Innovative Education Method for a More Effective, Faster, and Valued Training in Radiation Therapy Treatment Planning.

Purpose: Because of the automation of radiation therapy, competencies of radiation technologists (RTTs) change, and training methods are challenged. This study aims to develop, and pilot test an innovative training method based on lean management principles. Methods and Materials: A new training method was developed for lung cancer treatment planning (TP). The novelty is summarized by including a stable environment and an increased focus on the how and why of key decision making. Trainees have to motivate their decisions during TP process, and to argue their choices with peers. Six students and 6 RTTs completed this training for lung cancer TP. Effects of the training were measured by (1) quality of TP, using doses in organs at risk and target volumes, (2) perceived experiences (survey), measured at baseline (T0); after peer session (T1); and 6 months later (T2). Finally, training throughput time was measured. Results: At T0, RTTs showed a larger intragroup interquartile range (IIR) (2.63Gy vs 1.51Gy), but lower mean doses to heart and esophagus than students (6.79Gy vs 8.49Gy; 20.87Gy vs 24.62Gy). At T1, quality of TPs was similar between RTTs and students (IIR: 1.39Gy vs 1.33Gy) and no significant differences in mean dose to heart and esophagus (4.48Gy vs 4.69Gy; 17.75Gy vs 18.47Gy). At T2, students still performed equal to RTTs (IIR: 1.07Gy vs 1.45Gy) and achieved lower maximum dose to esophagus (44.75Gy vs 46.45Gy). The training method and peer sessions were experienced positive: at baseline (T0): 8 score on a scale 1-10, directly after the peer sessions; (T1): 8 by the students and 7 by the RTTs, after 9 months; (T2): 9 by the students and 7 by the RTTs. Training throughput time decreased from 12 to 3 months. Conclusions: This training method based on lean management principles was successfully applied to training of RTTs for lung cancer TP. Training throughput time was reduced dramatically and TP quality sustained after 6 months. This method can potentially improve training efficiency in diverse situations with complex decision-making.

A taskforce for national improvement of innovation implementation in radiotherapy.

BACKGROUND AND PURPOSE: Previous research among Dutch radiotherapy centres (RTCs) showed that 69% of innovations was simultaneously implemented in 7/19 centres, with a success rate of 51%. However, no structure to share lessons learned about the implementation process existed. Therefore, a national Taskforce Implementation (TTI) was raised to stimulate efficient implementation of innovations. The aim of the current study was to develop and pilot-evaluate a website for facilitating mutual learning on implementation issues. MATERIAL AND METHODS: First, we made an inventory in all Dutch RTCs on their 10 most valuable innovations between 2019 and 2022. In-depth interviews, structured according to the Consolidated Framework for Implementation Research, were performed on the four most mentioned topics. A website was built, and pilot evaluated 1 year after the launch, using a qualitative survey amongst the TTI members. RESULTS: In 13/18 centres, 19 interviews were conducted on 1) automation, 2) patient participation, 3) adaptive radiotherapy 4) surface guided radiotherapy and tracking. Most innovations (13/16) were implemented with a delay, with many comparable challenges: e.g. shortage of personnel (7/16) and prioritization of projects (9/16). The website allows users to upload and search for projects, including implementation experiences. After 1 year, 14 projects were uploaded. The qualitative evaluation was largely positive with room for improvement, i.e.75 % would recommend the website to others. CONCLUSION: This study showed that RTCs experience comparable challenges when implementing innovations, thereby underlining the need for a platform to share implementation-lessons learned. The first concept of this platform was evaluated positively.

External validation of a prediction model for timely implementation of innovations in radiotherapy.

