Precise Engineering of Growth Factor Presentation Using Extracellular Microenvironment-Mimicking Microfluidic Microparticles.

One of the main challenges in tissue engineering is finding a way to deliver specific growth factors (GFs) with precise spatiotemporal control over their presentation. Here, we report a novel strategy for generating microscale carriers with enhanced affinity for high content loading suitable for the sustained and localized delivery of GFs. Our developed microparticles can be injected locally and sustainably release encapsulated growth factors for up to 28 days. Fine-tuning of particles' size, affinity, microstructures, and release kinetics is achieved using a microfluidic system along with bioconjugation techniques. We also describe an innovative 3D micromixer platform to control the formation of core-shell particles based on superaffinity using a polymer-peptide conjugate for further tuning of release kinetics and delayed degradation. Chitosan shells block the burst release of encapsulated GFs and enable their sustained delivery for up to 10 days. The matched release profiles and degradation provide the local tissues with biomimetic, developmental-biologic-compatible signals to maximize regenerative effects. The versatility of this approach is verified using three different therapeutic proteins, including human bone morphogenetic protein-2 (rhBMP-2), vascular endothelial growth factor (VEGF), and stromal cell-derived factor 1 (SDF-1α). As in vivo morphogenesis is typically driven by the combined action of several growth factors, the proposed technique can be developed to generate a library of GF-loaded particles with designated release profiles.

Dental-derived stem cells in tissue engineering: the role of biomaterials and host response.

Dental-derived stem cells (DSCs) are attractive cell sources due to their easy access, superior growth capacity and low immunogenicity. They can respond to multiple extracellular matrix signals, which provide biophysical and biochemical cues to regulate the fate of residing cells. However, the direct transplantation of DSCs suffers from poor proliferation and differentiation toward functional cells and low survival rates due to local inflammation. Recently, elegant advances in the design of novel biomaterials have been made to give promise to the use of biomimetic biomaterials to regulate various cell behaviors, including proliferation, differentiation and migration. Biomaterials could be tailored with multiple functionalities, e.g., stimuli-responsiveness. There is an emerging need to summarize recent advances in engineered biomaterials-mediated delivery and therapy of DSCs and their potential applications. Herein, we outlined the design of biomaterials for supporting DSCs and the host response to the transplantation.

Exploring the association between a standardized extract of pequi peels (Caryocar brasiliense Cambess) and blue light as a photodynamic therapy for treating superficial wounds.

Natural products derived from plants can be used as photosensitizers for antimicrobial photodynamic therapy (aPDT) combining key therapeutic strategies for tissue repair while controlling microorganisms' growth. We investigated a standardized extract of pequi peels (Caryocar brasiliense Cambess) as a brownish natural photosensitizer for aPDT using blue light. Three concentrations of the pequi extract (PE; 10, 30, or 90 µg/mL) were tested solely or associated with blue laser (445 nm, 100 mW, 138 J/cm2 , 6 J, 60 s). In vitro, we quantified reactive oxygen species (ROS), assessed skin keratinocytes (HaCat) viability and migration, and aPDT antimicrobial activity on Streptococcus or Staphylococcus strains. In vivo, we assessed wound closure for the most active concentration disclosed by the in vitro assay (30 µg/mL). Upon aPDT treatments, ROS were significantly increased in cell monolayers regardless of PE concentration. PE at low doses stimulates epithelial cells. Although PE stimulated cellular migration, aPDT was moderately cytotoxic to skin keratinocytes, particularly at the highest concentration. The antimicrobial activity was observed for PE at the lowest concentration (10 µg/mL) and mostly at PE 10 µg/mL and 30 µg/mL when used as aPDT photosensitizers. aPDT with PE 30 µg/mL presents antimicrobial activity without compromising the initial phases of skin repair.

Efficacy of antiseptics and chemomechanical methods for dentin caries lesions: A systematic review with GRADE approach.

