Avaliação do aumento da estabilidade primária na instalação de implantes dentários com variação da instrumentação por meio do torque de inserção e análise de frequência de ressonância

Introdução: A descoberta da osseointegração determinou um marco para a terapia reabilitadora na odontologia, possibi­litando tratamentos previsíveis. Objetivo: O objetivo deste estudo foi avaliar uma técnica alternativa de instalação de im­plantes que proporcionasse melhor estabilidade primária. Materiais e métodos: Foram selecionadas seis costelas suínas frescas para a instalação de 60 implantes cilíndricos usinados divididos em três grupos. Anteriormente à instalação dos implantes, foi realizada a medição da densidade óssea em unidade de Hounsfield com tomografia computadorizada con­vencional. Os valores de densidade óssea foram medidos na posição dos implantes e correlacionados ao torque de inserção e à análise de frequência de ressonância. No grupo-controle usou-se a técnica de instalação onde a última broca utilizada foi a de 3,0 mm preconizada pelo fabricante, enquanto nos grupos 2 e 3 foi utilizada uma técnica alternativa de subinstrumentação e superinstrumentação, onde as últimas brocas utilizadas no preparo do leito cirúrgico foram as de 2,8 mm e 3,15 mm, respectivamente. Foram registrados os valores de torque de inserção máxima no momento da instalação dos implantes, e os valores da frequência de ressonância foram medidos a partir do quociente de estabilidade implantar (ISQ). Resultados: Foi registrado aumento do torque de inserção de 63,1219% quando se utilizou a broca de 2,8 mm como broca final, e se obteve um torque negativo de inserção na marca de -4,071% quando se utilizou a broca 3,15 mm como broca final, na comparação com o grupocontrole. Foi verificada uma correlação entre a estabilidade primária, obtida através da média do torque de inserção do implante, e o diâmetro de preparo do leito receptor do implante com a utilização do implante cilíndrico. Conclusão: Os resultados indicam que utilizando essa técnica de preparo alternativo de subinstrumentação o cirurgião pode atingir valores de torque de inserção mais elevados mesmo em osso de baixa densidade, possi­bilitando uma melhor estabilidade primária, adequada para a técnica de carga imediata. DESCRITORES | Carga Imediata; Torque; Osseointegração; Implante Dentário.Introduction: The discovery of osseointegration has set a milestone as rehabilitative therapy in dentistry, allowing for countless alternatives. Objective: The aim of this study was to evaluate an alternative technique of implant that provides a better primary stability. Materials and methods: fresh pork ribs were selected for the installation of 60 cylindrical machined implants divided into three groups. Prior to installation of the implants, bone density was measured in Hounsfield unit with conventional computed tomography. The values of bone density were measured in the position of the implants and were correlated with the insertion torque and resonance fre­quency analysis. In the control group, we used the installation technique in which the last drill used has 3.0 mm, as recommended by the manufacturer, whereas in group 2 and 3 an alternative technique for sub-instrumentation and super-instrumentation was used, in which the last drill used to prepare the surgical bed had 2.8 mm and 3.15 mm, respectively. The values of maximum insertion torque at the time of implant placement were recorded, and the values of resonance frequency were measured from the ratio of implant stability (ISQ). Results: An increase of 63.1219% was observed in the insertion torque when using the 2.8 mm as final drill, and a negative torque of insertion with -4071% was obtained using the 3.15 mm drill as final drill when compared with the control group. A correlation between primary stability was verified, achieved by the average insertion torque and the diameter of the preparation of the bed receiving the implant using the cylindrical implant. Conclusion: These results indicate that by using this alternative technique for sub-instrumentation, the surgeon can reach higher values of insertion torque even at low bone density, enabling a better primary stability, suitable for the immediate loading technique. DESCRIPTORS | Immediate Load; Torque; Osseointegration; Dental Implant

Superconductor to resistive state switching by multiple fluctuation events in NbTiN nanostrips

We report on measurements of the switching current distributions on two-dimensional superconducting NbTiN strips that are 5 nm thick and 80 nm wide. We observe that the width of the switching current distributions has a non-monotonous temperature dependence, where it is constant at the lowest temperatures up to about 1.5 K, after which it increases with temperature until 2.2 K. Above 2.5 K any increase in temperature decreases the distribution width which at 4.0 K is smaller than half the width observed at 0.3 K. By using a careful analysis of the higher order moments of the switching distribution, we show that this temperature dependence is caused by switching due to multiple fluctuations. We also find that the onset of switching by multiple events causes the current dependence of the switching rate to develop a characteristic deviation from a pure exponential increase, that becomes more pronounced at higher temperatures, due to the inclusion of higher order terms

Investigation of Superconducting Molybdenum Silicide Nanostrips and Microstrips for Single Photon Detectors

Superconducting nanostrip single photon detectors have emerged as the highest performing single-photon detectors; however, the possibility to use superconducting microstrip as single photon detectors is very appealing both to use them as larger areas detectors and for an easier technology in the manufacturing. The aim of this work is to test the photoresponse in liquid helium dewar of 9 nm thick MoSi covered with a very thin (2 nm) layer of Al, in two different configurations: nanomeanders and microstrips. We demonstrate that MoSi/Al microstrips can work as photodetectors also at T = 4.2 K. We also compare the dark count rate of the microstrip and the nanowire, confirming the lower noise for the microstrips also at 4.2 K

