PLGA+HA/ßTCP Scaffold Incorporating Simvastatin: A Promising Biomaterial for Bone Tissue Engineering.

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite/ß-tricalcium phosphate (PLGA+HA/ßTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% ßTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m/m) of this medication. Scaffolds were synthesized in a cylindric shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in phosphate-buffered saline at 37°C under constant stirring for 7, 14, 21, and 28 days. Nondegraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro-, meso-, and micropores in the polymer structure with HA/ßTCP particles homogeneously dispersed. Chemical and thermal analyses presented similar results for both PLGA+HA/ßTCP and PLGA+HA/ßTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/ßTCP and PLGA+HA/ßTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/ßTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

In vitro evaluation of bilayer membranes of PLGA/hydroxyapatite/ß-tricalcium phosphate for guided bone regeneration.

Membranes for guided bone regeneration represent valuable resources, preventing fibroblast infiltration and aiding anatomical bone reconstruction. Nonetheless, available membranes lack bone regenerative capacity, suitable mechanical behavior, or adequate degradation profile. Therefore, to overcome these limitations, this study developed bilayer membranes with a dense layer (dry phase inversion) of PLGA (poly(lactic-co-glycolic acid)):HAp (hydroxyapatite) - 95:05 (wt%) - and an electrospun layer of PLGA and HAp:ß-TCP (ß-tricalcium phosphate) with ratios of 60:40, 70:30 and 85:15 (wt%), evaluating its mechanical, morphological and in vitro properties. The bilayer membranes displayed adequate interlayer adhesion, dense layer pore size of 4.20 µm and electrospun layer with porosity degree of 38.2%, thus capable of preventing fibroblast infiltration while allowing osteoblast migration and nutrient permeation. They also showed Tg of 82 °C and higher storage modulus, which was constant up to 54.6 °C, characteristics important for membrane implantation and use with no mechanical compromise. In vitro degradation mass loss was only 10% after 60 days, a profile suitable for the application requirement. Membranes with calcium phosphates had better osteoblast attachment, proliferation and migration. Taken together, results indicate the great potential of PLGA/HAp/ß-TCP bilayer membranes on bone reconstruction with proper degradation profile, morphology, mechanical behavior and bone regenerative capacity.

Titanium coated with poly(lactic-co-glycolic) acid incorporating simvastatin: Biofunctionalization of dental prosthetic abutments.

OBJECTIVE: To propose a biofunctionalized prosthetic abutment by analyzing physico-chemical and morphological properties, simvastatin (SIM) release, and biocompatibility of titanium (Ti) disks coated with poly(lactic-co-glycolic) acid (PLGA) incorporating SIM. METHODS: Titanium disks (8 × 3 mm) were distributed into four groups: Ti: pure Ti; Ti + PLGA: Ti coated with PLGA; Ti + PLGA + SIM6%: Ti + PLGA with 6% SIM; and Ti + PLGA + SIM0.6%: Ti + PLGA incorporating 0.6% SIM. PLGA was prepared through chloroform evaporation technique. After complete dissolution of PLGA, SIM was diluted in the solution. Ti + PLGA, Ti + PLGA + SIM6%, and Ti + PLGA + SIM0.6% were dip coated with PLGA and PLGA + SIM, respectively. Samples were sterilized by ethylene oxide. For SIM release assay, disks were submerged in PBS, pH 7.4, 37°C, 30 rpm up to 600 hours. At different time intervals, SIM was quantified by spectrophotometry (238 nm). For characterization of the biomaterial components, it was performed Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy (SEM), optical profilometry, and atomic force microscopy. Biocompatibility analyses were performed by MTS colorimetric assay on murine fibroblasts L929, human gingival fibroblasts (HGFs), and stem cells from human exfoliated deciduous teeth (SHEDs). Absorbance was measured at 490 nm, and percentages of viable cells were calculated in relation to positive control (Ti). SEM images were obtained to verify cell adhesion and morphology. One-way ANOVA followed by Tukey's post hoc test was applied (P < 0.05) for statistical analyses. RESULTS: SIM release was slow and continuous, reaching about 21% of the incorporated SIM after 600 hours. Topographical analyses revealed success in coating Ti disks with PLGA incorporating SIM. Regarding biocompatibility test, Ti + PLGA + SIM0.6% showed the highest percentage of L929 viability at days 3 and 7. There was no significant difference for Ti, Ti + PLGA, and Ti + PLGA + SIM0.6% groups on cell viability of both SHEDs and HGFs at days 3 and 7. SEM corroborates that SHEDs and HGFs were able to adhere and proliferate on Ti, Ti + PLGA, and Ti + PLGA + SIM0.6% surfaces. CONCLUSION: A slow and controlled release of SIM was achieved, attributed to a diffusional mass transfer mechanism. Moreover, a homogenous coating topography was obtained. Additionally, 0.6% SIM incorporated into PLGA coating improved fibroblasts L929 viability compared to titanium or PLGA. Also, 0.6% SIM incorporated into PLGA promoted cell viability of about 100% for HGFs and approximately 150% for human mesenchymal stem cells. Therefore, this study allows to consider the use of PLGA-coated titanium incorporating SIM as a biofunctionalized abutment for dental implants.

