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Objective:To study the fit of pure titanium single crown fabricated by electron beam melting(EBM).Methods:Pure titanium crowns were fabricated by EBM,selective laser melting(SLM),CAD/CAM(R +K and DMG)and conventional lost wax technique(LW)respectively(n =5).Marginal and internal gap was copied by light-body silicone and measured using a digital mi-croscope .The data of marginal gap(MG)and internal gap(IG)were statisticaly analysed by ANOVA and SPSS statistical package version 17.0.Results:The MG and IG(μm)of pure titanium crowns in EBM group were 38.42 ±6.72 and 105.54 ±33.18,in SLMgroup 38.63 ±6.82 and 114.63 ±52.18,in DMG CAD/CAMgroup 26.18 ±4.36 and 102.18 ±40.81,in R +K CAD/CAM group 26.98 ±4.44 and 102.24 ±25.30,in LW group were 42.61 ±5.73 and 102.98 ±45.67,respectively.The marginal fit of the EBMgroup was significantly smaller than 120 μm of the generally accepted clinical standards.In the 2 CAD/CAM groups the MG was smaller than that of other 3 groups(P 0.05).Conclu-sion:The marginal fit of titanium single crown fabricated by EBMis similar to that by SLM,better than that of LW and inferior than that of CAD/CAM.The internal fit of the crowns made by the 5 systems is similar.
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Objective:To compare the marginal and internal fit of selective laser melting(SLM)titanium crowns with lost-wax cast (LW)titanium crowns.Methods:Titanium crowns of 10 subjects were fabricated by SLM and conventional LW respectively(n =10).The marginal and internal gaps of the crowns were recorded with silicon film using a replica technique.Each silicon film was cut into 2 parts and the thickness of silicon layer was measured at ×100 magnification using a stereomicroscope,the data of marginal gap (MG)and internal gap(IG)were statistically analysed by ANOVA and SPSS statistical package version 17.0.Results:The MG (μm)of the titanium crowns of SLMgroup and LMgroup were 90.67 ±14.7 and 94.77 ±21.9(P 0.05),respectively.Conclusion:The marginal fit of the SLMcrowns is better than that of the LW ones,and is significantly smaller than 120 μm of the clinical generally accepted standards.
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Objective To study the effectiveness and safety of intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis therapy for acute ischemic stroke in patients with atrial fibrillation (AF).Methods A total of 94 patients treated with intravenous rt-PA thrombolysis within 4.5 hours after cerebral stroke onset were analyzed and divided into two groups:a non-AF group (n =64) and an AF group (n =30).Another 30 acute ischemic stroke patients with AF without thrombolytic therapy were selected as a control group.The prognosis of the three groups was compared.The National Institute of Health Stroke Scale (NIHSS) was used for comparison among the three groups before therapy and 7 days after therapy.The incidences of intracerebral hemorrhage (ICH) and symptomatic ICH (SICH) were recorded.The patients were followed up for 90 days and their clinical outcomes were assessed by using the modified Rankin scale (mRS).Results There were no significant differences in the NIHSS scores among three groups before treatment (P ＞ 0.05).The NIHSS scores were significantly lower in the AF and non-AF groups 7 days after thrombolysis therapy than those before thrombolysis therapy (P ＜0.05 and P ＜0.01),and no significant difference in the NIHSS scores was found in the control group before and after therapy (P ＞ 0.05).The incidence of ICH was significantly higher in the AF group than in the non-AF group (26.7％ vs.9.4％,P ＜ 0.05).No significant difference in the incidence of SICH was found between the AF and non-AF groups (13.3％ vs.6.3％,P ＞ 0.05).The favorable prognosis rate was higher in the AF and nonAFgroups than in control group (40.0％ vs.16.7％,P＜0.05; 45.3％ vs.16.7％,P＜0.01).No significant difference in very unfavorable prognosis rate was found between the AF and non-AF groups (20.0％ vs.18.8％,P ＞0.05).Conclusions It is effective and safe of rt-PA thrombolysis therapy for acute ischemic stroke patients with AF.
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Objective To analyze the causes,neuroimaging and clinical manifestations of isolated unilateral pontine infarction and to discuss its relationship to progressive motor deficit(PMD).Methods All 58 patients with isolated acute unilateral pontine infarction confirmed by magnetic resonance imaging (MRI) were recruited in this study for retrospective review.Thirty-one patients of them had brain and neck multi-slice spiral CT angiography(CTA) within 1 week after admission.PMD severity was accessed using the dynamic National Institutes of Health Stroke Scale (NIHSS) within 5 days after onset.All 58 patients were divided into two groups:patients with PMD (23 cases) in group 1 and patients without PMD (35 cases) in group 2.Two groups were compared for the risk factors,initial NIHSS scores,modified Rankin Scale (mRS) scores at 1 month after onset,clinical manifestations,infarction distribution,size and morphology of infarctions and basilar artery lesions.Results The major cause was pathologic changes in basilar artery branch in both groups(6/12 in group 1 and 10/19 in group 2).The proportion of patients with infarction extending to the pontine surface in group 1 was higher than that in group 2 (21/23,91.3％ vs 20/35,57.1％,x2 =7.817,P =0.005).Initial NIHSS score in group 1 was higher than that in group 2(6.7 ±2.9 vs 4.5 ± 2.4,t =3.121,P =0.003).mRS score at 1 month after onset in group 1 was higher than that in group 2(2.2 ± 1.1 vs 1.5 ± 0.8,t =2.909,P =0.004).The Logistic regression analysis showed that isolated unilateral pontine infarction extending to the pontine surface was positively related to PMD (odds ratio 9.670,95％ confidence interval 1.171-79.856,P =0.035).Conclusions Progressive isolated unilateral pontine infarction is mostly caused by pathologic changes in basilar artery branch.Patients with PMD have a more severe initial clinical manifest and they have a worse short-term prognosis than patients without PMD.Isolated unilateral pontine infarction extending to the pontine surface may be a risk predictor in stroke evolution.