Crowns cemented on crown preparations lacking geometric resistance form. Part II: effect of cement.

PURPOSE: This study evaluated the effect of different cements on resistance to dislodgment of crowns cemented on preparations lacking geometric resistance form. MATERIALS AND METHODS: A preparation that offered no geometric resistance form, with 20 degrees total occlusal convergence (TOC), 0.9 mm wide shoulder finish line, and a 2.5 mm axial wall height was created on an ivorine tooth using a milling machine. Ten metal test specimen die replicas and 10 standardized metal crowns with recipient sites for the application of external forces through a universal testing machine were fabricated. The crowns were cemented on the dies under 5 and 10 kg external loads, the marginal openings measured, loaded to dislodgment, and cleaned of cement. The process was repeated using zinc oxide and eugenol (ZOE), zinc phosphate (ZPh), resin modified glass ionomer (RMGI), and composite resin (CR) cements. RESULTS: Marginal openings under 5 kg cementation loads were 74.63 (+/-15.04) for ZOE, 75.98 (+/-18.20) microm for ZPh, 98.58 (+/-22.62) microm for RMGI, and 105.82 (+/-20.07) microm for CR cements respectively; under 10 kg cementation loads they were 57.62 (+/-15.86) microm, 59.55 (+/-15.41) microm, 95.00 (+/-19.52) microm, 101.30 (+/-12.52) microm respectively. Oblique dislodgment forces, measured with a Universal testing machine, were 40.18 (+/- 6.76) N for ZOE, 215.65 (+/-45.79) N for ZPh, 165.43 (+/-19.53) N for RMGI, and 181.54 (+/-30.75) N for CR respectively when crowns were cemented under 5 kg loads. The corresponding values for 10 kg loads were 38.62 (+/-4.19), 274.86 (+/-54.22), 139.70 (+/-21.71), and 160.40 (+/-21.21) respectively. Only zinc phosphate cement produced statistically enhanced resistance when crowns were cemented under 10 kg force (p value = 0.035). CONCLUSIONS: Under the conditions of the present study only crowns cemented with zinc phosphate displayed increased resistance to dislodgment on preparations lacking resistance form.     

How superhydrophobicity breaks down

A droplet deposited or impacting on a superhydrophobic surface rolls off easily, leaving the surface dry and clean. This remarkable property is due to a surface structure that favors the entrainment of air cushions beneath the drop, leading to the so-called Cassie state. The Cassie state competes with the Wenzel (impaled) state, in which the liquid fully wets the substrate. To use superhydrophobicity, impalement of the drop into the surface structure needs to be prevented. To understand the underlying processes, we image the impalement dynamics in three dimensions by confocal microscopy. While the drop evaporates from a pillar array, its rim recedes via stepwise depinning from the edge of the pillars. Before depinning, finger-like necks form due to adhesion of the drop at the pillar’s circumference. Once the pressure becomes too high, or the drop too small, the drop slowly impales the texture. The thickness of the air cushion decreases gradually. As soon as the water–air interface touches the substrate, complete wetting proceeds within milliseconds. This visualization of the impalement dynamics will facilitate the development and characterization of superhydrophobic surfaces.     

Concomitant versus sequential therapy for the treatment of Helicobacter pylori infection: a Greek randomized prospective study

Objective: The objective of this study is to compare, in Greece, a region with >20% local resistance to clarithromycin, the efficacy rates of the concomitant versus the sequential H. pylori eradication therapy. Materials and methods: Our prospective randomized study included 364 patients with newly diagnosed H. pylori infection, randomized to receive a 10-day concomitant or 10-day sequential therapy. Treatment outcome was assessed by C¹³-urea breath test at least 4 weeks after therapy. Intention to treat (ITT) and per protocol (PP) analysis of the eradication rates were performed. Secondary end points included patient compliance and safety. Results: The concomitant therapy group achieved statistically significant higher eradication rates when compared with the sequential treatment group, both in the ITT and in the PP analysis (84.6% versus 70.9%, p?=?0.002, and 90.6% versus 78.1%, p?=?0.001, respectively), after adjusting for age, gender, smoking status, and the presence or not of ulcer and/or non-ulcer dyspepsia. Both groups displayed excellent compliance rates (99.5% for the concomitant therapy group and 96.2% for the sequential therapy group, p?=?0.067). Regarding treatment safety, major adverse events that led to the discontinuation of both regimens were few, with no statistical difference between the two groups (7.0% for the concomitant therapy group and 2.9% for the sequential therapy group). Conclusions: Concomitant therapy led to statistically significant higher eradication rates over sequential therapy. Both therapies showed excellent compliance and an acceptable safety profile. The 10-day quadruple concomitant scheme should be the adopted for first-line H. pylori eradication in Greece.     

