Resumo: A interface implante/pilar não pode ser totalmente selada para passagem de microrganismos, com isso o interior do implante torna-se um reservatório de microrganismos patogênicos que promovem e mantêm a inflamação crônica nos tecidos em volta dos implantes. Nanopartículas de prata são agentes antimicrobianos potentes e de amplo espectro. O objetivo deste estudo foi avaliar a capacidade das nanopartículas de prata em evitar a contaminação porCandida albicans do interior de implantes, originada da infiltração do fungo através da interface implante/pilar. 36 implantes foram utilizados neste experimento. Três grupos de estudo foram estabelecidos: grupo experimental (os implantes receberam aplicação de nanopartículas de prata na sua cavidade interna, antes da instalação do pilar); grupo controle positivo (os implantes receberam PBS estéril em vez das nanopartículas de prata) e grupo controle negativo (implantes receberam aplicação de nanopartículas de prata na cavidade interna, mas os implantes foram imersos em meio estéril). Nos grupos controle positivo e experimental, os implantes foram imersos em suspensão deCandida albicans. Os pilares protéticos de todos os grupos foram parafusados com torque de 10 N. Após 72 h imersos na suspensão deC. albicans ou em meio estéril, os pilares foram removidos e amostras da superfície interna dos implantes foram coletadas com cone de papel absorvente para a detecção de Candida. No grupo controle negativo não foi observada contaminação por C. albicans. O grupo-controle positivo mostrou valores de unidades formadoras de colônia deCandida estatisticamente maiores quando comparado com o grupo experimental. Conclui-se que nanopartículas de prata reduzem a colonização de C. albicans dentro dos implantes, mesmo quando o pilar é parafusado com torque baixo.

Abstract: Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface byCandida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.

PURPOSE: To assess the effectiveness of bipolar epicardial atrial pacing using an active fixation bipolar endocardial lead implanted on the atrial surface in an experimental model. METHODS: A total of ten Large White adult pigs underwent pacemaker implantation under general anesthesia. Atrial pacing and sensing parameters were obtained at the procedure, immediate postoperative period and on the 7th and the 30th postoperative in unipolar and bipolar configurations. RESULTS: All procedures were successfully performed. There were no perioperative complications and no early deaths. Atrial pacing and sensing parameters for both unipolar and bipolar modes remained stable throughout the study. We observed a progressive increase in atrial thresholds, ranging from 0.49 ± 0.35 (at implantation) to 1.86 ± 1.31 volts (30th postoperative day), in unipolar mode. Atrial impedance measurements decreased slightly over time, ranging from 486.80 ± 126.35 Ohms (at implantation) to 385.0 ± 80.52 Ohms (30th postoperative day). Atrial sensing measures remained stable from the immediate postoperative period until the end of the study. CONCLUSION: The bipolar active fixation endocardial lead implanted epicardially can provide stable conditions of pacing and sensing parameters throughout the postoperative follow-up.

The aim of this study was to evaluate the following acrylic resins: Clássico®, QC-20® and Lucitone®, recommended specifically for thermal polymerization, and Acron MC® and VIPI-WAVE®, made for polymerization by microwave energy. The resins were evaluated regarding their surface nanohardness and modulus of elasticity, while varying the polymerization time recommended by the manufacturer. They were also compared as to the presence of water absorbed by the samples. The technique used was nanoindentation, using the Nano Indenter XP®, MTS. According to an intra-group analysis, when using the polymerization time recommended by the manufacturer, a variation of 0.14 to 0.23 GPa for nanohardness and 2.61 to 3.73 GPa for modulus of elasticity was observed for the thermally polymerized resins. The variation for the resins made for polymerization by microwave energy was 0.15 to 0.22 GPa for nanohardness and 2.94 to 3.73 GPa for modulus of elasticity. The conclusion was that the Classico® resin presented higher nanohardness and higher modulus of elasticity values when compared to those of the same group, while Acron MC® presented the highest values for the same characteristics when compared to those of the same group. The water absorption evaluation showed that all the thermal polymerization resins, except for Lucitone®, presented significant nanohardness differences when submitted to dehydration or rehydration, while only Acron MC® presented no significant differences when submitted to a double polymerization time. Regarding the modulus of elasticity, it was observed that all the tested materials and products, except for Lucitone®, showed a significant increase in modulus of elasticity when submitted to a lack of hydration.

This study aimed to present a wireless mandibular motion tracking device and optoelectronic data acquisition system developed to analyze the real-time spatial motion of the entire mandible during mouth opening and closing with no restriction of any movement. The procedures were divided into three phases: confection of a kinematic arch, dynamic digital video image acquisition, and image processing and analysis by using graphic computation. Four sequences of jaw opening/closing movements were recorded in lateral view: two from the maximum intercuspation (MIC) and the other two from a forced mandibular retruded position. Jaw motion was recorded by a digital video camera and processed as spatial coordinates corresponding to the position variation of the markers in the kinematic arch. The results showed that the method was capable of recording and processing the dynamics of the mandibular movements during jaw opening/closing using pixel-magnitude points. The mandible showed points with less displacement located near the temporomandibular joint during the opening/closing movements from the mandibular retruded position. When the jaw movements were recorded from MIC, these points were located near the mandibular foramen.

