Evaluation of photodynamic therapy on nanoparticles and films loaded-nanoparticles based on chitosan/alginate for curcumin delivery in oral biofilms.

Nanoparticles and nanoparticle-loaded films based on chitosan/sodium alginate with curcumin (CUR) are promising strategies to improve the efficacy of antimicrobial photodynamic therapy (aPDT) for the treatment of oral biofilms. This work aimed to develop and evaluate the nanoparticles based on chitosan and sodium alginate encapsulated with CUR dispersed in polymeric films associated with aPDT in oral biofilms. The NPs were obtained by polyelectrolytic complexation, and the films were prepared by solvent evaporation. The photodynamic effect was evaluated by counting Colony Forming Units (CFU/mL). Both systems showed adequate characterization parameters for CUR release. Nanoparticles controlled the release of CUR for a longer period than the nanoparticle-loaded films in simulated saliva media. Control and CUR-loaded nanoparticles showed a significant reduction of 3 log10 CFU/mL against S. mutans biofilms, compared to treatment without light. However, biofilms of S. mutans showed no photoinactivation effect using films loaded with nanoparticles even in the presence of light. These results demonstrate the potential of chitosan/sodium alginate nanoparticles associated with aPDT as carriers for the oral delivery of CUR, offering new possibilities to improve the treatment of dental caries and infections. This work will contribute to advances in the search for innovative delivery systems in dentistry.

Potential Use of Brazilian Green Propolis Extracts as New Photosensitizers for Antimicrobial Photodynamic Therapy against Cariogenic Microorganisms.

The synergic effect of Streptococcus mutans and Candida albicans increases dental caries severity. Antimicrobial photodynamic therapy (aPDT) is a non-invasive treatment for antimicrobial aspects. However, the current photosensitizers (PS) have many downsides for dental applications. This study aimed to evaluate the efficiency of two different Brazilian green propolis (BGP-AF and BGP-AG) as PS for aPDT against these microorganisms. A single-species biofilm was irradiated with crude extracts and their fractions and controls. Such extracts showed the best results and were evaluated in dual-species biofilms. Photodegradation, reactive oxygen species (ROS), cytotoxicity, and color stability assays were also investigated. Reductions higher than 3 log10 CFU/mL (p < 0.0001) occurred for crude BGP in single- and dual-species biofilms. Singlet oxygen was produced in BGP (p < 0.0001). BGP-mediated aPDT delayed S. mutans and C. albicans regrowth after 24 h of treatment (p < 0.0001). Both BGP did not change the color of dental materials (p > 0.05). BGP-AF-mediated aPDT showed 72.41% of oral keratinocyte viability (p < 0.0001). BGP extracts may be used in aPDT against S. mutans and C. albicans. Specifically, BGP-AF may represent a promising PS for dental applications.

In Vitro Evaluation of Photodynamic Activity of Plant Extracts from Senna Species against Microorganisms of Medical and Dental Interest.

Background: Bacterial resistance requires new treatments for infections. In this context, antimicrobial photodynamic therapy (aPDT) is an effective and promising option. Objectives: Three plant extracts (Senna splendida, Senna alata, and Senna macranthera) were evaluated as photosensitizers for aPDT. Methods: Cutibacterium acnes (ATCC 6919), Streptococcus mutans (ATCC 35668), Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), and Candida albicans (ATCC 90028) were evaluated. Reactive oxygen species production was also verified. Oral keratinocytes assessed cytotoxicity. LC-DAD-MS analysis identified the chemical components of the evaluated extracts. Results: Most species cultured in the planktonic phase showed total microbial reduction (>6 log10 CFU/mL/p < 0.0001) for all extracts. C. albicans cultured in biofilm showed total microbial reduction (7.68 log10 CFU/mL/p < 0.0001) for aPDT mediated by all extracts. Extracts from S. macranthera and S. alata produced the highest number of reactive oxygen species (p < 0.0001). The S. alata extract had the highest cell viability. The LC-DAD-MS analysis of active extracts showed one naphthopyrone and seven anthraquinones as potential candidates for photoactive compounds. Conclusion: This study showed that aPDT mediated by Senna spp. was efficient in microbial suspension and biofilm of microorganisms of medical and dental interest.

Cymbopogon citratus Essential Oil Increases the Effect of Digluconate Chlorhexidine on Microcosm Biofilms.