Contemporary Antithrombotic Treatment in Patients with Non-valvular Atrial Fibrillation Undergoing Percutaneous Coronary Intervention: Rationale and Design of the Greek AntiPlatElet Atrial Fibrillation (GRAPE-AF) Registry

Background

Approximately 5 to 7% of patients undergoing percutaneous coronary intervention (PCI) for the treatment of coronary artery disease require chronic oral anticoagulation (OAC) on top of aspirin and a P2Y₁₂ receptor antagonist, mainly due to non-valvular atrial fibrillation (AF). The advent of non-vitamin K antagonist oral anticoagulants (NOACs) increased treatment options, while there is cumulative evidence that dual combination of a NOAC and a P2Y₁₂ receptor antagonist attenuates risk of bleeding, compared to traditional triple therapy, consisting of a vitamin K antagonist (VKA), aspirin, and a P2Y₁₂ receptor antagonist, without significantly compromising efficacy.

Study Design

Greek AntiPlatElet Atrial Fibrillation (GRAPE-AF, NCT 03362788) is an observational, nationwide study of non-valvular AF patients undergoing PCI, planning to enroll over 1-year period >?500 participants in 25 tertiary and non-tertiary PCI centers in Greece. Key data to be collected pre-discharge include demographics, detailed past medical history, and antithrombotic and concomitant treatment. Patients will be followed up at 1, 6, and 12 months post hospital discharge. Αt each follow-up visit, data on antithrombotic treatment, ischemic, bleeding, and adverse events will be collected. Study’s primary endpoint is clinically significant bleeding (Bleeding Academic Research Consortium, BARC ≥?2) at 12 months, between VKAs and NOACs-treated patients, analyzed using Cox proportional hazards models, by an intention-to-treat principle. An independent endpoint committee will adjudicate all clinical events.

Conclusions

This study aims at providing “real-world” information on current antithrombotic treatment patterns and clinical outcome of patients with non-valvular AF undergoing PCI.

     

Prevention,diagnostic evaluation,management and prognostic implications of liver disease in critically ill patients with COVID-19

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, broke out in December 2019 in Wuhan city of China and spread rapidly worldwide. Therefore, by March 2020, the World Health Organization declared the disease a global pandemic. Apart from the respiratory system, various other organs of the human body are also seriously affected by the virus. Liver injury in patients with a severe form of COVID-19 is estimated to be 14.8%-53.0%. Elevated levels of total bilirubin, aspartate aminotransferase and alanine aminotransferase and low levels of serum albumin and prealbumin are the main laboratory findings. Patients with pre-existing chronic liver disease and cirrhosis are much more prone to develop severe liver injury. This literature review presented the recent scientific findings regarding the pathophysiological mechanisms responsible for liver injury in critically ill patients with COVID-19, the various interactions between drugs used to treat the disease and the function of the liver and the specific tests providing the possibility of early diagnosis of severe liver injury in these patients. Moreover, it highlighted the burden that COVID-19 put on health systems worldwide and its effect on transplant programs and the care provided to critically ill patients in general and particularly to those with chronic liver disease.     

Posterior capsule rupture and vitreous loss during phacoemulsification with or without the use of an anterior chamber maintainer

PURPOSE: To compare the incidence of posterior capsule rupture and vitreous loss during phacoemulsification with and without the use of an anterior chamber maintainer (ACM) SETTING: Aristotle University Eye Clinic, Thessaloniki, Greece. METHODS: The surgical records of patients who had phacoemulsification by experienced surgeons over a 2-year period were reviewed. The cases were divided into 2 groups: surgery performed without the use of an ACM (no-ACM group) and surgery performed with the use of an ACM (ACM group). RESULTS: The no-ACM group comprised 231 cases and the ACM group, 312 cases. Posterior capsule rupture occurred in 19 cases (8.22%) and 22 cases (7.05%), respectively. Of the patients with posterior capsule rupture, 6 (31.57%) in the no-ACM group and 16 (72.72%) in the ACM group had vitreous loss and required an anterior vitrectomy; the difference between the 2 groups was statistically significant (P =.03). CONCLUSIONS: The use of an ACM in phacoemulsification provided a consistently deep anterior chamber and approximately the same rate of complications as with a standard technique in the hands of experienced surgeons. However, when posterior capsule rupture occurred, the incidence of vitreous loss was significantly higher in eyes with an ACM.