BACKGROUND AND PURPOSE: The aim of this study was to externally validate a model that predicts timely innovation implementation, which can support radiotherapy professionals to be more successful in innovation implementation. MATERIALS AND METHODS: A multivariate prediction model was built based on the TRIPOD (Transparent Reporting of a multivariate prediction model for Individual Prognosis Or Diagnosis) criteria for a type 4 study (1). The previously built internally validated model had an AUC of 0.82, and was now validated using a completely new multicentre dataset. Innovation projects that took place between 2017-2019 were included in this study. Semi-structured interviews were performed to retrieve the prognostic variables of the previously built model. Projects were categorized according to the size of the project; the success of the project and thepresence of pre-defined success factors were analysed. RESULTS: Of the 80 included innovation projects (32.5% technological, 35% organisational and 32.5% treatment innovations), 55% were successfully implemented within the planned timeframe. Comparing the outcome predictions with the observed outcomes of all innovations resulted in an AUC of the external validation of the prediction model of 0.72 (0.60-0.84, 95% CI). Factors related to successful implementation included in the model are sufficient and competent employees, desirability and feasibility, clear goals and processes and the complexity of a project. CONCLUSION: For the first time, a prediction model focusing on the timely implementation of innovations has been successfully built and externally validated. This model can now be widely used to enable more successful innovation in radiotherapy.

Clues to address barriers for access to proton therapy in the Netherlands.

BACKGROUND AND PURPOSE: The Netherlands has National Indication Protocols on proton therapy (PT) to select patients who benefit most from PT. However, referrals to proton therapy centres (PTCs) are lagging. The objective of this research is to identify the barriers for access to PT and to design interventions to address these barriers. MATERIAL AND METHODS: We conducted a nationwide survey among radiation oncologists (ROs), and semi- structured in-depth interviews with ROs and patients. Subsequently, four workshops were held, in which ROs from one PTC and ROs from referring hospitals participated. The workshops were based on design-thinking research, where ideas were co-created on a multidisciplinary basis to encourage joint problem ownership. Kruskal Wallis and X2 tests were used to analyze data. RESULTS: The most prominent barriers mentioned by ROs were patient selection, poor logistics, and logistical worries about the combination of radiation treatment with chemotherapy. Patients pointed out the inefficient coordination between organisations, poor communication, travel issues and discomfort during treatment. Clues to increase referrals revealed the need for additional tools for patient selection and innovative ways to improve logistics. A case manager was identified as beneficial to the patients' journey as part of a multidisciplinary approach. Such an approach should include the active involvement of medical oncologists, surgeons and pulmonologists. CONCLUSION: Barriers for access to PT were identified and prioritized in the inter-organisational care- pathway of proton therapy patients in The Netherlands. Innovative solutions were co- designed to solve the barriers.

Analyzing the determinants to accept a virtual assistant and use cases among cancer patients: a mixed methods study.

BACKGROUND: Technological progress in artificial intelligence has led to the increasing popularity of virtual assistants, i.e., embodied or disembodied conversational agents that allow chatting with a technical system in a natural language. However, only little comprehensive research is conducted about patients' perceptions and possible applications of virtual assistant in healthcare with cancer patients. This research aims to investigate the key acceptance factors and value-adding use cases of a virtual assistant for patients diagnosed with cancer. METHODS: Qualitative interviews with eight former patients and four doctors of a Dutch radiotherapy institute were conducted to determine what acceptance factors they find most important for a virtual assistant and gain insights into value-adding applications. The unified theory of acceptance and use of technology (UTAUT) was used to structure perceptions and was inductively modified as a result of the interviews. The subsequent research model was triangulated via an online survey with 127 respondents diagnosed with cancer. A structural equation model was used to determine the relevance of acceptance factors. Through a multigroup analysis, differences between sample subgroups were compared. RESULTS: The interviews found support for all factors of the UTAUT: performance expectancy, effort expectancy, social influence and facilitating conditions. Additionally, self-efficacy, trust, and resistance to change, were added as an extension of the UTAUT. Former patients found a virtual assistant helpful in receiving information about logistic questions, treatment procedures, side effects, or scheduling appointments. The quantitative study found that the constructs performance expectancy (ß = 0.399), effort expectancy (ß = 0.258), social influence (ß = 0.114), and trust (ß = 0.210) significantly influenced behavioral intention to use a virtual assistant, explaining 80% of its variance. Self-efficacy (ß = 0.792) acts as antecedent of effort expectancy. Facilitating conditions and resistance to change were not found to have a significant relationship with user intention. CONCLUSIONS: Performance and effort expectancy are the leading determinants of virtual assistant acceptance. The latter is dependent on a patient's self-efficacy. Therefore, including patients during the development and introduction of a VA in cancer treatment is important. The high relevance of trust indicates the need for a reliable, secure service that should be promoted as such. Social influence suggests using doctors in endorsing the VA.

