Einfluss der Zirkonabutmentpräparation auf die Bruchfestigkeit von Einzelimplantatrestaurationen nach Kausimulation

Zirconia implant abutments offer enhanced esthetics and promote biological sealing; however, the effect of mechanical processing due to preparation has not been investigated under functional loading. The purpose of the study was to evaluate the influence of the zirconia abutment preparation depth and preparation mode on the survival rate, the fracture strength and fracture mode of all-ceramic single implant crowns. Seventy single implant-supported lithium disilicate glass-ceramic crowns (IPS e.max Press, Ivoclar Vivadent) were adhesively cemented (Multilink Automix, Ivoclar Vivadent) onto zirconia abutments (ZirDesign, Astra Tech) using implants with a diameter of 4.5 mm and a length of 15.0 mm (Osseospeed, Astra Tech). They replaced a maxillary central incisor (11.0 mm in height and 8.0 mm in width). Lithium disilicate implant crowns were divided into 5 study groups (n=14) according to the abutment preparation depth [(A: control) 0.5, (B:) 0.7, (C:) 0.9 mm, and preparation mode [milling by the manufacturer, (P:) milling by the Celay System (Mikrona)]. Subgroups (n=7) were subjected to dynamic loading (C) at 135° with 98N in a thermomechanical chewing simulator (Kausimulator, Willytech) up to 1.2x106 loading cycles; followed by quasi-static loading until fracture. All specimens survived dynamic loading except one (in group CPB) that fractured early and was considered as manufacturer’s mal-production. Additional subgroups (n=7) were subjected to quasi-static loading (S) at 135° in a universal testing machine (0.5 mm/min, Z010/TN2S, Zwick). Mean fracture strengths (N) were: Group SA: 384±84; Group CA: 403±67; Group SB: 294±95; Group CB: 374±75; Group SC: 332±52; Group CC: 373±105; Group SPB: 332±80; Group CPB: 499±91; Group SPC: 380±101; Group CPC: 358±54. Statistical analysis using multiple linear regression showed that both the preparation depth and mode had no influence on the fracture strength of the implant crowns (p>0.05), however; fracture strength increased statistically significantly after dynamic loading (p=0.01). Adhesively luted single implant lithium disilicate crowns placed on zirconia abutments have the potential to withstand physiological maximal incisive biting forces for more than 5 years of simulated fatigue. Manually controlled circumferential chamfer zirconia abutment preparation had no effect after 5 years simulated dynamic loading. However, single implant lithium disilicate crowns placed on zirconia abutments seem to increased fracture strength after dynamic loading.Zirkonimplantatabutments erfüllen erhöhte ästhetische Ansprüche und verbesserte biologische Integration. Die Auswirkung mechanischer Belastungen in Abhängigkeit unterschiedlicher präparativer Bearbeitung wurde noch nicht unter funktioneller Belastung untersucht. In dieser Studie wurde die Überlebensrate, Bruchfestigkeit und Art des Versagens von Lithiumdisilikat-Glaskeramikkronen (IPS e.max Press, Ivoclar Vivadent) auf Zirkonoxidkeramikabutments (Astra Tech AB) nach künstlicher Alterung im Kausimulator überprüft. Siebzig einzelne implantatgetragene Lithiumdisilikat-Glaskeramikkronen (IPS e.maxPress, Ivoclar Vivadent) wurden adhäsiv (Multilink Automix, Ivoclar Vivadent) auf Zirkonoxidkeramikabutments (ZirDesign, Astra Tech) befestigt. Die Implantate (Osseospeed, Astra Tech) hatten einen Durchmesser von 4,5 mm und eine Länge von 15 mm. Die Implantatkronen ersetzen zentrale Oberkiefer-Frontzähne mit einer Höhe von 11 mm und einer Breite von 8 mm. Die Implantatkronen aus Lithiumdisilikat wurden unter Berücksichtigung der Abutmentpräparationstiefe [A (Kontrollgruppe): 0.5, B: 0.7, C: 0.9 mm und Präparationsart - Fräsung durch den Hersteller, P: Fräsung mit Hilfe des Celay-Systems (Mikrona)] in 5 Gruppen (n=14) eingeteilt. Untergruppen (n=7) wurden für 1,2x106 Zyklen in einem Kausimulator (Willytech) dynamischen Belastungen (C) unter einem Winkel von 135° mit 98 N ausgesetzt. Anschließend folgte eine quasi-statische Belastung bis zum Bruch. Alle Proben überlebten die dynamischen Belastungen außer eine aus der Gruppe CPB, die vorzeitig gebrochen war; dieses Versagen wurde einem Herstellungsfehler zugeordnet. Zusätzliche Untergruppen (n=7) wurden quasi-statischen Belastungen (S) in einem Winkel von 135° in einer universellen Testmaschine (0,5 mm/min, Z010/TN2S, Zwick) ausgesetzt. Die resultierenden Bruchfestigkeiten (N) waren: Gruppe SA: 384.8±83.9; Gruppe CA: 403.4±67.0; Gruppe SB: 294.3±95.4; Gruppe CB: 374.0±75.0; Gruppe SC: 331.7±52.4; Gruppe CC: 372.7±105.0; Gruppe SPB: 332.4±79.9; Gruppe CPB: 499.0±90.7; Gruppe SPC: 380.7±101.5; Gruppe CPC: 358.1±53.6. Die statistische Analyse mittels multipler linearer Regression zeigte, dass weder die Präparationsart noch die Präparationstiefe einen signifikanten Einfluss auf die Bruchfestigkeit der Implantatkronen (p>0,05) hatte: hingegen war die Bruchfestigkeit nach dynamischer Belastung statistisch signifikant erhöht (p=0,01). Adhäsiv befestigte Lithiumdisilikat-Einzelkronen auf Zirkonabutments haben das Potential, maximalen, physiologischen Kaukräfte für mehr als 5 Jahre simulierter Abnutzung zu widerstehen. Manuell durchgeführte umlaufende Stufenpräparationen hatten keine Auswirkung nach 5 Jahren auf die Belastbarkeitund nach dynamischer Belastung. Lithiumdisilikatkronen auf Einzelimplantaten mit Zirkonabutments wiesen nach dynamischer Belastung eine Erhöhung ihre Bruchfestigkeit auf.

