries excavationandafter aPDT application, from closely adjacent locations. Tungsten carbide round burs, size 016 (Jota, Rüthi, Switzerland), mounted on low-speed handpieces, were used for sampling.All cavities were restored using conventional glass-ionomer cement Equia Forte® (GC, Tokyo, Japan). Microbiological analysis Thirty-six specimens were collected from patients before and after treatment (total 72 samples). Dental drills were placed in 1 ml of tryptic soy broth (TSB) supplemented with 30% of glycerine. All specimens were stored in -80 ⁰C until further analysis. Samples were cultured on the following media: Columbia Agar with 5% sheep blood PLUS (OXOID Ltd., Basingstoke, UK), Sabouraud Dextrose Agar with chloramphenicol and gentamicin (BioMaxima S.A., Poland), Mitis Salivarius Agar supplemented with sucrose (MSA-S), Mitis Salivarius Agar with 1% bacitracin (MSA-B) (Sigma-Aldrich Co., St. Louis, MO, USA), and Rogosa SL Agar (BioMaxima S.A., Poland). Strain identification was performed using the VITEK® MS system (bioMérieux SSC, France). The samples were then gradually diluted in a series. The samples were plated in triplicate on the Columbia Agar with sheep blood PLUS to evaluate the viability of the microorganisms and to assess the total number of microorganisms. Subsequently, the diluted samples were plated on the following media: Mitis Salivarius Agar supplemented with sucrose for total Streptococci , Mitis Salivarius Agar with bacitracin for mutans Streptococci , Rogosa SL Agar for Lactobacilli , and Sabouraud Dextrose Agar for fungi. All agar plates were incubated under aerobic conditions at 37°C with 5% CO₂ for 48 hours. After that time the colony forming units counts were conducted using the OpenCFUprogramme [ 4 ] and reported as colony forming units per milliliter (CFU/ml). Data analysis and statistical methods The unit used as a parameter for analysis was a tooth. The data were compiled in tables in Excel. The number of CFUs before and after aPTD was compared in each culture substrate: Columbia Agar with 5% sheep blood PLUS, MSA-S, MSA-B. Nonparametric Wilcoxon and Mann-Whitney tests were used for this purpose. The significance level was set at p < 0.05. Statistica software was used to perform the analysis. Results Follow-up examinations were performed after 3, 6, and 12 months. No pain symptoms or signs of treatment failure were observed. Microorganisms were found in all 36 samples before aPTD treatment. After treatment, a statistically significant reduction in the total number of microorganisms was observed. There was also a reduction in the number of bacteria on selective media for Streptococci in general and Streptococcus mutans (Table 1 , Fig. 1 ). Because bacterial growth on Rogosa SL Agar was observed in only a very small number of samples, these results were excluded from the analysis. The low detection rate of Lactobacillus spp. did not allow for reliable statistical comparison. No fungal colonies were detected in any of the samples tested. The percentage reduction in CFU/ml was calculated as the difference between the mean CFU/ml before and after aPTD (Table 2 ). Table 3 and Fig. 2 show that the degree of microbial reduction did not differ significantly depending on the photosensitizer used. Table 1 Comparison of bacterial growth (CFU/mL) before and after the use of aPTD (Wilcoxon tests) Substrate Photo-sensitizer Before the use of aPTD After the use of aPTD p Average (CFU/ml) Standard Deviation Median (CFU/mL) Average (CFU/m) Standard Deviation Median (CFU/mL) Columbia Agar supplemented with 5% sheep blood PLUS Toluidine blue 28505.8 70173.7 2800 1232.1 3161.7 240 0.000 Curcumin 10565.3 23184.3 1010 1099.4 1851.5 130 0.000 Total 20033.9 53486.0 1310 1169.4 2590.8 235 0.000 Mitis Salivarius Agar supplemented with sucrose Toluidine blue 463.6 569.9 315 32.1 68.0 5 0.001 Curcumin 347.8 417.3 150 97.8 147.2 40 0.008 Total 418.3 508.5 210 57.8 108.1 20 0.000 Mitis Salivarius Agar supplemented with 1% bacitracin Toluidine blue 88.9 90.5 30 18.9 28.5 0 0.007 Curcumin 63.3 54.7 50 25.0 51.7 5 0.027 Total 78.7 76.9 40 21.3 37.8 0 0.001 Table 2 Percentage reduction in CFU/mL after application of aPTD Substrate and photosensitizer Percentage reduction (%) Columbia Agar Columbia Agar supplemented with 5% sheep blood PLUS + Toluidine blue 95.7% Columbia AgarColumbia Agar supplemented with 5% sheep blood PLUS + Curcumin 89.6% Mitis Salivarius Agar supplemented with sucrose + Toluidine blue 93.1% Mitis Salivarius Agar supplemented with sucrose + Curcumin 71.9% Mitis Salivarius Agar supplemented with 1% bacitracin + Toluidine blue 78.7% Mitis Salivarius Agar supplemented with 1% bacitracin + Curcumin 60.5% Table 3 Comparison of growth (CFU/mL) depending on the photosensitizer used (CFU/mL) Substrate aPTD Toluidine blue Curcumin p Average CFU/mL Standard Deviation Median CFU/mL Average CFU/mL Standard Deviation Average CFU/mL Columbia Agar supplemented with 5% sheep blood PLUS Before 28505.8 70173.7 2800 10565.3 23184.3 1010 0.401 After 1232.1 3161.7 240 1099.4 1851.5 130 0.788 Mitis Salivarius Agar supplemented with sucrose Before 463.6 569.9 315 347.8 417.3 150 0.659 After 32.1 68.0 5 97.8 147.2 40 0.131 Mitis Salivarius Agar supplemented with 1% bacitracin Before 88.9 90.5 30 63.3 54.7 50 0.676 After 18.9 28.5 0 25.0 51.7 5 0.949 DISCUSSION Partial removal of decayed dentin and tight filling of the cavity promotes the formation of a microbiological niche, which makes it possible to avoid more complicated procedures such as endodontic treatment. Bitello-Firmino et al. [ 5 ] even claim that selective removal of caries is as effective in reducing bacteria remaining in the dentin as complete removal, and that a tight filling of the cavity plays a key role. Minimally invasive dentistry also has an important psychological aspect, which is particularly important in pediatric patients. Therefore, conducting research that contributes to the least invasive treatment methods is of great value. The aim of our study was to evaluate the reduction of bacteria in deep cavities of deciduous teeth after photodynamic therapy with the LAD FotoSan® 630 lamp and two types of photosensitizers — one containing toluidine blue, and the other containing curcumin. The study showed high efficacy of this therapy, regardless of the photosensitizer used, in reducing the