Implementation of MR-linac and proton therapy in two radiotherapy departments in The Netherlands: Recommendations based on lessons learned.

Recently, two new treatment techniques, i.e. proton therapy and MR-linac based radiotherapy (RT), have been introduced in Dutch RT centres with major impact on daily practice. The content and context of these techniques are frequently described in scientific literature while little is reported about the implementation phase. This process is complex due to a variety of aspects, such as the involvement of multiple stakeholders, significant unpredictability in the start-up phase, the impact of the learning curve, standard operating procedures under development, new catchment areas, and extensive training programs. Insight about implementation in daily care is utterly important for clinics that are about to introduce these new technologies in order to prevent that every centre needs to reinvent the wheel. This position paper gives an overview of the implementation of proton therapy and MR-linac based RT in two large academic RT centres in the Netherlands, i.e. Maastro and Radboudumc respectively. With this paper we aim to report our lessons learned, in order to facilitate other RT centres that consider introducing these and other new techniques in their departments.

The barriers and facilitators of radical innovation implementation in secondary healthcare: a systematic review.

PURPOSE: This study aimed to identify the barriers and facilitators related to the implementation of radical innovations in secondary healthcare. DESIGN/METHODOLOGY/APPROACH: A systematic review was conducted and presented in accordance with a PRISMA flowchart. The databases PubMed and Web of Science were searched for original publications in English between the 1st of January 2010 and 6th of November 2020. The level of radicalness was determined based on five characteristics of radical innovations. The level of evidence was classified according to the level of evidence scale of the University of Oxford. The Consolidated Framework for Implementation Research was used as a framework to classify the barriers and facilitators. FINDINGS: Based on the inclusion and exclusion criteria, nine publications were included, concerning six technological, two organizational and one treatment innovation. The main barriers for radical innovation implementation in secondary healthcare were lack of human, material and financial resources, and lack of integration and organizational readiness. The main facilitators included a supportive culture, sufficient training, education and knowledge, and recognition of the expected added value. ORIGINALITY/VALUE: To our knowledge, this is the first systematic review examining the barriers and facilitators of radical innovation implementation in secondary healthcare. To ease radical innovation implementation, alternative performance systems may be helpful, including the following prerequisites: (1) Money, (2) Added value, (3) Timely knowledge and integration, (4) Culture, and (5) Human resources (MATCH). This study highlights the need for more high-level evidence studies in this area.

Factors predicting timely implementation of radiotherapy innovations: the first model.

OBJECTIVE: The improvement of radiotherapy depends largely on the implementation of innovations, of which effectivity varies widely. The aim of this study is to develop a prediction model for successful innovation implementation in radiotherapy to improve effective management of innovation projects. METHODS: A literature review was performed to identify success factors for innovation implementation. Subsequently, in two large academic radiotherapy centres in the Netherlands, an inventory was made of all innovation projects executed between 2011 and 2017. Semi-structured interviews were performed to record the presence/absence of the success factors found in the review for each project. Successful implementation was defined as timely implementation, yes/no. Cross-tables, Χ2 tests, t-tests and Benjamin-Hochberg correction were used for analysing the data. A multivariate logistic regression technique was used to build a prediction model. RESULTS: From the 163 identified innovation projects, only 54% were successfully implemented. We found 31 success factors in literature of which 14 were significantly related to successful implementation in the innovation projects in our study. The prediction model contained the following determinants: (1) sufficient and competent employees, (2) complexity, (3) understanding/awareness of the project goals and process by employees, (4) feasibility and desirability. The area Under the curve (AUC) of the prediction model was 0.86 (0.8-0.92, 95% CI). CONCLUSION: A prediction model was developed for successful implementation of innovation in radiotherapy. ADVANCES IN KNOWLEDGE: This prediction model is the first of its kind and, after external validation, could be widely applicable to predict the timely implementation of radiotherapy innovations.

