Avaliação do efeito antimicrobiano em parafuso protético de implantes revestido com filme de carbono tipo diamante dopados com prata depositado por plasma / Evaluation of antimicrobial action in prosthetic screws of implants with diamond-like carbon films doped with plasma deposited silver

Apesar da confiabilidade, as falhas mecânicas e biológicas das reabilitações protéticas sobre implantes ainda são persistentes. A capacidade altamente adaptativa das bactérias e sua colonização na superfície dos implantes e componentes protéticos ainda hoje é um sério problema clínico, causando mucosite e peri-implantite. O objetivo do trabalho foi avaliar o efeito antimicrobiano do fino filmes de carbono tipo diamante (DLC) dopado com nanopartículas de prata, depositado nos parafusos protéticos. Os filmes de DLC e DLC-Ag foram depositados pelo processo conhecido como PECVD (Plasma Enhanced Chemical Vapour Deposition). A caracterização do material foi realizada em discos da liga Ti6Al4V pelas análises scratch test, espectroscopia de espalhamento Raman, perfilometria mecânica, goniometria e espectroscopia de energia dispersiva (EDS). A atividade antimicrobiana foi avaliada utilizando uma cepa padrão de Enterococcus faecalis (ATCC 29212). Para avaliar a efetividade dos filmes depositados, foram realizados ensaios nos discos e nos parafusos (isolados e no modelo implante/pilar). Foram utilizados implantes hexágono externo de plataforma regular 4,1 mm com os respectivos pilares. Para todas as análises, as amostras foram divididas em 3 grupos de acordo com o tipo de tratamento: Grupo controle (sem tratamento); Grupo DLC, amostras revestidas com filme de DLC, Grupo DLC-Ag, amostras revestidas com filme de DLC com prata. As amostras foram analisadas por MEV. Também foi avaliada a citotoxicidade dos filmes frente a células de fibroblastos (3T3) através do ensaio de MTT. A caracterização dos filmes por espectroscopia de espalhamento raman e EDS, apresentaram resultados característicos ao DLC e DLC-Ag, como uma distribuição homogênea de carbono, prata e silício. As análises de scratch test, perfilometria mecânica e goniometria, apresentaram filmes com características hidrofóbicas, sendo DLC-Ag o grupo de maior rugosidade e coeficiente de atrito. Os dados obtidos foram analisados estatisticamente com auxílio do programa GraphPad Prism versão 9.0 (GraphPad Software Inc., San Diego, CA, USA) e realizado os testes ANOVA e de Tukey para comparações entre os grupos (discos), e os testes Kruskal-Wallis e post-hoc de Dunn (parafusos). O nível de significância para todos os testes foi estabelecido em 5%. Os resultados demonstraram que a deposição do filme de DLC e DLC-Ag apresentaram redução de maneira significativa (p<0,05) na contagem de UFC/ml nos discos e parafusos isolados. Porém a dopagem com prata não trouxe um resultado superior ao filme DLC e ambos os materiais se apresentaram como não citotóxico. Concluímos que o revestimento com DLC e DLC-Ag é um material promissor, com efeito antimicrobiano, porém com limitação de aplicação (AU)

Despite the reliability, the mechanical and biological failures in rehabilitating implantsupported dental are still persistent. Mucositis and peri-implantitis are still severe clinical problems due to the high adaptive capacity of bacteria that colonize the surface of implants and prosthetic components. The present study aimed to evaluate, in vitro, the antimicrobial action of thin films of diamond-like carbon (DLC) doped with silver nanoparticles, deposited on prosthetic screws. The deposition of the films was performed by PECVD (Plasma Enhanced Chemical Vapor Deposition). The characterizations were performed of both deposited samples and control (Ti6Al4V) by scratch test analysis, raman scattering spectroscopy, mechanical profilometry, goniometry, and energy dispersive spectroscopy (EDS). The antimicrobial was evaluated activity against Enterococcus faecalis (ATCC 29212). To evaluate the effectiveness of the deposited films, tests were performed on disks and screws (isolated and on the implant/abutment model) Using 30 regular platforms with 4.1 mm external hexagon implants with the respective abutments, distributed into 3 groups according to the type of prosthetic screw treatment (n=10): Group control screw (no treatment); Group screw coated with DLC film, Group screw coated with DLC film doped with silver nanoparticles (Ag-DLC). The samples were also analyzed by SEM The cytotoxicity of the films against (3T3) fibroblast cells was also assessed using the MTT assay. The caracterization was performed from raman spectroscopy and EDS, showed results which are characteristics of DLC and Ag-DLC films, such as a homogeneous distribution of carbon, silver and silicon. The scratch test, mechanical profilometry and goniometry analyzes showed films with hydrophobic characteristics, with Ag-DLC being the group with the higher coefficient of friction values and roughness Data were statistically analyzed using GraphPad Prism version 9.0 (GraphPad Software Inc., San Diego, CA, USA). ANOVA and Tukey tests were performed, followed by comparisons between groups (disks) and Kruskal-Walis and post-hoc Dunn (screw) tests The significance level for all tests was set at 5%. The results demonstrated that the deposition of the DLC and Ag-DLC film showed a significant reduction (p<0.05) in the CFU/ml count compared to the contro, disks and isolated screwl. However, silver doping did not enhance the DLC films; both materials were non-cytotoxic. It concludes that titanium alloys coated with DLC and Ag-DLC are promising materials with antibacterial properties to prevent peri-implantitis (AU)

