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PURPOSE: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. MATERIAL AND METHODS: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. RESULTS: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. CONCLUSION: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

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ABSTRACT Fixed implant-supported complete maxillary dentures aim to rehabilitate aesthetic, phonetic, and functional aspects of edentulous arches. A previous prosthetic preparation without a flange in the anterior sector makes it possible to evaluate the labial support and the existing space for the future prosthesis. Thus, it allows the most appropriate choice of the type of rehabilitation and surgical technique. However, follow-up studies have shown that when proceeding this way, problems in the posterior sector are still occurring, such as the lack of vertical space for an adequate bar design and concave internal designs, which make access to hygiene difficult. Faced with the problem, the aim of this study is to report a clinical case in which the previous prosthetic preparation included the removal of the flange also from the posterior sector during the teeth try-in and the duplication of this assembly in a transparent multifunctional guide that allowed the visualization of the amount of bone removal needed. The osteotomy, performed before the installation of the implants, provided enough space for the bar, acrylic, and prefabricated denture teeth in the prosthesis that was installed, an important fact considering that this is an area with greater chewing efforts. It also allowed for correct internal design in the prosthesis, which will ensure access to correct hygiene. Based on the analysis of the rehabilitated case, it seems fair to conclude that the total removal of the buccal flange at the time of testing the wax try-in of the teeth and its duplication is a differential in the approach of cases and should always be adopted to ensure a lower margin of error and greater longevity in the proposed rehabilitative treatment.

RESUMO Próteses totais fixas implantossuportadas objetivam reabilitar arcos edêntulos nos aspectos estético, fonético e funcional. Um preparo protético prévio sem flange no setor anterior permite avaliar o suporte labial e o espaço presente para a futura prótese, auxilinado na escolha do tipo de reabilitação e da técnica cirúrgica mais adequada. No entanto, estudos de acompanhamento tem mostrado que ao proceder dessa maneira ainda estão ocorrendo problemas no setor posterior, como falta de espaço vertical para um desenho adequado da barra e desenhos internos côncavos, que dificultam o acesso à higienização. Frente ao problema, o objetivo do presente trabalho é relatar um caso clínico no qual o preparo protético prévio incluiu a remoção do flange também do setor posterior durante a prova dos dentes e a duplicação dessa montagem em um guia multifuncional transparente permitindo a visualização da quantidade de remoção óssea necessária. A osteotomia, realizada antes da instalação dos implantes, proporcionou espaço suficiente para a barra, acrílico e dentes de estoque na prótese que foi instalada, fato importante considerando ser essa uma zona com maiores esforços mastigatórios. Também permitiu a confecção de desenho interno correto na prótese, que garantirá o acesso para correta higiene. Com base na análise do caso reabilitado, parece lícito concluir que a remoção total do flange vestibular no momento da prova dos dentes em cera e sua duplicação é um diferencial na abordagem dos casos e que deveria sempre ser adotada para garantir menor margem de erros e maior longevidade no tratamento reabilitador proposto.

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OBJECTIVE: To assess actual data on the safety, effectiveness, and hemodynamic performance of Bovine Pericardium Organic Valvular Bioprosthesis (BVP). METHODS: The BIOPRO Trial is an observational, retrospective, non-comparative, non-randomized, and multicenter study. We collected data from 903 patients with symptomatic, moderate, or severe valve disease who underwent BVP implants in the timeframe from 2013 to 2020 at three Brazilian institutions. Death, valve-related adverse events (AEs), functional recovery, and hemodynamic performance were evaluated at the hospital, at discharge, and six months and one year later. Primary analysis compared late (> 30 days after implant) linearized rates of valve-related AEs, such as thromboembolism, valve thrombosis, major hemorrhage, major paravalvular leak, and endocarditis, following objective performance criteria (OPC). Analysis was performed to include at least 400 valve-years for each valve position (aortic and mitral) for complete comparisons to OPC. Kaplan-Meier survival and major adverse cardiovascular and cerebrovascular event analyses were also performed. RESULTS: This retrospective study analyzed follow-up data collected from 903 patients (834.2 late patient-years) who have undergone surgery for 455 isolated aortic valve replacement (50.4%), 382 isolated mitral valve replacement (42.3%), and 66 combined valve replacement or other intervention (7.3%). The linearized rates of valve-related AEs were < 2 × OPC. One-year survival rates were 95.1% and 92.7% for aortic and mitral valve replacement, respectively. This study demonstrated an improvement in the New York Heart Association classification from baseline and hemodynamic performance within an expected range. CONCLUSION: According to this analysis, BVP meets world standards for safety and clinical efficacy.