Electronic Health Record implementation in a large academic radiotherapy department: Temporarily disruptions but long-term benefits.

PURPOSE: To study the number of disruptions in patient processes in a radiotherapy centre after the replacement of an Electronic Health Record (EHR), integrating information tools for patient care and billing. METHODS: Our self-made Electronic Medical Record was replaced by a new EHR, including clinical path and workflow-management. A social-technological approach was used to reduce complexity. We measured disruptions in patient processes by the number and type of EHR related root causes and EHR-related incidents that reached patients, in our patient safety system 12 months before implementing the new EHR, 6 months after implementation (transition period) and 24 months after the transition period. We used Mann-Whitney U and X² tests to compare data before and after implementation. RESULTS: An increase of disruptions occurred only temporarily during 6 months. After this period, the number stabilized to the level before implementation while having more functionalities and benefits. Neither the number nor the severity of incidents reaching patients increased. CONCLUSIONS: Disruptions in patient processes are considered as a main barrier for implementing an EHR. Using a social/technical approach, the increase in disruptions did only temporarily occur and did not reach patients. We think it is important to share this insight with physicians because literature shows that their long-term opinion regarding the usefulness of the EHR is often based on the experience in the first months after implementation. Management of expectations is recommended. ADVANCES IN KNOWLEDGE: This study is the first of its kind measuring long-term effects of EHR on patient processes in radiotherapy.

[Implementation of innovations in healthcare: radiotherapy as an example]. / Implementatie van innovaties in de zorg.

The implementation of innovations is considered necessary in healthcare, both for improving patient outcomes and services and to reduce costs. Two problems can occur during the implementation process: innovations that have not been properly evaluated in terms of patient outcomes or cost-effectiveness can sometimes spread quickly, whereas innovations that have shown to lead to significant improvements in a research study setting may struggle to find their way into clinical practice. Problems may also arise when organizational innovations are implemented that are not evidence-based: an example would be the implementation of a new ICT system that affects the patient's environment negatively upon introduction. In this article, the problems surrounding innovation implementation in medical care are described in general and in more concrete terms, we describe how Dutch radiotherapy centres perform in this area. Based on the findings, a systematic plan is described that can help to innovate more effectively and efficiently to the benefit of clinical practice in all disciplines.

What is the impact of innovation on output in healthcare with a special focus on treatment innovations in radiotherapy? A literature review.

OBJECTIVE: To analyse how often innovations in healthcare are evaluated regarding output, especially in radiotherapy. Output was defined as either survival, toxicity, safety, service, efficiency or cost-effectiveness. METHODS: A systematic literature review was conducted, using three search strategies: (1) innovations in general healthcare; (2) radiotherapy-specific innovations, i.e. organizational innovations and general implementation of innovations; (3) innovations per tumour group/radiotherapy technique. Scientific levels were classified according to the system used in European Society for Medical Oncology guidelines. Finally, we calculated the percentage of implemented innovations in Dutch radiotherapy centres for which we found evidence regarding output in the literature review. RESULTS: Only 94/1072 unique articles matched the inclusion criteria. Significant results on patient outcome, service or safety were reported in 65% of papers, which rose to 76% if confined to radiotherapy reviews. A significant technological improvement was identified in 26%, cost-effectiveness in 10% and costs/efficiency in 36% of the papers. The scientific level of organizational innovations was lower than that of clinical papers. Dutch radiotherapy treatment innovations were adequately evaluated on outcome data before implementation in clinical routine in a minimum of 64-92% of cases. CONCLUSION: Only few studies report on output when considering innovations in general, but radiotherapy reviews give a reasonably good insight into innovation output effects, with a higher level of evidence. In Dutch radiotherapy centres only small improvements are possible regarding evaluation of treatment innovations before implementation. Advances in knowledge: This study is the first of its kind measuring how innovations are evaluated in scientific literature, before implementation in clinical practice.

