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641.
This systematic review (PROSPERO-CRD42020147333) aimed to compare the effects of conservative, ultraconservative and truss access cavities with traditional access cavities on the load capacity of root-canal-treated teeth. Online databases were searched until December 2021, and 25 ex vivo studies in which the effects of different access cavities on load capacity of permanent teeth had been investigated were included. Quality assessment was completed using a modified risk of bias tool for in vitro studies adapted from previous studies. Meta-analysis was performed using the maximum-likelihood-based random-effects model with similar groups. Conservative access cavities significantly improved the load capacity of maxillary premolars (p < 0.01 [−1.32, −0.028]) and molars (p < 0.05 [−0.89, −0.02]) compared to traditional access cavities. Additionally, truss access cavities significantly improved the load capacity of mandibular molars with (p < 0.05, [−1.18, −0.02]) mesio-occluso-distal cavity preparations. Higher levels of evidence are needed to determine the long-term implications of minimal preparations for treatment outcomes.  相似文献   
642.
Abernethy malformation or congenital portosystemic shunt is a rare congenital vascular malformation and anomaly of the splanchnic venous system defined by diverting portal blood away from the liver. It is commonly associated with multiple congenital anomalies. Imaging modalities such as computed tomography or magnetic resonance have a crucial role in prompting diagnosis and determining the prognosis based on the type of malformation and associated anomalies. Misdiagnosis could be harmful and may lead to inappropriate treatment. We present a case of Abernethy malformation with a complete end-to-side shunt of portal venous flow into the systemic venous flow and complete bypass of the liver, which was initially misdiagnosed with portal venous thrombosis.  相似文献   
643.
Tourniquet use creates a reduced blood surgical field during total knee arthroplasty (TKA), however, prolonged ischemia may cause postoperative tourniquet complications. To understand the effects of tourniquet-induced ischemia, we performed a prospective observational study using quantitative broadband diffuse optical spectroscopy (DOS) to measure tissue hemodynamics and water and lipid concentrations before, during, and after tourniquet placement in subjects undergoing TKA. Data was collected for 6 months and, of the total subjects analyzed (n = 24), 22 were primary TKAs and 2 were revision TKA cases. We specifically investigated tourniquet-induced hemodynamics based upon subject-specific tissue composition and observed a significant relationship between the linear rate of deoxygenation after tourniquet inflation and water/lipid ratio (W/L, p < 0.0001) and baseline somatic tissue oxygen saturation, StO2 (p = 0.05). Subjects with a low W/L ratio exhibited a lower tissue metabolic rate of oxygen consumption, (tMRO2) (p = 0.008). Changes in deoxyhemoglobin [HbR] (p = 0.009) and lipid fraction (p = 0.001) were significantly different between high and low W/L subject groups during deoxygenation. No significant differences were observed for hemodynamics during reperfusion and total tourniquet time was neither significantly related to the hemodynamic hyperemic response (p = 0.73) nor the time to max StO2 after tourniquet release (p = 0.57). In conclusion, we demonstrate that DOS is capable of real-time monitoring of tissue hemodynamics distal to the tourniquet during TKA, and that tissue composition should be considered. DOS may help surgeons stratify hemodynamics based upon tissue composition and eventually aid the preoperative risk assessment of vascular occlusions from tourniquet use during TKA.  相似文献   
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