In vitro evaluation of the osteogenic and antimicrobial potential of porous wollastonite scaffolds impregnated with ethanolic extracts of propolis.

Context: The development of porous devices using materials modified with various natural agents has become a priority for bone healing processes in the oral and maxillofacial field. There must be a balance between the proliferation of eukaryotic and the inhibition of prokaryotic cells to achieve proper bone health. Infections might inhibit the formation of new alveolar bone during bone graft augmentation. Objective: This study aimed to evaluate the in vitro osteogenic behavior of human bone marrow stem cells and assess the antimicrobial response to 3D-printed porous scaffolds using propolis-modified wollastonite. Methodology: A fractional factorial design of experiments was used to obtain a 3D printing paste for developing scaffolds with a triply periodic minimal surface (TPMS) gyroid geometry based on wollastonite and modified with an ethanolic propolis extract. The antioxidant activity of the extracts was characterized using free radical scavenging methods (DPPH and ABTS). Cell proliferation and osteogenic potential using Human Bone Marrow Stem Cells (bmMSCs) were assessed at different culture time points up to 28 days. MIC and inhibition zones were studied from single strain cultures, and biofilm formation was evaluated on the scaffolds under co-culture conditions. The mechanical strength of the scaffolds was evaluated. Results: Through statistical design of experiments, a paste suitable for printing scaffolds with the desired geometry was obtained. Propolis extracts modifying the TPMS gyroid scaffolds showed favorable cell proliferation and metabolic activity with osteogenic potential after 21 days. Additionally, propolis exhibited antioxidant activity, which may be related to the antimicrobial effectiveness of the scaffolds against S. aureus and S. epidermidis cultures. The mechanical properties of the scaffolds were not affected by propolis impregnation. Conclusion: These results demonstrate that propolis-impregnated porous wollastonite scaffolds might have the potential to stimulate bone repair in maxillofacial tissue engineering applications.

Antibacterial and osteoinductive properties of wollastonite scaffolds impregnated with propolis produced by additive manufacturing.

Biocompatible ceramic scaffolds offer a promising approach to address the challenges in bone reconstruction. Wollastonite, well-known for its exceptional biocompatibility, has attracted significant attention in orthopedics and craniofacial fields. However, the antimicrobial properties of wollastonite have contradictory findings, necessitating further research to enhance its antibacterial characteristics. This study aimed to explore a new approach to improve in vitro biological response in terms of antimicrobial activity and cell proliferation by taking advantage of additive manufacturing for the development of scaffolds with complex geometries by 3D printing using propolis-modified wollastonite. The scaffolds were designed with a TPMS (Triply Periodic Minimal Surface) gyroid geometric shape and 3D printed prior to impregnation with propolis extract. The paste formulation was characterized by rheometric measurements, and the presence of propolis was confirmed by FTIR spectroscopy. The scaffolds were comprehensively assessed for their mechanical strength. The biological characterization involved evaluating the antimicrobial effects against Staphylococcus aureus and Staphylococcus epidermidis, employing Minimum Inhibitory Concentration (MIC), Zone of Inhibition (ZOI), and biofilm formation assays. Additionally, SaOs-2 cultures were used to study cell proliferation (Alamar blue assay), and potential osteogenic was tested (von Kossa, Alizarin Red, and ALP stainings) at different time points. Propolis impregnation did not compromise the mechanical properties of the scaffolds, which exhibited values comparable to human trabecular bone. Propolis incorporation conferred antibacterial activity against both Staphylococcus aureus and Staphylococcus epidermidis. The implementation of TPMS gyroid geometry in the scaffold design demonstrated favorable cell proliferation with increased metabolic activity and osteogenic potential after 21 days of cell cultures.

Evaluación de la fricción en arcos ortodóncicos de acero inoxidable con y sin recubrimiento vítreo aplicado por el método Sol-Gel / Friction evaluation in stainless steel arches with and withouth glass coating using the Sol-Gel method

Introducción: el propósito de este estudio in vitro fue comparar la fuerza de fricción estática y dinámica generada entre brackets y alambres de acero inoxidable con y sin recubrimiento vítreo aplicado por el método Sol-Gel. Métodos: en todas las pruebas de fricción fueron utilizados brackets (0,018 x 0,025”), alambres de acero inoxidable (0,016 x 0,016”) y ligaduras elásticas. Se realizó una caracterización con microscopia óptica y microscopia electrónica de barrido (SE M). La fuerza friccional fue evaluada utilizando una máquina de pruebas Testresources® en medio seco. Resultados: los resultados mostraron que el grupo de alambres de acero inoxidable sin modificación (grupo control) presentaron los valores más bajos de fuerza de fricción estática, seguido del grupo de alambres recubiertos por el método Sol-Gel (grupo Sol-Gel) y el grupo de alambres con tratamiento térmico (grupo térmico). Para la fricción dinámica, el grupo Sol-Gel mostró los valores más bajos, seguido del grupo control y el grupo térmico. Conclusión: los recubrimientos evaluados no mostraron mejor comportamiento friccional sobre brackets de acero inoxidable cuando son comparados con el grupo control.