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Tooth reduction guides allow clinicians to obtain the ideal space required for ceramic restorations. This case report describes a novel design (CAD) for an additive computer-aided manufactured (a-CAM) tooth reduction guide with channels that permitted access for the preparation and evaluation of the reduction with the same guide. The guide features innovative vertical and horizontal channels that permit comprehensive access for preparation and evaluation of the reduction with a periodontal probe, ensuring uniform tooth reduction and avoiding overpreparation. This approach was successfully applied to a female patient with non-carious lesions and white spot lesions, resulting in minimally invasive tooth preparations and hand-crafted laminate veneer restorations that met the patient's aesthetic demands while preserving tooth structure. Compared to traditional silicone reduction guides, this novel design offers greater flexibility, enabling clinicians to evaluate tooth reduction in all directions and providing a more comprehensive assessment. Overall, this 3D printed tooth reduction guide represents a significant advancement in dental restoration technology, offering clinicians a useful tool for achieving optimal outcomes with minimal tooth reduction. Future work is warranted to compare tooth reductions and preparation time for this guide to other 3D printed guides.

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Objective: The rehabilitation choice for the edentulous patients usually lies between the fixed and removable prosthetic options. The treatment decisions are affected by many factors where complications and maintenance needs are both considered crucial factors, in addition to the cost effectiveness of the chosen treatment. Material and Methods: This study was applied on 44 edentulous patients, where 22 patient for each group were enrolled in the outpatient clinic of prosthodontics, Cairo University as per a set of eligibility criteria. Four inter-foraminal implants were installed for all eligible participants. Three months later, healing abutments were used for soft tissue preparation prior to the fabrication of the final prosthesis. A prosthetic treatment option was then randomly allocated to obtain two equal groups via computer generated randomization program; Group. A received telescopic implant overdentures, and Group. B received screw retained dentures. All Complications (Screw loosening or fracture, tooth or denture base fracture and mucositis) were reported after overdenture insertion along the follow up period (1, 6, 9 and 12 months respectively). Results: The frequency of the screw loosening for hybrid overdentures where (59.1%) compared to (27.3%) of telescopic prosthesis at 12 months follow up period (p=0.035), mucositis reporting at 6m interval had shown the highest frequency in both groups (Group A (54.5%), Group B (81.8%), (p=0.045), all other reported complications that lack statistical significance either within the same group or between both groups at different time intervals. Conclusion: Both treatment modalities; telescopic implant overdenture and hybrid fixed screw-retained are reliable for restoring the completely edentulous arches, the decision whether to make a fixed or removable implant denture shall be guided with the patient preference together with the dentist assessment in relation (AU)

Objetivo: A escolha da reabilitação para pacientes edêntulos geralmente recai entre próteses fixas e removíveis. As decisões de tratamento são afetadas por muitos fatores onde as complicações e as necessidades de manutenção são consideradas critérios cruciais, além do custo-efetividade do tratamento escolhido. Material e Métodos: Este estudo foi aplicado em 44 pacientes edêntulos, onde 22 pacientes para cada grupo foram matriculados no ambulatório de prótese dentária da Universidade do Cairo de acordo com um conjunto de critérios de elegibilidade. Quatro implantes interforaminais foram instalados para todos os participantes elegíveis. Três meses depois, pilares de cicatrização foram utilizados para preparação dos tecidos moles antes da fabricação da prótese final. Uma opção de tratamento protético foi então alocada aleatoriamente para obter dois grupos iguais por meio de andomização gerada através programa de computador. O Grupo A recebeu overdentures de implantes telescópicos e o Grupo B recebeu dentaduras fixas parafusadas sobre os implantes. Todas as complicações (afrouxamento ou fratura do parafuso, fratura da base do dente ou da prótese e mucosite) foram relatadas após a inserção da overdentures ao longo do período de acompanhamento (1, 6, 9 e 12 meses, respectivamente). Resultados: A frequência do afrouxamento do parafuso para Overdentures híbridas (59,1%) em comparação com (27,3%) da prótese telescópica no período de acompanhamento de 12 meses (p=0,035), o relato de mucosite no intervalo de 6 meses mostrou a maior frequência em ambos os grupos (Grupo A (54,5%), Grupo B (81,8%), p=0,045, todas as outras complicações relatadas foram sem significância estatística dentro do mesmo grupo ou entre os dois grupos em intervalos de tempo diferentes. Conclusão: Ambas as modalidades de tratamento; overdentures sobre implantes telescópicos e próteses híbridas fixas parafusadas são confiáveis para reabilitar as arcadas completamente edêntulas. A decisão de fazer uma prótese fixa ou removível sobre implantes deve ser guiada pela preferência do paciente juntamente com a avaliação do dentista em relação ao estado geral do paciente e sua saúde bucal. (AU)