The effects of a lean transition on process times, patients and employees.

Purpose Treatment delays must be avoided, especially in oncology, to assure sustainable high-quality health care and increase the odds of survival. The purpose of this paper is to hypothesize that waiting times would decrease and patients and employees would benefit, when specific lean interventions are incorporated in an organizational improvement approach. Design/methodology/approach In 2013, 15 lean interventions were initiated to improve flow in a single radiotherapy institute. Process/waiting times, patient satisfaction, safety, employee satisfaction, and absenteeism were evaluated using a mixed methods methodology (2010-2014). Data from databases, surveys, and interviews were analyzed by time series analysis, χ2, multi-level regression, and t-tests. Findings Median waiting/process times improved from 20.2 days in 2012 to 16.3 days in 2014 ( p<0.001). The percentage of palliative patients for which waiting times had exceeded Dutch national norms (ten days) improved from 35 (six months in 2012: pre-intervention) to 16 percent (six months in 2013-2014: post-intervention; p<0.01), and the percentage exceeding national objectives (seven days) from 22 to 17 percent ( p=0.44). For curative patients, exceeding of norms (28 days) improved from 17 (2012) to 8 percent (2013-2014: p=0.05), and for the objectives (21 days) from 18 to 10 percent ( p<0.01). Reported safety incidents decreased 47 percent from 2009 to 2014, whereas safety culture, awareness, and intention to solve problems improved. Employee satisfaction improved slightly, and absenteeism decreased from 4.6 (2010) to 2.7 percent (2014; p<0.001). Originality/value Combining specific lean interventions with an organizational improvement approach improved waiting times, patient safety, employee satisfaction, and absenteeism on the short term. Continuing evaluation of effects should study the improvements sustainability.

Decision support systems for personalized and participative radiation oncology.

A paradigm shift from current population based medicine to personalized and participative medicine is underway. This transition is being supported by the development of clinical decision support systems based on prediction models of treatment outcome. In radiation oncology, these models 'learn' using advanced and innovative information technologies (ideally in a distributed fashion - please watch the animation: http://youtu.be/ZDJFOxpwqEA) from all available/appropriate medical data (clinical, treatment, imaging, biological/genetic, etc.) to achieve the highest possible accuracy with respect to prediction of tumor response and normal tissue toxicity. In this position paper, we deliver an overview of the factors that are associated with outcome in radiation oncology and discuss the methodology behind the development of accurate prediction models, which is a multi-faceted process. Subsequent to initial development/validation and clinical introduction, decision support systems should be constantly re-evaluated (through quality assurance procedures) in different patient datasets in order to refine and re-optimize the models, ensuring the continuous utility of the models. In the reasonably near future, decision support systems will be fully integrated within the clinic, with data and knowledge being shared in a standardized, dynamic, and potentially global manner enabling truly personalized and participative medicine.

Import Testing: An Outdated Practice? Opportunities for Improved Access to Safe and Efficient Medicines.

Import testing of medicines is performed in the middle of the legitimate supply chain when a product enters a country. Risks, however, are identified in the illegitimate supply chain and in the trade within a country. Hence, import testing does not add any significant value to the quality and safety of drugs nor reduces risks, provided the manufacturers apply good practices, for example, Good Manufacturing Practices (GMPs) and Good Distribution Practices (GDPs). The consideration to implement additional regulations does not correlate with the increasing convergence between National Regulatory Authorities (NRAs) and international harmonization, for example, Pharmaceutical Inspection Co-Operation Scheme (PIC/S) and International Council for Harmonisation (ICH). This publication reflects the historical application of import testing and today's practice, concerns, and misconceptions of this redundant procedure. It explains why postmarketing surveillance testing is better suited to control the quality of medicines, addressing highly relevant concerns: counterfeits and supply interruptions.

What is the degree of innovation routinely implemented in Dutch radiotherapy centres? A multicentre cross-sectional study.

