The effects of antimicrobial photodynamic therapy (aPDT) with nanotechnology-applied curcumin and 450nm blue led irradiation on multi-species biofilms in root canals.

This study aimed to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) utilizing nanotechnology-applied curcumin activated by blue LED (450 nm) on the elimination of microorganisms arranged in multispecies biofilms inside the root canals of extracted human teeth. Forty single-rooted human teeth were used; these were randomized into four experimental groups, each comprising 10 teeth: control group, no treatment; photosensitizer (PS) group, nanotechnology-applied curcumin alone; light group, blue LED used separately; and aPDT group, nanotechnology-applied curcumin activated by blue LED. To carry out the tests, the interiors of the root canals were inoculated with species of Candida albicans (ATCC 90029), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), and methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43300), using a multispecies biofilm. After the incubation period, the canals were treated according to the experimental groups, with no treatment given in the control group. Studied inasmuch as the antimicrobial effectiveness of aPDT was concerned, it was observed that the greatest reduction in microbial counts using aPDTs was achieved against MRSA (mean reduction = 2.48 Log10 CFU/mL), followed by Escherichia coli (mean reduction = 1.72), and Enterococcus faecalis (mean reduction = 1.65); a reduction greater than 1.5 Log10 CFU/mL showed relevant effectiveness of aPDT against these microorganisms. Of note, aPDT has also shown considerable effectiveness against Candida albicans (mean reduction = 0.71), with a statistical difference in the reduction between the groups. aPDT was effective in reducing all microorganisms examined. The average reduction was greater than 1.5 Log10 in all microorganisms except for Candida albicans. HIGHLIGHTS: • aPDT was a viable treatment for root canals; • Nanotechnological curcumin aPDT was effective in reducing multispecies biofilm microorganisms; • aPDT technique showed efficacy under the worst microbiological conditions , such as mature multispecies biofilm; • Nanotechnological curcumin aPDT was able to reduce Gram positive, negative bacterial and yeasts in root canals.

Characterization of Brazilian green propolis as a photosensitizer for LED light-induced antimicrobial photodynamic therapy (aPDT) against methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-intermediate Staphylococcus aureus (VISA).

Staphylococcus aureus is the primary cause of skin and soft tissue infections. Its significant adaptability and the development of resistance are the main factors linked to its spread and the challenges in its treatment. Antimicrobial photodynamic therapy emerges as a promising alternative. This work aimed to characterize the antimicrobial photodynamic activity of Brazilian green propolis, along with the key bioactive compounds associated with this activity. Initially, a scanning spectrometry was conducted to assess the wavelengths with the potential to activate green propolis. Subsequently, reference strains of methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300) and vancomycin-intermediate Staphylococcus aureus (VISA ATCC 700699) were exposed to varying concentrations of green propolis: 1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg /mL and 100 µg/mL and were stimulated by blue, green or red LED light. Finally, high-performance liquid chromatography coupled with a diode array detector and tandem mass spectrometry techniques, along with classic molecular networking analysis, was performed to identify potential bioactive molecules with photodynamic activity. Brazilian green propolis exhibits a pronounced absorption peak and heightened photo-responsiveness when exposed to blue light within the range of 400 nm and 450 nm. This characteristic reveals noteworthy significant photodynamic activity against MRSA and VISA at concentrations from 5 µg/mL. Furthermore, the propolis comprises compounds like curcumin and other flavonoids sourced from flavone, which possess the potential for photodynamic activity and other antimicrobial functions. Consequently, Brazilian green propolis holds promise as an excellent bactericidal agent, displaying a synergistic antibacterial property enhanced by light-induced photodynamic effects.

Porphyrin-associated fluorescence spectroscopy (Photogen®) for the optical diagnosis of dental biofilm in orthodontic treatment: An observational clinical trial.

