Porous titanium for biomedical applications : an experimental study on rabbits

Objective: The aim of this study was to carry out an in vivo assessment of bone ingrowth in two different types of porous titanium -the first being completely porous, and the second with a porous surface and dense nucleus, manufactured by powder metallurgy- and to evaluate their mechanical properties. Study design: Ten scaffolds from each group were submitted to metallographic analysis and compression tests. Next, two scaffolds of each type were inserted into 14 rabbits, which were sacrificed 8 weeks after surgery. The samples were submitted for histological examination. Results: Metallographic analysis revealed interconnected pores, and the average interconnected pore diameter was about 360 mm, with 36% total porosity. The totally porous titanium samples and the titanium samples with porous surface and dense nucleus showed an average compressive strength of 16.19 MPa and 69.27 MPa, respectively. After 8 weeks, the animals showed bone ingrowth, even into the most internal pores. Conclusions: The pore morphology was effective in permitting bone ingrowth in both groups. Titanium scaffolds with a porous surface and dense nucleus showed the best mechanical properties and most adequate interface

Análise histomorfométrica de implantes de titânio puro com superfície porosa versus superfície rugosa

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (pO propósito deste estudo foi avaliar a reparação óssea ao redor de implantes de superfície porosa comparados com implantes de superfície rugosa, ambos confeccionados de titânio puro grau 2 por meio da técnica de metalurgia do pó. Os implantes foram inseridos em tíbias de coelhos. Foram utilizados neste estudo 7 coelhos machos, sendo que cada um recebeu 3 implantes de superfície porosa na tíbia esquerda e 3 implantes de superfície rugosa na tíbia direita. Os animais foram sacrificados 4 semanas após a cirurgia e os fragmentos das tíbias contendo os implantes foram submetidos à análise histológica e histomorfométrica, visando analisar a neoformação óssea na interface osso-implante. As médias (%) obtidas na análise histomorfométrica foram avaliadas por meio do teste estatístico t-student de amostras pareadas com nível de significância de 5%. Os resultados da análise histológica mostraram que a osseointegração foi obtida nos dois tipos de implantes com similar qualidade de tecido ósseo. Na análise histomorfométrica, verificaram-se médias de neoformação óssea na interface osso-implante de 79,69% ± 1,00 e 65,05 ± 1,23 para os implantes de superfície porosa e rugosa, respectivamente, e foi observada diferença estatisticamente significante entre os dois tipos de implantes com relação à quantidade de neoformação óssea. Concluiu-se que os implantes de superfície porosa contribuíram para a osseointegração devido à sua maior superfície de contato na interface osso-implante

Conteúdos em Áudio: o Uso do Podcast como Recurso Educacional na Disciplina de Histologia