Introduction: the aim of this in vitro study was to compare the static and dynamic frictional force generated between surfaces of metallic brackets and glass coated applied by the Sol-Gel method, and non coated wires. Methods: metallic brackets (0,018 x 0,025″), stainless steel wires (0,016 x 0,016″) and elastic ligatures were used in all frictional tests. All components were characterized using SEM and optical microscopy. The frictional force was evaluated using a machine of tests Testresources® in dry environment. Results: the results showed that the stainless steel wires without modification (control group) showed the lowest values of static friction force followed by the stainless steel wires group coated by Sol-Gel method and the wires group with thermic treatment (thermic group). For dynamic friction force, the Sol-Gel group showed the smallest values, followed by the control group and the thermal group. Conclusion: the evaluated coating did not show a better frictional performance applied on stainless steel brackets in comparison with the control group.

Evaluación in vitro de la resistencia friccional entre brackets cerámicos y arcos de acero inoxidable con y sin recubrimiento vítreo aplicado por el metodo sol-gel / In vitro evaluation of frictional resistance between ceramic brackets and orthodontic steel arches with and without glass coatings applied by sol-gel method

Introducción: comparar la resistencia friccional estática y dinámica in vitro entre brackets cerámicos y alambres de acero inoxidable con recubrimiento vítreo aplicado por el método Sol-Gel y sin él. Métodos: se prepararon 58 alambres de acero inoxidable AISI 304 de 0.016 x 0.016 con recubrimiento vítreo aplicado por Sol-Gel y sin él. Posteriormente se evaluó la resistencia a la fricción estática y dinámica in vitro de los alambres sobre brackets cerámicos de zafiro monocristalino y se caracterizaron las superficies en contacto por microscopia óptica y electrónica de barrido (SEM). Resultados: se encontraron diferencias estadísticamente significativas entre ambos grupos tanto para la fuerza de fricción estática (p = 0,000) como dinámica (p = 0,001). El grupo de los alambres recubiertos presentó una fuerza de fricción estática y dinámica mayor (estática: 1,78 ± 0,44 N, dinámica: 1,75 ± 0,49 N) que el grupo sin recubrimientos (estática: 1,37 ± 0,31 N, dinámica: 1,41 ± 0,27 N). La caracterización por SEM mostró que se producen defectos superficiales en los recubrimientos después de las pruebas de fricción. Conclusión: los recubrimientos evaluados no mostraron mejor comportamiento friccional sobre brackets de zafiro monocristalino cuando son comparados con el grupo control.

Introduction: to compare the in vitro static and dynamic frictional resistance between ceramic brackets and stainless steel wires with and without glass coatings applied by sol-gel method. Methods: 58 commercial stainless steel orthodontic wires AISI 304 (0.016 x 0.016 inch) were prepared with and without vitreous coating applied by Sol- Gel method. The in vitro static and dynamic frictional resistance of the wires on the mono-crystalline ceramic brackets were evaluated; also, the wire surfaces were characterized by means of Optical Microscopy and scanning electronic microscopy (SEM). Results: statistically significant differences were found between both groups under static (p = 0.000) as well as dynamic (p = 0.001) friction test. The friction values found in the coated group were higher (Static friction: 1.78 ± 0.44 N, Dynamic friction: 1.75 ± 0.49 N) than the group with no coating (Static friction: 1.37 ± 0.31 N, Dynamic friction: 1.41 ± 0.27 N). Characterization by SEM showed surface defects in both groups after the friction tests. Conclusion: the evaluated coatings did not perform better in terms of frictional behavior on sapphire mono-crystalline ceramic brackets when compared with the control group.

Dientes de bovino como sustituto de dientes humanos para su uso en la odontología. Revisión de literatura / Use of bovine teeth as replacement of missing human teeth. A review of literature

Los dientes humanos son similares morfológica e histológicamente a los de algunos mamíferos, pero los dientes bovinos presentan algunas características especiales como son: la composición histológica y su forma anatómica, que entre otras características, los hacen ideales para su utilización como sustitutos de los dientes humanos en investigaciones sobre materiales dentales...

Comparación de la reproductibilidad de dos materiales de impresión de hidrocoloide irreversible. Estudio “in Vitro” / Comparision of the reproducibility of two irreversible hydrocolloid

El hidrocoloide irreversible (alginato) es el material de impresión mas comúnmente utilizado es la elaboración de modelos diagnósticos.Este estudio comparo la seguridad en la reproductibilidad de dos alginatos: Jeltrate (Caulk, Co., USA) y Olympic (New Stetic Ltda., Colombia). Para ello se utilizó un modelo maxilar ideal con 12 dientes, al cual se le tomaron 12 impresiones con cada uno de los alginatos y luego se hizo el vaciado en yeso tipo IV. Sobre estos modelos se tomaron 8 mediciones con un microscopio de taller de indicación digital con una precisión de lectura de 0.001 mm.Los resultados mostraron que no hay diferencia significativa entre los troqueles obtenidos de los dos tipos de alginato evaluados; aunque una diferencia significativa se encontró cuando se comparo la distancia intermolar entre el modelo maestro y los modelos de yeso. Los modelos vaciados fueron de dimensiones mayores que el modelo maestro...

Computación evolutiva: una herramienta de modelamiento en ciencias de la salud / Evolutive computing: a modeling tool in health sciences

Este artículo presenta una revisión de la computación evolutiva como una alternativa en la generación de conocimiento, se exploran los conceptos básicos de la te´cnica y algunas aplicaciones en ciencias de la salud. Se presentan los aspectos más importantes en la modelación de sistemas y procesos biológicos. Estos modelos pueden ser utilizados para la toma de decisiones en la vida real.