OBJECTIVE: This study assessed the presence of dental biofilm with fluorescence spectroscopy associated with porphyrin (Photogen®) in users of orthodontic appliances. METHODS: This cross-sectional observational clinical trial included 21 patients with metallic orthodontic fixed appliances. The presence of biofilm was evaluated by fluorescence spectroscopy (Evince-MMÓptics. São Carlos-SP, Brazil) with a porphyrin photo-evidence device (Photogen®). Digital images of the buccal surface of the upper anterior teeth (central and lateral incisors and canines) without and with porphyrin were analyzed using the histogram R (red) function in ImageJ software. The results were analyzed using the maximum and mode values of the red pixels from the histograms. The statistical analysis considered the significance level of 5%. RESULTS: The maximum values and modes of the red pixels were significantly higher in biofilms analyzed by porphyrin-associated optical spectroscopy compared to optical spectroscopy alone. CONCLUSIONS: Porphyrin-associated fluorescence spectroscopy was able to detect dental biofilm in the oral environment of patients with orthodontic treatment. This method better evidenced the presence of biofilm on the buccal surfaces of the upper teeth compared to that observed with fluorescence spectroscopy without porphyrin.

Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

OBJECTIVE: To investigate the effects of different sterilization/disinfection methods on the mechanical properties of orthodontic elastomeric chains. METHODS: Segments of elastomeric chains with 5 links each were sent for sterilization by cobalt 60 (Co60) (20 KGy) gamma ray technology. After the procedure, the elastomeric chains were contaminated with clinical samples of Streptococcus mutans. Subsequently, the elastomeric chains were submitted to sterilization/disinfection tests carried out by means of different methods, forming six study groups, as follows: Group 1 (control - without contamination), Group 2 (70°GL alcohol), Group 3 (autoclave), Group 4 (ultraviolet), Group 5 (peracetic acid) and Group 6 (glutaraldehyde). After sterilization/disinfection, the effectiveness of these methods, by Colony forming units per mL (CFU/mL), and the mechanical properties of the material were assessed. Student's t-test was used to assess the number of CFUs while ANOVA and Tukey's test were used to assess elastic strength. RESULTS: Ultraviolet treatment was not completely effective for sterilization. No loss of mechanical properties occurred with the use of the different sterilization methods (p > 0.05). CONCLUSION: Biological control of elastomeric chains does not affect their mechanical properties.

Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

OBJECTIVE: To investigate the effects of different sterilization/disinfection methods on the mechanical properties of orthodontic elastomeric chains. METHODS: Segments of elastomeric chains with 5 links each were sent for sterilization by cobalt 60 (Co60) (20 KGy) gamma ray technology. After the procedure, the elastomeric chains were contaminated with clinical samples of Streptococcus mutans. Subsequently, the elastomeric chains were submitted to sterilization/disinfection tests carried out by means of different methods, forming six study groups, as follows: Group 1 (control - without contamination), Group 2 (70°GL alcohol), Group 3 (autoclave), Group 4 (ultraviolet), Group 5 (peracetic acid) and Group 6 (glutaraldehyde). After sterilization/disinfection, the effectiveness of these methods, by Colony forming units per mL (CFU/mL), and the mechanical properties of the material were assessed. Student's t-test was used to assess the number of CFUs while ANOVA and Tukey's test were used to assess elastic strength. RESULTS: Ultraviolet treatment was not completely effective for sterilization. No loss of mechanical properties occurred with the use of the different sterilization methods (p > 0.05). CONCLUSION: Biological control of elastomeric chains does not affect their mechanical properties. .

OBJETIVO: verificar os efeitos de diferentes métodos de esterilização/desinfecção nas propriedades mecânicas de elásticos ortodônticos em cadeia. MÉTODOS: segmentos de elástico em cadeia com 5 elos cada foram enviados para esterilização em radiação gama com cobalto 60 (20 KGy). Após esterilização, esses foram contaminados com amostras clínicas de Streptococcus mutans. Passado esse período, foram submetidos aos testes de esterilização/desinfecção por diferentes métodos, formando seis grupos de estudo, assim denominados: Grupo 1 (controle - sem ter sido contaminado), Grupo 2 (álcool 70°GL), Grupo 3 (autoclave), Grupo 4 (ultravioleta), Grupo 5 (ácido peracético) e Grupo 6 (glutaraldeído). Após esterilização/desinfecção, avaliou-se a efetividade desses métodos, por meio de contagem de unidades formadoras de colônias por mL (UFC/mL), e as propriedades mecânicas desses materiais. Utilizou-se o teste t de Student para avaliar o número de UFC, além do ANOVA e, posteriormente, do teste de Tukey para avaliação da força. RESULTADOS: verificou-se que o ultravioleta não obteve eficácia total quanto à esterilização. E não ocorreu perda das propriedades mecânicas dos elásticos, com os diferentes métodos de esterilização utilizados (p > 0,05). CONCLUSÃO: o controle biológico de elásticos em cadeia não interfere nas suas propriedades mecânicas. .

