不同高度的箍结构与牙根抗力的实验研究

目的研究不同高度的箍结构设计对预成纤维桩核修复后牙体抗力的影响。方法32颗完整离体下颌第一前磨牙于颊侧釉牙骨质界上1mm处截冠,预备残根模型;按箍结构高度不同(0.0mm、1.0mm、2.0mm、3.0mm)分为4组,预成碳纤维桩联合复合树脂核修复残根。试件自铸造全冠颈缘完成线下2mm包埋于自凝塑料内,电子万能试验机以与牙长轴成150°、横梁位移速度1.0mm/min于颊尖顶加载,测定断裂载荷并进行统计学分析(α=0.05)。结果箍结构高度为1.0mm组与箍结构高度为2.0mm和3.0mm组相比,均表现出较高的折裂载荷(P<0.05)。结论采用牙冠延长术设计高度2.0mm以上的箍结构,会降低桩核冠修复后牙体的抗力。     

Cortical Atrophy Predicts Visual Performance in Long-Term Central Retinal Disease; GCL,pRNFL and Cortical Thickness Are Key Biomarkers

PurposeThe aim of this study was to assess both retinal and cortical structure in a cohort of patients with long-term acquired central retinal disease in order to identify potential disease biomarkers and to explore the relationship between the anterior and posterior visual pathways.MethodsFourteen participants diagnosed with long-term central retinal disease underwent structural assessments of the retina using spectral-domain optical coherence tomography, including macular ganglion cell layer (GCL) and peripapillary retinal nerve fiber layer (pRNFL) thickness. Structural magnetic resonance imaging was used to measure visual cortex, including cortical volume of the entire occipital lobe and cortical thickness of the occipital pole and calcarine sulcus, representing the central and peripheral retina, respectively.ResultsMean thickness was significantly reduced in both the macular GCL and the inferior temporal pRNFL across patients. Cortical thickness was significantly reduced in both the occipital pole and calcarine sulcus, representing the central and peripheral retina, respectively. Disease duration significantly correlated with GCL thickness with a large effect size, whereas a medium effect size suggests the possibility that cortical thickness in the occipital pole may correlate with visual acuity.ConclusionsLong-term central retinal disease is associated with significant structural changes to both the retina and the brain. Exploratory analysis suggests that monitoring GCL thickness may be a sensitive biomarker of disease progression and reductions in visual cortical thickness may be associated with reduced visual acuity. Although this study is limited by its heterogeneous population, larger cohort studies would be needed to better establish some of the relationships detected between disease dependent structural properties of the anterior and posterior visual pathway given the effect sizes reported in our exploratory analysis.     

Infill Density Influence on Mechanical and Thermal Properties of Short Carbon Fiber-Reinforced Polyamide Composites Manufactured by FFF Process

In three-dimensional (3D) printing, one of the main parameters influencing the properties of 3D-printed materials is the infill density (ID). This paper presents the influence of ID on the microstructure, mechanical, and thermal properties of carbon fiber-reinforced composites, commercially available, manufactured by the Fused Filament Fabrication (FFF) process. The samples were manufactured using FFF by varying the infill density (25%, 50%, 75%, and 100%) and were subjected to tensile tests, three-point bending, and thermal analyses by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). It was shown that the samples with 100% ID had the highest values of both tensile, 90.8 MPa, and flexural strengths, 114 MPa, while those with 25% ID had the lowest values of 56.4 MPa and 62.2 MPa, respectively. For samples with infill densities of 25% and 50%, the differences between the maximum tensile and flexural strengths were small; therefore, if the operating conditions of the components allow, a 25% infill density could be used instead of 50%. After DSC analysis, it was found that the variation in the ID percentage determined the change in the glass transition temperature from 49.6 °C, for the samples with 25% ID, to 32.9 °C, for those with 100% ID. TGA results showed that the samples with IDs of 75% and 100% recorded lower temperatures of onset degradation (approximately 344.75 °C) than those with infill densities of 25% and 50% (348.5 °C, and 349.6 °C, respectively).     