total number of bacterial colonies and in reducing bacteria on selective media for Streptococci in general and Streptococci mutans . Most authors evaluated the effectiveness of antibacterial photodynamic therapy using conventional microorganism culture on selected media using CFU [ 1 ]. Other researchers performed quantitative real-time polymerase chain reaction (PCR) [ 3 ]. In the current study, in addition to culture on selected media, species identification was performed using the VITEK® MS system (bioMérieux SSC, France). VITEK MS is a modern device used to identify microorganisms. This system uses mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology to identify microorganisms cultured from human samples [ 6 , 7 ]. In our research, we used two photosensitizers—toluidine blue and curcumin. Toluidine blue (TB) is a cationic photosensitizer approved by the FDA for clinical use. It is characterized by low excitation energy and high permeability through cell membranes. Due to its small particle size, hydrophilicity, and ability to form dimers, TB binds perfectly to the cell membranes of microorganisms. Many studies have confirmed the effectiveness of TB in the treatment of oral diseases. Vahabi et al. [ 8 ] applied 0.1% TB to a bacterial suspension containing Streptococcus mutans. The sample was then exposed to a diode laser with a wavelength of 633 nm. The results showed that the combination of TB and laser significantly reduced the number of live bacteria. Curcumin (CUR), on the other hand, is a natural phenolic compound with a low molecular weight that occurs in nature. The authors suggest that CUR has potential as an effective photosensitizer and can effectively eliminate microorganisms from the oral cavity. Importantly, curcumin is more effective against Gram-positive bacteria than Gram-negative bacteria [ 9 ]. The literature also reports on the high effectiveness of using Bixa orellana extract [ 9 ], a combination of Papacaria with methylene blue [ 2 , 11 ], erythrosine [ 12 , 13 ], indocyanine green, chlorella, and rose Bengal [ 9 ] as photosensitizers in aPTD in deep cavities. Soria-Lozano and colleagues [ 9 ] studied the effect of photodynamic therapy on cariogenic bacteria. In their experiment, they used white light and three photosensitizers: methylene blue, rose bengal, and curcumin. They found that photodynamic therapy using these compounds is effective in eliminating Streptococcus mutans and Streptococcus sanguis bacteria. At the same time, they noted that the best therapeutic effects were achieved with methylene blue (MB) and rose bengal (RB), while the effectiveness of curcumin (CUR) was slightly lower. Our research also confirmed the effectiveness of aPTD. The differences between the effectiveness of toluidine blue and curcumin, despite the slight advantage of TB, were not statistically significant. Ornellas et al. [ 1 ] conducted a literature review and meta-analysis of data, which clearly confirmed the hypothesis that aPTD is an effective tool for reducing or eliminating bacteria in deep carious lesions of primary and permanent teeth. Melo et al. [ 14 ] also addressed this issue: they compared the effect of photodynamic therapy on the reduction of bacteria in deep cavities of permanent posterior teeth. They demonstrated a significant reduction in the number of S. mutans , Lactobacillus , and the total number of microorganisms after the use of aPTD with toluidine blue photosensitizer, compared to the control group where the cavity was rinsed with 0.89% NaCl. Araujo et al. [ 15 ] also demonstrated a significant reduction in the total number of microorganisms after the application of aPTD in their study. Steiner-Oliveira et al. [ 3 ] addressed this issue and distinguished three research groups in their work. In the first group, after preparation, they rinsed the cavities with a 2% chlorhexidine solution. In the second and third groups, they used photodynamic therapy with toluidine blue as a photosensitizer, using a diode lamp (second group) and a low-power laser (third group). The total number of bacteria was determined using quantitative polymerase chain reaction. Although they observed a significant reduction in the total number of bacteria, including Streptococcus mutans , Lactobacillus casei , and Fusobacterium nucleatum , they did not find a statistically significant difference between aPTD and rinsing cavities with a 2% chlorhexidine solution. Interestingly, they also noted that photodynamic therapy does not reduce Streptococcus sobrinus . The authors believe that all these therapies can be considered effective and that further research should be conducted on their effectiveness in reducing bacteria in deep cavities. Ornellas et al. [ 16 ] noted that photodynamic therapy after selective treatment of deep cavities in primary teeth reduces the total number of microorganisms by 69.88% to 86.29%, Streptococcus spp. and Lactobacillus spp . In their study, they used a low-power diode laser emitting red light, and a methyl blue photosensitizer. The study sample consisted of 18 teeth in 18 patients. The authors detected the presence of Candida spp . in only one of the dentin samples tested. In our study, no fungal colonies were detected in any of the samples tested. Comparing our results with those of the authors mentioned above, a similar reduction in CFU/ml was obtained, despite methodological differences: a different photosensitizer, light source, and sample size. Reports on the antibacterial efficacy of photodynamic therapy are inconclusive. Unlike most authors, Neves et al. [ 17 ] did not observe a significant difference in the reduction of microorganisms after the use of aPTD in deep cavities of deciduous teeth. This may be due to different experimental conditions, especially regarding the light source, wavelength, and photosensitizer used. The authors used an InGaAlP diode laser with a wavelength of 660 nm with a methylene blue photosensitizer, while in our study we used an LAD diode lamp with a wavelength of 630 nm with photosensitizers: toluidine blue and curcumin. Conclusions Based on the results obtained, we can conclude that photodynamic therapy appears to be highly effective in reducing bacteria in deep cavities of deciduous teeth. It can be successfully used as an adjunct to selective cavity preparation. The combination of aPTD with selective cavity preparation is less traumatic which is particularly important in pediatric patients. Although the results of the study are promising, further clinical research is needed to gain a more complete understanding of the potential of aPTD in the treatment of caries in primary teeth. Declarations Competing interests The authors declare that they have no competing interests. Ethics Approval: The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Medical University of Bialystok (approval number: APK.002.5.2023 ). Funding This research was funded by the Medical University of Bialystok from institutional subsidy funds. Author Contribution S.K., G.M.