Disinfection protocols to prevent cross-contamination between dental offices and prosthetic laboratories.

Control of cross-contamination between dental offices and prosthetic laboratories is of utmost importance to maintain the health of patients and dental office staff. The purpose of this study was to evaluate disinfection protocols, considering antimicrobial effectiveness and damage to the structures of prostheses. Solutions of 1% sodium hypochlorite, 2% chlorhexidine digluconate, 50% vinegar and sodium perborate were evaluated. Specimens were contaminated in vitro with standardized suspensions of Candida albicans, Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Bacillus subtilis spores. Disinfection by immersion for 10 min was performed. Final counts of microorganisms were obtained using the plating method. Results were statistically compared by Kruskal-Wallis ANOVA and Dunn's test. The surface roughness of 40 specimens was analyzed before and after 10 disinfection cycles, and results were compared statistically using Student's t test. The solution of 50% vinegar was as effective as 1% sodium hypochlorite and 2% chlorhexidine against C. albicans, E. coli and S. mutans. The sodium perborate solution showed the lowest antimicrobial effectiveness. Superficial roughness increased after cycles in 1% sodium hypochlorite (p=0.02). Solutions of 1% sodium hypochlorite, 2% chlorhexidine and 50% vinegar were effective for the disinfection of heat-polymerized acrylic specimens. Sodium hypochlorite increased the superficial roughness.

Eficácia da instrumentação associada à Terapia Fotodinâmica Antimicrobiana e medicação intracanal na eliminação de biofilmes e na neutralização de endotoxinas em canais radiculares / In vitro effectiveness of photodynamic therapy with low potency AsGaAl laser in the elimination of microorganisms and neutralization of endotoxins in root canals

O uso de radiação laser como método de desinfecção intracanal diante de microrganismos persistentes à terapia convencional e endotoxinas, que representam um dos principais agentes etiológicos envolvidos na patogênese das lesões periapicais, tem sido estudada atualmente. Deste modo, o objetivo deste estudo foi avaliar in vitro a eficácia da instrumentação associada a Terapia Fotodinâmica Antimicrobiana com laser de baixa potência e corante azuleno, na eliminação de biofilmes intracanal mono espécies de Candida albicans ATCC 18804, Enterococcus faecalis ATCC 29212 e Escherichia coli ATCC 25922 e de biofilmes multi espécies desses microrganismos associados, e na neutralização de endotoxinas do sistema de canais radiculares. Foi também objetivo deste estudo analisar a efetividade da medicação intracanal de clorexidina gel 2%, associada à polimixina B, sobre microrganismos e endotoxinas remanescentes do tratamento com instrumentação e Terapia Fotodinâmica Antimicrobiana. Foram utilizadas 80 raízes de dentes humanos unirradiculados padronizadas em 16mm e devidamente preparadas. Os espécimes foram contaminados e incubados por 14, 21 ou 28 dias respectivamente para Escherichia coli e Enterococcus faecalis, Candida albicans e os microrganismos associados. No grupo contaminado com Escherichia coli foi também verificada a neutralização de endotoxinas. Após período de incubação, foi realizada uma coleta do conteúdo intracanal que foi semeada em meio de cultura seletivo para cada espécie. Os dentes foram instrumentados (Kerr 35-80) e, a seguir, a associação do corante azuleno 25% com Endo-PTC foi inserida no interior do canal e os espécimes foram irradiados com laser AsGaAl por 3 minutos. Subseqüentemente foram realizadas duas coletas do conteúdo do canal radicular, sendo uma imediatamente após a instrumentação e Terapia Fotodinâmica e outra após 7 dias. Em seguida, os canais receberam como medicação intracanal, uma associação de polimixina...