Investigation of dark count rate in NbRe microstrips for single photon detection

Superconducting microstrip single photon detectors (SMSPDs) received great interest since they are expected to combine the excellent performance of superconducting nanostrip single photon detectors with the possibility to cover large active areas using low-cost fabrication techniques. In this work, we fabricated SMSPDs based on NbRe to investigate the role of vortices in the dark counts events in this innovative material and in devices with micrometer size. We realized devices with different layouts, namely single microstrips and pairs of parallel microstrips. The energy barriers related to the motion of single vortices or vortex-antivortex pairs, responsible of detection events, have been determined and compared with the ones of similar devices based on different materials, such as MoSi, WSi and NbN. The analysis confirms the high potential of NbRe for the realization of superconducting single photon detectors with large areas

Waiting times for diagnosis of attention-deficit hyperactivity disorder in children and adolescents referred to Italian ADHD centers must be reduced

BACKGROUND: To investigate timely access to and the time needed to complete the diagnostic path of children and adolescents with suspected attention deficit hyperactivity disorder (ADHD) in the 18 Italian Lombardy Region ADHD reference centers. METHODS: Data of children and adolescents enrolled in the Regional ADHD disease-oriented Registry for suspected ADHD who requested their first visit in 2013-2017 were analyzed. RESULTS: The sample comprised 2262 children and adolescents aged 5-17\u2009years who accessed the ADHD centers for diagnostic classification and management. The median waiting time was of 177\u2009days (range 66-375) from the request for the initial appointment to the completion of the diagnostic path, with a three - fold difference between centers. In addition to the center, the strongest significant predictors of long waiting times were age comorbidities, the severity of the disorder, and having already completed some diagnostic procedures provided by the common standard path. CONCLUSIONS: To guarantee an equal standard of care in ADHD centers for all children and adolescents there is a pressing need to reduce the times to complete the diagnostic path. It is the task of both policymakers and each center to optimize the quality of the service and of the care delivered

Italian regional health service costs for diagnosis and 1-year treatment of ADHD in children and adolescents

The main aim of this study was to estimate the costs associated with diagnostic assessment and 1-year therapy in children and adolescents enrolled in 18 ADHD reference centres. Data concerning 1887 children and adolescents from the mandatory ADHD registry database during the 2012-2014 period were analysed. The overall diagnostic and treatment costs per patient amounts to \u20ac574 and \u20ac830, respectively. The ADHD centre, the school as sender, and the time to diagnosis constitute cost drivers. Non-pharmacological therapy resulted as being more expensive for patients concomitantly treated with drugs (\u20ac929) compared to those treated with psychological interventions alone (\u20ac590; p=0.006). This study gives the first and reliable estimate of the costs associated with both diagnosis and treatment of ADHD in Italy. Although costs associated with mental disorders are difficult to estimate, continuing efforts are need to define costs and resources to guarantee appropriate care, also for ADHD

Development of a tool for the analysis and optimisation of atmospheric re-entry trajectories

Atmospheric re-entry relies on different aspects of the space sector, such as the return of manned or unmanned payloads back to Earth, the exploration with landers and rovers of the outer planets with atmosphere, or additionally the demise of satellites at their End-Of-Life; all aspects nowadays of interest both for Space Agencies and private companies. The atmospheric re-entry from space is one of the most critical and complex engineering problems in the aerospace field. Stringent and specific mission requirements shall be satisfied to properly ensure a non-destructive and safe landing of the managed asset. The requirements' severity strongly depends on the type of the hosted payload by the spacecraft: manned or un-manned. Especially in the first case, the stringent mission requirements deeply affect the design of the spacecraft re-entry trajectory or 're-entry corridor', strongly impacting on the spacecraft overall design and mass budget. This paper deals with the preliminary analysis and design of re-entry corridors for manned and unmanned spacecraft. Physical and mathematical models have been developed to simulate the environment (i.e. atmosphere and gravity field) and the aerothermodynamics phenomena affecting the spacecraft along the re-entry phase. To verify the validity of the developed tool, different real missions have been firstly simulated, such as IXV by ESA and AS202 by NASA. The results have been then compared to the real mission data. An optimisation methodology has been further developed and implemented into a flexible numerical program in Matlab language. The program gives the opportunity to set initial conditions like the spacecraft's geometry and mass, and the so-called 'target conditions'. The outputs of the tool provide the users with the possibility to find the optimised re-entry corridors, identifying all the best-candidate Entry Interface Points that shall be achieved by the spacecraft to satisfy the imposed mission requirements. As additional output, structural, aerodynamic and thermal stresses acting on the vehicle are estimated in order to minimize their peak values. Furthermore, the re-entry windows from the parking orbit and the related de-orbit manoeuvres are also estimated, as well as the communication windows with the selected ground stations. Moreover, a sensitivity analysis has been implemented for completeness and to enhance the reliability of the produced solutions from statistical point of view. An applied study will be reported as example, together with the obtained results, highlighting their importance for planning and operating re-entry missions of present and future applications