OBJECTIVE: To study the implementation of innovation activities in Dutch radiotherapy (RT) centres in a broad sense (product, technological, market and organizational innovations). METHODS: A descriptive cross-sectional study was conducted in 15 Dutch RT centres. A list of innovations implemented from 2011 to 2013 was drawn up for each centre using semi-structured interviews. These innovations were classified into innovation categories according to previously defined innovation indicators. Where applicable, each innovation was rated by each centre on the effort required to implement it and on its expected effects, to get an impression of how far reaching and radical the innovations were and to be able to compare the number of innovations between centres. RESULTS: The participating RT centres in the Netherlands implemented 12 innovations per year on average (range 5-25); this number was not significantly different for academic (n = 13) or non-academic centres (n = 10). Several centres were dealing with the same innovations at the same time. The average required effort and expected output did not differ significantly between product, technological and organizational innovation or between academic and non-academic centres. CONCLUSION: The number of innovations observed per centre varied across a large range, with a large overlap in terms of the type of innovations that were implemented. Registering innovations using the innovation indicators applied in our study would make it possible to improve collaboration between centres, e.g. with common training modules, to avoid duplication of work. Advances in knowledge: This study is the first of its kind investigating innovation implementation in RT in a broad sense.

How efficient is translational research in radiation oncology? The example of a large Dutch academic radiation oncology department.

OBJECTIVE:: To study the efficiency of research implementation in a large radiotherapy institute, in either an internal review board-approved clinical trial or clinical routine. METHODS:: Scientific publications of the institute were listed. We asked clinicians from tumour expert groups whether the study had been implemented yet in a clinical trial or in clinical practice and which facilitators or barriers were relevant. An independent investigator verified all results. We calculated the implementation rates and the frequency of mentioned facilitators and barriers. RESULTS:: Resident researchers had published 234 studies over the past 4 years. Overall, 70/234 (30%) technical or preclinical studies were tested or implemented in a clinical environment in either trials or routine. In total, 45/234 (19%) studies were routinely implemented; in the 61 clinical studies, this percentage was higher: 38% (23/61). The main facilitator was the level of evidence and the main barriers were workload and high complexity. CONCLUSION:: We were able to calculate the implementation ratio of published research into clinical practice and set benchmark figures for other radiotherapy clinics. Level of evidence was an important facilitator, while workload and high complexity of the new procedures were important barriers for implementation. Recent articles suggest that academic entrepreneurship will facilitate this process further. ADVANCES IN KNOWLEDGE:: This study is the first of its kind calculating implementation rates of published studies in the clinical environment and can contribute to the efficiency of translational research in radiotherapy. We propose to use this metric as a quality indicator to evaluate academic departments.

Modern clinical research: How rapid learning health care and cohort multiple randomised clinical trials complement traditional evidence based medicine.

BACKGROUND: Trials are vital in informing routine clinical care; however, current designs have major deficiencies. An overview of the various challenges that face modern clinical research and the methods that can be exploited to solve these challenges, in the context of personalised cancer treatment in the 21st century is provided. AIM: The purpose of this manuscript, without intending to be comprehensive, is to spark thought whilst presenting and discussing two important and complementary alternatives to traditional evidence-based medicine, specifically rapid learning health care and cohort multiple randomised controlled trial design. Rapid learning health care is an approach that proposes to extract and apply knowledge from routine clinical care data rather than exclusively depending on clinical trial evidence, (please watch the animation: http://youtu.be/ZDJFOxpwqEA). The cohort multiple randomised controlled trial design is a pragmatic method which has been proposed to help overcome the weaknesses of conventional randomised trials, taking advantage of the standardised follow-up approaches more and more used in routine patient care. This approach is particularly useful when the new intervention is a priori attractive for the patient (i.e. proton therapy, patient decision aids or expensive medications), when the outcomes are easily collected, and when there is no need of a placebo arm. DISCUSSION: Truly personalised cancer treatment is the goal in modern radiotherapy. However, personalised cancer treatment is also an immense challenge. The vast variety of both cancer patients and treatment options makes it extremely difficult to determine which decisions are optimal for the individual patient. Nevertheless, rapid learning health care and cohort multiple randomised controlled trial design are two approaches (among others) that can help meet this challenge.