-K., P.S., and E.T. conceived and designed the study. S.K. performed the clinical procedures and collected the samples. Ł.K., P.M., D.C., and P.S. conducted the microbiological analyses and contributed to data interpretation. A.K., E.T., G.M.-K., P.S., and Ł.K. contributed to the development of the study methodology and provided scientific supervision. J.K. and P.M. performed the statistical analyses and contributed to data interpretation. S.K. and Ł.K. prepared the original draft of the manuscript. All authors critically revised the manuscript and approved the final version. Data Availability The data supporting the findings of this study are available from the corresponding author upon reasonable request. References Ornellas PO, Antunes LD, Fontes KB, Póvoa HC, Küchler EC, Iorio NL, Antunes LA (2016) Effect of the antimicrobial photodynamic therapy on microorganism reduction in deep caries lesions: a systematic review and meta-analysis. J Biomed Opt 21(9):90901. 10.1117/1.JBO.21.9.090901 da Mota AC, Leal CR, Olivan S, Leal Gonçalves ML, de Oliveira VA, Pinto MM, Bussadori SK (2016) Case Report of Photodynamic Therapy in the Treatment of Dental Caries on Primary Teeth. 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PhotodiagnosisPhotodynTher 12(4):581-6. 10.1016/j.pdpdt.2015.09.005 Araújo PV, Correia-Silva Jde F, Gomez RS, MassaraMde L, Cortes ME, Poletto LT (2015) Antimicrobial effect of photodynamic therapy in carious lesions in vivo, using culture and real-time PCR methods. 12(3):401–407. 10.1016/j.pdpdt.2015.06.003 Ornellas PO, Antunes LS, Motta PC, Mendonça C, Póvoa H, Fontes K, Iorio N, Antunes LAA (2018) Antimicrobial Photodynamic Therapy as an Adjunct for Clinical Partial Removal of Deciduous Carious Tissue: A Minimally Invasive Approach. PhotochemPhotobiol94(6):1240–1248. 10.1111/php.12966 Neves PA, Lima LA, Rodrigues FC, Leitão TJ, Ribeiro CC (2016) Clinical effect of photodynamic therapy on primary carious dentin after partial caries removal. Braz Oral Res 30(1):S1806-83242016000100246. doi: 10.1590/1807-3107BOR-2016.vol30.0047 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Apr, 2026 Read the published version in Clinical Oral Investigations → Version 1 posted Editorial decision: Revision requested 18 Feb, 2026 Reviews received at journal 17 Feb, 2026 Reviews received at journal 17 Feb, 2026 Reviewers agreed at journal 01 Feb, 2026 Reviewers agreed at journal 27 Jan, 2026 Reviewers invited by journal 27 Jan, 2026 Editor assigned by journal 15 Jan, 2026 Submission checks completed at journal 15 Jan, 2026 First submitted to journal 11 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Białystok","correspondingAuthor":false,"prefix":"","firstName":"Elżbieta","middleName":"","lastName":"Tryniszewska","suffix":""},{"id":581234480,"identity":"eab9b34b-2bde-4932-8981-a4fa0aaa62d0","order_by":8,"name":"Grażyna Marczuk-Kolada","email":"","orcid":"","institution":"Medical University of Białystok","correspondingAuthor":false,"prefix":"","firstName":"Grażyna","middleName":"","lastName":"Marczuk-Kolada","suffix":""}],"badges":[],"createdAt":"2026-01-11 22:08:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8575895/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8575895/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00784-026-06858-z","type":"published","date":"2026-04-01T15:57:30+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":101437934,"identity":"886c684d-abd4-4993-82ff-889a4316b6da","added_by":"auto","created_at":"2026-01-29 16:37:28","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":142731,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8575895/v1/d7bac64fbbcfb0c6e41d4f47.png"},{"id":101751300,"identity":"39223a22-ed06-46f4-bea9-eaef485ffb89","added_by":"auto","created_at":"2026-02-03 10:19:06","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":294359,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8575895/v1/a9d76840c23f1884348bf163.png"},{"id":106343377,"identity":"55acdce2-b06f-4e35-89fe-afa886d8515f","added_by":"auto","created_at":"2026-04-07 16:03:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1122365,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8575895/v1/46b899c2-a933-40ae-a9e1-6e9c23a31211.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Assessment of the effect of photodynamic therapy on the reduction of bacteria in deep dental caries lesions of primary teeth","fulltext":[{"header":"Background","content":"\u003cp\u003eDental caries remains one of the most common chronic diseases affecting humans [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Minimally invasive dentistry (MID) is a modern concept of preventive and therapeutic treatment. The idea behind this concept is to perform minimally invasive medical procedures in order to preserve as much of the mineralized tooth tissue as possible. The treatment of deep caries lesion remains a challenge for dentists due to the high risk of tooth pulp exposure during the removal of caries. Selective caries excavation, while preserving the internal demineralized layer of dentin helps avoid the need for endodontic treatment, which is particularly important in pediatric dentistry, due to the varying emotional state of children often hindering conventional treatment [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The reduction of caries bacteria that remain in the cavity may pose a challenge. There are publications indicating that photodynamic therapy (aPTD) may be a promising method for eliminating bacteria that remain in the dentin after partial or even complete cavity preparation [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. This increases the chance of dentin remineralization and promotes positive treatment outcomes.