The aim of this study was to evaluate the effect of the Cymbopogon citratus essential oil and its association with chlorhexidine on cariogenic microcosm biofilm composition and acidogenicity. Minimum inhibitory and bactericide concentrations from the essential oil and chlorhexidine were determined by broth microdilution assay. Microcosms (polymicrobial) biofilms were produced on glass coverslips, using inoculum from human saliva in McBain culture medium (0.5% sucrose exposure for 6 h/day) for 3 days in 24-well plates. The biofilms were treated twice a day and their composition was evaluated by microorganism quantification. The acidogenicity was evaluated by measuring the pH of the spent culture medium in contact with the biofilm. Overall, the association of C. citratus and chlorhexidine reduced total bacterial counts and aciduric bacteria (maximum reduction of 3.55 log UFC/mL) in microcosm biofilms. This group also presented the lowest acidogenicity even when exposed to sucrose-containing medium. C. citratus essential oil increases the effect of digluconate chlorhexidine on microcosm biofilms. Based on these findings, this study can contribute to the development of new formulations that might allow for the use of mouthwashes for a shorter period, which may reduce undesirable effects and increase patient compliance to the treatment.

Photobiomodulation in the treatment of xerostomia associated with hyposalivation in a pediatric patient with systemic scleroderma.

Scleroderma is a rare autoimmune disease characterized by excessive collagen production. The oral manifestations of the patient with scleroderma can include microstomia, xerostomia, and changes in the resorption teeth. We report the case of a 7-year-old female patient diagnosed with systemic scleroderma where photobiomodulation therapy was used to treat xerostomia associated with hyposalivation. She attended a pediatric clinic and presented with dry and rigid facial skin, trismus, xerostomia, malocclusion, and difficulty swallowing. Stimulated salivary flow was assessed before, during, and after treatment. Photobiomodulation therapy was conducted at four points at the sublingual glands with 660 nm, 100 mW, and 0.8 J/cm2 to each point; eight points at the parotid glands; and six points at the submandibular glands with 808 nm, 100 mW, and 0.8 J/cm2 for 8 seconds at each point. After this therapy, an increase in salivary flow, remission of the xerostomia, and an improvement in mastication and swallowing were observed. Photobiomodulation therapy was effective in controlling xerostomia in this pediatric patient, resulting in increased salivary flow and an improvement in her quality of life.

Photobiomodulation in the treatment of xerostomia associated with hyposalivation in a pediatric patient with systemic scleroderma

Scleroderma is a rare autoimmune disease characterized by excessive collagen production. The oral manifestations of the patient with scleroderma can include microstomia, xerostomia, and changes in the resorption teeth. We report the case of a 7-year-old female patient diagnosed with systemic scleroderma where photobiomodulation therapy was used to treat xerostomia associated with hyposalivation. She attended a pediatric clinic and presented with dry and rigid facial skin, trismus, xerostomia, malocclusion, and difficulty swallowing. Stimulated salivary flow was assessed before, during, and after treatment. Photobiomodulation therapy was conducted at four points at the sublingual glands with 660 nm, 100 mW, and 0.8 J/cm2 to each point; eight points at the parotid glands; and six points at the submandibular glands with 808 nm, 100 mW, and 0.8 J/cm2 for 8 seconds at each point. After this therapy, an increase in salivary flow, remission of the xerostomia, and an improvement in mastication and swallowing were observed. Photobiomodulation therapy was effective in controlling xerostomia in this pediatric patient, resulting in increased salivary flow and an improvement in her quality of life.

Effect of Photodynamic Therapy on Microorganisms Responsible for Dental Caries: A Systematic Review and Meta-Analysis.

The aim of this study was to perform a systematic review of the literature followed by a meta-analysis about the efficacy of photodynamic therapy (PDT) on the microorganisms responsible for dental caries. The research question and the keywords were constructed according to the PICO strategy. The article search was done in Embase, Lilacs, Scielo, Medline, Scopus, Cochrane Library, Web of Science, Science Direct, and Pubmed databases. Randomized clinical trials and in vitro studies were selected in the review. The study was conducted according the PRISMA guideline for systematic review. A total of 34 articles were included in the qualitative analysis and four articles were divided into two subgroups to perform the meta-analysis. Few studies have achieved an effective microbial reduction in microorganisms associated with the pathogenesis of dental caries. The results highlight that there is no consensus about the study protocols for PDT against cariogenic microorganisms, although the results showed the PDT could be a good alternative for the treatment of dental caries.