Release of simvastatin from scaffolds of poly(lactic-co-glycolic) acid and biphasic ceramic designed for bone tissue regeneration.

The aim of this study was to evaluate the release of simvastatin from scaffolds composed of poly(lactic-co-glycolic) acid (PLGA) and biphasic ceramic designed for bone engineering and to assess the physico-chemical and mechanical properties of the scaffolds. Samples with 30% and 70% porosity were obtained with 0, 2, 5, and 8 wt %. of simvastatin through the solvent evaporation technique and leaching of sucrose particles. Scaffold degradation and simvastatin release were evaluated in phosphate-buffered saline. Scaffolds were analyzed by scanning electron microscopy and microtomography for two-dimensional and three-dimensional morphological characterization of the porosity, connectivity, and intrinsic permeability. The mechanical characterization was conducted based on the compressive strength and the chemical characterization by differential scanning calorimetry and energy dispersive X-ray spectroscopy. Gradual and prolonged simvastatin release from the scaffolds was observed. The release followed the Korsmeyer kinetics model with the predominance of case II transport for 30% porosity scaffolds, and anomalous behavior for the 70% porosity samples. Simvastatin release was also influenced by the slow scaffold degradation due to the strong chemical interaction between simvastatin and PLGA, as observed by differential scanning calorimetry. The scaffolds presented spherical and sucrose crystal-shaped pores that resulted in a homogenous porosity, with a predominance of open pores, ensuring interconnectivity. Simvastatin incorporation into the scaffolds and increased porosity did not influence the mechanical properties. The scaffolds presented gradual and prolonged simvastatin release, with satisfactory physico-chemical and mechanical properties. The scaffolds presented gradual and prolonged simvastatin release, with satisfactory physico-chemical and mechanical properties, a promise for applications in bone regeneration. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2152-2164, 2019.

CELL growth and viability analysis in poli membranes (L-lactic acid-CO-glycolic acid): an in vitro study / Análise do crescimento e viabilidade celular em membranas de poli (L-ácido láctico-CO-ácido glicólico): um estudo in vitro

ABSTRACT Objective: Performing an in vitro evaluation of the biological effects on cell growth and viability of fibroblasts in PLGA membranes with and without simvastatin. Methods: Two groups of resorbable synthetic polymeric membranes were used: PLGA, with and without simvastatin, cut into a suitable format to fit to 24 thermometric wells. Fibroblasts were grown on resorbable membranes and evaluated for proliferation and viability at 24, 48 and 72 hours after the beginning of cultivation, being the tests performed in triplicate. For the cell growth analysis, the Trypan blue exclusion method was applied, while cell viability was observed by the MTT test. The results were statistically analyzed applying the Two-Way ANOVA, followed by the Bonferroni test, with 95% confidence interval and P value smaller than 0.05 was accepted as statistically significant. Results: Statistical difference (p <0.01) was seen between the control group (2.16x104 ± 0.51 cells) and the PLGA group with simvastatin (1.58x104 ± 0.36 cells) in the 48-hour period. After 72 hours, statistical differences (p <0.001) were observed between the PLGA group with simvastatin (1.66x104 ± 0.49 cells) and the PLGA group without simvastatin (2.25x104 ± 0.2 cells) when compared to the control group (2.81x104 ± 0.33 cells) for cell proliferation. Statistical differences (p <0.05) were observed between the control group (0.27 ± 0.05) and the PLGA group with simvastatin (0.21 ± 0.03). Likewise, a statistical difference (p <0.001) was seen between the PLGA group without simvastatin (0.19 ± 0.02) and the control group after 24 hours. In the 48 - 72-hour period, statistical differences (p <0.001) were observed between the control group (0.36 ± 0.09 and 0.55 ± 0.05, after 48 and 72 hours respectively) and the PLGA group without simvastatin (0.26 ± 0.05 and 0.34 ± 0.07, after 48 and 72 hours respectively), as well as in the PLGA group with simvastatin (0.27 ± 0.04 and 0.31 ± 0, 04, after 48 and 72 hours respectively) for the cell viability test. Conclusion: The association of simvastatin to PLGA membranes had an inhibitory effect on fibroblast proliferation, as well as induced a reduction in cell viability. Thus, the use of PLGA along with simvastatin may assist in guided bone regeneration.

