Biomechanical Effects of Different Load Cases with an Implant-Supported Full Bridge on Four Implants in an Edentulous Mandible: A Three-Dimensional Finite Element Analysis (3D-FEA).

The long-term success and predictability of implant-supported restorations largely depends on the biomechanical forces (stresses) acting on implants and the surrounding alveolar bone in the mandible. The aim of our study was to investigate the biomechanical behavior of an edentulous mandible with an implant-supported full bridge on four implants under simulated masticatory forces, in the context of different loading schemes, using a three-dimensional finite element analysis (3D-FEA). A patient-specific 3D finite element model was constructed using pre- and post-implantation computer tomography (CT) images of a patient undergoing implant treatment. Simplified masticatory forces set at 300 N were exerted vertically on the denture in four different simulated load cases (LC1-LC4). Two sets of simulations for different implants and denture materials (S1: titanium and titanium; S2: titanium and cobalt-chromium, respectively) were made. Stress outputs were taken as maximum (Pmax) and minimum principal stress (Pmin) and equivalent stress (Peqv) values. The highest peak Pmax values were observed for LC2 (where the modelled masticatory force excluded the cantilevers of the denture extending behind the terminal implants), both regarding the cortical bone (S1 Pmax: 89.57 MPa, S2 Pmax: 102.98 MPa) and trabecular bone (S1 Pmax: 3.03 MPa, S2 Pmax: 2.62 MPa). Overall, LC1-where masticatory forces covered the entire mesio-distal surface of the denture, including the cantilever-was the most advantageous. Peak Pmax values in the cortical bone and the trabecular bone were 14.97-15.87% and 87.96-94.54% higher in the case of S2, respectively. To ensure the long-term maintenance and longevity of treatment for implant-supported restorations in the mandible, efforts to establish the stresses of the surrounding bone in the physiological range, with the most even stress distribution possible, have paramount importance.

[The effect of intraocular pressure on refractive power of the cornea and the human eye, based on the Liou-Brennan model eye]. / A szemnyomás változásának hatása a szaruhártya és a szem töroerejére a Liou­Brennan-modellszem alapján.

INTRODUCTION: It is a clinical experience that with significantly higher intraocular pressure, glass ordering may be inaccurate, therefore, it should be performed after adjustment of intraocular pressure. OBJECTIVE: To analyze the effect of intraocular pressure on the refractive power of the cornea and of the eye, using geometrical properties of the Liou-Brennan model eye and finite element modeling. METHODS: Using corneal parameters of the Liou-Brennan model eye, a parametric geometrical model and with these data finite element modelling, using the Ansys (Ansys, Canonsburg, PA, USA) program, has been performed. Corneal tissue properties have been defined based on trilinear material model of Wollensak and boundary conditions based on Pandolfi. The effect of changes in intraocular pressure on geometrical corneal properties with optical impact (corneal curvature at the anterior and posterior corneal surface at the optical center and axial displacement of the anterior and posterior corneal surface points at the optical center) have been analyzed. Based on the geometric characteristics obtained, using the paraxial ray tracing method, changes in the optical properties of the cornea and the eye have been calculated. RESULTS: With increasing intraocular pressure load, anterior and posterior central corneal radius of curvature decreased and corneal surface points at the optical center at the anterior and posterior surface moved forwards, the cornea thinned. Axial displacement of corneal volume points was maximal for all pressure load values at the optical center of the posterior corneal surface. The refractive power of the cornea decreased as eye pressure increased, while the refractive power of the entire eye increased. CONCLUSION: We verified using the Liou-Brennan model eye and finite element modelling that a change of the intraocular pressure load between 10 and 30 mmHg may result in 0.31-0.86 mm decrease of the corneal radius of curvature, in 1.5-4.8 D increase in the keratometric values and in about 1.2-3.9 D increase in the total optical power of the eye. A decrease of 0.14 D to 0.69 D has been measured in the corneal optical power in the examined eye pressure range. Orv Hetil. 2022; 163(47): 1872-1879.

The Role of Personality Dimensions in the Etiopathogenesis of Primary Hypertension.

Background: Although hypertension is the most important cardiovascular risk factor, we still do not understand all the factors that contribute to the disease onset. The aim of this study was to examine the association between personality dimensions and primary hypertension. Methods: In total, 310 participants were recruited in a case-control design. The association of personality dimensions with primary hypertension was examined in normotensive (n = 156) and hypertensive (n = 120) patients following assessment of the 5 personality dimensions with the DECAS Personality Inventory. A binary logistic regression model was used to assess the predictive value of personality traits for hypertension, controlling for recognized confounders such as age, gender, obesity, smoking history, parental history of hypertension, and education. Results: Low or very low emotional stability was almost twice as frequent in the hypertensive group (71.7%) as in the normotensive study population (43.5%). The binary logistic regression model showed that low emotional stability is a significant predictor for hypertension, the risk of being hypertensive decreasing by 7% with each point increase on the emotional stability score. Very low or low emotional stability increased the odds of being hypertensive by 3.55 times (odds ratio: 3.55, 95% CI: 2.18-9.35, P < .001). No association between the severity of hypertension and personality traits was found. Conclusions: People with low emotional stability/high neuroticism have more than 3-fold increased odds of developing primary hypertension. The assessment of personality traits could be used as a tool to identify individuals at risk to develop primary hypertension as well as patients with primary hypertension where psychotherapy could be of potential value. This study highlights the need for further research, in order to establish effective, patient-oriented prevention strategies and treatment options.