OBJETIVOS: Avaliar a incidência e a causa de choques de CDI em crianças e adolescentes e sua repercussão na qualidade de vida (QV). MÉTODOS: De março/1997 a fevereiro/2006, 29 pacientes (15,7±5,4 anos) foram submetidos a implante de CDI. Parada cardiorrespiratória recuperada (41,5%), taquicardia ventricular sustentada (27,6%) e profilaxia primária de morte súbita cardíaca (30,9%) motivaram os implantes. O número de terapias foi avaliado por entrevista e pela telemetria dos CDI. A QV foi avaliada pela aplicação do questionário SF-36 e comparada à de indivíduos saudáveis. Empregou-se o método de Kaplan-Meier para análise da sobrevida livre de choques. RESULTADOS: Após 2,6±1,8 anos de seguimento, 8 (27,6%) pacientes receberam 141 choques apropriados em razão de TV polimórfica (6) ou FV (2), e 11 (37,9%) sofreram 152 choques inapropriados em razão de taquiarritmias supraventriculares (8) ou oversensing (3). A expectativa de sobrevida livre de choques apropriados foi de 74,2%±9,0 após um ano, e de 66,7%±10,7 após três anos. Observou-se diminuição da QV nos aspectos físicos (61,7±28,7), na vitalidade (64,7±19,1), na saúde mental (65,9±22,7) e nos aspectos emocionais (66,7±38,5). Medo e preocupações relacionados ao CDI foram referidos por todos os pacientes. CONCLUSÃO: A despeito da grande eficácia dessa terapêutica, a incidência elevada de choques interferiu na QV e na adaptação ao dispositivo.

OBJECTIVES: To analyze the incidence and causes of ICD therapies in children and young adults and verify their impact on the quality of life (QoL). METHODS: From March/1977 to February/2006, 29 patients (15.7±5.4 years old) were submitted to ICD implants. Aborted cardiac arrest (41.5%), sustained ventricular tachycardia (27.6%) and primary prophylaxis of sudden cardiac death (30.9%) indicated device therapy. The number of therapies was evaluated by interviewing patients and by ICD diagnostic data. The SF-36 questionnaire was used to measure the QoL and the results were compared to healthy population. The expectative of freedom from ICD therapies were estimated by the Kaplan-Meier method. RESULTS: After 2.6±1.8 years follow-up, 8 (27.6%) patients received 141 appropriate ICD shocks due to ventricular tachycardia (6) or ventricular fibrillation (2), and 11 (37.9%) patients received 152 inappropriate ICD shocks due to supraventricular tachyarrhythmias (8) or oversensing (3). Expectative of freedom from appropriate shocks was 74.2±9.0% and 66.7±10.7% after one and three years, respectively. Compared to healthy population, QoL decreased in physical function (61.7±28.7), vitality (64.7±19.1), mental health (65.9±22.7) and role-emotional domains (66.7±38.5). All patients referred fear and concern related to ICD use. CONCLUSION: Despite the efficacy of ICD therapies, the high incidence of appropriate and inappropriate shocks interfered in patients’ QoL and adaptation to the device.

OBJETIVO: Avaliar a evolução tardia de crianças com marca-passo definitivo por bradicardia pós-operatória, e identificar fatores de risco para a mortalidade. MÉTODO: De 1980 a 2004, 120 crianças receberam implante de marca-passo definitivo por bradicardia pós-operatória. O intervalo médio entre a correção do defeito e o implante foi de 1,2 ± 2,8 anos, com mediana de 21 dias. Bloqueio atrioventricular esteve presente em 94,2% dos pacientes. A via de acesso transvenosa (78,3%) e marca-passos (MP) definitivos ventriculares (79,2%) foram os mais utilizados. Empregou-se o método de Kaplan-Meier e o teste de Log-Rank para a análise de sobrevivência. RESULTADOS: Após 5,7 ± 5,9 anos de seguimento (máximo= 22,5 anos), 97 pacientes estavam vivos e 11 haviam sido perdidos para o seguimento. As principais causas de morte foram insuficiência cardíaca (10), infecção não relacionada ao marca-passo (seis) e morte súbita (três). A expectativa de sobrevida aos cinco, 10 e 15 anos de seguimento mostrou, respectivamente, índices de 80,9 ± 4,1%, 75,4 ± 5,5% e 67,2 ± 7,4%. A persistência de problemas hemodinâmicos após a correção (correções paliativas, uso de próteses valvares ou defeitos residuais) foi identificada como única variável preditora independente de risco para mortalidade, alterando significativamente as curvas de sobrevivência (p = 0,0123). CONCLUSÕES: O implante de marca-passo em casos de bradicardia pós-operatória possibilitou boa expectativa de sobrevida. A realização de correções paliativas, assim como a presença de defeitos residuais ou de próteses valvares, foram os únicos fatores preditores de mau prognóstico para essas crianças.