Immediate, Early (6 Weeks) and Delayed Loading (3 Months) of Single, Partial and Full Fixed Implant- Supported Prostheses: Three-year Post- Loading Data From a Multicentre Randomised Controlled Trial

PURPOSE. To compare the clinical outcomes of single, partial and complete fixed im-plant-supported prostheses immediately loaded (within 48 hours), early loaded at 6 we-eks, and conventionally loaded at 3 months (delayed loading). MATERIALS AND METHODS. Fifty-four patients (18 requiring single implants, 18 partial fixed prostheses, and 18 total fixed cross-arch prostheses) were randomised in equal numbers in two private practices to immediate loading (18 patients), early loading (18 patients), and conventional loading (18 patients) according to a parallel group design with three arms. To be immediately or early loaded, implants had to be inserted with a torque superior to 40 Ncm. Implants were initially loaded with provisional prostheses, replaced after 4 months by definitive ones. Outcome measures were prosthesis and implant failu-res, complications and peri-implant marginal bone levels. RESULTS. Two conventionally loaded patients rehabilitated with cross-arch fixed total prostheses dropped-out before 3-year post-loading follow-up. No implant failed. One early-loaded partial prosthesis had to be remade (P = 1.0). Three complications occurred in the immediately loaded group, two in the early-loaded and one in the conventionally loaded group with no statistically significant differences across groups (P = 0.861). Pe-ri-implant marginal bone loss was-0.04 ± 0.85 mm at immediately loaded implants,-0.01 ± 0.55 mm at early-loaded implants and 0.33 ± 0.36 mm at conventional loaded implants with no statistically significant differences between the three loading strategies (P=0.191). CONCLUSIONS. All loading strategies were highly successful, and no differences were observed in terms of implant survival and complications when implants were loaded immediately, early or conventionally

Efficacy and Safety of Oral Factor XIa Inhibitors in Stroke Prevention: A Systematic Review and Meta-Analysis