Retinal Layers Measurements following Silicone Oil Tamponade for Retinal Detachment Surgery

This study aimed to investigate the influence of silicone oil on the retinal nerve fiber layer (RNFL) thickness in patients with primary rhegmatogenous retinal detachment who underwent vitreoretinal surgery. The study included 47 patients (eyes), who underwent a pars plana vitrectomy with the silicone oil tamponade. The control group included unoperated eye of all participants. Spectral-domain optical coherence tomography (SD-OCT) was used for the measurements of peripapilar and macular RNFL thickness. The average peripapillary RNFL thickness was significantly higher in the silicone oil filled eyes during endotamponade and after its removal. The eyes with elevated IOP had less thickening of the RNFL in comparison to the eyes with normal IOP. Central macular thickness and macular volume were decreased in the silicone oil filled eyes in comparison to the control eyes. In conclusion, silicone oil caused peripapilar RNFL thickening in the vitrectomized eyes during endotamponade and after silicone oil removal.     

恶性高血压性视网膜病变的光学相干断层扫描观察

目的　评价使用光学相干断层扫描（ｏｐｔｉｃａｌｃｏｈｅｒｅｎｃｅｔｏｍｏｇｒａｐｈｙ,ＯＣＴ）对恶性高血压性视网膜病变疗效观察的有效性。方法　对２６例（３１眼）恶性高血压性视网膜病变患者的资料进行回顾性分析,对比分析治疗前及治疗后１５ｄ、１个月、３个月时的视力、视盘周围视网膜神经纤维层厚度、黄斑区视网膜神经上皮层厚度和黄斑区６ｍｍ直径神经上皮总体容积的变化。结果　与治疗前相比,治疗后１５ｄ视力提高者２２眼,治疗后１个月为２６眼,治疗后３个月为２９眼。患者视盘周围视网膜神经纤维层厚度及黄斑区视网膜神经上皮层厚度治疗前为（３９３．２０±１８．０５）μｍ和（４８６．５８±６９．００）μｍ,治疗后１５ｄ、１个月、３个月分别为（３６３．２０±２６．８０）μｍ和（３９２．１３±３０．６５）μｍ、（３４２．７５±２５．８２）μｍ和（３１５．０３±２２．３３）μｍ、（３０５．６４±２３．３８）μｍ和（２１３．８７±２５．６８）μｍ;黄斑区６ｍｍ直径神经上皮总体容积治疗前为（１７．０４±３．３１）ｍｍ３,治疗后１５ｄ、１个月、３个月分别为（１１．０７±２．０２）ｍｍ３、（９．３６±０．９３）ｍｍ３、（８．４２±０．７５）ｍｍ３;各指标与治疗前比较差异均具有统计学意义（均为Ｐ＜０．０５）,治疗后各时间点间两两比较差异亦均有统计学意义（均为Ｐ＜０．０５）。结论　恶性高血压性视网膜病变的视盘周围视网膜神经纤维层厚度、黄斑区视网膜神经上皮层厚度和黄斑区６ｍｍ直径神经上皮总体容积变化与其病变程度相关,ＯＣＴ对恶性高血压性视网膜病变疗效评价具有重要意义,能够为病情的追踪和指导用药提供客观依据。     