Survival Analysis and Torque Loosening of Experimental Screw After Mechanical Performance for Micro Conical Abutment

ABSTRACT: The most common failure in implantology are due to mechanical instability. Torque loosening or fracture of the screws are the most frequent complications. Furthermore, the fractured screw retrieval is complicated and time-consuming. So, modifications in the design of implant systems are justifiable to offer a greater degree of biomechanical stability. Thus, the present study proposes to evaluate an experimental geometry for abutment screw regarding failure probability and torque loss. Twenty implant/abutments sets (e-fix, A.S. Technology - Titanium Fix) were divided into the following groups (n=10 in each group): (1) Conventional screw (Screw neck ø 1.5 mm) and (2) Experimental screw (screw neck constricted ø 1.2 mm). The abutments were tightened with a controlled torque meter device following the manufacturer's recommendations. Mechanical cycling was carried out with a load of 50 N.cm during 5 x 10 6 cycles with a frequency of 2 Hz at a temperature of 37°C (ISO 14801). A digital torque meter was used to measure the reverse torque values of the prosthetic screw and the micro abutment screw, before and after loading. Data were statistically analyzed by One-way Anova and Tukey test (95 %). The results of the mean values of torque loss of the micro abutment screw were 58.44 % for the control group and 55.31 % for the experimental group and the mean torque loss for the prosthetic screw was 53.3 % and 61.3 % of the conventional and experimental groups, respectively. The survival probability was 100 % for both screw groups. It was concluded that experimental screw showed a similar behavior to conventional screws, showing similar reliability after fatigue life testing.

RESUMEN: En implantología las fallas más habituales se deben a la inestabilidad mecánica. El aflojamiento del torque o la fractura de los tornillos son las complicaciones más frecuentes. Además, la recuperación del tornillo fracturado es complicada y requiere mucho tiempo. Por tanto, las modificaciones en el diseño de los sistemas de implantes están justificados para ofrecer un mayor grado de estabilidad biomecánica. Por lo tanto, el presente estudio propone evaluar una geometría experimental para tornillo de pilar en cuanto a probabilidad de falla y pérdida de torque. Se dividieron veinte conjuntos de implantes / pilares (e-fix, AS Technology - Titanium Fix) en los siguientes grupos (n = 10 en cada grupo): (1) Tornillo convencional (cuello de tornillo ø 1,5 mm) y (2) Tornillo experimental (cuello de rosca estrechado ø 1,2 mm). Los pilares se apretaron con un dispositivo medidor de torque controlado siguiendo las recomendaciones del fabricante. El ciclo mecánico se realizó con una carga de 50 N.cm durante 5 x 10 6 ciclos con una frecuencia de 2 Hz a una temperatura de 37° C (ISO 14801). Se utilizó un medidor de torque digital para medir los valores de torque inverso del tornillo protésico y el tornillo de micro pilar, antes y después de la carga. Los datos se analizaron estadísticamente mediante la prueba One-way Anova y Tukey (95%). Los resultados de los valores medios de pérdida de torque del micro tornillo de pilar fueron 58,44 % para el grupo de control y 55,31 % para el grupo experimental y la pérdida de torque media para el tornillo protésico fue 53,3 % y 61,3 % de los grupos convencional y experimental, respectivamente. La probabilidad de supervivencia fue del 100 % para ambos grupos de tornillos. Se concluyó que el tornillo experimental mostró un comportamiento similar a los tornillos convencionales, mostrando una fiabilidad similar después de la prueba de vida a fatiga.

Influence of Different Fibreglass Post Geometries on the Stress Distribution and Pull-Out Bond Strength Before and After Mechanical Cycling.