\u003c/p\u003e \u003cp\u003ePhotodynamic therapy involves the destruction of target cells by reactive oxygen forms generated as a result of the interaction of a photosensitizer, light, and oxygen. Photosensitizers have a cationic charge and quickly bind to bacterial cells, exhibiting a high degree of selective destruction of microorganisms without damaging the host cells. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/p\u003e\n\u003ch3\u003eAim\u003c/h3\u003e\n\u003cp\u003eThe aim of our study was to evaluate the effect of photodynamic therapy on the reduction of bacteria in deep caries lesions of deciduous teeth using the FotoSan\u0026reg; lamp (CMS Dental, Roslev, Denmark).\u003c/p\u003e"},{"header":"Materials and method","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eResearch group and clinical procedure\u003c/h2\u003e \u003cp\u003eThe study was conducted on patients visiting the Pediatric Dentistry Clinic of the Medical University of Białystok between January 2023 and June 2024. The experiment was approved by the Bioethics Committee of the Medical University of Białystok (number APK.002.5.2023). The parents/guardians of the patients gave their voluntary, informed, written consent to participate in the study, and the children themselves also consented to the treatment.\u003c/p\u003e \u003cp\u003eThe study group consisted of 36 children aged 5 to 8 years (average age 6.4), 22 boys and 14 girls. The following inclusion criteria were applied: generally healthy children who had not taken antibiotics in the three months prior, and who had at least one deciduous molar with deep caries on the occlusal surface, covering at least \u0026frac12; of the inner layer of dentin (ICDAS II 5,6). Exclusion criteria: uncooperative behavior, systemic diseases, antibiotic use within the last three months, teeth presenting pain symptoms indicative of irreversible pulpitis, or radiographic evidence of periapical inflammation.\u003c/p\u003e \u003cp\u003eParticipants were randomly assigned to two groups:\u003c/p\u003e \u003cp\u003e\u0026mdash; in the first group the treatment consisted of an antibacterial photodynamic therapy (aPTD) with a photosensitizer of 0.1% toluidine blue gel \u0026mdash; FotoSan Agent\u0026reg; High (CMS Dental, Roslev, Denmark)\u003c/p\u003e \u003cp\u003e\u0026mdash; the second group also underwent antibacterial photodynamic therapy, with the photosensitizer being curcumin QroxB2\u0026reg; (CMS Dental, Roslev, Denmark).\u003c/p\u003e \u003cp\u003eThe therapy used a LAD FotoSan\u0026reg;630 diode lamp emitting red light with a wavelength of 630 nm. A bunt tip with a diameter of approximately 4 mm was used. The estimated power of the lamp was approximately 3500\u0026ndash;4000 mW/cm2.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eClinical procedure:\u003c/h3\u003e\n\u003cp\u003eAll clinical procedures were performed by a single operator. Treatments were conducted under isolation of the operating field. Thirty-six deep carious lesions were selectively excavated according to the principles of minimally invasive dentistry. Carious tissue was completely removed from the lateral walls, while on the pulpal wall a layer of demineralized, moderately hard dentin was intentionally preserved. The photosensitizer\u0026mdash;either toluidine blue or curcumin, depending on group allocation\u0026mdash;was applied directly into the cavity from a syringe. After a 1-minute pre-incubation, the cavity was irradiated with the FotoSan\u0026reg;630 lamp for 30 seconds. The photosensitizer was then rinsed with distilled water, and the cavity was dried.Dentin samples were collected twice: after caries excavationandafter aPDT application, from closely adjacent locations. Tungsten carbide round burs, size 016 (Jota, R\u0026uuml;thi, Switzerland), mounted on low-speed handpieces, were used for sampling.All cavities were restored using conventional glass-ionomer cement Equia Forte\u0026reg; (GC, Tokyo, Japan).\u003c/p\u003e\n\u003ch3\u003eMicrobiological analysis\u003c/h3\u003e\n\u003cp\u003eThirty-six specimens were collected from patients before and after treatment (total 72 samples). Dental drills were placed in 1 ml of tryptic soy broth (TSB) supplemented with 30% of glycerine. All specimens were stored in -80 ⁰C until further analysis. Samples were cultured on the following media: Columbia Agar with 5% sheep blood PLUS (OXOID Ltd., Basingstoke, UK), Sabouraud Dextrose Agar with chloramphenicol and gentamicin (BioMaxima S.A., Poland), Mitis Salivarius Agar supplemented with sucrose (MSA-S), Mitis Salivarius Agar with 1% bacitracin (MSA-B) (Sigma-Aldrich Co., St. Louis, MO, USA), and Rogosa SL Agar (BioMaxima S.A., Poland). Strain identification was performed using the VITEK\u0026reg; MS system (bioM\u0026eacute;rieux SSC, France). The samples were then gradually diluted in a series. The samples were plated in triplicate on the Columbia Agar with sheep blood PLUS to evaluate the viability of the microorganisms and to assess the total number of microorganisms. Subsequently, the diluted samples were plated on the following media: \u003cem\u003eMitis Salivarius\u003c/em\u003eAgar supplemented with sucrose for total \u003cem\u003eStreptococci\u003c/em\u003e, \u003cem\u003eMitis Salivarius\u003c/em\u003eAgar with bacitracin for \u003cem\u003emutans Streptococci\u003c/em\u003e, Rogosa SL Agar for \u003cem\u003eLactobacilli\u003c/em\u003e, and Sabouraud Dextrose Agar for fungi. All agar plates were incubated under aerobic conditions at 37\u0026deg;C with 5% CO₂ for 48 hours. After that time the colony forming units counts were conducted using the OpenCFUprogramme [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] and reported as colony forming units per milliliter (CFU/ml).\u003c/p\u003e\n\u003ch3\u003eData analysis and statistical methods\u003c/h3\u003e\n\u003cp\u003eThe unit used as a parameter for analysis was a tooth. The data were compiled in tables in Excel. The number of CFUs before and after aPTD was compared in each culture substrate: Columbia Agar with 5% sheep blood PLUS, MSA-S, MSA-B. Nonparametric Wilcoxon and Mann-Whitney tests were used for this purpose. The significance level was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Statistica software was used to perform the analysis.