RESUMO
Staphylococcus aureus is a pathogen widely involved in wound infection due to its ability to release several virulence factors that impair the skin healing process, as well as its mechanism of drug resistance. Herein, sodium alginate and chitosan were combined to produce a hydrogel for topical delivery of neomycin to combat S. aureus associated with skin complications. The hydrogel was formulated by combining sodium alginate (50 mg/mL) and chitosan (50 mg/mL) solutions in a ratio of 9:1 (HBase). Neomycin was added to HBase to achieve a concentration of 0.4 mg/mL (HNeo). The incorporation of neomycin into the product was confirmed by scanning electron microscopy, FTIR and TGA analysis. The hydrogels produced are homogeneous, have a high swelling capacity, and show biocompatibility using erythrocytes and fibroblasts as models. The formulations showed physicochemical and pharmacological stability for 60 days at 4 ± 2 °C. HNeo totally inhibited the growth of S. aureus after 4 h. The antimicrobial effects were confirmed using ex vivo (porcine skin) and in vivo (murine) wound infection models. Furthermore, the HNeo-treated mice showed lower severity scores than those treated with HBase. Taken together, the obtained results present a new low-cost bioproduct with promising applications in treating infected wounds.
Assuntos
Alginatos , Antibacterianos , Quitosana , Hidrogéis , Neomicina , Staphylococcus aureus , Quitosana/química , Quitosana/farmacologia , Alginatos/química , Alginatos/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Camundongos , Neomicina/farmacologia , Neomicina/química , Neomicina/administração & dosagem , Antibacterianos/farmacologia , Antibacterianos/química , Infecções Estafilocócicas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/microbiologia , Infecções Cutâneas Estafilocócicas/patologia , Portadores de Fármacos/química , Pele/efeitos dos fármacos , Pele/microbiologiaRESUMO
OBJECTIVE: To evaluate the effect of dimethyl sulfoxide (DMSO) on the microtensile bond strength (µTBS) and nanoleakage (NL) of universal adhesives on eroded dentine, immediately and after four years of water storage. METHODS: Sixty-four sound human molars were distributed into 16 groups according to (1) Dentine surface (sound and eroded dentine); (2) dimethyl sulfoxide application (with or without); (3) Application mode (etch-and-rinse or self-etch) and (4) Storage time (immediate and four years). One mild universal adhesive was used (Scotchbond Universal). The restoration was then performed with a composite resin and the specimens were sectioned into resin-dentine bonded sticks. Resin-dentine bonded sticks were tested (immediately and after four years of water storage) for µTBS (0.5 mm/min) or used to assess NL. Data on µTBS and NL were analyzed using four-way ANOVA and Tukey's test (α = 0.05). RESULTS: Only the 3-way cross-product interaction 'substrate vs DMSO vs time' was statistically significant (p = 0.007). Eroded dentine showed a lower mean of µTBS and a higher mean of NL values than sound dentine. However, when DMSO was applied, no significant decrease of µTBS or NL values was observed after four years of water storage, regardless of adhesive strategies, or dentine evaluated, when compared to immediate results. SIGNIFICANCE: Water-based DMSO pre-treatments not only prevent degradation of MDP-containing simplified adhesives but also serve as a potential alternative to improve long-term bonding properties to eroded dentine. The versatility of using a single pre-treatment for both self-etch or etch-and-rinse bonding to eroded dentin may facilitate future clinical applications.
Assuntos
Colagem Dentária , Dimetil Sulfóxido , Humanos , Cimentos Dentários , Colagem Dentária/métodos , Adesivos Dentinários/química , Condicionamento Ácido do Dente/métodos , Cimentos de Resina/química , Dentina , Água/química , Resistência à Tração , Teste de MateriaisRESUMO
OBJECTIVES: To evaluate the microtensile bond strength (µTBS) and nanoleakage (NL) of several universal adhesives to eroded dentine (ED) using etch-and-rinse (ER) and self-etch (SE) strategies, immediately and after 6 years of water storage. MATERIAL AND METHODS: Four hundred and eighty human molars were distributed into 60 groups according to dentine substrate (sound dentine [SD], eroded with soft drink, or eroded with citric acid), application method of the adhesive (SE or ER), and the adhesives used: 1. All-Bond Universal, 2. Ambar Universal, 3. Clearfil Universal, 4. Futurabond U, 5. One Coat 7 Universal, 6. Peak Universal Bond, 7. Prime&Bond Elect, 8. Scotchbond Universal, 9. Tetric n-bond Universal, and 10. Xeno Select. The restoration was then performed with a composite resin, and the specimens were sectioned into resin-dentine bonded sticks. The sticks were tested (immediately or after 6 years of storage) for µTBS (0.5 mm/min) or used to assess NL. The eroded dentine surfaces were also examined using FE-SEM to evaluate the NL. Data for µTBS were analyzed by four-way ANOVA and Tukey's post-hoc test (a = 0.05), and the NL was analyzed by Kruskal-Wallis and the Wilcoxon Signed Rank Sum test (a = 0.05). RESULTS: In ED, there was no difference in µTBS and NL between ER and SE strategies (p > 0.05). Most µTBS and NL values obtained for ED were lower and higher, respectively, than those for SD (p < 0.005). Additionally, the worst results (µTBS and NL) were observed for erosion with citric acid groups in comparison with erosion with soft-drink groups (p < 0.007). After 6y, µTBS was generally lower and NL higher for all substrates, adhesives, and strategies (p < 0.05), except for AMB, SBU, and TEU in dentine eroded with citric acid. The lowest µTBS and highest NL values were observed for ABU, FBU, OCU, PUB, PBE, and XEN in both types of eroded dentine and evaluation times (p < 0.002). CONCLUSION: The use of MDP-containing adhesives seems to be essential to maintain adhesion to eroded dentine. However, other factors such as acidity should be considered. CLINICAL SIGNIFICANCE: The bonding of eroded dentine is a challenge. However, the use of MDP-containing universal adhesives showed less degradation after long-term evaluation.