Anticoagulation; Factor Xia inhibitors; Ischemic strokeAnticoagulació; Inhibidors del factor Xia; Ictus isquèmicAnticoagulación; Inhibidores del factor Xia; Ictus isquémicoIntroduction: Despite preventive measures, stroke rates remain high in the primary and secondary prevention settings. Factor XIa inhibition may offer a novel, safe and effective antithrombotic option for stroke prevention. Methods: We conducted a systematic review and meta-analysis including all available randomized controlled clinical trials (RCTs) that investigated the efficacy and safety of factor XIa inhibitors versus controls in primary or secondary stroke prevention. The primary efficacy and safety outcomes of interest were symptomatic ischemic stroke (IS) and the composite of major bleeding and clinically relevant non-major bleeding. Results: Four phase II dose-finding RCTs were included, comprising a total of 4732 patients treated with factor XIa inhibitors versus 1798 controls. Treatment with factor XIa inhibitors did not reduce the risk of IS compared to controls (RR: 0.89; 95% CI: 0.67–1.17). The composite of symptomatic IS and covert infarcts on brain MRI (RR: 1.01; 95% CI: 0.87–1.18), the composite of symptomatic IS and transient ischemic attack (TIA; RR: 0.78; 95% CI: 0.61–1.01), and the composite of major adverse cardiovascular events (RR: 1.07; 95% CI: 0.87–1.31) did not differ between the treatment groups. Treatment with factor XIa inhibitors did not increase the risk of the composite of major bleeding and clinically relevant non-major bleeding (RR: 1.19; 95% CI: 0.65–2.16), major bleeding alone (RR: 1.19; 95% CI: 0.64–2.22), intracranial bleeding (RR: 0.91; 95% CI: 0.26–3.19) or all-cause mortality (RR: 1.21; 95% CI: 0.77–1.90). Conclusion: This meta-analysis provides reassuring evidence regarding the safety of factor XIa inhibitors. These findings, coupled with potential signals of efficacy in reducing IS (and TIA), underscore the importance of ongoing phase III RCTs for providing definitive data regarding the effect of factor XIa inhibition on stroke prevention

Advancements in the Treatment of Cerebrovascular Complications of Cancer

Purpose of review: To present the new guidelines and therapeutic options regarding cerebrovascular complications of cancer, mainly ischemic stroke, cerebral venous thrombosis (CVT), and leptomeningeal carcinomatosis (LMC). Recent findings: A temporal trend study (2019) revealed that clinicians are still reluctant to apply thrombolysis to cancer patients, although two new studies (2018) reported no increased mortality. Several clinical trials on direct oral anticoagulants (DOACs) showed their superiority or, at least, non-inferiority compared with low molecular weight heparins in the treatment of venous thromboembolism (VTE) (2018–2019). These trials helped in formulating the new guidelines that are being published and the decisions made for cancer-associated thrombosis (CAT) as a whole. A new DOAC antidote was also officially released (US 2018, Europe 2019). Summary: Thrombolysis is safe in a malignancy setting, thus cancer per se should not be considered a contraindication for thrombolysis. Clinical trials assessing the newest DOACs for cancer-associated arterial thrombosis are scarce; however, based on data from VTE studies, the newest DOACs seem to be safe for CAT in patients that are not in high risk of bleeding or suffering from certain malignancies. The treatment should not be ceased after 6 months, but rather continued as long as the cancer remains active. Decompressive craniectomy should maintain its place in patients with CVST in risk of herniation. Last, the future also holds much promise on the role of novel compounds to be used in LMC

Degree of corticospinal tract damage correlates with motor function after stroke

Objectives: Direct injury to the corticospinal tract (CST) is a major factor defining motor impairment after stroke. Diffusion tensor imaging (DTI) tractography allows definition of the CST. We sought to determine whether DTI-based assessment of the degree of CST damage correlates with motor impairment at each phase of ischemic stroke. Methods: We evaluated patients at the acute (3–7 days), subacute (30 days), and chronic (90 days) phases of ischemic stroke with DTI and clinical motor scores (upper extremity Fugl-Myer test [UE-FM], motor items of the National Institutes of Health Stroke Scale [mNIHSS]). The CST was identified and virtual fiber numbers (FN) were calculated for the affected and contralateral CST. We used Spearman correlation to study the relationship of FN ratio (FNr) (affected/unaffected CST) with motor scores at each time point, and the regression model to study the association of the acute parameters with chronic motor scores. Results: We studied 23 patients. Mean age was 66.7 (±12) years. FNr correlated with UE-FM score in the acute (r = 0.50, P = 0.032), subacute (r = 0.57, P = 0.007), and chronic (r = 0.67, P = 0.0008) phase, and with mNIHSS in the acute (r = −0.48, P = 0.043), subacute (r = −0.58, P = 0.006), and chronic (r = −0.75, P = 0.0001) phase. The combination of acute NIHSS and FNr significantly predicted chronic UE-FM score (r = 0.74, P = 0.0001). Interpretation DTI-defined degree of CST injury correlates with motor impairment at each phase of ischemic stroke. The combination of baseline FNr and NIHSS predicts motor outcome. DTI-derived CST assessment could become a surrogate marker of motor impairment in the design of neurorestorative clinical trials