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ABSTRACT Objective: To assess actual data on the safety, effectiveness, and hemodynamic performance of Bovine Pericardium Organic Valvular Bioprosthesis (BVP). Methods: The BIOPRO Trial is an observational, retrospective, non-comparative, non-randomized, and multicenter study. We collected data from 903 patients with symptomatic, moderate, or severe valve disease who underwent BVP implants in the timeframe from 2013 to 2020 at three Brazilian institutions. Death, valve-related adverse events (AEs), functional recovery, and hemodynamic performance were evaluated at the hospital, at discharge, and six months and one year later. Primary analysis compared late (> 30 days after implant) linearized rates of valve-related AEs, such as thromboembolism, valve thrombosis, major hemorrhage, major paravalvular leak, and endocarditis, following objective performance criteria (OPC). Analysis was performed to include at least 400 valve-years for each valve position (aortic and mitral) for complete comparisons to OPC. Kaplan-Meier survival and major adverse cardiovascular and cerebrovascular event analyses were also performed. Results: This retrospective study analyzed follow-up data collected from 903 patients (834.2 late patient-years) who have undergone surgery for 455 isolated aortic valve replacement (50.4%), 382 isolated mitral valve replacement (42.3%), and 66 combined valve replacement or other intervention (7.3%). The linearized rates of valve-related AEs were < 2 × OPC. One-year survival rates were 95.1% and 92.7% for aortic and mitral valve replacement, respectively. This study demonstrated an improvement in the New York Heart Association classification from baseline and hemodynamic performance within an expected range. Conclusion: According to this analysis, BVP meets world standards for safety and clinical efficacy.

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Objective The present study aimed to correlate functional outcomes and implant positioning in a case series of partial shoulder resurfacing arthroplasties. Methods A total of 25 patients were assessed for range of motion, functional outcome per the University of California at Los Angeles (UCLA) score and radiographic findings. Pre- and postoperative data were compared. In addition, patients were grouped according to the cervical-diaphyseal angle (CDA) determined by an anteroposterior radiography and to the retroversion angle (RVA) determined by an axillary radiography. A CDA from 130° to 140° and a RVA from 20° to 40° consisted in ideal positioning (anatomical standard). Data were analyzed using the Wilcoxon signed-rank test, analysis of variance (ANOVA) followed by the Kruskal-Wallis test or the Mann-Whitney test as appropriate. Results The mean follow-up time was 48.3 months (12 to 67 months). The postoperative functional score (31.5) was higher than the preoperative score (15.5) ( p < 0.001). In 6 patients, the implant was in anatomical positioning, while implant positioning was considered "nonstandard" in 19 subjects. Seven patients had a CDA < 130°, and 14 patients had a CDA ranging from 130° to 140°; in addition, the CDA was > 140° in 4 subjects. The RVA was up to 20° in 15 patients and ranged from 20° to 40° in 10 subjects. Using these criteria to group patients, the postoperative clinical-functional parameters were not statistically different from the preoperative findings ( p > 0.05). Conclusion Partial shoulder resurfacing results in significant postoperative functional recovery in patients with degenerative joint diseases. However, implant positioning assessed by CDA and RVA does not correlate with clinical-functional outcomes and, therefore, it is an inaccurate indicator of surgical success. Level of Evidence IV; Case Series.

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Abstract Objective The present study aimed to correlate functional outcomes and implant positioning in a case series of partial shoulder resurfacing arthroplasties. Methods A total of 25 patients were assessed for range of motion, functional outcome per the University of California at Los Angeles (UCLA) score and radiographic findings. Preand postoperative data were compared. In addition, patients were grouped according to the cervical-diaphyseal angle (CDA) determined by an anteroposterior radiography and to the retroversion angle (RVA) determined by an axillary radiography. A CDA from 130° to 140° and a RVA from 20° to 40° consisted in ideal positioning (anatomical standard). Data were analyzed using the Wilcoxon signed-rank test, analysis of variance (ANOVA) followed by the Kruskal-Wallis test or the Mann-Whitney test as appropriate. Results The mean follow-up time was 48.3 months (12 to 67 months). The postoperative functional score (31.5) was higher than the preoperative score (15.5) (p < 0.001). In 6 patients, the implant was in anatomical positioning, while implant positioning was considered "nonstandard" in 19 subjects. Seven patients had a CDA < 130°, and 14 patients had a CDA ranging from 130° to 140°; in addition, the CDA was > 140° in 4 subjects. The RVA was up to 20° in 15 patients and ranged from 20° to 40° in 10 subjects. Using these criteria to group patients, the postoperative clinical-functional parameters were not statistically different from the preoperative findings (p > 0.05). Conclusion Partial shoulder resurfacing results in significant postoperative functional recovery in patients with degenerative joint diseases. However, implant positioning assessed by CDA and RVA does not correlate with clinical-functional outcomes and, therefore, it is an inaccurate indicator of surgical success. Level of Evidence IV; Case Series.

