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Comparative Effect of Two Red Lights on <i>Streptococcus mutans</i> Biofilms and Assessment of Temperature Variances in Human Teeth During <i>In Vitro</i> Photodynamic Antimicrobial Chemotherapy
摘要： Objective: The goals of this investigation were to compare the effect of photodynamic antimicrobial chemotherapy (PACT) with two different red lights on in vitro Streptococcus mutans biofilms, as well as to assess the temperature variances caused by PACT on human teeth. Methods: S. mutans biofilms (n = 3) were grown on hydroxyapatite disks, and the antimicrobial effect of PACT was evaluated using toluidine blue O (100 lg/mL) associated with Laserbeam(cid:2) (LB 56.6 J/cm2) and LumaCare(cid:3) (LC -56.6, 158.5, 317.0, and 475.6 J/cm2). Pulpal temperature variances were analyzed using a digital thermocouple placed into the pulp chamber and positioned at the cement–enamel junction level of five teeth samples during irradiation times of 300, 600, and 900 sec for LB, and 22, 60, 120, and 180 sec for LC. The mean average temperature variance was calculated for each group. All data were analyzed through analysis of variance. Results: LB (900 sec) and LC (22 sec) induced similar reductions in the viability of microorganisms. LB did not cause statistically significant increase of temperature, regardless of experimental time, and LC caused temperature increase within the safe spectrum up to 60 sec. Conclusions: PACT seems to be a minimal invasive approach for reducing the viability of cariogenic bacteria. Thus, when applied in vitro for times equal or inferior to 900 and 60 sec for LB and LC, respectively, these light sources might be considered harmless to tooth structures.
关键词： biofilms,anti-infective agents,Streptococcus mutans,photochemotherapy,temperature,dental pulp cavity
更新于2025-09-23 15:22:29
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Comparative evaluation of photodynamic therapy using LASER or light emitting diode on cariogenic bacteria: An in vitro study
摘要： Objective: The aim of this study was to evaluate in vitro the effect of photodynamic therapy (PDT) using LASER or light emitting diode (LED) on cariogenic bacteria (Streptococcus mutans [SM] and Lactobacillus casei [LC]) in bovine dentin. Materials and Methods: Twenty five fragments of dentin were contaminated with SM and LC strands and divided into five experimental groups according to the therapy they received (n = 5): C – control (no treatment), SCLED – no dye/LED application (94 J/cm2), SCLASER – no dye/LASER application (94 J/cm2), CCLED – dye/LED application (94 J/cm2) and CCLASER – dye/LASER application (94 J/cm2). The dye used was methylene blue at 10 mM. Dentin scrapes were harvested from each fragment and prepared for counts of colony forming units (CFU)/mL. The data were analyzed using Kruskal–Wallis, followed by Student–Newman–Keuls (α =0.05). Results: Regarding SM, groups CCLASER and CCLED showed a significant reduction in CFU/mL, which was statistically superior to the SCLASER, SCLED and C groups. Regarding LC, the groups CCLASER and CCLED caused a significant reduction in CFU/mL when compared with SCLASER, which showed intermediate values. SCLED and C had a lesser effect on reducing CFU/mL, where the former showed values similar to those of SCLASER. Conclusions: In conclusion, PDT combined with LASER or LED and methylene blue had a significant antimicrobial effect on cariogenic bacteria in the dentin.
关键词： Lactobacillus casei,Streptococcus mutans,semi-conductor lasers,photodynamic therapy
更新于2025-09-16 10:30:52
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Evaluations of antibacterial effects of 5-aminolevulinic acids in combination with light emitting diode (LED: 635nm) with different disinfection methods
摘要： This study evaluates the in vitro antibacterial effects of 5-ALA (photoactive dye) in regard to different disinfection methods (2% Chlorhexidine gluconate, 1% Sodium Hypochlorite) on cariogenic bacteria (Streptococcus mutans and Streptococcus sobrinus). After inoculation of dentin specimens with S. mutans and S. sobrinus separately, the reduction in bacterial count was evaluated by the colony counting method. A total of sixty specimens were assigned to six groups (Ten per each group, with five in each group inoculated with S. mutans and the other five inoculated with S.sobrinus); group one: positive control where no treatment was performed, group two: 1% NaOCl was applied, group three: 2% CHX was used, group four: 5-ALA with LED light (635nm) was applied, group five: 5-ALA was used without LED light activation, group six: LED light was used without dye application. There was a significant reduction in the number of S. mutans in the group treated with 5-ALA with LED light, followed by CHX and then NaOCl, whilst minimum bacterial reduction was detected in the groups that were treated with LED light alone and 5-ALA without LED. However, NaOCl exhibited a better effect regarding reduction of S. sobrinus, followed by 5-ALA and LED light and then CHX. All the disinfected groups showed a significant relation with the positive control non-treated group(p<0.05).
关键词： Caries disinfection,5-Aminolevulinic acid,Streptococcus mutans,Photodynamic therapy,Streptococcus sobrinus
更新于2025-09-12 10:27:22
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Effects of UVB and UVC irradiation on cariogenic bacteria in vitro
摘要： The aim of this study was to evaluate the bactericidal effect of ultraviolet (UV) light at 265-nm (UVC) and 310-nm (UVB) wavelengths from a newly developed UV light-emitting diode (LED) device against cariogenic bacteria in vitro. Suspensions of Streptococcus mutans (S. mutans) and Streptococcus sobrinus were directly irradiated by UVB or UVC for 2.5 min or 5 min. Numbers of colonies were counted and calculated as colony forming units (CFU) per milliliter. Fluorescence microscopy (FM) and optical density measurements at 490 nm (OD490) were also taken after irradiation. In addition, the bactericidal effects of irradiation against S. mutans under 0.5 mm-thick dentin were compared using culture tests and OD490 measurements. Direct UV-LED irradiation with both UVB and UVC showed strong bactericidal effects. UVB showed superior bactericidal effect through 0.5-mm-thick dentin than did UVC, especially after demineralization. These results suggest that UVB irradiation could be utilized for the prevention and management of dental caries.
关键词： UVB,UVC,Demineralized dentin,Streptococcus sobrinus,Streptococcus mutans,UV-LED
更新于2025-09-10 09:29:36