Mouthwash containing Croton doctoris essential oil: in vitro study using a validated model of caries induction.

AIM: To validate an in vitro caries model and to evaluate an experimental mouthwash containing Croton doctoris essential oil.  Materials & methods: To validate the experimental model, we used McBain medium and polymicrobial biofilms. The EOM (essential oil mouthwash) was tested using the validated model. Microbial composition (colony-forming unit/ml), acidogenicity, enamel demineralization (percentage of surface enamel hardness loss), cytotoxicity and essential oil composition were evaluated. RESULTS: The model was validated with 0.5% sucrose, duration of 4 days and treatments twice per day. There were statistically significant differences between the EOM, the negative control and chlorhexidine mouthwash in colony-forming unit/ml and percentage of surface enamel hardness loss. Cytotoxicity was similar to that of chlorhexidine mouthwash.  A total of 66.11% of the essential oil consists of sesquiterpenes. CONCLUSION: The experimental mouthwash showed antimicrobial activity against polymicrobial biofilms and reduced enamel demineralization.

Screening of plants with antimicrobial activity against enterobacteria, Pseudomonas spp. and Staphylococcus spp.

AIM: This study screened plants for antibacterial properties against bacteria of medical importance. MATERIALS & METHODS: 60 extracts were obtained from the leaves of ten plants (Jatropha weddelliana, Attalea phalerata, Buchenavia tomentosa, Croton doctoris, Mouriri elliptica, Mascagnia benthamiana, Senna aculeata, Unonopis guatterioides, Allagoptera leucocalyx and Bactris glaucescens) using different extraction methods: A) Ethanol 70°C/72 h; B) Water/5 min/100°C; C) Water/1 h/55°C; D) Water/72 h; E) Hexane/72 h and F) Ethanol 99°C/72 h. Enterobacteria/Pseudomonas and staphylococci reference strains and 201 clinical isolates were used. Primary screening was done using agar well-diffusion assay. MIC/minimum bactericidal concentration and chemical characterization were determined. RESULTS: Extracts 5F and 3A showed the best MIC/minimum bactericidal concentration against clinical isolates and showed the presence of phenols. CONCLUSION: The present study demonstrated that Mouriri elliptica and Buchenavia tomentosa were the most active plants against the studied bacteria.

Plant extracts: initial screening, identification of bioactive compounds and effect against Candida albicans biofilms.

AIM: This study screened plants from Brazilian Pantanal for Candida albicans antibiofilm activity. MATERIAL & METHODS: Sixty extracts were obtained from ten plants using different extraction methods. Antifungal activity was assessed. Effects on biofilm inhibition and disruption and cytotoxicity were also evaluated. The most active extract was chemically characterized. RESULTS: Buchenavia tomentosa ethanolic extract showed noticeable antifungal activity and was selected for biofilm experiments. Subinhibitory concentration of extract inhibited fungal adhesion. Maximum killing reached 90% of C. albicans cells in suspension and 65% of cells in biofilms. The active extract was noncytotoxic. Chemical characterization showed the presence of phenols. Ellagic and gallic acids showed activity on C. albicans. CONCLUSION: B. tomentosa extract and its isolated compound, ellagic acid, presented antibiofilm activity and low toxicity.

Terapias alternativas para o tratamento da estomatite por prótese total: modelo experimental in vivo em ratos / Alternative therapies for denture stomatitis treatment: in vivo experimental model in rats

A estomatite por prótese (EP) é uma condição multifatorial que acomete frequentemente usuários de prótese total e geralmente é relacionada com Candida albicans. Devido aos efeitos tóxicos da terapia antifúngica, novas terapias para EP são necessárias. Objetivos: O objetivo deste estudo foi avaliar a eficácia do extrato aquoso de Buchenavia tomentosa e bicarbonato de sódio frente a C. albicans em um modelo de EP em ratos. Material e Métodos: Um aparelho de resina acrílica simulando a base da prótese total foi fixado cobrindo o palato de 48 ratos machos seguido por indução da candidose. Os ratos foram divididos em 4 grupos (n=12): controle, bicarbonato de sódio, B. tomentosa e nistatina (controle positivo). Cada grupo foi subdividido de acordo com o período de tratamento; 24 horas (n=6) e 48 horas (n=6). Os animais foram sacrificados e os aparelhos foram removidos para contagem de C. albicans e análise por microscopia eletrônica de varredura. Resultados: Após 24 horas de tratamento, observou-se redução significativa da contagem de C. albicans tanto B. tomentosa quanto nistatina (nistatina x controle, p<0,01; B. tomentosa x controle, p=0,03). Os resultados foram confirmados pela análise histológica. Conclusão: Tanto o extrato aquoso de B. tomentosa e o bicarbonato de sódio foram capazes de reduzir significativamente as contagens de C. albicans em modelo experimental de EP (AU)