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eFollow-up examinations were performed after 3, 6, and 12 months. No pain symptoms or signs of treatment failure were observed.\u003c/p\u003e \u003cp\u003eMicroorganisms were found in all 36 samples before aPTD treatment. After treatment, a statistically significant reduction in the total number of microorganisms was observed. There was also a reduction in the number of bacteria on selective media for \u003cem\u003eStreptococci\u003c/em\u003e in general and \u003cem\u003eStreptococcus mutans\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Because bacterial growth on Rogosa SL Agar was observed in only a very small number of samples, these results were excluded from the analysis. The low detection rate of \u003cem\u003eLactobacillus\u003c/em\u003e spp. did not allow for reliable statistical comparison. No fungal colonies were detected in any of the samples tested. The percentage reduction in CFU/ml was calculated as the difference between the mean CFU/ml before and after aPTD (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e show that the degree of microbial reduction did not differ significantly depending on the photosensitizer used.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of bacterial growth (CFU/mL) before and after the use of aPTD (Wilcoxon tests)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSubstrate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePhoto-sensitizer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003eBefore the use of aPTD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003eAfter the use of aPTD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAverage (CFU/ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMedian\u003c/p\u003e \u003cp\u003e(CFU/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003cp\u003e(CFU/m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMedian\u003c/p\u003e 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morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with sucrose\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eToluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e463.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e569.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e315\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e32.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e68.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCurcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e347.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e417.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e97.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e147.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e418.3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e508.5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e210\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e57.8\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e108.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e20\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with 1% bacitracin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eToluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e88.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e18.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCurcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e63.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e51.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e78.7\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e76.9\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e40\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e21.3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e37.8\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePercentage reduction in CFU/mL after application of aPTD\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubstrate and photosensitizer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePercentage reduction (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eColumbia Agar Columbia Agar supplemented with 5% sheep blood PLUS\u0026thinsp;+\u0026thinsp;Toluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e95.7%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eColumbia AgarColumbia Agar supplemented with 5% sheep blood PLUS\u0026thinsp;+\u0026thinsp;Curcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e89.6%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with sucrose\u0026thinsp;+\u0026thinsp;Toluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e93.1%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003eAgar supplemented with sucrose\u0026thinsp;+\u0026thinsp;Curcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e71.9%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with 1% bacitracin\u0026thinsp;+\u0026thinsp;Toluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e78.7%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with 1% bacitracin\u0026thinsp;+\u0026thinsp;Curcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e60.5%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of growth (CFU/mL) depending on the photosensitizer used (CFU/mL)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSubstrate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eaPTD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c6\" namest=\"c3\"\u003e \u003cp\u003eToluidine blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c9\" namest=\"c7\"\u003e \u003cp\u003eCurcumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003cp\u003eCFU/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMedian\u003c/p\u003e \u003cp\u003eCFU/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003cp\u003eCFU/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003cp\u003eCFU/mL\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eColumbia Agar supplemented with 5% sheep blood PLUS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28505.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70173.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2800\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e10565.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e23184.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.401\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAfter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1232.