青光安对抗青光眼术后滤过道瘢痕组织中弹性纤维、MMP-7、TlMP-1的实验研究

目的：通过观察4种青光安有效组份和青光安颗粒剂对抗青光眼术后滤过道瘢痕瘢痕组织中弹性纤维、MMP-7、TIMP-1的影响,来探讨青光安的有效组份和青光安颗粒剂对抗滤过道瘢痕化的作用机制,并对比青光安有效组份与青光安颗粒剂对抗瘢痕化作用的优劣。方法：将青光安4种有效组份与青光安颗粒剂中药混悬液作用于滤过手术后D、E、F、G、H组,通过与A组空白对照组、B组模型组和C组丝裂霉素C组进行比较,观察青光安4种有效组份与青光安中药混悬液对青光眼术后滤过道瘢痕组织中弹性纤维、MMP-7、TIMP-1的影响。结果：C组、E组和H组术前基础眼压与术后第2d;1,2,4 wk的眼压比较,现眼压较其他组回升缓慢,第28 d时仍然是最小值,与其余A、B、D、F、G组比较差异具有统计学意义。弹性纤维面积密度比较：手术组与空白对照组比较,差异均有统计学意义(P<0.05),C组与H组、C组与E组比较,差异无明显统计学意义(P>0.05),H组与E组比较,差异无统计学意义(P>0.05)。其他各组间比较,差异有显著统计学意义(P<0.01)。结论：青光眼术后滤过道瘢痕化,是导致滤过性手术失败的重要原因;青光安有效组份2、青光安混悬液和丝裂霉素C可通过增加MMP-7的表达和抑制弹性纤维、TIMP-1的表达而减少瘢痕组织增生,具有明显的抗青光眼术后滤过道瘢痕化的作用;通过实验观察可初步说明青光安有效组份2与青光安混悬液都具有明显的抑制滤过道瘢痕化的作用,且二者效果持平,青光安中药组略优于青光安有效组份2组。     

[In Press] Optical coherence tomography with or without enhanced depth imaging for peripapillary retinal nerve fiber layer and choroidal thickness

AIM: To assess peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness obtained with enhanced depth imaging (EDI) mode compared with those obtained without EDI mode using Heidelberg Spectralis optical coherence tomography (OCT). METHODS: Fifty eyes of 25 normal healthy subjects and 32 eyes of 20 patients with different eye diseases were included in the study. All subjects underwent 3.4 mm diameter peripapillary circular OCT scan centered on the optic disc using both the conventional and the EDI OCT protocols. The visualization of RNFL and choroidoscleral junction was assessed using an ordinal scoring scale. The paired t-test, intraclass correlation coefficient (ICC), 95% limits of agreement (LoA), and Bland and Altman plots were used to test the agreement of measurements. RESULTS: The visibility score of RNFL obtained with and without EDI was of no significant difference(P=0.532), the visualization of choroidoscleral junction was better using EDI protocol than conventional protocol (P＜0.001). Peripapillary RNFL thickness obtained with EDI was slightly thicker than that obtained without EDI (103.25±9.42 μm vs 101.87±8.78 μm, P=0.010). The ICC of the two protocols was excellent with the value of 0.867 to 0.924, the 95% LoA of global RNFL thickness was between -10.0 to 7.4 μm. Peripapillary choroidal thickness obtained with EDI was slightly thinner than that obtained without EDI (147.23±51.04 μm vs 150.90±51.84 μm, P＜0.001). The ICC was also excellent with the value of 0.960 to 0.987, the 95% LoA of global choroidal thickness was between -12.5 to 19.8 μm. CONCLUSION: Peripapillary circular OCT scan with or without EDI mode shows comparable results in the measurement of peripapillary RNFL and choroidal thickness.     

频域-OCT在观察高眼压症视网膜神经纤维层及神经节细胞复合体中的应用

使用频域相干光断层扫描（ SD-OCT）观察高眼压症患者视盘形态学参数、视网膜神经纤维层（RNFL）及黄斑区神经节细胞复合体（GCC）的表现。方法选取52例（96只眼）高眼压患者,按照眼压高低分为两组,与20例（40只眼）正常人进行SD-OCT检查,测量视盘形态学参数、整体平均RNFL厚度（RNFL-Avg）、上方平均RNFL厚度（RNFL-Sup）、下方平均RNFL厚度（RNFL-Inf）、整体平均GCC的厚度（GCC-Avg）、上方平均GCC厚度（ GCC-Sup）、下方平均GCC厚度（ GCC-Inf）,比较两组高眼压症患者与正常对照组之间的差异,并分析高眼压症组RNFL与GCC的相关性。结果两组高眼压症患者与正常对照组比较,视盘各形态学参数（ P ＞0．05）、RNFL-Avg（ P ＝0．9017）、RNFL-Sup（ P ＝0．9659）、 RNFL-Inf（ P ＝0．7465）、 GCC-Avg（ P ＝0．3498）、GCC-Sup（ P ＝0.4203）、GCC-Inf（ P ＝0．3071）均无显著的统计学差异。而RNFL与GCC在整体、上方及下方的厚度均呈明显的正相关（ r ＝0．5631 P ＝0．001;r ＝0．5122 P ＝0．005;r ＝0．5459 P ＝0．002）。结论 SD-OCT是一种比较敏感的能够观察到视网膜结构改变的检查方法,对青光眼的早期诊断具有重要的作用。高眼压症患者在眼压明显高于正常的情况下,并无RNFL及GCC的改变,对于高眼压症应该强调严格随诊。     