Resumo Objetivo O objetivo do presente estudo é correlacionar os resultados funcionais de uma série de casos de artroplastias parciais de recobrimento do ombro com o posicionamento do implante. Métodos Um total de 25 pacientes foram avaliados em relação à amplitude de movimentos, à avaliação funcional pelo escore de Universidade da Califórnia Los Angeles (UCLA) e por análise radiográfica. Os dados pré- e pós-operatórios foram comparados. Adicionalmente, os pacientes foram agrupados quanto ao ângulo cérvico-diafisário (ACD) avaliado na radiografia em anteroposterior e quanto ao ângulo de retroversão (ARV) avaliado na radiografia em posição axilar. Foi considerado como posicionamento ideal (padrão anatômico) um ACD entre 130° e 140° e um ARV entre 20° e 40°. Os dados foram analisados pelo teste pareado de Wilcoxon, pela análise de variância (ANOVA, na sigla em inglês) seguida pelo pós-teste de Kruskal-Wallis ou pelo teste de Mann-Whitney, quando apropriado. Resultados O seguimento médio foi de 48,3 meses (12 a 67 meses). A avaliação funcional pós-operatória (31,5) foi melhor do que a pré-operatória (15,5) (p < 0,001). Seis pacientes apresentaram posicionamento anatômico do implante, enquanto 19 pacientes foram considerados "fora do padrão." Sete pacientes apresentaram um ACD < 130°, quatorze apresentaram um ACD entre 130° e 140°, e quatro apresentaram um ACD >140°. Quinze pacientes apresentaram um ARV ≤ 20°, e 10 entre 20° e 40°. Utilizando esses critérios para agrupar os pacientes, a comparação dos parâmetros da avaliação clínico-funcional pós-operatória não foi estatisticamente diferente (p > 0,05). Conclusão A artroplastia parcial de recobrimento do ombro oferece significativa recuperação funcional pós-operatória em pacientes com doenças degenerativas articulares. Entretanto, o posicionamento do implante avaliado pelos ACD e ARV não se correlaciona com o resultado clínico-funcional, sendo, portanto, uma medida imprecisa de sucesso da cirurgia. Nível de Evidência IV, Série de Casos.

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AIM: The aim of this study was to evaluate the stress distribution of a planned removable partial denture (RPD) using new proposals for calibrated gauges of 0.3 mm and 0.35 mm undercuts through the three-dimensional (3D) finite element methodology, and compare them with 0.25 mm and 0.5 mm gauges that are already existing in clinical practice. MATERIALS AND METHODS: Kennedy class-I edentulous 3D models and their respective RPDs (InVesalius software; Rhinoceros and SolidWorks CAD) were created and exported to the finite element program HyperMesh 2019 for mesh configuration. In the following steps, axial loading (0º) of 40 N per point was performed, with 3 points on the molars and 2 points on the premolars, totaling 280 N unilaterally. The model was processed by the OptiStruct 2019 software and imported into the HyperView 2019 software to obtain the stress maps (MPa). RESULTS: The use of 0.30 and 0.35 mm calibrated gauges presented tensions similar to those with the 0.25 mm gauge (gold standard) and caused no significant damage to biological structures. The use of a 0.5 mm undercut caused greater traction force in the periodontal ligament of the abutments. CONCLUSIONS: The 0.35 mm undercut seems promising as it presented more favorable results in this simulation, on the other hand, a 0.5 mm undercut is greater than that necessary for retainers made of CoCr. CLINICAL SIGNIFICANCE: This study aims to measure a new undercut gauge (0.35 mm) to increase the retention area in abutment teeth of removable partial dentures.

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Background: The artistic techniques necessary to fabricate facial prostheses mainly depend on individual skill and are not a resource easily reproduced. Digital technology has contributed to improved outcomes, often combining analog and new digital techniques in the same workflow. Methods: This article aims to present an innovative workflow to produce a final colored 3D printed and facial prosthesis by UV-map color translation into colored resin 3D printing. A modified +ID Methodology was used to obtain 3D models with the calibrated 3D printable patient's skin color. No hands-on physical molding, manual sculpture, or intrinsic silicone coloration was used. Results: The outcome resulted in acceptable aesthetics, adaptation, and an approximate color match after extrinsic coloration. The patient reported good comfort and acceptance. Conclusions: A direct resin 3D printed prosthesis may be a viable alternative, especially for rapid delivery as an immediate prosthesis or an option when there is no experienced anaplastogist to manufacture a conventional prosthesis.