The CHA2DS2-VASc Score Predicts New-Onset Atrial Fibrillation and Hemodynamic Complications in Patients with ST-Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention.

Arrhythmic and hemodynamic complications related to ST-segment elevation myocardial infarction (STEMI) represent a major clinical challenge. Several scores have been developed to predict mortality in STEMI. However, those scores almost exclusively include factors related to the acute phase of STEMI, and no score has been evaluated to date for its ability to specifically predict arrhythmic and hemodynamic complications. We, thus, aimed to assess the ability of chronic risk factors burden, as expressed by the CHA2DS2-VASc score, to predict STEMI-related arrhythmic and hemodynamic complications. Data were collected from 839 consecutive STEMI patients treated by primary percutaneous coronary interventions (pPCI). CHA2DS2-VASc and GRACE scores were calculated for all patients, and their ability to predict STEMI-related arrhythmic (i.e., new-onset atrial fibrillation (AF), ventricular tachycardia/fibrillation) and hemodynamic (i.e., cardiogenic shock, asystole) complications was assessed in univariate and multiple regression analysis. Arrhythmic and hemodynamic complications occurred in 14.8% and 10.2% of patients, respectively. Although the GRACE score outweighed the CHA2DS2-VASc score in the ability to predict STEMI-related hemodynamic complications (p < 0.0001), both scores had a similar predictive value for STEMI-related new-onset AF (p = 0.20), and both remained independent predictors of new-onset AF and of hemodynamic complications in the multiple regression analyses. A CHA2DS2-VASc score > 2 points independently predicted new-onset AF (p < 0.01) and hemodynamic complications (p = 0.04). Alongside the GRACE score, the CHA2DS2-VASc score independently predicted new-onset AF and hemodynamic complications in STEMI patients treated by pPCI. These data suggest that a combination of acute and chronic risk factors could provide additional benefit in identifying patients at risk of STEMI-related complications, who could benefit from closer follow-up and more intensive prophylactic and therapeutic strategies.

Chronic kidney disease predicts atrial fibrillation in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention.

Background: Atrial fibrillation (AF) often complicates ST-segment elevation myocardial infarction (STEMI). Predictors of AF in this setting include factors related to the acute phase of STEMI and pre-existing conditions. More recently, novel AF predictors have been identified in the general population. We aimed to assess the ability of such novel factors to predict STEMI-related AF.Methods: Data were collected from STEMI patients treated by primary PCI. Factors related to the acute phase of STEMI (Killip class, heart rate, blood pressure on admission, post-PCI TIMI flow), classic (age, hypertension, heart failure, previous myocardial infarction), and more novel (body mass index [BMI], diabetes, chronic kidney disease [CKD], chronic obstructive pulmonary disease [COPD]) AF predictors were evaluated. The ability of these novel factors to predict STEMI-related AF was assessed.Results: Of the 629 studied patients, 10.5% presented STEMI-related AF. AF patients had higher Killip class on admission (p < .0001) and lower post-PCI TIMI flow (p < .01), they were older (p < .0001) and more likely to have a history of heart failure (p = .02) and myocardial infarction (p = .04). BMI, history of diabetes and COPD were similar between patients with and without AF (all p > .05), but CKD was more common in AF patients (p < .0001). In multiple regression analysis, CKD remained a strong independent predictor of STEMI-related AF (p < .0001).Conclusion: Irrespective of other factors, CKD was associated with increased risk of STEMI-related AF. CKD could be used to identify patients who will develop AF in this setting and who would benefit from closer follow-up and more intensive prophylactic strategies.

Impact of chronic obstructive pulmonary disease on in-hospital morbidity and mortality in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) presenting with ST-segment elevation myocardial infarction (STEMI) are less likely to beneficiate of primary percutaneous coronary intervention (pPCI), and have poorer prognosis. We aimed to evaluate the impact of COPD on the in-hospital outcomes of pPCI-treated STEMI patients. METHODS: Data were collected from 418 STEMI patients treated by pPCI. Inotropics and diuretics usage, cardiogenic shock, asystole, kidney dysfunction, and left ventricular ejection fraction were used as markers of hemodynamic complications. Atrial and ventricular fibrillation, conduction disorders, and antiarrhythmics usage were used as markers of arrhythmic complications. In-hospital mortality was evaluated. The associations between these parameters and COPD were assessed. RESULTS: COPD was present in 7.42% of STEMI patients. COPD patients were older (p=0.02) and less likely to receive beta-blockers (OR 0.29; 95%CI 0.13-0.64; p<0.01). They had higher Killip class on admission (p<0.001), received more often inotropics (p<0.001) and diuretics (p<0.01), and presented more often atrial (p=0.01) and ventricular fibrillation (p=0.02). Unadjusted in-hospital mortality was higher in COPD patients (OR 4.18, 95%CI 1.55-11.30, p<0.01). After adjustment for potentially confounding factors except beta-blockers, COPD remained an independent predictor of in-hospital mortality (p=0.02). After further adjustment with beta-blocker therapy, no excess mortality was noted in COPD patients. CONCLUSIONS: Despite being treated by pPCI, COPD patients with STEMI are more likely to develop hemodynamic and arrhythmic complications, and have higher in-hospital mortality. This appears to be due to lower beta-blockers usage in COPD patients. Increasing beta-blockers usage in COPD patients with STEMI may improve survival.

