Natália Costa Araújo1, Rebeca Ferraz de Menezes2,3, Vanda Sanderana Macêdo Carneiro1,4, Alexandrino Pereira Dos Santos-Neto2, Carla Raquel Fontana5, Vanderlei Salvador Bagnato6, Catherine Malinda Harvey3, Marleny Elizabeth Martinez Gerbi7. 1. 1 Department of Restorative Dentistry, Dental School of Pernambuco, University of Pernambuco (UPE) , Camaragibe, Brazil . 2. 2 Department of Endodontics, University of Pernambuco (UPE) , Camaragibe, Brazil . 3. 3 Center for Biophotonics, University of California , Davis (UCDavis), Sacramento, California. 4. 7 Faculty of Dentistry, University Center Tabosa de Almeida ASCES-UNITA, Caruaru, Brazil . 5. 4 Department of Clinical Analysis, School of Pharmaceutical Sciences , Universidade Estadual Paulista (UNESP), Araraquara, Brazil . 6. 5 Optics Group from Physics Institute of São Carlos (IFSC), University of São Paulo (USP) , São Carlos, Brazil . 7. 6 Laser Center, University of Pernambuco (UPE) , Camaragibe, Brazil .
Abstract
OBJECTIVE: This investigation assessed the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to Photodynamic Therapy (PDT) when grown simultaneously in dentine carious lesions. BACKGROUND DATA: PDT is a technique that utilizes light to activate photosensitizers in the presence of oxygen to produce reactive radicals. MATERIALS AND METHODS: A culture medium of 1% glucose, 2% sucrose, 1% young primary culture of L. acidophilus 108 CFU/mL, and S. mutans 108 CFU/mL was utilized to inoculate the bacterial induced caries on human dentine slabs. Different concentrations of the photosensitizer (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were activated through exposure to the light-emitting diode source with a central wavelength of 450 nm and a fluency of 5.7 J/cm2. Two light intensities (19 and 47.5 mW/cm2) were tested. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D+1 (PDT group 1, light intensity of 19 mW/cm2), and L+D+2 (PDT group 2, light intensity of 47.5 mW/cm2). ANOVA/Tukey tests were utilized to compare groups (α = 5%). RESULTS: Both light intensities required 5.0 g/L of curcumin for significant bacterial reduction (p < 0.05). No significant effect was found for L-D+, thus proving the absence of a potential inherent toxicity. CONCLUSIONS: Curcumin has a toxic effect on microorganisms at appreciable concentrations upon photoactivation. However, it was required to use the maximum concentration of the drug for a successful procedure.
OBJECTIVE: This investigation assessed the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to Photodynamic Therapy (PDT) when grown simultaneously in dentine carious lesions. BACKGROUND DATA: PDT is a technique that utilizes light to activate photosensitizers in the presence of oxygen to produce reactive radicals. MATERIALS AND METHODS: A culture medium of 1% glucose, 2% sucrose, 1% young primary culture of L. acidophilus 108 CFU/mL, and S. mutans 108 CFU/mL was utilized to inoculate the bacterial induced caries on human dentine slabs. Different concentrations of the photosensitizer (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were activated through exposure to the light-emitting diode source with a central wavelength of 450 nm and a fluency of 5.7 J/cm2. Two light intensities (19 and 47.5 mW/cm2) were tested. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D+1 (PDT group 1, light intensity of 19 mW/cm2), and L+D+2 (PDT group 2, light intensity of 47.5 mW/cm2). ANOVA/Tukey tests were utilized to compare groups (α = 5%). RESULTS: Both light intensities required 5.0 g/L of curcumin for significant bacterial reduction (p < 0.05). No significant effect was found for L-D+, thus proving the absence of a potential inherent toxicity. CONCLUSIONS:Curcumin has a toxic effect on microorganisms at appreciable concentrations upon photoactivation. However, it was required to use the maximum concentration of the drug for a successful procedure.
Authors: Li Huang; Ken W L Yong; W Chrishanthi Fernando; Matheus Carpinelli de Jesus; James J De Voss; Yasmina Sultanbawa; Mary T Fletcher Journal: Toxins (Basel) Date: 2021-03-09 Impact factor: 4.546