OBJECTIVE: There are no reports in the literature on whether FGP geometry influences the bond strength of the endodontically restored tooth. This study aimed to determine the stress distribution and the pull-out bond strength of different FGP geometries, before and after chewing loads simulation. METHODS: One hundred and twenty root analogues were prepared and randomly distributed in six groups according to the post geometry. Half of the specimens were aged in water at 37 °C using a mechanical fatigue machine (84 N, 2 bar, 45°, 106 cycles, 4 Hz); while the remaining specimens were immediately submitted to the pull-out bond strength test. The specimens were tested in a universal testing machine and the bond strength in MPa was calculated. To assess the stress concentration, the finite element method was used simulating the same post geometries that were used in the in vitro test. RESULTS: Two-way ANOVA (95%) showed no influence of post geometry on the bond strength (P=0.055) while fatigue cycling was statistical significant to reduce the bond strength values (P=0.000). The factors interaction was significant (P=0.019); however, TUKEY test (5%) showed no significant difference between post geometries after mechanical cycling. The tensile stress result showed critical areas in the post's cervical region regardless of the design. CONCLUSION: The FGP geometry does not affect the root stress distribution and the long-term bond strength. However, FGP that allow a reduced cement layer thickness can improve the immediate pull-out bond strength value.

Atividade antimicrobiana de diferentes concentrações da prata coloidal aplicada em implantes dentários com plataforma do tipo hexágono externo: estudo in vitro / Antibacterial properties of a silver nanoparticles reduce internal contamination of external hexagon implants, in vitro study

Os implantes dentários osseointegrados apresentam altas taxas de sucesso no tratamento reabilitador a longo prazo. No entanto, complicações biológicas estão relacionadas com a ocorrência de peri-implantite, perda óssea marginal e insucessos clínicos. A busca de uma condição que diminua a colonização microbiana e estabelecimento de biofilmes tem crescido. O tratamento com nanoprata tem sido amplamente estudado como agente antimicrobiano por apresentar seu largo espectro de ação contra bactérias Gram positivas, Gram negativas e fungos. O presente estudo teve por objetivo avaliar, in vitro, a ação antimicrobiana de nanopartículas de prata coloidal, sobre Enterococcus faecalis e a ocorrência de infiltração bacteriana na interface dos implantes de plataforma hexágono externo (HE) e pilares protéticos. Foi determinada a concentração inibitória mínima da solução de nanoprata coloidal. A citotoxicidade foi avaliada sobre células Vero (ECACC 84113001) pela técnica de MTT. A infiltração bacteriana na interface implante/pilar (TiBase®, Conexão Sistemas de Prótese), foi avaliada utilizando 40 conjuntos de implantes e pilares HE (n=10) divididos em 4 grupos de acordo com o tratamento: (1) prata coloidal 29 ppm; (2) prata coloidal 58 ppm; (3) controle negativo (sem tratamento) e (4) controle positivo (digluconato de clorexidina 2%). Inicialmente, da suspensão padronizada 1x106 células/mL de Enterococcus faecalis foi inoculada no interior dos implantes, e, a seguir, os respectivos pilares (TiBase®, Conexão Sistemas de Prótese) foram instalados com torque de 30N de acordo com o fabricante. Os conjuntos foram testados para contaminação externa imediata, suspensos em tubos de ensaio contendo 3 mL de meio de cultura BHI (Brain Heart Infusion), incubados por 24h a 37ᵒC em estufa de CO2. A turvação do caldo indicou infiltração bacteriana. A seguir, os corpos de prova foram incubados em aerobiose a 37ᵒC, por 120 horas. Após incubação, os pilares foram desparafusados e o conteúdo interno dos implantes foi coletado com auxílio de cone de papel estéril e semeado em ágar para a determinação do número de células viáveis. Os dados de log10 UFC/mL dos grupos foram comparados estatisticamente com auxílio do programa GraphPad Prism versão 6.0 (GraphPad Software Inc., San Diego, CA, USA). Para tanto, foi realizado um teste de normalidade, e, a seguir, foram aplicados os testes estatísticos Kruskal-Wallis e Dunn's post hoc com nível de significância de 5%. Resultados: Nenhum corpo de prova apresentou contaminação externa imediata. O número de células viáveis foi significativamente menor no grupo tratado com a nanoprata coloidal a 58 ppm em relação ao grupo controle negativo. O grupo tratado com digluconato de clorexidina a 2% obteve a contagem significativamente menor em relação aos demais grupos testados. A nanoprata coloidal 58 ppm foi severamente citotóxica. Conclui-se que a nanoprata coloidal na concentração de 58 ppm apresentou atividade antimicrobiana sobre o Enterococcus faecalis, porém com elevada citotoxicidade para células eucarióticas(AU)