RESUMO Objetivo: Esse trabalho avaliou, in vitro, os efeitos biológicos no crescimento e viabilidade celular de fibroblastos em membranas de PLGA com e sem sinvastatina. Materiais e métodos: Foram utilizados dois grupos de membranas reabsorvíveis de polímeros sintéticos: PLGA com sinvastantina e sem sinvastantina, recortadas em formato apropriado para adaptar nas placas de 24 wells termométricas. Os fibroblastos foram cultivados em membranas reabsorvíveis, sendo avaliadas em relação à proliferação e viabilidade em 24, 48 e 72 horas após o início do cultivo, os testes foram realizados em triplicata. Para a análise do crescimento celular foi utilizado o método de exclusão vital azul de Tripan, enquanto a viabilidade celular foi observada pelo teste MTT. Os resultados obtidos foram estatisticamente analisados utilizando Two-Way ANOVA, seguido pelo teste de Bonferroni, com intervalo de confiança de 95% e um valor de P inferior a 0,05 foi aceito como estatisticamente significativo. Resultados: Foi observado diferença estatística (p<0,01) entre o grupo controle (2,16x104 ± 0,51 células) e o grupo PLGA com sinvastatina (1,58x104 ± 0,36 células) no período de 48 horas. Após 72 horas, diferenças estatísticas (p<0,001) foram observadas entre o grupo PLGA com sinvastatina (1,66x104 ± 0,49 células) e o grupo PLGA sem sinvastatina (2,25x104 ± 0,2 células) em comparação ao grupo controle (2,81x104 ± 0,33 células) quanto a proliferação celular. Diferenças estatísticas (p<0,05) foram observadas entre o grupo controle (0,27 ± 0,05) e o grupo PLGA com sinvastatina (0,21 ± 0,03), da mesma forma que, diferença estatística (p<0,001) foram observadas entre o grupo PLGA sem sinvastatina (0,19 ± 0,02) e grupo controle após 24 horas. No período de 48 horas e 72 horas diferenças estatísticas (p<0,001) foram observadas entre o grupo controle (0,36 ± 0,09 e 0,55 ± 0,05, após 48 e 72 horas respectivamente) e o grupo PLGA sem sinvastatina (0,26 ± 0,05 e 0,34 ± 0,07, após 48 e 72 horas respectivamente), assim como, o grupo PLGA com sinvastatina (0,27 ± 0,04 e 0,31 ± 0,04, após 48 e 72 horas respectivamente) quanto ao teste de viabilidade celular. Conclusão: A associação de sinvastatina às membranas de PLGA apresentou um efeito inibitório na proliferação de fibroblastos, bem como induziu uma redução da viabilidade celular destes, deste modo, sugere-se a utilização de PLGA associado à sinvastatina como uma ferramenta para auxiliar na regeneração óssea guiada.

Ridge Preservation After Maxillary Third Molar Extraction Using 30% Porosity PLGA/HA/ß-TCP Scaffolds With and Without Simvastatin: A Pilot Randomized Controlled Clinical Trial.

