OBJETIVO: avaliar as diversas cores de ligaduras elásticas do tipo modular da marca Morelli. METODOLOGIA: estas ligaduras foram estiradas em cilindros de aço inoxidável com diâmetro aproximado de um braquete de incisivo central superior, imersas em saliva artificial a 37ºC e tiveram suas forças medidas em uma máquina de ensaios de tração, antes da colocação nos estiletes (0h) e após 24 horas de imersão em saliva artificial. Os resultados foram obtidos através de um computador que opera conectado à máquina de tração e foram submetidos a testes estatísticos (ANOVA e Tuckey) com p<0,05. RESULTADOS E CONCLUSÕES: as médias das forças obtidas foram: md=0,3792KgF para 0h e md=0,1286KgF para 24h e o desvio padrão do percentual de degradação da força foi de 66,07% ± 2,31%. Diante dos resultados, pode-se concluir que existe uma diferença significativa entre as forças geradas em 0h e 24h. Em 0h, mesmo antes da ação do tempo e da imersão em saliva artificial, já existem diferenças significativas entre algumas cores, com valores mais altos (md=0,4024KgF) para a pérola e mais baixos (md=0,3511KgF) para a verde clara. Em 24h, também foram constatadas diferenças significativas, sendo que a distribuição das cores por grupos foi diferente da observada em 0h. As cores verde clara, vermelha, amarela e branca tiveram menor percentual de degradação da força, sendo a verde clara com melhor desempenho (62,60%). Já as cores pérola, prata e cinza demonstraram maior percentual, sendo a pérola com pior desempenho (69,23%).

metamaterials. Although typical metamaterials are produced in crystal-like repetitive structures, [3][4][5][6] this is not an absolute requirement, as for instance acoustical negative index materials have been realized as soft metafluids. [7] Here, we develop an injectable metamaterial specifically designed to provide dynamic tissue mechanical matching. Indeed, tissues have strongly non-linear elastic responses, [8] yet it remains a challenge to match more than a given single mechanical parameter. [9] We use here metamaterial design to provide, for the first time, dynamic matching of effective shear modulus over a wide range of deformation amplitudes in a biocompatible injectable. Our aim here is to apply the metamaterial development to soft tissue reconstruction in nearly arbitrary shapes, yet naturally following local tissue movement and mechanics.Disease, trauma, surgery, and aging can indeed result in loss of soft tissue, producing major medical demand for tissue reconstruction. [10,11] Reconstructive procedures should be minimally invasive to decrease patient burden and surgical complications. [12] Ideally, this is addressed by injectability through thin needles. [10] To match patient-specific defect geometries, surgeons desire in situ shapeability, [13] and most importantly, shape-and volume-stability following the procedure. Therefore, an ideal material-based A novel type of injectable biomaterial with an elastic softening transition is described. The material enables in vivo shaping, followed by induction of 3D stable vascularized tissue. The synthesis of the injectable meta-biomaterial is instructed by extensive numerical simulation as a suspension of irregularly fragmented, highly porous sponge-like microgels. The irregular particle shape dramatically enhances yield strain for in vivo stability against deformation. Porosity of the particles, along with friction between internal surfaces, provides the elastic softening transition. This emergent metamaterial property enables the material to reversibly change stiffness during deformation, allowing native tissue properties to be matched over a wide range of deformation amplitudes. After subcutaneous injection in mice, predetermined shapes can be sculpted manually. The 3D shape is maintained during excellent host tissue integration, with induction of vascular connective tissue that persists to the end of one-year follow-up. The geometrical design is compatible with many hydrogel materials, including cell-adhesion motives for cell transplantation. The injectable meta-biomaterial therefore provides new perspectives in soft tissue engineering and regenerative medicine.

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Objective: This cross-sectional observational study was designed to assess the biosafety conducts adopted by orthodontists, and possible differences regarding training time. Methods: Both the application of methods for sterilization/disinfection of instruments and materials, and the use of personal protective equipment (PPE) were collected through questionnaires via e-mail. Results: The questionnaires were answered by 90 orthodontists with a mean age of 37.19 ± 9.08 years and mean training time of 13.52 ± 6.84 years. Regarding orthodontic pliers, 63.23% use an autoclave, except 1 who does not perform any procedure. All participants use autoclave to sterilize instruments, and 95.6% of respondents perform cleaning with chemicals prior to sterilization. Most of them (65.56%) use an autoclave to sterilize orthodontic bands, with some still associating disinfection methods, while few (18.89%) do nothing at all. There was a high incidence of the answer “nothing” for the methods used for elastic, accessories, bandages, metal springs, and arches. All respondents use mask and gloves in attendance, 78.92% use aprons, 58.92% use protective goggles, and 50.01% use cap. Training time significantly influenced (p = 0.003) only the use of glutaraldehyde for sterilization/disinfection of pliers. Conclusions: The sterilization and cleaning of pliers, instruments, and bands, besides the use of PPE, received more uniform and positive responses, while other items suggest disagreements and possible failures. Only orthodontists trained for more than 13 years choose using glutaraldehyde for pliers sterilization/disinfection, the only adopted method with a significant difference in relation to training time.

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