Osseointegrated dental implants have high success rates in long-term rehabilitative treatments However; oral conditions could affect peri-implant tissues health and are associated to the occurrence of peri- implantitis, marginal bone loss and clinical failures. The search for a condition that can decrease the microbial colonization and the establishment of biofilms increased. Nanosilver has been widely used as an antimicrobial agent due large spectrum of action against Gram positive, Gramnegative bacteria and fungi. The present study aimed to evaluate, in vitro, the antimicrobial action of colloidal silver nanoparticles on Enterococcus faecalis and on the infiltration at the interface between hexagonal external platform (EH) implants and prosthetic abutments. To obtain the optimal silver concentration, the minimum inhibitory concentration. Cytotoxicity evaluated on Vero cells (ECACC 84113001) by MTT assay. Bacterial infiltration through implant / abutment interface (TiBase®, Conexão Sistemas de Prótese) was evaluated using 40 sets of HE implants and abutments (n = 10) divided into 4 groups according to the treatment: (1) colloidal silver 29 ppm; (2) 58 ppm colloidal silver; (3) negative control (no treatment) and (4) positive control (2% chlorhexidine digluconate). Initially, under sterile conditions, 1 µL of a standardized 1x106 cels / mL suspension of Enterococcus faecalis was inoculated inside the implants, and the respective abutments (TiBase®, Conexão Sistemas de Prótese) were torqued to 30N according to the manufacturer's instructions. The systems were tested for immediate external contamination, suspended in test tubes containing 3 mL Brain Heart Infusion broth. The tubes were incubated for 24h at 37ᵒC under a CO2 atmosphere. Turbidity indicated external contamination. After the incubation period, the abutments unscrewed, and the internal content of the implants was collected with the aid of a sterile paper point. The bacterial cells were dispersed, and the suspension was plated to quantify the viable cells. Values of log10CFU / mL obtained for the groups were statistically compared using the GraphPad Prism version 6.0 software (GraphPad Software Inc., San Diego, CA, USA). A normality test was performed followed by Kruskal-Wallis and post hoc statistical tests with significance level of 5%. Results: No specimen showed immediate external contamination. Viable cells count was significantly lower in the 58-ppm colloidal nano-silver group when compared to the negative control group The group treated with 2% chlorhexidine digluconate showed significantly lower counts when to the other groups tested. Colloidal nano silver 58 ppm was severely cytotoxic. It concluded that the 58-ppm colloidal nano silver presented antimicrobial activity on Enterococcus faecalis however with high cytotoxicity to eucariotic cells(AU)

IL-6 blockers in systemic onset juvenile idiopathic arthritis.

IL-6 has a key role in the pathogenesis, clinical manifestations and activity of Systemic Onset Idiopathic Arthritis (sJIA). Tocilizumab (TCZ), the first humanized antihuman IL-6 receptor antibody, inhibits the activity of IL-6. In this review, we summarize the main studies performed, to date, about the use of TCZ in children affected by sJIA refractory to conventional treatment. Nowadays TCZ can be used, alone or in association with Metotrexate, in children older than 2 years. Its use in children younger than 2 years is being investigated. Further study about its use in sJIA and other type of idiopathic arthritis should be done.

Agreement among musculoskeletal pediatric specialists in the assessment of radiographic joint damage in juvenile idiopathic arthritis.

OBJECTIVE: To evaluate agreement among musculoskeletal pediatric specialists in assessing radiographic joint damage in juvenile idiopathic arthritis (JIA). METHODS: Two pediatric rheumatologists, 2 pediatric radiologists, and 2 pediatric orthopedic surgeons evaluated independently 60 radiographs of both wrists and hands of children with polyarticular-course JIA. Films were scored using an adapted and simplified version of the Larsen score, ranging from 0-5. Study radiographs were selected from 568 films used in a previous study aimed to validate an adapted pediatric version of the Sharp/van der Heijde (SHS) score. To enable comparison of specialists' scores with the adapted SHS score, the 60 radiographs were divided into 6 classes of severity of damage based on quintiles of the adapted SHS score. Agreement was evaluated in terms of absolute agreement and through weighted kappa statistics. RESULTS: The pediatric radiologists tended to assign lower scores and to provide more frequently scores of 0 than did the other specialists. Weighted kappa for the 3 pairs of specialists ranged from 0.67-0.69, indicating substantial agreement. Absolute agreement ranged from 51.3-55.7%, depending on the pair of specialists examined. Both absolute and weighted kappa concordance between specialists' scores and the adapted SHS score were poorer for the pediatric radiologist than for the other specialists. CONCLUSION: We observed fair agreement in the assessment of radiographic damage among pediatric specialists involved in the care of children with JIA. The radiologists tended to be more reserved than the rheumatologists and orthopedic surgeons in labeling radiographs as damaged or in considering changes as important.