OBJECTIVE: To evaluate clinically and radiographically, in humans, the healing of maxillary third molars postextraction sockets after application of different ridge preservation techniques 3 months after tooth extraction. MATERIALS AND METHODS: Twenty-six sockets (13 patients) were randomly assigned to 4 treatment modalities: deproteinized bovine bone mineral with 10% collagen (DBBM-C), poly(D,L-lactide-co-glycolide) with hydroxyapatite/ß-TCP scaffold (PLGA/HA), PLGA/HA/ß-TCP with 2.0% simvastatin scaffold (PLGA/HA/S), and spontaneous healing (control). Clinical complications were assessed, and cone-beam computed tomographies were taken in 5 patients 3 months after surgeries. For statistical purposes, the Fisher exact test was used (P < 0.05). RESULTS: After 3 months, 6 of 9 grafts from the PLGA/HA group were lost (P < 0.05). PLGA/HA/S' loss was only 2 of 8 (P > 0.05), but no loss was observed in the DBBM-C group. Pain was present in 3 of 8 sites that lost the graft (37.5%) (P > 0.05) and infection in 1 of 8 (12.5%) (P > 0.05), with these only occurring in the PLGA/HA group. CONCLUSIONS: Poly (D, L-lactide-co-glycolide) with hydroxyapatite/ß-TCP (PLGA/HA/ß-TCP) scaffolds, with and without simvastatin, failed to obtain the initial expected results and presented more complications. Scaffolds with simvastatin showed to be superior, with less clinical complications than scaffolds without simvastatin.

Pesquisa a serviço da sociedade: área de concentração de Implantodontia do PPGO/UFSC / Scientific research for social benefits: oral Implantology at the PPGO/UFSC

Este manuscrito descreve as atividades desenvolvidas na PPGO/UFSC, concentradas em três linhas de pesquisa: 1) neoformação óssea peri-implantar; 2) engenharia tecidual; e 3) microbiologia aplicada à Implantodontia. Na linha um, diversos métodos analíticos quantitativos e qualitativos (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) têm sido usados para investigação de diferentes intensidades de corrente elétrica na superfície do Ti-cp e Ti-6Al-4V, quando imersos em meios fisiológicos simulados, na adsorção de proteínas, proliferação celular com fibroblastos, queratinócitos e osteoblastos. Na linha dois, o desenvolvimento in vitro de um arcabouço poroso de PLGA e cerâmica bifásica, incorporado com sinvastatina, sera testado in vivo na resposta de fibroblastos gengivais provenientes de cultura primaria, em meio de cultura com plasma rico em plaquetas (PRP), depositado sobre matriz dérmica acelular e matriz de celulose bacteriana (BC). A linha três concentra a atuação com dois centros internacionais (Belgica e EUA) para a incorporação de compostos antibiofilme em polímeros biocompatíveis, e verificação da eficiência de um método de liberação prolongada de antibióticos incorporados em superfícies nanoestruturadas. Estes projetos devem resultar em melhoria de saúde aos pacientes e no desenvolvimento econômico e social da comunidade.

This paper describes the activities developed at PPGO/UFSC divided into three research lines: 1) peri-implant bone neoformation; 2) tissue engineering, and 3) microbiology applied to implant dentistry. On the first line, several quantitative and qualitative (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) analytical methods have been used to investigate the different electric current intensities on Ti c.p. and Ti6Al4V implant surfaces when immersed into simulated physiological media, protein adsorption, cell proliferation with fibroblasts, keratinocytes, and osteoblasts. On the second line, the in vitro development of a 3D PLGA and biphasic ceramic, simvastatin-incorporated scaffold will be tested in vivo for gingival fibroblast response from primary culture in platelet-rich plasma (PRP) enriched vehicle over an acellular dermal (Sure- Derm) and bacterial cellulose matrix (BC). For line three, two international research centers (Belgium and USA) joined common efforts to incorporate polymer anti-biofi lm compounds and to verify the efficiency of a prolonged release method for antibiotics attached to nanostructured surfaces. All those projects must result in better health conditions and social and economic development of our community.

Analysis of tensile strength of poly(lactic-coglycolic acid) (PLGA) membranes used for guided tissue regeneration

Introduction: The challenge of restoring patient's function that presented some loss of an organ or tissue encourages the Tissue Engineering and Biotechnology to develop materials that promote bone regeneration. Poly(lactic-co-glycolic acid) (PLGA) copolymer is among of the most biomaterials used. Objective: To evaluate the tensile strength of PLGA membranes at different conditions of humidity and temperature. Material and methods: PLGA membranes were hourglass-shape cut and prepared at three different conditions of temperature and humidity (n = 10): (I) dry membrane at environment temperature of about 20ºC (control group), (II) moist membrane plasticized at 55ºC, (III) moist membrane plasticized at 55ºC, which subsequently underwent cooling. Subsequently, the membranes were subjected to tensile tests in a universal testing machine (DL-2000, EMIC) at 1.0 mm/min. Data was submitted to ANOVA and Tukey's test (p < 0.05). Results: Group I showed the highest tensile strength mean (16.7 ± 1.9a MPa, p = 0.0022). There was no statistically significant difference between the means of groups II (14.6 ± 1.4 MPab) and III (13.9 ± 1.7 MPab). Conclusion: The dried PLGA membranes showed higher tensile strength than the membranes that were only either plasticized or cooled.