Clinical risk scores predict procedural complications of primary percutaneous coronary intervention.

OBJECTIVE: The predictive value of five risk score models containing clinical (PAMI-PMS, GRACE-GRS, and modified ACEF-ACEFm-scores), angiographic SYNTAX score (SXS) and combined Clinical SYNTAX score (CSS) variables were evaluated for the incidence of three procedural complications of primary percutaneous coronary intervention (pPCI): iatrogenic coronary artery dissection, angiographically visible distal embolization and angiographic no-reflow phenomenon. METHODS: The mentioned scores and the incidence of procedural complications were retrospectively analyzed in 399 consecutive patients with acute ST-elevation myocardial infarction who underwent pPCI. RESULTS: Coronary dissection, distal embolization and no-reflow occurred in 39 (9.77%), 71 (17.79%), and 108 (27.07%) subjects, respectively. Coronary dissections were significantly associated with higher GRS, ACEFm, and CSS values (all p<0.05). PMS, GRS, ACEFm, and CSS were significantly higher in patients with no-reflow (all p<0.05), while distal embolization was not predicted by any of the calculated scores. In multiple logistic regression models, GRS and ACEFm remained independent predictors of both coronary dissections (OR 3.20, 95% CI 1.56-6.54, p<0.01 and OR 2.87, 95% CI 1.27-6.45, p=0.01, respectively) and no-reflow (OR 1.71, 95% CI 1.04-2.82, p=0.03 and OR 1.86, 95% CI 1.10-3.14, p=0.01, respectively). CONCLUSION: Whereas SXS failed to predict procedural complications related to pPCI, two simple, noninvasive risk models, GRS and ACEFm, independently predicted coronary dissections and no-reflow. Pre-interventional assessment of these scores may help the interventional cardiologist to prepare for procedural complications during pPCI.

Material Properties of the Mandibular Trabecular Bone.

The present paper introduces a numerical simulation aided, experimental method for the measurement of Young's modulus of the trabecular substance in the human mandible. Compression tests were performed on fresh cadaveric samples containing trabecular bone covered with cortical layer, thus avoiding the destruction caused by the sterilization, preservation, and storage and the underestimation of the stiffness resulting from the individual failure of the trabeculae cut on the surfaces. The elastic modulus of the spongiosa was determined by the numerical simulation of each compression test using a specimen specific finite element model of each sample. The received mandibular trabecular bone Young's modulus values ranged from 6.9 to 199.5 MPa.

O conceito saúde-doença analisado através dos tempos e práticas previdenciárias no Brasil / An analysis of health-disease concepts through time and the social security policy in Brazil

O histórico da assistência ao doente é analisado no contexto social em evoluçäo, em seus dois mais destacados momentos: o pré-capitalista e o capitalista, nas áreas da medicina e da enfermagem, expondo as principais etapas, na participaçäo da instituiçäo hospitalar, da hegemonia profissional, do conceito saúde-doença, da visäo religiosa da doença, do modo de produçäo dos homens, da hierarquia, do trabalho e da luta pelo poder. A interferência do sistema previdenciário no Brasil, a política assistencial em constante processo de mutaçäo em virtude do momento e dos fatores econômicos, colocam o indivíduo à mercê de decisöes imediatistas e de transformaçöes rápidas, diante da fragilidade do financiamento da assistência à saúde. (AU)

O conceito saúde-doença analisado através dos tempos e práticas previdenciárias no Brasil / An analysis of health-disease concepts through time and the social security policy in Brazil

O histórico da assistência ao doente é analisado no contexto social em evoluçäo, em seus dois mais destacados momentos: o pré-capitalista e o capitalista, nas áreas da medicina e da enfermagem, expondo as principais etapas, na participaçäo da instituiçäo hospitalar, da hegemonia profissional, do conceito saúde-doença, da visäo religiosa da doença, do modo de produçäo dos homens, da hierarquia, do trabalho e da luta pelo poder. A interferência do sistema previdenciário no Brasil, a política assistencial em constante processo de mutaçäo em virtude do momento e dos fatores econômicos, colocam o indivíduo à mercê de decisöes imediatistas e de transformaçöes rápidas, diante da fragilidade do financiamento da assistência à saúde. (AU)