OBJECTIVE: To evaluate the long-term outcomes of children submitted to permanent cardiac pacing due to postoperative bradycardia and to identify risk factors for mortality. METHODS: From 1980 to 2004, 120 children were submitted to permanent pacemaker (PM) implantation. Interval between the defect correction and PM implantation was 1.2 ± 2.8 years, on average (median = 21 days). Atrioventricular blocks were present in 94.2% of patients. Transvenous leads (78.3%) and ventricular pacemaker systems (79.2%) were used in most of the cases. Risk factors were studied using the Cox proportional model. The Kaplan-Meier method and the Log-Rank test were used to analyze survival. RESULTS: After a mean of 5.7 ± 5.9 years (maximum = 22.5 years) of follow-up, 97 patients were alive and 11 were lost from the follow-up study. The main causes of death were terminal heart failure (10), infection not related to implantation (six), and sudden death (three). The 5-, 10-, and 15-year survival rates were 80.9 ± 4.1%, 75.4 ± 5.5% and 67.2 ± 7.4%, respectively. The persistence of hemodynamic problems (palliative procedures, the use of valve prostheses or the presence of residual defects) was identified as the only independent risk predictors for mortality, with significant alterations in the survival curves (p=0.0123). CONCLUSION: The implant of permanent pacemakers in children provided good survival expectancy, mainly depending on the underlying disease and the type of the correction made. Palliative corrections, such as the presence of residual defects or valve prostheses were the only predictors of poor results in these children.

OBJETIVO: A estimulação cardíaca permanente melhora a sobrevida de crianças com bradicardia congênita ou adquirida, embora a mortalidade após o implante de marcapasso permaneça relativamente alta. O objetivo deste estudo foi avaliar os resultados em longo prazo de crianças submetidas a implante de marcapasso endocárdico pela veia femoral, incluindo a identificação de fatores de risco associados à mortalidade. MÉTODO: De 1981 a 2000, 99 pacientes variando em idade de um dia a 13 anos (4,1 ± 3,6 com mediana = 3 anos) foram submetidos a implante de marcapasso permanente pela via femoral devido a bradicardia de origem congênita (39,4%), pós-cirúrgica (54,5%) ou adquirida não cirurgicamente (6,1%). RESULTADOS: Ao final de 7,1 ± 5,3 anos (708,3 pacientes-anos) de seguimento, 18 (18,2%) pacientes haviam morrido. A sobrevida atuarial foi de 85%, 79,5%, e 74,2%, aos cinco, 10, e 15 anos, respectivamente. Os fatores independentes de mortalidade identificados pela análise proporcional de Cox foram: menor idade ao implante (p = 0,028), presença de anomalias cardíacas não corrigidas ou presença de próteses intracardíacas (p = 0,0001) e evidências radiográficas de cardiomegalia (p = 0,035). CONCLUSÕES: A estimulação cardíaca endocárdica permanente pela via femoral apresenta expectativa de sobrevida comparável a outras técnicas, com baixas taxas de complicações devidas ao implante de marcapasso. A sobrevida em longo prazo foi limitada pela menor idade e dilatação cardíaca no momento do implante, assim como pela presença de defeitos cardíacos sem correção ou de próteses valvares.

OBJECTIVE: Permanent cardiac pacing improves survival of children with congenital or acquired bradycardia, although mortality after pacing remains relatively high. The aim of this study was to evaluate the long-term outcomes of children who undergo permanent endocardial cardiac pacing via the femoral vein, including the identification of associated risk factors for mortality. METHOD: From 1981 to 2000, 99 patients ranging in ages from one day to 13 years (4.1 ± 3.6 and median = 3 years) underwent permanent transfemoral pacemaker implantation due to congenital (39.4%), postsurgical (54.5%), or non-surgically acquired bradycardia (6.1%). RESULTS: By the end of 7.1 ± 5.3 years (708.3 patient-years) of prospective follow-up, 18 (18.2%) patients had died. The actuarial survival rates were 85%, 79.5%, and 74.2%, at 5, 10, and 15 years, respectively. Independent predictors of mortality identified by Cox proportional hazards analysis were younger age at implantation (p = 0.028), the presence of untreated cardiac anomalies or intracardiac prostheses (p = 0.0001), and radiographic evidence of cardiomegaly (p = 0.035). CONCLUSIONS: Permanent endocardial pacing via the femoral vein presented survival expectance comparable to other techniques with a low rate of pacing complications. Long-term survival was limited by lower ages and cardiac dilatation at the time of implantation as well as by the presence of untreated cardiac defects or valve prostheses.