Increased use of online tools and digital media along with the speed in which information becomes available over the last few years, asks for adaptations on the educational environments. Recently, due to restrictions imposed by the Covid-19 pandemic, the world has witnessed profound changes in the educational scenario, with a real disruption in the teaching-learning process, which has forcibly been mediated by digital interfaces. In the present work, an experience will be presented, within the scope of education carried out in other classrooms, and also carried out in a Dentistry course at a Brazilian public university. A podcast, with 20 episodes, was implemented as a complementary educational resource, in the Histology discipline. The podcast was made available on the Spotify platform and associated with an Instagram account for dissemination and placement of materials, such as summaries and photos from the course's slide bank. At the end of the school year, a form had been sent to assess the perception of students that listened to the podcast. The project reached 1,262 people, including 14 foreigners. From 87 participants who answered the form, 89.7% noticed a great improvement in their subject understanding and 96.6% rated the content as excellent. The results bring a successful experience during emergency remote teaching, reinforcing the possibility of adopting new digital technologies, which can privilege distant activities and with the potential to generate greater engagement and autonomy for students.    Keywords: Learning. Technology. Podcast. Histology.O crescente uso de ferramentas online e mídias digitais e a velocidade com a qual as informações tornam-se disponíveis ao longo dos últimos anos, vêm requerendo adaptações dos ambientes educacionais. Recentemente, devido às restrições impostas pela pandemia de Covid-19, o mundo presenciou profundas mudanças no cenário educacional, havendo uma verdadeira disruptura no processo de ensino e aprendizagem, que passou forçosamente a ser mediado pelas interfaces digitais. No presente trabalho será apresentada uma experiência, no âmbito das educações realizadas em outras presencialidades, desenvolvida em um curso de Odontologia de uma universidade pública brasileira, durante o período de pandemia. Um podcast, com 20 episódios, foi implementado como recurso educacional complementar, na disciplina de Histologia. O podcast foi disponibilizado na plataforma Spotify e associado a uma conta no Instagram para divulgação e veiculação de material, como resumos e fotos do banco de lâminas da disciplina. Ao término do ano letivo foi enviado um formulário para avaliar a percepção dos estudantes usuários do podcast. O projeto alcançou 1.262 pessoas, incluindo 14 estrangeiros. Dos 87 participantes que responderam o formulário, 89,7% perceberam grande melhora no entendimento da matéria após ouvir o podcast e 96,6% classificaram o conteúdo como excelente. Os resultados trazem uma experiência exitosa durante o ensino remoto emergencial, reforçando a possibilidade da adoção de novas tecnologias digitais, que possam privilegiar atividades à distância e com potencial de gerar maior engajamento e autonomia dos estudantes.   Palavras-chave: Aprendizagem. Tecnologia. Podcast. Histologia

Evaluation of dentists' knowledge of the use of oral exfoliative cytology in clinical practice

Oral exfoliative cytology (EC) is a rapid and practical complementary test that can be used in the diagnosis of various diseases. The objectives of this study were to assess dentists'knowledge of EC and to disseminate information on the technique. The study included 240 dentists from the city of Anapolis (Goias, Brazil) who answered a questionnaire regarding demographic data and data relating to EC and who then received information on the technique. The data revealed that 26.92% of the dentists did not know about EC. Among those who reported knowledge of EC, 33.91% did not know the procedures for performing the technique, and 85.38% had no experience with EC. In addition, 54.09% of the answers regarding the instrument used to collect the material and 56.82% of the answers concerning suitable fixatives were inappropriate. Although 73.02% of the dentists adequately identified the pathologies for which EC is recommended, it was concluded that the respondents had poor knowledge of EC. There is a need to increase dentists'awareness of this subject and of EC's use in diagnostic practices

Axial loads on implant-supported partial fixed prostheses for external and internal hex connections and machined and plastic copings: strain gauge analysis

The aim of this in vitro study was to use strain gauge (SG) analysis to compare the effects of the implant-abutment joint, the coping, and the location of load on strain distribution in the bone around implants supporting 3-unit fixed partial prostheses. Three external hexagon (EH) implants and 3 internal hexagon (IH) implants were inserted into 2 polyurethane blocks. Microunit abutments were screwed onto their respective implant groups. Machined cobalt-chromium copings and plastic copings were screwed onto the abutments, which received standard wax patterns. The wax patterns were cast in a cobalt-chromium alloy (n = 5): group 1 = EH/machined. group 2 = EH/plastic, group 3 = IH/machined, and group 4 = IH/plastic. Four SGs were bonded onto the surface of the block tangentially to the implants. Each metallic structure was screwed onto the abutments and an axial load of 30 kg was applied at 5 predetermined points. The magnitude of microstrain on each SG was recorded in units of microstrain (mu epsilon). The data were analyzed using 3-factor repeated measures analysis of variance and a Tukey test (alpha = 0.05). The results showed statistically significant differences for the type of implant-abutment joint, loading point, and interaction at the implant-abutment joint/loading point. The IH connection showed higher microstrain values than the EH connection. It was concluded that the type of coping did not interfere in the magnitude of microstrain, but the implant/abutment joint and axial loading location influenced this magnitude