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3161.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e240\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e1099.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1851.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e130\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.788\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with sucrose\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e463.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e569.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e315\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e347.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e417.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.659\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAfter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e68.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e97.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e147.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.131\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eMitis Salivarius\u003c/em\u003e Agar supplemented with 1% bacitracin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e88.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e63.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e54.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.676\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAfter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e25.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e51.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.949\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003ePartial removal of decayed dentin and tight filling of the cavity promotes the formation of a microbiological niche, which makes it possible to avoid more complicated procedures such as endodontic treatment. Bitello-Firmino et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] even claim that selective removal of caries is as effective in reducing bacteria remaining in the dentin as complete removal, and that a tight filling of the cavity plays a key role. Minimally invasive dentistry also has an important psychological aspect, which is particularly important in pediatric patients. Therefore, conducting research that contributes to the least invasive treatment methods is of great value.\u003c/p\u003e \u003cp\u003eThe aim of our study was to evaluate the reduction of bacteria in deep cavities of deciduous teeth after photodynamic therapy with the LAD FotoSan\u0026reg; 630 lamp and two types of photosensitizers \u0026mdash; one containing toluidine blue, and the other containing curcumin. The study showed high efficacy of this therapy, regardless of the photosensitizer used, in reducing the total number of bacterial colonies and in reducing bacteria on selective media for \u003cem\u003eStreptococci\u003c/em\u003e in general and \u003cem\u003eStreptococci mutans\u003c/em\u003e. Most authors evaluated the effectiveness of antibacterial photodynamic therapy using conventional microorganism culture on selected media using CFU [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Other researchers performed quantitative real-time polymerase chain reaction (PCR) [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In the current study, in addition to culture on selected media, species identification was performed using the VITEK\u0026reg; MS system (bioM\u0026eacute;rieux SSC, France). VITEK MS is a modern device used to identify microorganisms. This system uses mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology to identify microorganisms cultured from human samples [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our research, we used two photosensitizers\u0026mdash;toluidine blue and curcumin.\u003c/p\u003e \u003cp\u003eToluidine blue (TB) is a cationic photosensitizer approved by the FDA for clinical use. It is characterized by low excitation energy and high permeability through cell membranes. Due to its small particle size, hydrophilicity, and ability to form dimers, TB binds perfectly to the cell membranes of microorganisms.\u003c/p\u003e \u003cp\u003eMany studies have confirmed the effectiveness of TB in the treatment of oral diseases. Vahabi et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] applied 0.1% TB to a bacterial suspension containing Streptococcus mutans. The sample was then exposed to a diode laser with a wavelength of 633 nm. The results showed that the combination of TB and laser significantly reduced the number of live bacteria.\u003c/p\u003e \u003cp\u003eCurcumin (CUR), on the other hand, is a natural phenolic compound with a low molecular weight that occurs in nature. The authors suggest that CUR has potential as an effective photosensitizer and can effectively eliminate microorganisms from the oral cavity. Importantly, curcumin is more effective against Gram-positive bacteria than Gram-negative bacteria [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe literature also reports on the high effectiveness of using Bixa orellana extract [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], a combination of Papacaria with methylene blue [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], erythrosine [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], indocyanine green, chlorella, and rose Bengal [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] as photosensitizers in aPTD in deep cavities.\u003c/p\u003e \u003cp\u003eSoria-Lozano and colleagues [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] studied the effect of photodynamic therapy on cariogenic bacteria. In their experiment, they used white light and three photosensitizers: methylene blue, rose bengal, and curcumin. They found that photodynamic therapy using these compounds is effective in eliminating \u003cem\u003eStreptococcus mutans\u003c/em\u003e and Streptococcus sanguis bacteria. At the same time, they noted that the best therapeutic effects were achieved with methylene blue (MB) and rose bengal (RB), while the effectiveness of curcumin (CUR) was slightly lower. Our research also confirmed the effectiveness of aPTD. The differences between the effectiveness of toluidine blue and curcumin, despite the slight advantage of TB, were not statistically significant.