Polymeric Material With Controlled Release of Antimicrobial Agents for Medical Application

@#Introduction: Nowadays the use of synthetic polymers has become an integral part of modern medicine. Poly(2-hydroxyethyl methacrylate) has attracted special attention for therapeutic use. The objective of this study was to develop novel polymeric material based on poly(2-hydroxyethyl methacrylate) by addition of water as pore-forming agent and antimicrobial components, which would differ from similar materials by controlled release of active substances. Methods: The antimicrobial release kinetics study materials were immersed into distilled water followed by sampling and measuring their concentration. Concentration of chlorhexidine bigluconate and metronidazole was determined using spectrophotometric method and decamethoxine by photocolorimetric method based on reaction with eosin. The swelling rate was determined by gravimetric method. Results: Conventional dressing materials, after being soaked with antiseptic solutions, have demonstrated limited abilities in releasing active substances. Gauze pads were found to release antimicrobials during a short period of time reaching 50–80 % for decamethoxine containing samples and almost 100 % for those with metronidazole and chlorhexidine bigluconate at 2 h of observation. No study active substances were released from activated charcoal dressings. Similar results were obtained with porcine xenografts. Unlike the above mentioned dressing materials, modified polymer matrix based on poly(2-hydroxyethyl methacrylate) showed the controlled release of antimicrobial substances into water medium. Study material containing 3.0 % of decamethoxine and 76.3 % of water demonstrated optimal efficiency in the rate and duration of release, exerting high physical and mechanical properties. Conclusion: The synthesized polymers are similar to conventional dressings in antimicrobial release kinetics, but in some characteristics they are better for practical application.

Pulp fibroblast cell apoptosis after application of hema dentine bonding material with ethanol and water solvent

Abstract The most common main materials for dentin bonding for composite resin restoration is 2-hydroxyethyl methacrylate (HEMA). HEMA has beneficial physical and chemical properties, and stable, yet toxic. The addition of ethanol or water, may reduce the toxic effect of HEMA. Ethanol solvent has lower H-bonding capacity compared to water solvent, so it can bind less free radicals from the residual monomer. This study aimed to analyze apoptosis due to dentine bonding application with ethanol and water solvent. Fibroblast culture cells were obtained from extracted third molar, by means of tripsinasion method. The cells were divided into 4 groups as reached confluent: cell culture without treatment as control, cell culture with scaffold chitosan, cell culture with scaffold and polymerized dentin bonding with ethanol or water solvent. Apoptosis observation was conducted using immunohistochemistry method with ethidium bromide acridin orange staining, under fluorescent microscope with 40´ magnification. There was a significant difference among groups (p=0.0001), yet no differences found between different solvent. Apoptosis rate in fibroblast cells culture exposed to HEMA bonding with ethanol solvent was 67%, while the cells exposed to HEMA bonding with water solvent was 44%. The effect of dentin bonding with ethanol solvent and water solvent towards apoptosis rate of pulp fibroblast cells is not different.

Resumo Os principais materiais para adesão dentinária em restaurações de resina composta são o 2-hidroxietil metacrilato (HEMA). O HEMA possui propriedades físicas e químicas benéficas e estáveis, ainda que tóxicas. A adição de etanol ou água pode reduzir o efeito tóxico do HEMA. O solvente etanol possui uma menor capacidade de ligação H em comparação com o solvente água, de modo que pode ligar menos radicais livres do monômero residual. Este trabalho teve como objetivo analisar a apoptose pela aplicação de adesivos dentinários com solventes etanol e água. Células de cultura de fibroblastos foram obtidas a partir do terceiro molar extraído, por meio do método de tripsinaion. As células foram divididas em 4 grupos como confluentes: cultura celular sem tratamento como controle, cultura celular com arcabouço de quitosana, cultura celular com arcabouço e adesivo dentinário polimerizado com solvente etanol ou água. A observação da apoptose foi realizada utilizando o método imunohistoquímico com coloração com brometo de etídio e acridina laranja, sob microscópio de fluorescência com aumento de 40´. Houve uma diferença significativa entre os grupos (p = 0,0001), mas não houve diferenças entre os solventes. A taxa de apoptose em cultura de células de fibroblastos expostos à adesão baseada em HEMA com solvente etanol foi de 67%, enquanto as células expostas à adesão baseada em HEMA com solvente de água foi de 44%. O efeito da adesão dentinária com solvente etanol e solvente água sobre a taxa de apoptose de células de fibroblastos de polpa não é diferente.

Investigation of flexural strength and cytotoxicity of acrylic resin copolymers by using different polymerization methods

PURPOSE: The aim of this study was to appraise the some mechanical properties of polymethyl methacrylate based denture base resin polymerized by copolymerization mechanism, and to investigate the cytotoxic effect of these copolymer resins. MATERIALS AND METHODS: 2-hydroxyethyl methacrylate (HEMA) and isobutyl methacrylate (IBMA) were added to monomers of conventional heat polymerized and injection-molded poly methyl methacrylate (PMMA) resin contents of 2%, 3%, and 5% by volume and polymerization was carried out. Three-point bending test was performed to detect flexural strength and the elasticity modulus of the resins. To determine the statistical differences between the study groups, the Kruskall-Wallis test was performed. Then pairwise comparisons were performed between significant groups by Mann-Whitney U test. Agar-overlay test was performed to determine cytotoxic effect of copolymer resins. Chemical analysis was determined by FTIR spectrum. RESULTS: Synthesis of the copolymer was approved by FTIR spectroscopy. Within the conventional heat-polymerized group maximum transverse strength had been seen in the HEMA 2% concentration; however, when the concentration ratio increased, the strength decreased. In the injection-molded group, maximum transverse strength had been seen in the IBMA 2% concentration; also as the concentration ratio increased, the strength decreased. Only IBMA showed no cytotoxic effect at low concentrations when both two polymerization methods applied while HEMA showed cytotoxic effect in the injection-molded resins. CONCLUSION: Within the limitations of this study, it may be concluded that IBMA and HEMA may be used in low concentration and at high temperature to obtain non-cytotoxic and durable copolymer structure.

Investigation of bonding properties of denture bases to silicone-based soft denture liner immersed in isobutyl methacrylate and 2-hydroxyethyl methacrylate

PURPOSE: The purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time. MATERIALS AND METHODS: Polymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (alpha=0.05). RESULTS: The highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063). CONCLUSION: Immersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group.