Mini-implante: um novo conceito em ancoragem ortodôntica: [revisão] / Mini screws: a new concept in orthodontics anchorage: [review]

O mini-implante é um dispositivo utilizado pelos ortodontistas como um método de ancoragem, eliminando em grande parte a necessidade de cooperação dos pacientes e ampliando as possibilidades de tratamento em diversos tipos de movimentos ortodônticos. O presente trabalho teve como objetivo realizar uma revisão da literatura, discorrendo sobre as diversas aplicações clínicas do miniimplante, suas vantagens e desvantagens, o procedimento cirúrgico, demonstrar a técnica para localização exata do sitio de instalação do mini-implante e ainda relatar um caso clínico de paciente portadora de sintomatologia dolorosa da ATM, mordida cruzada e desvio da linha média, onde o plano de tratamento foi a utilização de mini-implante associado a barra transpalatina. De acordo com a literatura consultada pode-se concluir que o mini-implante é bastante efetivo como dispositivo de ancoragem.

The mini screws are devices used by orthodontists as a method of anchorage, largely eliminating the need for patient cooperation and expanding the possibilities for treatment in various types of orthodontic movements. This study aimed to conduct a review of the literature, discussing the various clinical applications of the mini screw, their advantages and disadvantages, surgical procedures, demonstrate exact localization technique of the installation site mini screw and also report a case of a patient with symptoms of TMJ pain, cross bite and deviation midline, where the treatment plan was the use of mini-implants associated with transpalatal bar. According to the literature and after completion of the case, one can conclude that the mini screw was quite effective as a method of anchorage the correction of midline.

Hidroxiapatita microgranular em pulpotomias de molares decíduos de humanos: avaliaçäo clínica e radiográfica / Microgranular hidroxyapatite in pulpotomy of human deciduous molars: clinical and radiographical evaluation

O propósito deste estudo foi avaliar 42 molares decíduos submetidos à pulpotomia, por indicaçäo clínica, cujo capeamento pulpar foi feito com hidroxiapatita microgranular sintetizada no Departamento de Bioquímica da Faculdade de Odontologia de Bauru da Universidade de Säo Paulo. O material capeador foi usado em 21 dentes sob a forma de material pó, e 21 dentes na forma de pasta (21), sendo esta pasta preparada no momento de intervençäo, por meio da adiçäo de uma soluçäo antiinflamatória ao pó de hidroxiapatita. Após o período de 6 meses foram realizadas análises clínica e radiográfica. Com base nos resultados obtidos, segundo as condiçöes experimentais em que foi realizado este trabalho, podem-se verificar que: a análise radiográfica quando associada a análise clínica como controle pós-operatório é mais segura que somente a análise clínica; o material capeador pulpar na forma de pasta pareceu ser melhor aceito pelos tecidos pulpares que o na forma de pó; a adiçäo de uma soluçäo antiinflamatória ao pó para formar a pasta pode ter sido responsável pela tendência de maior sucesso com o material na forma de pasta; a hidroxiapatita microgranular pode ser considerada uma opçäo como material regenerador na técnica de pulpotomia em dentes decíduos

Fusäo na dentiçäo decídua: apresentaçäo de caso clínico e alternativa de tratamento / Fusion in deciduous teeth: management and case relate

A fusäo e a geminaçäo representa 1 por cento das anomalias dentárias. Em crianças de pouca idade, onde há necessidade de extraçäo é importante restabelecer a funçäo e a estética. Nestes casos, a colaboraçäo do paciente no tratamento nem sempre é positiva sendo necessário o uso de uma técnica reabilitadora simples e eficaz. A reabilitaçäo de uma prótese adesiva no local foi o tratamento de eleiçäo neste caso apresentado

Coroas de aço inoxidável em odontopediatria / The stainless steel crown in pedodontics

Devido à importância das coroas de aço em odontopediatria, muitas técnicas operatórias têm sido apresentadas com o objetivo de aumentar sua resistência e adaptaçäo. Uma revisäo de literatura a este respeito será apresentrada