\u003c/p\u003e \u003cp\u003eOrnellas et al. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] conducted a literature review and meta-analysis of data, which clearly confirmed the hypothesis that aPTD is an effective tool for reducing or eliminating bacteria in deep carious lesions of primary and permanent teeth.\u003c/p\u003e \u003cp\u003eMelo et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] also addressed this issue: they compared the effect of photodynamic therapy on the reduction of bacteria in deep cavities of permanent posterior teeth. They demonstrated a significant reduction in the number of \u003cem\u003eS. mutans\u003c/em\u003e, \u003cem\u003eLactobacillus\u003c/em\u003e, and the total number of microorganisms after the use of aPTD with toluidine blue photosensitizer, compared to the control group where the cavity was rinsed with 0.89% NaCl.\u003c/p\u003e \u003cp\u003eAraujo et al. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] also demonstrated a significant reduction in the total number of microorganisms after the application of aPTD in their study.\u003c/p\u003e \u003cp\u003eSteiner-Oliveira et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] addressed this issue and distinguished three research groups in their work. In the first group, after preparation, they rinsed the cavities with a 2% chlorhexidine solution. In the second and third groups, they used photodynamic therapy with toluidine blue as a photosensitizer, using a diode lamp (second group) and a low-power laser (third group). The total number of bacteria was determined using quantitative polymerase chain reaction. Although they observed a significant reduction in the total number of bacteria, including \u003cem\u003eStreptococcus mutans\u003c/em\u003e, \u003cem\u003eLactobacillus casei\u003c/em\u003e, and \u003cem\u003eFusobacterium nucleatum\u003c/em\u003e, they did not find a statistically significant difference between aPTD and rinsing cavities with a 2% chlorhexidine solution. Interestingly, they also noted that photodynamic therapy does not reduce \u003cem\u003eStreptococcus sobrinus\u003c/em\u003e. The authors believe that all these therapies can be considered effective and that further research should be conducted on their effectiveness in reducing bacteria in deep cavities.\u003c/p\u003e \u003cp\u003eOrnellas et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] noted that photodynamic therapy after selective treatment of deep cavities in primary teeth reduces the total number of microorganisms by 69.88% to 86.29%, \u003cem\u003eStreptococcus spp.\u003c/em\u003e and \u003cem\u003eLactobacillus spp\u003c/em\u003e. In their study, they used a low-power diode laser emitting red light, and a methyl blue photosensitizer. The study sample consisted of 18 teeth in 18 patients. The authors detected the presence of \u003cem\u003eCandida spp\u003c/em\u003e. in only one of the dentin samples tested. In our study, no fungal colonies were detected in any of the samples tested. Comparing our results with those of the authors mentioned above, a similar reduction in CFU/ml was obtained, despite methodological differences: a different photosensitizer, light source, and sample size.\u003c/p\u003e \u003cp\u003eReports on the antibacterial efficacy of photodynamic therapy are inconclusive. Unlike most authors, Neves et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] did not observe a significant difference in the reduction of microorganisms after the use of aPTD in deep cavities of deciduous teeth. This may be due to different experimental conditions, especially regarding the light source, wavelength, and photosensitizer used. The authors used an InGaAlP diode laser with a wavelength of 660 nm with a methylene blue photosensitizer, while in our study we used an LAD diode lamp with a wavelength of 630 nm with photosensitizers: toluidine blue and curcumin.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eBased on the results obtained, we can conclude that photodynamic therapy appears to be highly effective in reducing bacteria in deep cavities of deciduous teeth. It can be successfully used as an adjunct to selective cavity preparation. The combination of aPTD with selective cavity preparation is less traumatic which is particularly important in pediatric patients. Although the results of the study are promising, further clinical research is needed to gain a more complete understanding of the potential of aPTD in the treatment of caries in primary teeth.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics Approval:\u003c/strong\u003e \u003cp\u003e The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Medical University of Bialystok (approval number: APK.002.5.2023 ).\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research was funded by the Medical University of Bialystok from institutional subsidy funds.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eS.K., G.M.-K., P.S., and E.T. conceived and designed the study. S.K. performed the clinical procedures and collected the samples. Ł.K., P.M., D.C., and P.S. conducted the microbiological analyses and contributed to data interpretation. A.K., E.T., G.M.-K., P.S., and Ł.K. contributed to the development of the study methodology and provided scientific supervision. J.K. and P.M. performed the statistical analyses and contributed to data interpretation. S.K. and Ł.K. prepared the original draft of the manuscript. All authors critically revised the manuscript and approved the final version.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data supporting the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eOrnellas PO, Antunes LD, Fontes KB, P\u0026oacute;voa HC, K\u0026uuml;chler EC, Iorio NL, Antunes LA (2016) Effect of the antimicrobial photodynamic therapy on microorganism reduction in deep caries lesions: a systematic review and meta-analysis. 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Med (Baltim) 98(15):e15110. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/MD.0000000000015110\u003c/span\u003e\u003cspan address=\"10.1097/MD.0000000000015110\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNagata JY, Hioka N, Kimura E, Batistela VR, Terada RS, Graciano AX, Baesso ML, Hayacibara MF (2012) Antibacterial photodynamic therapy for dental caries: evaluation of the photosensitizers used and light source properties. 