Editorial: Understanding PFO-associated stroke

Cryptogenic stroke; Paradoxical embolismIctus criptogènic; Embòlia paradoxalIctus criptogénico; Embolia paradójic

The Nose as a Route for Therapy: Part 1. Pharmacotherapy

This article reviews nasal structure and function in the light of intranasal pharmacotherapy. The nose provides an accessible, fast route for local treatment of nose and sinus diseases, with lower doses than are necessary systemically and few adverse effects. It can also be used for other medications as it has sufficient surface area protected from local damage by mucociliary clearance, absence of digestive enzymes, responsive blood flow, and provides a rapid route to the central nervous system.Peer reviewe

Percutaneous transluminal angioplasty and stenting for symptomatic intracranial arterial stenosis: a systematic review and meta-analysis

OBJECTIVES: The cumulative safety and efficacy measures of percutaneous transluminal angioplasty and stenting (PTAS) for secondary stroke prevention in patients with symptomatic intracranial arterial stenosis (sICAS) have not previously been evaluated using a meta-analytical approach. METHODS: We conducted a systematic review and random effects meta-analysis of all available randomized controlled trials (RCTs) evaluating the safety and efficacy of PTAS (in comparison with medical therapy) for sICAS. RESULTS: Three RCTs (678 total patients) were included in the quantitative analysis. PTAS was associated with a higher risk of recurrent ischemic stroke in the territory of qualifying artery both within 30 days [risk ratio (RR) = 2.21, 95% confidence interval (CI) 1.10-4.43] and 1 year (RR = 1.92, 95% CI 1.10-3.36). PTAS was also related to a higher risk of any ischemic stroke within 30 days from the index event (RR = 2.08, 95% CI 1.17-3.71). The risk for intracranial hemorrhage was found to be higher in PTAS patients both within 30 days (RR = 10.60, 95% CI 1.98-56.62) and 1 year (RR = 8.15, 95% CI 1.50-44.34). The composite outcome of any stroke or death within 1 year (RR = 2.29, 95% CI 1.13-4.66) and 2 years (RR = 1.52, 95% CI 1.04-2.21) was higher in PTAS than in medical therapy. PTAS was associated with a higher risk of any stroke or death within 2 years in the sICAS subgroup located in posterior circulation (RR = 2.37, 95% CI 1.27-4.42). CONCLUSIONS: PTAS is associated with adverse early and long-term outcomes and should not be recommended in patients with sICAS. Further research to identify subgroups of patients who could also serve as candidates for future interventional trials along with efforts to reduce procedure-related complications are needed

Lack of an association between SCFD1 rs10139154 polymorphism and amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease. Through a genome‑wide association study (GWAS), the Sec1 family domain‑containing protein 1 (SCFD1) rs10139154 variant at 14q12 has emerged as a risk factor gene for ALS. Moreover, it has been reported to influence the age at onset (AAO) of patients with ALS. The aim of the present study was to assess the association of the SCFD1 rs10139154 polymorphism with the risk of developing ALS. For this purpose, 155 patients with sporadic ALS and 155 healthy controls were genotyped for the SCFD1 rs10139154. The effect of the SCFD1 rs10139154 polymorphism was then examined on the following parameters: i) The risk of developing ALS; ii) the AAO of ALS; iii) the site of ALS onset (patients with bulbar onset ALS vs. healthy controls; and patients with limb onset ALS vs. healthy controls); and iv) the AAO of ALS onset with subgroup analyses based on the site of onset (bulbar and limb, crude and adjusted for sex). The analysis of all the outcomes was performed assuming five genetic models. Crude and adjusted analyses were applied. The threshold for statistical significance was set at 0.05. The results revealed no association between SCFD1 rs10139154 and any of the examined phenotypes in any of the models examined. On the whole, based on the findings of the present study, SCFD1 rs10139154 does not appear to play a determining role in the risk of developing ALS