Objectives: Selective caries removal aims to remove carious tissue in deep dentin lesions. However, a discussion stands on the value of antiseptics and chemomechanical adjuvant methods to reduce the bacterial load on residual caries lesions. This systematic review has addressed two main clinical questions to compare the antimicrobial efficacy of available methods using (1) antiseptic or (2) chemomechanical agents before restoring dentin carious lesions. Methods: We included randomized and non-randomized controlled trials (RCTs/ NRCTs). We searched eight databases from inception to October 2021. Paired reviewers independently screened studies, extracted data, and assessed the risk of bias. The primary outcome was the reduction in the number of total bacterial in dentin, whereas secondary outcomes were reduction in the number of Lactobacillus and Streptococcus. We used the ratio of ratio of post-treatment to baseline means between two interventions in the logarithmic scale as a proper effect measure. Certainty of evidence was assessed with the Grading of Recommendations, Assessment, Development and Evaluation approach. Results: We included 14 RCTs and 9 NRCTs, with nine interventions. Regardless the method, the number of bacteria at baseline was similar or exceeded that after the intervention, particularly in NRCTs. The evidence was inconclusive for most comparisons. Among antiseptic agents, chlorhexidine (CHX) resulted in an average of 1.14 times [95% confidence interval (CI): 1.08-1.21] more total bacterial than photodynamic therapy in RCTs. Among NRCTS, the natural agents resulted in five times more total bacterial than CHX (95% CI: 2-11). For chemomechanical methods, the control resulted in eight times (95% CI: 4-17) more total bacterial than Carisolv (SHAA). Conclusions: The certainty of the evidence was very low for all comparisons showing uncertainty whether one treatment could be more effective than another for dentin disinfection. So far, exclusively removing soft carious dentin would be enough to reduce the bacterial count.

Adjunctive therapies for in vitro carious lesions: Antimicrobial activity, activation of dentin metalloproteinases and effects on dental pulp cells.

BACKGROUND: Adjunctive therapies used before dental restorative procedures may encourage carious tissue removal. Beyond promising antimicrobial properties, treatments could positively modulate the dentin-pulp complex while not interfering with restoration survival. Herein, we evaluated a set of substances and their effects on carious lesions and the underlying dentin or pulp cells. METHODS: Artificial caries lesions were developed in bovine teeth cavities immersed in Streptococcus mutans and Lactobacillus casei co-cultures. The cavities were treated according to the following groups: Phosphate Buffer Saline (PBS), Chlorhexidine (CHX), Papacárie® (Papain gel), Ozone (O3), and antimicrobial Photodynamic Therapy (aPDT). After treatments, samples were cultivated to count isolated microbial colonies. The zymography assay evaluated the activity of dentin metalloproteinases (MMP-2 and MMP-9). Cell viability was indirectly assessed on human dental pulp cells after 24, 72, or 120 h, whereas the odontodifferentiation potential was evaluated after ten days of cell culture. RESULTS: CHX and aPDT led to around 1 log bacterial load reduction. PBS, CHX, and aPDT showed the eventual expression of MMP-2 and MMP-9. Cell viability was reduced (< 30%) after 120 h for all groups compared to the control. CHX, O3, and aPDT induced greater odontodifferentiation (≈ 20% higher) than PBS and papain gel. CONCLUSION: Adjunctive therapies presented little or no biological significance in reducing bacterial load in artificial carious lesions. Although the activation of endogenous metalloproteinases may represent a possible concern for adhesive restorations, some of these treatments may have a positive role in dental pulp tissue repair.

Enhanced mechanical properties, anti-biofilm activity, and cytocompatibility of a methacrylate-based polymer loaded with native multiwalled carbon nanotubes.

OBJECTIVES: We aimed to optimize the mechanical and biological properties of a conventional methacrylate-based dental polymer by loading it with double- and triple-walled carbon nanotubes as growth (DTWCNTG). METHODS: A formulation of bisphenol A-glycidyl methacrylate and triethylene glycol dimethacrylate (mass ratio = 2:1) was mixed with DTWCNTG at concentrations of 0.0% (control), 0.001%, 0.005%, and 0.010%. The concentrations were physicochemical and morphologically evaluated, and antibacterial activity was assessed by seeding a Streptococcus mutans strain (ATCC 25175) on the experimental polymeric surfaces. Cellular survival and osteodifferentiation were evaluated in epithelial (HaCat) and preosteoblast cells (MC3T3-E1). RESULTS: The 0.001% DTWCNTG concentration yielded higher compressive strength, elastic modulus, flexural strength, flexural modulus, water sorption, and solubility than the control. The degree of conversion and color did not significantly change with a low amount of DTWCNTG incorporated into the polymer. Antibacterial activity significantly improved when tested on the 0.001% DTWCNTG discs. No groups showed cytotoxicity in a short-term analysis and adding DTWCNTG favored MC3T3-E1 mineralization over the control, particularly in the 0.001% formulation. SIGNIFICANCE: The micro-addition of 0.001% DTWCNTG confers mechanical resistance, antimicrobial properties, and bioactivity to methacrylate-based polymers without significantly compromising color. Incorporating DTWCNTG improved dental composite properties and could be a biomodified material for minimally invasive procedures.