Background: Denture stomatitis (DS) is a multifactorial condition that commonly affects denture users and is mainly caused by Candida albicans. Due to the toxic effects of antifungal therapy, new therapies for DS are claimed. Objective: The aim of the study was to evaluate the efficacy of aqueous extract of Buchenavia tomentosa and sodium bicarbonate against C. albicans in a model of DS in rats. Material and Methods: An acrylic resin device simulating a denture base was fixed covering the palate of forty-eight male rats followed by candidiasis induction. Rats were divided into 4 groups (n = 12): Control, sodium bicarbonate, B. tomentosa and nystatin (positive control). Each group was subdivided according to the period of treatment; 24 h (n = 6) and 48 h (n = 6). Animals were sacrificed and had their devices removed for C. albicans counts and SEM analysis. The palate mucosa was removed and processed for histopathologic analysis. Results: After 24 h of treatment, both B. tomentosa and nystatin groups reduced significantly C. albicans counts when compared to control (nystatin x control, p < 0.01; B. tomentosa x control, p = 0.03). The results were confirmed by the histologic analysis. Conclusion: Both the aqueous extract of B. tomentosa and sodium bicarbonate was able to significantly decrease C. albicans counts in an experimental model of DS (AU)

Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

Abstract The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

Effect of low fluoride acidic dentifrices on dental remineralization.

This study evaluated the capacity of fluoride acidic dentifrices (pH 4.5) to promote enamel remineralization using a pH cycling model, comparing them with a standard dentifrice (1,100 µgF/g). Enamel blocks had their surface polished and surface hardness determined (SH). Next, they were submitted to subsurface enamel demineralization and to post-demineralization surface hardness analysis. The blocks were divided into 6 experimental groups (n=10): placebo (without F, pH 4.5, negative control), 275, 412, 550, 1,100 µgF/g and a standard dentifrice (positive control). The blocks were submitted to pH cycling for 6 days and treatment with dentifrice slurries twice a day. After pH cycling, surface and cross-sectional hardness were assessed to obtain the percentage of surface hardness recovery (%SHR) and the integrated loss of subsurface hardness (ΔKHN). The results showed that %SHR was similar among acidic dentifrices with 412, 550, 1,100 µgF/g and to the positive control (Tukey's test; p>0.05). For ΔKHN, the acidic dentifrice with 550 µg F/g showed a better performance when compared with the positive control. It can be concluded that acidic dentifrice 550 µgF/g had similar remineralization capacity to that of positive control.

Hydroxyurea therapy in sickle cell anemia patients aids to maintain oral fungal colonization balance.

BACKGROUND: The aim of this study was to evaluate the frequency of Candida species and presence of lesions in the oral cavity of patients with sickle cell anemia (SS). METHODS: The study included 30 patients diagnosed with sickle cell anemia and taking hydroxyurea for at least 90 days (SS/HU+); and 39 patients with sickle cell anemia and without hydroxyurea therapy (SS/HU-). Two control groups were constituted by healthy individuals matched to the test groups in age, gender, and oral conditions (C/HU+ for SS/HU+ and C/HU- for SS/HU-). Oral clinical examination and anamnesis were performed. Yeasts were collected by oral rinses and identified by API system. Antifungal susceptibility evaluation was performed according to the CLSI methodology. Data obtained for microorganisms counts were compared by Student's t test (SS/HU+ vs. C/HU+ and SS/HU- vs. C/HU-) using MINITAB for Windows 1.4. Significance level was set at 5%. RESULTS: No oral candidosis lesions were detected. Significant differences in yeasts counts were observed between SS/HU- group and the respective control, but there were no differences between SS/HU+ and C/HU+. Candida albicans was the most prevalent species in all groups. Candida famata was observed both in SS and control groups. Candida dubliniensis, Candida glabrata, Candida krusei, Candida tropicalis, Candida pelliculosa, and Candida parapsilosis were observed only in SS groups. Most strains were susceptible to all antifungal agents. CONCLUSION: Hydroxyurea therapy seems to decrease candidal counts and resistance rate in sickle cell anemia patients. However, further studies should be conducted in the future to confirm this finding. Hydroxyurea therapy in sickle cell anemia patients maintains fungal species balance in oral cavity.