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Introducción: Gracias a su eficiencia y al uso exclusivo de cerámicas libres de metal, en rehabilitación oral se ha logrado alcanzar los estándares estéticos y mecánicos, manteniendo o, incluso, superando, la calidad de los tratamientos en comparación con las restauraciones metal cerámicas tradicionales. Actualmente los mecanismos de confeccion de cerámica libre están evolucionando cada vez mas hacia las tecnologías maquinadas CAD-CAM y disminuyendo su producción mediante la técnica de Inyeccion PRESS. Objetivo: Comparar la tasa de supervivencia de prótesis fija unitaria realizadas con cerámicas feldespáticas convencionales y reforzadas con disilicato de litio, confeccionadas con sistema CAD/CAM de CEREC® chair-side, en comparación con el método de inyección de laboratorio PRESS convencional de prensión. Métodos: Revisión sistemática realizada a través de búsqueda de evidencia científica en PubMed, PubMed Clinical Queries, Epistemónikos, Tripdatabase, Cochrane Library, recursos electrónicos de la Universidad de los Andes y bibliografía retrógrada, de artículos publicados hasta el año 2019. Se incluyeron todos aquellos estudios referentes a prótesis fija unitaria de cerámicas feldespática convencional y feldespática reforzada con disilicato de litio, confeccionadas mediante CAD/CAM y/o método convencional. Resultados: Un total de 28 artículos cumplieron los criterios de inclusión: 21 estudios observacionales de cohorte, 4 ensayos clínicos aleatorizados y 3 no aleatorizados. A corto y mediano plazo, CAD/CAM de CEREC® registró tasas de supervivencia de 98 por ciento y 91,9 por ciento, respectivamente. El sistema convencional registró tasas de supervivencia de 97,5 por ciento a corto plazo y 93 por ciento a mediano. Conclusiones: A corto plazo se describe en la literatura que CAD/CAM de CEREC® tuvo una tasa de supervivencia ligeramente superior al sistema convencional. Por otro lado, a mediano plazo CAD/CAM de CEREC® presentó una leve disminución respecto al sistema convencional. Aún no hay estudios disponibles para determinar la supervivencia clínica de los tratamientos a largo plazo(AU)

Introduction: Thanks to its efficiency and the exclusive use of metal-free ceramics, in oral rehabilitation it has been possible to achieve aesthetic and mechanical standards, maintaining or even exceeding the quality of the treatments compared to traditional metal-ceramic restorations. Currently, free ceramic manufacturing mechanisms are increasingly evolving towards CAD-CAM machined technologies and decreasing their conventional production through the PRESS Injection technique. Objective: Compare the survival rate of single-unit fixed prostheses made with conventional feldspathic ceramics and reinforced with lithium disilicate by the CEREC® CAD/CAM chairside system, with the conventional PRESS laboratory injection method. Methods: A systematic review was conducted of scientific evidence included in papers published until the year 2019 in PubMed, PubMed Clinical Queries, Epistemonikos, Tripdatabase, Cochrane Library, electronic resources of Los Andes Peruvian University, and retrograde bibliography. The papers selected dealt with conventional and lithium-disilicate reinforced feldspathic ceramic single-unit prostheses made by CAD/CAM and/or the conventional method. Results: A total 28 papers met the inclusion criteria. Of these, 21 were observational cohort studies, four were randomized clinical assays and three were non-randomized assays. Short- and mid-term, CEREC® CAD/CAM achieved survival rates of 98 percent and 91.9 percent, respectively. The conventional system achieved survival rates of 97.5 percent short-term and 93 percent mid-term. Conclusions: As described in the literature, CEREC® CAD/CAM had a slightly higher survival rate than the conventional system in the short term. In the medium term, however, CEREC® CAD/CAM displayed a slight reduction in comparison with the conventional system. No studies are available to determine the clinical survival of the treatments in the long term(AU)

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Objective To evaluate the wear of polyethylene in a Brazilian ultracongruent knee prosthesis with a rotating platform (Rotaflex, Víncula, Rio Claro, SP, Brasil). Methods We used the test method with the loading and preparation parameters mentioned in the standards regulation ISO 14243-1:2009 , and the measurement methods mentioned in the standards regulation ISO 14243-2:2009 , for the evaluation of the wear behavior of a Brazilian prosthesis with a rotating platform. The equipment used for the wear test was the ISO 14243-1 gait simulator (EndoLab, Riedering, Germany). Results After 10 million cycles, the evaluation of the polyethylene wear showed a regular appearance of surface wear at a mean rate of 2.56 mg per million cycles. Conclusion The wear of the polyethylene of the evaluated prosthesis was minimal after the tests performed and with safety limits higher than those recommended by biomechanical engineering.