Comparison of instrumental methods for color change assessment of Giomer resins.

Objectives: The aim of this study was to compare the color change of the Giomer resin composite (Beautifil-Bulk) by using photographs obtained with a smartphone (iPhone 6S) associated with Adobe Photoshop software (digital method), with the spectrophotometric method (Vita Easyshade) after immersion in different pigment solutions. Materials and Methods: Twenty resin composite samples with a diameter of 15.0 mm and thickness of 1.0 mm were confectioned in A2 color (n = 5). Photographs and initial color readings were performed with a smartphone and spectrophotometer, respectively. Then, samples were randomly divided and subjected to cycles of immersion in distilled water (control), açai, Coke, and tomato sauce, 3 times a day, 20 minutes for 7 days. Later, new photographs and color readings were taken. Results: The analysis (2-way analysis of variance, Holm-Sidak, p < 0.05) demonstrated no statistical difference (p < 0.005) between the methods in all groups. Similar color changes were observed for all pigment solutions when using the spectrophotometric method. For the digital method, all color changes were clinically unacceptable, with distilled water and tomato sauce similar to each other and with statistical differences (p < 0.005) for Coke and açai. Conclusions: Only the tomato sauce produced a color change above the acceptability threshold using both methods of color assessment. The spectrophotometric and digital methods produce different patterns of color change. According to our results, the spectrophotometric method is more recommended in color change assessment.

Métodos quimiomecânicos no tratamento de lesões cariosas profundas: um estudo in vitro / Chemomechanical methods in the treatment of deep carious lesions: an in vitro study

Este trabalho teve como objetivo investigar as propriedades antimicrobianas de substâncias utilizadas em métodos quimiomecânicos e seus efeitos na dentina e em células pulpares. Uma lesão de cárie artificial em dentina foi desenvolvida em cavidades padronizadas realizadas em dentes bovinos com amostras de Streptococcus mutans (ATCC 25175) e Lactobacillus casei (ATCC 7463). As cavidades foram tratadas de acordo com os grupos: G1 - Tampão FosfatoSalino (PBS); G2 - Clorexidina (CHX); G3 ­ Papacárie®; G4 - Água ozonizada (O3) e G5 - Terapia Fotodinâmica (PDT). O depósito microbiano coletado foi diluído e cultivado para obtenção de colônias isoladas na técnica pour-plate. A atividade de metaloproteinases dentinárias gelatinases (MMP-2 e MMP-9) foi avaliada pelo ensaio de zimografia qualitativamente. A viabilidade celular foi avaliada em células pulpares após 24, 72 e 120h e a osteodiferenciação após 10 dias. A CHX e PDT apresentaram redução bacteriana em comparação aos demais grupos (p<0,05). O tratamento feito com PBS, CHX e PDT apresentou atividade gelatinolítica após o tratamento para as MMP-2 e MMP-9. A viabilidade celular reduziu em 120 h para todos os grupos em relação ao controle. CHX, O3 e PDT induziram maior osteodiferenciação em relação ao PBS e ao Papacárie. Concluiu-se que CHX e PDT promoveram leve diminuição da carga bacteriana na lesão cariosa artificial. Todos os tratamentos causaram, em parte, atividade gelatinolítica, por meio da expressão de MMP-2 e MMP-9. Apesar de diminuírem a viabilidade celular, nenhum tratamento interferiu com a diferenciação das células pulpares. A utilização dos métodos quimiomecânicos testados resultou em baixa redução bacteriana nas lesões cariosas artificiais. Concomitantemente, alguns desses tratamentos podem ativar metaloproteinases e interferir com funções essenciais de células pulpares.