Assuntos
Colagem Dentária , Cimentos Dentários , Humanos , Adesivos Dentinários/química , Colagem Dentária/métodos , Cimentos de Resina/química , Água/química , Dentina , Resistência à Tração , Teste de Materiais , AdesivosRESUMO
Abstract To investigate the effect of the dimethyl sulfoxide combined with cross-linking agents on microtensile bond strength, silver nitrate penetration and in situ degree of conversion analysis of adhesives to the erosive dentin treatment with Cola-based soft drink. One hundred and sixty-six molars were assigned to 20 groups: (1) Treatment: Sound dentin; Erosive dentin; Erosive dentin treated with primer of dimethyl sulfoxide; Erosive dentin treated with DMSO primer containing proanthocyanidin and rivoflavin; (2) Adhesive systems: iBond Universal and Scotchbond Universal; and (3) adhesive strategy: etch-and-rinse or self-etch strategy. After restoration, specimens were sectioned into sticks to be tested. The data from microtensile bond strength (MPa), silver nitrate penetration (%) and in situ degree of conversion (%) were analyzed by (three- and two-factor ANOVA; Tukey's test α=5%). The application of dimethyl sulfoxide combined of not with cross-linkers improved all properties evaluated when compared to only erosive dentin treatment with Cola-based soft drink. However, only when dimethyl sulfoxide was combined to cross-linkers, the values of the microtensile bond strength, silver nitrate penetration and in situ degree of conversion in erosive dentin treatment with Cola-based soft drink was similar to sound dentin, for both adhesives and adhesive strategies. The application of dimethyl sulfoxide combined with the collagen cross-linking agent contributed to increasing the bond strength and degree of conversion in erosive lesion dentin, at the same time that significantly reduction of nanoleakage in this substrate.
Resumo Este estudo investigou o efeito do dimetil sulfóxido combinado a agentes de reticulação de colágeno na resistência de união à microtração, infiltração de nitrato de prata e análise do grau de conversão por Micro-Raman de sistemas adesivos universais para a dentina erosionada por refrigerante a base de Cola. Cento e sessenta molares foram divididos em 20 grupos: (1) Tratamento: Dentina sadia; Dentina erosionada; Dentina erosionada tratada com primer de dimetil sulfóxido; Dentina erosionada tratada com primer contendo 6,5% de proantocianidina e; Dentina erosionada tratada com primer contendo 0,1% de rivoflavina; (2) Sistemas adesivos: iBond Universal e Scotchbond Universal; e (3) estratégia adesiva: estratégia condicionamento e lavagem ou autocondicionate. Após a restauração, os espécimes foram seccionados em palitos e testados. Os dados dos três testes foram analisados estatisticamente (ANOVA de 2 e 3 fatores e teste de Tukey; α = 5%). A aplicação de dimetil sulfóxido combinado ou não agentes de reticulação de colágeno melhorou todas as propriedades avaliadas quando comparado a dentina erosionada. Entretanto, apenas quando o dimetil sulfóxido foi combinado com agentes de reticulação de colágeno, os valores de adesão a dentina, infiltração de nitrato de prata e grau de conversão em dentina erosionada foi semelhante a dentina sadia, para os dois adesivos e estratégias adesivas. A aplicação de dimetil sulfóxido combinado com agentes de reticulação de colágeno contribuiu para aumentar a resistência de união e o grau de conversão dentro da camada híbrida na dentina erodida, ao mesmo tempo que reduziu significativamente a nanoinfiltração neste substrato.
RESUMO
To investigate the effect of the dimethyl sulfoxide combined with cross-linking agents on microtensile bond strength, silver nitrate penetration and in situ degree of conversion analysis of adhesives to the erosive dentin treatment with Cola-based soft drink. One hundred and sixty-six molars were assigned to 20 groups: (1) Treatment: Sound dentin; Erosive dentin; Erosive dentin treated with primer of dimethyl sulfoxide; Erosive dentin treated with DMSO primer containing proanthocyanidin and rivoflavin; (2) Adhesive systems: iBond Universal and Scotchbond Universal; and (3) adhesive strategy: etch-and-rinse or self-etch strategy. After restoration, specimens were sectioned into sticks to be tested. The data from microtensile bond strength (MPa), silver nitrate penetration (%) and in situ degree of conversion (%) were analyzed by (three- and two-factor ANOVA; Tukey's test α=5%). The application of dimethyl sulfoxide combined of not with cross-linkers improved all properties evaluated when compared to only erosive dentin treatment with Cola-based soft drink. However, only when dimethyl sulfoxide was combined to cross-linkers, the values of the microtensile bond strength, silver nitrate penetration and in situ degree of conversion in erosive dentin treatment with Cola-based soft drink was similar to sound dentin, for both adhesives and adhesive strategies. The application of dimethyl sulfoxide combined with the collagen cross-linking agent contributed to increasing the bond strength and degree of conversion in erosive lesion dentin, at the same time that significantly reduction of nanoleakage in this substrate.