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Abstract Objective To evaluate the wear of polyethylene in a Brazilian ultracongruent knee prosthesis with a rotating platform (Rotaflex, Víncula, Rio Claro, SP, Brasil). Methods We used the test method with the loading and preparation parameters mentioned in the standards regulation ISO 14243-1:2009, and the measurement methods mentioned in the standards regulation ISO 14243-2:2009, for the evaluation of the wear behavior of a Brazilian prosthesis with a rotating platform. The equipment used for the wear test was the ISO 14243-1 gait simulator (EndoLab, Riedering, Germany). Results After 10 million cycles, the evaluation of the polyethylene wear showed a regular appearance of surface wear at a mean rate of 2.56 mg per million cycles. Conclusion The wear of the polyethylene of the evaluated prosthesis was minimal after the tests performed and with safety limits higher than those recommended by biomechanical engineering.

Resumo Objetivo Avaliar o desgaste do polietileno de uma prótese de joelho brasileira ultracongruente de base rotatória (Rotaflex, Víncula, Rio Claro, SP, Brasil). Métodos Utilizou-se o método de ensaio com os parâmetros de carregamento e preparação citados na norma ISO 14243-1:2009, e os métodos de medição citados na norma ISO 14243-2:2009, para a avaliação do comportamento de desgaste de uma prótese nacional com base rotatória. O equipamento utilizado para o teste de desgaste foi o simulador de marcha ISO 14243-1 (EndoLab, Riedering, Alemanha). Resultados Após 10 milhões de ciclos, a avaliação do desgaste do polietileno mostrou uma aparência regular do desgaste da superfície com taxa média de 2,56 mg por milhão de ciclos. Conclusão O desgaste do polietileno da prótese avaliada foi mínimo após os ensaios realizados e com os limites de segurança superiores aos preconizados pela engenharia biomecânica.

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ABSTRACT Introduction: There is no consensus as to which cemented or screwed retention system is best to avoid bone loss around the implant from a fixed implant-supported restoration. Objective: To evaluate the prosthesis retention systems on screw and cemented implants, regarding: bone loss, survival and failure rate, biological complications and microbiological analysis. Methods: A search was made for scientific articles that contemplated the subject through the databases Pubmed and SciELO, without period restriction. The titles, abstracts and then access to the full text has been verified. Results: It was found that excess cement may play an important role in the development of peri-implant disease. Technical failures are most seen in prosthesis retained by screws, and biological complications in cemented crowns. The success rate for both restraint systems is high, and retention-independent implant prosthesis treatment provides predictability. Conclusion: The appropriate retention system for the patient depends on several factors, including indication, advantages and disadvantages, retention provided, aesthetics and clinical performance.

RESUMO Introdução: Não há consenso sobre qual sistema de retenção, cimentado ou parafusado, é o melhor para evitar perda óssea ao redor do implante de uma restauração fixa implanto-suportada. Objetivo: Avaliar os sistemas de retenção de próteses sobre implantes parafusadas e cimentadas, quanto aos fatores: perda óssea, taxa de sobrevivência e de falhas, complicações biológicas e análises microbiológicas. Métodos: Foi realizada uma busca por artigos científicos que contemplassem o tema através das bases de dados Pubmed e SciELO, sem restrição de período. Os títulos, resumos e em seguida o acesso ao texto completo foi verificado. Resultados: Foi observado que o excesso de cimento pode desempenhar um papel importante no desenvolvimento da doença peri-implantar. Falhas técnicas são mais observadas em próteses retidas por parafusos e complicações biológicas em coroas cimentadas. A taxa de sucesso para os dois sistemas de retenção é alta e o tratamento com próteses sobre implantes independente da retenção oferece previsibilidade ao caso. Conclusão: O sistema de retenção apropriado para o paciente depende de diversos fatores, incluindo a indicação, vantagens e desvantagens, retenção fornecida, estética e desempenho clínico.

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Objective This study aims to compare the in vitro wear rate of crosslinked, high molecular weight polyethylene coupled to 36-mm diameter ceramic heads and 32-mm diameter metal heads. Methods Ceramic-on-polyethylene (36 mm) and metal-on-polyethylene (32 mm) tribological pairs were submitted to biomechanical tests in a simulator to determine the wear rate after 15 × 10 6 cycles. Results A statistically significant difference ( p = 0.0005) was detected when comparing the wear rate of assemblies with metallic heads (average wear: 14.12 mg/MC) and ceramic heads (average wear: 7.46 mg/MC). Conclusion The present study demonstrated the lower wear rate in prosthetic assemblies using 36-mm crosslinked ceramic-on-polyethylene tribological pairs compared to 32-mm crosslinked metal-on-polyethylene assemblies. This finding demonstrates the effectiveness of ceramic-on-polyethylene tribological pairs, even with large diameter heads.

