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Purpose: The purpose of this study was to perform a systematic review and meta-analysis to critically evaluate the available literature to statistically analyze the effects of platform matched (PM) and platform switching (PS) implants on the peri-implant soft tissue changes and esthetic outcomes. Materials and methods: Electronic databases of the Cochrane Library, Embase, CINAHL and PubMed were searched for human randomized controlled trials (RCTs) with clearly outcome measurement in comparison between PM and PS implant. Primary outcomes included midfacial keratinized gingiva (KG) thickness, width of KG, marginal gingiva height gain, papilla height, and pink esthetic score. Secondary outcomes included bone level, probing depth, plaque index, and sulcus bleeding index. All the included studies had to follow up for at least 1 year after function. Results: A total of 7 RCTs were included in the meta-analysis. Midfacial KG thickness (weighted mean difference (WMD) = 1.34 mm, P < 0.0001), marginal gingiva height (WMD = 0.30 mm, P = 0.01), papilla height (WMD = 0.18 mm, P = 0.003), bone level (WMD = 0.34 mm, P < 0.00001) and probing depth (WMD = -0.22 mm, P = 0.002) demonstrated statistically difference in comparison of PS and PM implants. The result of width of KG (P = 0.92), PES score (P = 0.73), plaque index (P = 0.97) and sulcus bleeding index (P = 0.78) showed no statistical difference. Conclusion: Meta-analysis showed better performance of midfacial KG thickness, marginal gingiva height and papilla height in PS implant than that in PM implants. No statistically difference was found in width of KG and PES score between PS implants and PM implants. &nbsp

Purpose: Enamel matrix derivative (EMD), the active component of Emdogain®, has been demonstrated to affect cytokines related to fibroplasia, angiogenesis, inflammation, and chemotaxis both in vitro and in vivo. However, whether the adjunctive application of EMD has clinical benefits on treating peri-mucositis and peri-implantitis has not been investigated thoroughly. The aim of this systematic review is to investigate the clinical outcomes of treating peri-implant diseases with adjunctive EMD application. Materials and Methods: A systematic search of multiple electronic databases including PubMed, Cochrane library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, and Scopus was carried out based on the PICOs structure for articles published up to September 2020. The primary outcomes were bleeding on probing (BoP), probing depth (PD), and radiographic bone level (RBL). Data and risk of bias were explored qualitatively. Results: The search identified 942 studies with 7 studies included for qualitative analysis. These studies reported 200 participants with 270 implants diagnosed with peri-mucositis (n=41) and peri-implantitis (n=229). For implants with peri-mucositis, BoP reduced significantly (83 to 25%) at the 3-month follow-up period for those treated with non-surgical mechanical debridement combined with adjunctive EMD (EMD group), while there was limited improvement for those treated by mechanical debridement alone (control group). PD also decreased (4.5 to 3.12 mm) in EMD group whereas an increase to 5.17 mm was demonstrated in the control group. For cases diagnosed with peri-implantitis, the high prevalence rate (83% - 100%) of BoP at baseline was significantly reduced in 2 prospective studies at the 2-10-years follow-up after surgical debridement, surface decontamination with bone graft, and EMD application. However, there was no statistical difference between surgical treatment with or without adjunctive EMD application in the other randomized controlled trials (RCTs) and half of the implants still demonstrated persistent BoP. Moreover, the PD can also be reduced significantly from 8.12 to 3.17 mm for those treated with adjunctive EMD while the RBL reduced from 4.41 to 2.31 mm at 2-10 year follow-up. The overall survival rate was 85-100% at 2-10 years follow-up. Conclusion: This review investigated the efficacy of adjunctive EMD for treating peri-implant diseases and was able to demonstrate its effect in reducing PD, reducing BoP, and increasing survival rate of treated implants from 2 to 10 years. The beneficial impacts of traditional surgical therapy on implants diagnosed with peri-implantitis were investigated; however, in terms of treating peri-implantitis, the definite efficacy of adjunctive usage of EMD should be determined based on more quantitative analysis and research in future. &nbsp

The rail wagon coupler is casting part. Some of foreign products’ error dispersion is significantly greater than domestics’. What influence generated by the results acting on the actual use of performance is still not clear. To this end, this article studied the influence generated by the angle of surface S tangent of coupler-knuckle on coupling connection contour and starting bearing line (referred to as surface S angle) to traction reliability, coupling feasibility and acting force in tangent line, systematically. And authors explored the value ranges of surface S angle in order to ensure the operation performance of coupler-knuckle. Firstly, find the major factors which are associated to surface S angle by studying the movement mechanism of coupling and traction. For example, the maximum level angle of coupler-knuckles, the ability for vehicle to pass the curves, etc. And then, get analytical expression of coupler surface S angle and related factors by means of theoretical derivation. After that, obtain value ranges of surface S angle. Finally, carry on experiments with multi-body dynamics simulation software RecurDyn. On the one hand, eliminate unreasonable value ranges obtained by theoretical derive, on the other hand, analyze the changing rule of the acting force on coupler-knuckle contour. The results prove that, when coupler surface S angle is , the traction performance of coupler is relatively stable, the coupling performance is relatively reliable, the contact force on coupler-knuckle contour is smaller. The conclusion is consistent with surface S angle parameter required by the standard system of Association of American Railroads. The research results above provided the theoretical basis for improving coupler’s manufacturability.

As the EMUs (Electrical Multiple Unit) light frame structure, combined of many complex surfaces, building its geometric model directly is a big challenge. Reverse Engineering Technology is adopted to make the light frame redesign. Considering the characteristics of the frame surface with big curvature changed, irregular contours of structural features and IGES based model, authors proposed the model reconstruction method, by using independent geometric module in Pro/E. Firstly, establish base planes from IGES file, then duplicate light frame surface from IGES file to generate a set of intersection curves with the base planes and surface duplicated above as mixed guide curves. After that, curvature analysis technique is presented for intersection curves precision check. And finally, the 3D model is reconstructed by boundary blend technology. The original data imported can be removed from this model in order to support parts redesign as well as their manufacturability analysis. Research outcomes above offer an efficient innovation solution for surface reconstruction with curvature changed dramatically and IGES based model as well.