This work aimed to investigate the antimicrobial properties of substances used in chemo mechanical methods and their effects on dentin and pulp cells. An artificial caries lesion was developed in standardized cavities performed in bovine teeth with strains of Streptococcus mutans (ATCC 25175) and Lactobacillus casei (ATCC 7463). The cavities were treated according to the following groups: G1 - Phosphate Buffer Saline (PBS); G2 - Chlorhexidine (CHX); G3 ­ Papacárie®; G4 - Ozonized water (O3) and G5 - Photodynamic Therapy (PDT). A microbial sample was collected, diluted, and cultivated to obtain isolated colonies through pour-plate technique. The activity of dentin gelatinase metalloproteinases (MMP-2 and MMP9) was qualitatively evaluated by zymography assay. Cell viability was evaluated in pulp cells after 24, 72, and 120h and osteodifferentiation after 10 days. CHX and PDT caused bacterial reduction compared to the other groups (p<0.05). PBS, CHX, and PDT showed gelatinolytic activity through the expression of MMP-2 and MMP-9. Cell viability was reduced at 120 h for all groups in comparison to control. CHX, O3, and PDT induced greater osteodifferentiation compared to PBS and Papacárie®. It was concluded that CHX and PDT promoted a slight decrease in bacterial load in the artificial carious lesion. All treatments caused, in part, gelatinolytic activity, through the expression of MMP-2 and MMP-9. Despite decreasing cell viability, no treatment interfered with the differentiation of pulp cells. The use of chemo mechanical methods has a slight biological significance in reduction of bacterial load in artificial carious lesions. In addition, some of these treatments can activate metalloproteinases and interfere with essential pulp cell functions.

Avaliação da alteração de cor de uma resina composta "beautiful bulk" submetida à imersão em soluções pigmentantes / Color change evaluation of a composite resin "beautiful bulk" submitted to immersion in pigmentant solutions

Objetivo:O objetivo do estudo foi verificar, in vitro, a alteração de cor da resina composta Beautiful-Bulk®, exposta aos líquidos pigmentantes. Métodos:Foram confeccionados 60 espécimes da resina (15,0 mm de diâmetro e 1,0 mm de espessura, n = 5) nas cores A2, B2 e C2. Os espécimes foram mantidos em uma sala escura por sete dias, em ambiente seco, a 37 °C e, em seguida, foram fotografados com aparelho celular iPhone 6S®. Os espécimes foram divididos aleatoriamente e submetidos a ciclos de imersão em quatro líquidos: água destilada (controle), suco de açaí, Coca-Cola® e molho de tomate. As imersões foram realizadas em sete e quatorze dias de forma cíclica, após a confecção dos espécimes, três vezes ao dia, durante 20 minutos. Ao fim de cada ciclo, novas fotografias foram realizadas. As imagens foram analisadas no programa Adobe Photoshop® e os dados convertidos em L*a*b através de um histograma. A variação de cor (∆E) foi analisada pela escala CIE-Lab. Resultados:A análise dos resultados (One-way ANOVA, Teste de Tukey, p < 0,05) demonstrou que o grupo controle produziu maior alteração de cor (p < 0,05) em sete e quatorze dias na cor A2. A cor B2, no ciclo de quatorze dias, apresentou maior alteração de cor (p < 0,05) para os espécimes imersos em molho de tomate sem diferença estatística (p > 0,05) do controle. Para a cor C2, os espécimes imersos em molho de tomate tiveram maior alteração de cor (p < 0,05) em sete dias. Conclusão:Conclui-se que todas as substâncias pigmentantes e a água destilada foram capazes de produzir grandes alterações de cor na resina Beautifil Bulk®. Existe uma interação significativa entre a cor da resina e agentes pigmentantes.

Aim: This study sought to verify, in vitro, the color change of the nanoparticle composite resin, Beautiful Bulk®, exposed directly to pigmented liquids. Methods: Sixty test specimens were made in a Metal matrix (15.0 mm X 1.0 mm) using composite resin (n = 5) in colors A2, B2, and C2. The specimens were photographed with a smartphone (iPhone 6S®) seven days after the preparation. The specimens were kept in the dark for seven days, dry, at 37°C. The specimens were then randomly divided and immersed in four liquids: distilled water (control), açaí juice, Coca-Cola®, and tomato sauce. The immersions were performed in seven and fourteen days cyclically, three times a day, for 20 minutes. At the end of each immersion cycle, new photographs were taken with the same smartphone. The images were analyzed in the Adobe Photoshop® program, and the data was converted to L* a* b* through a histogram. The color variation (∆E) was analyzed by the CIE-Lab scale. Results: Analysis of the results (Tukey's test, p < 0.05) showed that the control group produced a greater color change (p < 0.05) in seven and fourteen days in the A2 shade. The B2 shade, in fourteen days, showed a greater color change (p < 0.05) for the specimens immersed in tomato sauce with no statistical difference (p > 0.05) of the control. For the C2 shade, the specimens immersed in tomato sauce presented a greater color change (p < 0.05) at seven days. Conclusion: It could therefore be concluded that there is a significant interaction between the composite resin and pigment agents. All pigmented substances produced color changes in the composite resin.