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Abstract Objective This study aims to compare the in vitro wear rate of crosslinked, high molecular weight polyethylene coupled to 36-mm diameter ceramic heads and 32-mm diameter metal heads. Methods Ceramic-on-polyethylene (36 mm) and metal-on-polyethylene (32 mm) tribological pairs were submitted to biomechanical tests in a simulator to determine the wear rate after 15 × 106 cycles. Results A statistically significant difference (p= 0.0005) was detected when comparing the wear rate of assemblies with metallic heads (average wear: 14.12 mg/MC) and ceramic heads (average wear: 7.46 mg/MC). Conclusion The present study demonstrated the lower wear rate in prosthetic assemblies using 36-mm crosslinked ceramic-on-polyethylene tribological pairs compared to 32-mm crosslinked metal-on-polyethylene assemblies. This finding demonstrates the effectiveness of ceramic-on-polyethylene tribological pairs, even with large diameter heads.

Resumo Objetivo: O objetivo do presente estudo foi comparar, in vitro, a taxa de desgaste do polietileno de alto peso molecular reticulado acoplado a cabeças cerâmicas de 36 mm de diâmetro e acoplado a cabeças metálicas de 32 mm de diâmetro. Métodos: Foram realizados ensaios biomecânicos em simulador de desgaste para os pares tribológicos cerâmica-poli (36 mm) e metal-poli (32 mm) a fim de verificar a taxa de desgaste após em 15 × 106 ciclos. Resultados: Na comparação entre as medidas de taxa de desgaste dos conjuntos com cabeças metálicas (média:14,12 mg/MC) e cerâmicas (média:7,46 mg/MC) houve diferença estatitsticamente significativa (p= 0,0005). Conclusão: O presente estudo demonstrou menor taxa de desgaste em conjuntos protéticos que utilizaram o par tribológico cerâmica-polietileno reticulado de 36 mm em comparação aos conjuntos com metal-polietileno reticulado de 32 mm. Tal achado demonstra a eficácia do par tribológico cerâmica-poli, mesmo com a utilização de cabeças de grande diâmetro.

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Objective To determine if the dimensions of selected national and imported implants used in total hip arthroplasty surgeries are adequate regarding the anthropometric profile of the Brazilian population. Methods A retrospective study of patients submitted to primary total hip arthroplasty. Patients with femoral or acetabular morphological deformities that could influence the choice of implant size, including dysplasia and previous fractures, were excluded from the study. Two national implants and six imported implants were included in the study. Every patient was treated by the same group, with one of the four senior authors or under their strict supervision, following the same surgical technique. The data were analyzed regarding gender, age, fixation type and implant model. Results The analysis of 682 hips submitted to total hip arthroplasty demonstrated that 2 models of cemented femoral stems and 1 of non-cemented stem did not seem to be perfectly adequate for the femoral morphology of the studied population, since these 3 implants were mostly used in the smallest size available, resulting in a non-Gaussian curve. The mean diameter of the native acetabulum was 54 mm in men and 52 mm in women. Conclusion Out of the eight models studied, five were deemed adequate for the studied population. The other three models available in our market (two national models and one imported model) apparently require more appropriate sizing. We emphasize that anthropometric studies of the Brazilian hip are necessary to give scientific subsidies to the ideal implant design for our market.

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Introducción: La artroplastía cervical es una cirugía que implica el uso de implantes discales con la capacidad de conservar el movimiento del segmento. Constituye un reto para paises como el nuestro desarrollar alternativas a los altos costos de los mencionados implantes, con diseños patentado, elaborado viables de manufacturar, con biocompatibilidad, seguridad, y que simule lo máximo posible los movimientos cervicales fisiológicos. Objetivo: Desarrollar la geometría y mecánica de un diseño discal patentado, elaborado, sea por manufactura aditiva de titanio ELI, así como verificar su compatibilidad con la fisiología de los movimientos cervicales. Métodos: El diseño del estudio tuvo tres etapas iterativas: la primera, el desarrollo de la geometría del implante y el estudio de elementos finitos utilizando como referencia normas internacionales; en segundo lugar, se desarrollaron estudios de metalografía, caracterización del material incluyendo pruebas de fatiga del implante; finalmente, se utilizó un modelo animal cadavérico para confirmar la compatibilidad del implante con los movimientos cervicales. Resultados: Se demostró que el implante elaborado sea por manufactura aditiva o por forja, fue compatible con las normas internacionales. Se realizaron 84 estudios de rayos X en 18 cuellos de porcino. En el 100% de las columnas cervicales de los porcinos, el rango en flexión fue menor que el de extensión. Existió mayor rango de movimiento cuando se utilizaron dos implantes y cuando el implante fue más grande. Conclusiones: El implante cervical flexible elaborado por forja o por manufactura aditiva de titanio ELI presentó resultados prometedores, por lo que podría postularse su uso experimental en pacientes tributarios de artroplastía cervical.