非动脉炎性前部缺血性视神经病变光相干断层扫描研究

目的 探讨非动脉炎性前部缺血性视神经病变(non-arteritic anterior ischemic optic neuropathy,NAION)患眼远期视盘周围视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度及其与视野检查结果的相关性.方法 回顾性病例对照研究.对2007年8月至2009年8月在无锡市,第二人民医院眼科21例单眼发病NAION患者42只眼(21只发病眼为实验组,21只对侧正常眼为对照组)进行了视网膜神经纤维层厚度的光学相干断层扫描(optical coherence tomography,OCT),并检查视野(visual field,VF)、图形视觉诱发电位(pattern-reversal visual evoked potential,P-VEP)等检查.结果 NAION患者RNFL厚度较对照组变薄,上半侧易受累,相应下方视野缺损多见,且视盘非病变区域的RNFL厚度也比正常对照组相应区域变薄.平均RNFL厚度与视野平均缺损有相关性(r=0.38,P ＜0.05).结论 NAION患者远期盘周视神经纤维层厚度变薄,缺血区明显变薄,OCT检查非缺血区的RNFL厚度也变薄,提示NAION的RNFL丢失可能超过了视野检查的视野缺损的范围.NAION患眼盘周RNFL厚度与视野检查结果相关.     

OCT测量视网膜神经纤维层厚度及视盘参数在青光眼早期诊断中的应用及意义

目的探讨光学相干断层扫描仪(optical coherence tomography,OCT)测量视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度及视盘参数在青光眼早期诊断中的应用及意义。方法青光眼患者120例(192眼)分为早期青光眼组42例(66眼)、中期青光眼组46例(76眼)和晚期青光眼组32例(50眼),另设正常对照组50例(82眼),均采用Topcon 3D OCT检测RNFL厚度和视盘参数,计算各个参数的受试者工作特征曲线下面积(are aunder the receiver operating characteristi ccurve,AROC),并对检测结果进行比较分析。结果正常对照组、早期青光眼组、中期青光眼组和晚期青光眼组的平均RNFL厚度分别为(112.31±9.34)μm、(105.45±6.74)μm、(82.19±7.28)μm、(52.48±7.85)μm;与正常对照组比较,各青光眼组的RNFL厚度差异均有显著统计学意义(均为P<0.01);各青光眼组之间两两比较差异也均有显著统计学意义(均为P<0.01)。与正常对照组相比,各青光眼组的视盘面积无明显变化,差异均无统计学意义(均为P>0.05),而视杯面积、视杯容积、杯盘比、水平杯盘比和垂直杯盘比均显著增加,差异均有显著统计学意义(均为P<0.01);盘沿面积和盘沿容积均显著降低,差异均有显著统计学意义(均为P<0.01);各青光眼组间除视盘面积外,各参数差异也均有显著统计学意义(均为P<0.01)。在正常对照组与早期青光眼组和全部青光眼组之间,对于RNFL厚度来说,平均RNFL厚度的AROC值最大;对于视盘参数来说,杯盘比的AROC值最大。结论 RNFL厚度和视盘参数是早期诊断青光眼的敏感指标,OCT检测RNFL厚度和视盘参数有助于青光眼的早期诊断。