Effect of low fluoride acidic dentifrices on dental remineralization

This study evaluated the capacity of fluoride acidic dentifrices (pH 4.5) to promote enamel remineralization using a pH cycling model, comparing them with a standard dentifrice (1,100 µgF/g). Enamel blocks had their surface polished and surface hardness determined (SH). Next, they were submitted to subsurface enamel demineralization and to post-demineralization surface hardness analysis. The blocks were divided into 6 experimental groups (n=10): placebo (without F, pH 4.5, negative control), 275, 412, 550, 1,100 µgF/g and a standard dentifrice (positive control). The blocks were submitted to pH cycling for 6 days and treatment with dentifrice slurries twice a day. After pH cycling, surface and cross-sectional hardness were assessed to obtain the percentage of surface hardness recovery (%SHR) and the integrated loss of subsurface hardness (ΔKHN). The results showed that %SHR was similar among acidic dentifrices with 412, 550, 1,100 µgF/g and to the positive control (Tukey's test; p>0.05). For ΔKHN, the acidic dentifrice with 550 µg F/g showed a better performance when compared with the positive control. It can be concluded that acidic dentifrice 550 µgF/g had similar remineralization capacity to that of positive control.

O presente estudo objetivou avaliar a capacidade de dentifrícios fluoretados acidulados (pH 4,5) em promover a remineralização do esmalte utilizando um modelo de ciclagem de pH e compará-lo a um dentifrício padrão (1.100 µgF/g). Blocos de esmalte tiveram suas superfícies polidas e a dureza de superfície determinada (SH). Em seguida, foram submetidos à desmineralização subsuperficial e a dureza de superfície pós-desmineralização foi determinada. Os blocos foram divididos em seis grupos experimentais (n=10): placebo (controle negativo), 275, 412, 550, 1.100 µgF/g e um dentifrício padrão (controle positivo). Os blocos foram submetidos à ciclagem de pH durante seis dias e tratamentos com dentifrício diluído duas vezes por dia. Após a ciclagem de pH, a dureza de superfície e em secção transversal foram avaliadas para obtenção da porcentagem de recuperação de dureza de superfície (%SHR) e área integrada da perda de dureza de subsuperfície (ΔKHN). Os resultados mostraram que %SHR foi semelhante entre os dentifrícios ácidos 412, 550, 1.100 µgF/g e controle positivo (teste de Tukey; p>0,05). Para ΔKHN, o dentifrício acidulado com 550 µgF/g mostrou uma performance melhor quando comparado ao controle positivo. Conclui-se que os dentifrícios acidulados 550 µgF/g apresentaram capacidade de remineralização semelhante ao controle positivo.

Effect of Psidium cattleianum leaf extract on enamel demineralisation and dental biofilm composition in situ.

OBJECTIVE: Previous evaluations of Psidium cattleianum leaf extract were not done in conditions similar to the oral environment. The aim of this study was to evaluate the effect of P. cattleianum leaf extract on enamel demineralisation, extracellular polysaccharide formation, and the microbial composition of dental biofilms formed in situ. DESIGN: Ten volunteers took part in this crossover study. They wore palatal appliances containing 4 enamel blocks for 14 days. Each volunteer dripped 20% sucrose 8 times per day on the enamel blocks. Twice a day, deionised water (negative control), extract, or a commercial mouthwash (active control) was dripped after sucrose application. On the 12th and 13th days of the experiment, plaque acidogenicity was measured with a microelectrode, and the pH drop was calculated. On the 14th day, biofilms were harvested and total anaerobic microorganisms (TM), total streptococci (TS), mutans streptococci (MS), and extracellular polysaccharides (EPS) were evaluated. Enamel demineralisation was evaluated by the percentage change of surface microhardness (%ΔSMH) and integrated loss of subsurface hardness (ΔKHN). The researcher was blinded to the treatments during data collection. RESULTS: The extract group showed lower TM, TS, MS, EPS, %ΔSMH, and ΔKHN values than the negative control group. There were no differences between the active and negative control groups regarding MS and EPS levels. There were no differences in pH drop between the extract and active control groups, although they were significantly different from the negative control group. For all other parameters, the extract differed from the active control group. CONCLUSION: Psidium cattleianum leaf extract exhibits a potential anticariogenic effect.