Introduction: Cervical arthroplasty is a surgical procedure that involves the use of disc implants with the capacity of preserving segmental movement. It is a challenge for countries like ours to develop alternatives to the high costs of the aforementioned implants, with patented designs, feasible to manufacture, with biocompatibility, safety, and that simulates as much as possible the physiological cervical movements. Objectives: To develop the geometry and mechanics of a patented disc design elaborated with titanium ELI by additive manufacturing, as well as, to verify its compatibility with the physiology of cervical movements. Methods: The study design had three iterative stages: the first one was the development of the implant geometry and the finite-element study using international standards as a reference. In second place, studies of metallography, characterization of the material and fatigue tests of the implant were developed. Finally, a cadaverous animal model was used to confirm the compatibility of the implant with cervical movements. Results: The implants manufactured by forging or by additive manufacturing are compatible with international standards. 84 x-ray studies were performed on 18 pig necks. In 100% of the cervical columns of the pigs, the range in flexion was smaller than that of extension. There was a greater range of motion when two implants were used and when the implant was larger. Conclusions: The flexible cervical implant made by forging or a titanium-ELI additive manufacturing have promising results, because of that, an experimental use in patients, who needs cervical arthroplasty, could be considered.

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Abstract Objective To determine if the dimensions of selected national and imported implants used in total hip arthroplasty surgeries are adequate regarding the anthropometric profile of the Brazilian population. Methods A retrospective study of patients submitted to primary total hip arthroplasty. Patients with femoral or acetabular morphological deformities that could influence the choice of implant size, including dysplasia and previous fractures, were excluded from the study. Two national implants and six imported implants were included in the study. Every patient was treated by the same group, with one of the four senior authors or under their strict supervision, following the same surgical technique. The datawere analyzed regarding gender, age, fixation type and implant model. Results The analysis of 682 hips submitted to total hip arthroplasty demonstrated that 2 models of cemented femoral stems and 1 of non-cemented stem did not seem to be perfectly adequate for the femoral morphology of the studied population, since these 3 implants were mostly used in the smallest size available, resulting in a non-Gaussian curve. The mean diameter of the native acetabulum was 54mm in men and 52mm in women. Conclusion Out of the eight models studied, five were deemed adequate for the studied population. The other three models available in our market (two national models and one imported model) apparently require more appropriate sizing. We emphasize that anthropometric studies of the Brazilian hip are necessary to give scientific subsidies to the ideal implant design for our market.

Resumo Objetivo Definir se as dimensões de alguns implantes de fabricação nacional e estrangeira utilizados nas cirurgias de artroplastia do quadril estão adequadas ao perfil antropométrico da população brasileira. Métodos Estudo retrospectivo de pacientes submetidos a cirurgia primária de substituição artroplástica total do quadril. Foram excluídos deste estudo pacientes comalterações morfológicas femorais ou acetabulares que pudessem influenciar na escolha do tamanho dos implantes, tais comosequelas de displasia, trauma, entre outras. Foramincluídos neste estudo dois implantes de fabricação nacional e seis modelos importados. Todos os pacientes foram operados pela mesma equipe, por um dos quatro autores seniores ou sob sua supervisão direta, seguindo a mesma técnica cirúrgica. Os dados foram estatisticamente analisados em relação a gênero, idade, tipo de fixação e modelo dos implantes. Resultados A análise estatística de 682 quadris submetidos a artroplastia total demonstrou que 2 modelos de hastes femorais cimentadas e 1 de haste não cimentada não estão perfeitamente adequados à morfologia femoral da população estudada, pois, na maioria dos casos, nestes 3 implantes, foi utilizado o menor tamanho disponível, resultando em uma curva não gaussiana. O diâmetro médio do acetábulo nativo foi de 54mm nos homens e de 52mm nas mulheres. Conclusão Dos oitomodelos estudados, cinco semostraram adequados à população estudada. Outros três modelos disponíveis em nosso mercado (dois nacionais e um importado) parecem necessitar de um escalonamento mais adequado. Destacamos que são necessários estudos antropométricos do quadril da população brasileira para dar subsídios científicos ao desenho ideal dos implantes para o nosso mercado.

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