9(2):122\u0026ndash;131. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.pdpdt.2011.11.006\u003c/span\u003e\u003cspan address=\"10.1016/j.pdpdt.2011.11.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFracalossi C, Nagata JY, Pellosi DS, Terada RS, Hioka N, Baesso ML, Sato F, Rosalen PL, Caetano W, Fujimaki M (2016) Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans. 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PhotodiagnosisPhotodynTher 12(4):581-6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.pdpdt.2015.09.005\u003c/span\u003e\u003cspan address=\"10.1016/j.pdpdt.2015.09.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAra\u0026uacute;jo PV, Correia-Silva Jde F, Gomez RS, MassaraMde L, Cortes ME, Poletto LT (2015) Antimicrobial effect of photodynamic therapy in carious lesions in vivo, using culture and real-time PCR methods. 12(3):401\u0026ndash;407. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.pdpdt.2015.06.003\u003c/span\u003e\u003cspan address=\"10.1016/j.pdpdt.2015.06.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOrnellas PO, Antunes LS, Motta PC, Mendon\u0026ccedil;a C, P\u0026oacute;voa H, Fontes K, Iorio N, Antunes LAA (2018) Antimicrobial Photodynamic Therapy as an Adjunct for Clinical Partial Removal of Deciduous Carious Tissue: A Minimally Invasive Approach. PhotochemPhotobiol94(6):1240\u0026ndash;1248. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/php.12966\u003c/span\u003e\u003cspan address=\"10.1111/php.12966\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNeves PA, Lima LA, Rodrigues FC, Leit\u0026atilde;o TJ, Ribeiro CC (2016) Clinical effect of photodynamic therapy on primary carious dentin after partial caries removal. Braz Oral Res 30(1):S1806-83242016000100246. doi: 10.1590/1807-3107BOR-2016.vol30.0047\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"photodynamic therapy, primary teeth, dental caries, FotoSan","lastPublishedDoi":"10.21203/rs.3.rs-8575895/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8575895/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003e\u003cbr\u003e\nThe aim of this study was to evaluate the effect of photodynamic therapy on the reduction of bacteria in deep carious lesions of primary teeth.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods:\u003c/strong\u003e\u003cbr\u003e\nThe study group consisted of 36 children with deep carious lesions in primary teeth. A LAD FotoSan®630 diode lamp was used for the therapy. Participants were randomly assigned to two groups: in the first group, antibacterial photodynamic therapy (aPDT) was performed using a 0.1% toluidine blue gel photosensitizer (FotoSan Agent® High, CMS Dental, Roslev, Denmark); in the second group, curcumin QroxB2® (CMS Dental, Roslev, Denmark) was used as the photosensitizer. Thirty-six carious lesions were selectively excavated. Dentin samples were collected twice—after caries removal and after aPDT application. Samples were cultured on Columbia Agar with sheep blood PLUS to assess microbial viability and the total number of microorganisms. Strain identification was performed using the VITEK® MS system (bioMérieux SSC, France). Diluted samples were then inoculated onto selective media: Mitis Salivarius Agar supplemented with sucrose for total streptococci, Mitis Salivarius Agar with bacitracin for \u003cem\u003eStreptococcus mutans\u003c/em\u003e, Rogosa SL Agar for \u003cem\u003eLactobacilli\u003c/em\u003e, and Sabouraud Dextrose Agar for fungi.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003cbr\u003e\nA statistically significant reduction in the total number of microorganisms was noted after therapy. A decrease in bacterial counts was also observed on selective media for total \u003cem\u003eStreptococci\u003c/em\u003eand \u003cem\u003eStreptococcus mutans\u003c/em\u003e. The degree of microbial reduction did not significantly differ depending on the photosensitizer used.\u003c/p\u003e\n\u003cp\u003eFollow-up examinations were performed at 3, 6, and 12 months. No pain symptoms or signs of treatment failure were observed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e\u003cbr\u003e\nPhotodynamic therapy appears to be highly effective in reducing bacteria in deep carious lesions of primary teeth.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Significance:\u003c/strong\u003e\u003cbr\u003e\nPhotodynamic therapy may be successfully used as an adjunct in selective caries excavation.\u003c/p\u003e","manuscriptTitle":"Assessment of the effect of photodynamic therapy on the reduction of bacteria in deep dental caries lesions of primary teeth","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-29 16:37:23","doi":"10.21203/rs.3.rs-8575895/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-18T06:05:32+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-18T03:07:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-17T10:27:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"213197289167969576009833796783295960761","date":"2026-02-01T15:12:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"64481743270790378275467457308507253735","date":"2026-01-27T14:51:59+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-27T11:24:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-15T07:00:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-15T06:58:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Clinical Oral Investigations","date":"2026-01-11T22:02:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9a36d851-da83-4366-a5ba-4bb0496e1397","owner":[],"postedDate":"January 29th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T16:01:31+00:00","versionOfRecord":{"articleIdentity":"rs-8575895","link":"https://doi.org/10.1007/s00784-026-06858-z","journal":{"identity":"clinical-oral-investigations","isVorOnly":false,"title":"Clinical Oral Investigations"},"publishedOn":"2026-04-01 15:57:30","publishedOnDateReadable":"April 1st, 2026"},"versionCreatedAt":"2026-01-29 16:37:23","video":"","vorDoi":"10.1007/s00784-026-06858-z","vorDoiUrl":"https://doi.org/10.1007/s00784-026-06858-z","workflowStages":[]},"version":"v1","identity":"rs-8575895","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8575895","identity":"rs-8575895","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}