Estudo comparativo in vitro da microinfiltraçäo entre preparos de CL V, realizados com alta rotaçäo e com lasers de Er: YAG, restaurados com resina composta / Comparative study in vitro of the microinfiltration among CL V preparations, accomplished with high rotation and with Er: YAG lasers, restored with composed resin

Mesmo com a evoluçäo dos sistemas adesivos e resinas compostas, a microinfiltraçäo continua sendo um dos problemas a ser sanado, pois está relacionada diretamente com a longevidade das restauraçöes. Pesquisas científicas, com os mais diversos materiais e técnicas, vem testando e comprovando a microinfiltraçäo, o que tem colaborado sobremaneira para o aperfeiçoamento dos materiais restauradores, muito embora, ainda, sem o sucesso esperado que seria entre outras coisas a ausência da microinfiltraçäo. Dentre as técnicas de preparos atuais, destacamos o laser de Er: YAG e, estudos, através do teste de microinfiltraçäo. Este estudo teve como objetivo comparar a microinfiltraçäo em cavidades de Classe V, restauradas com dois tipos de resinas compostas e, preparadas com alta-rotaçäo e lasers de Er: YAG. Para este experimento foram utilizados 60 dentes pré-molares humanos extraídos e, divididos em 6 grupos: G1 - preparados com alta-rotaçäo e restaurados com resina microparticulada (A 110 - 3M)/ G2 - preparados com alta-rotaçäo e restaurados com resina híbrida (Z 250 - 3M)/ G3 - preparados com laser de Er: YAG Kavo Key e restaurados de acordo com o G1/ G4 - preparados com laser de Er: YAG Kavo Key e restaurados de acordo com o G2/ G5 - preparados com laser de Er: YAG Opus 20 e restaurados de acordo com o G1/ G6 - preparados com laser de Er: YAG Opus 20 e restaurados de acordo com o G2. Os dentes foram restaurados seguindo a orientaçäo do fabricante. As amostras foram entäo, termocicladas e submersas em uma substância corante de azul de metileno a 2 por cento por 24h, para o teste de microinfiltraçäo, em seguida foram seccionadas para as avaliaçöes que foram realizadas por três avaliadores através de imagens computadorizadas, obtidas dos cortes através das restauraçöes. Os resultados foram submetidos à análise estatística que indicaram näo haver diferença estatisticamente significante entre os grupos testados, sendo que apenas entre os G1 e G2 houve diferença significante, quando as margens gengivais foram comparadas. Concluímos que todos os grupos apresentaram microinfiltraçäo, mas comparando-se os três tipos de preparos näo houve diferença significante e que, a resina microparticulada infiltrou mais que a resina híbrida somente no grupo preparado com alta-rotaçäo

Estudo de resistência à traçäo de três sistemas adesivos associados a resina composta em superfícies dentinárias / Study of the tensile bond strength of three different adhesive systems associated to composites on dentinal surfaces

Este trabalho teve como objetivo comparar a resistência à traçäo de três sistemas adesivos associados a resina composta aderidos à superfície dentinária. Quarenta e cinco superfícies de dentina foram obtidas a partir de molares humanos extraídos, sobre elas foi preparado "smear layer" e foram divididas em 3 grupos: G1) adesivo autocondicionante + resina micro-híbrida; G2) adesivo de componente único + ácido e resina micro-híbrida e G3) adesivo convencional (ácido + "primer" + bond) + resina micro-híbrida, aplicados de acordo com as instruçöes dos fabricantes. Os corpos-de-prova foram preparados para teste de traçäo, imersos em água destilada por 24 horas a 37ºC. Findo este tempo, o teste de traçäo foi realizado em máquina de ensaio Instron com velocidade constante de 0,5 mm/min. Os resultados foram expressos em MPa e submetidos a análise de variância (p<0,05). Os autores concluíram que: o tipo de sistema adesivo influenciou na resistência à traçäo das resinas compostas testadas; o sistema adesivo de componente único apresentou os melhores resultados de resistência adesiva