Physical-Mechanical and Technological Characteristics of Ti10Zr Alloy for Dental Applications

Progress reported over time in dentistry can be attributed largely to the dynamics of acquiring new materials. A biomaterial is considered ideal in the absence of any biomaterial-tissue interaction, which means a biomaterial totally inert to the biological medium. Biomaterials currently used as implants that come in contact with the tissues and substances and fluids in the body must meet two basic characteristics, called bio-functionality and biocompatibility. They define both the ability to fulfill its function properly and the compatibility of the implant biomaterial with the tissue that it incorporates. The most common are metallic biomaterials (metals and alloys) due to their very good mechanical properties and their accepted biocompatibility. Issues related to the use of metallic materials in dental biomaterials (prostheses, implants) include mainly corrosion, release of toxic metal ions and wear. The toxicity of the metal ions as particles resulting from wear is a major disadvantage in the use of metallic biomaterials as they may induce multiple tissue reactions, such as osteolysis, damage the normal structure of the bone, severe reaction of macrophages, granuloma, fibrous capsule, inflammatory and immune reactions. All this can lead to implant destabilization and loosening. This paper summarizes the physical-mechanical and technological characteristics of a new titanium-based alloy having high biocompatibility due to the chemical composition. The alloy is composed of 10% zirconium designed to improve fatigue strength in corrosive environment and does not contain harmful elements present in conventional titanium-based alloys composition

Research on Chemical Deposition of Silver with Antibacterial Role in Implantology

The paper presents a synthesis of the laboratory research on the conditions of achieving chemical deposition of silver on oral implants made of Ti base alloy (bioalloy Ti10Zr). There were used several chemical deposition regimes in which were modified deposition parameters (temperature, stirring time) for two types of implants (different screw thread geometry). Study of the influence of deposition conditions was performed through analysis at scanning electron microscope (SEM) with EDX analyzer. The results revealed the presence of silver, microdispersed particles with morphologies and degrees of dispersion dependent on the factors and technological conditions of obtaining the chemical deposition

Physiological parameters for Prognosis in Abdominal Sepsis (PIPAS) Study : a WSES observational study

BackgroundTiming and adequacy of peritoneal source control are the most important pillars in the management of patients with acute peritonitis. Therefore, early prognostic evaluation of acute peritonitis is paramount to assess the severity and establish a prompt and appropriate treatment. The objectives of this study were to identify clinical and laboratory predictors for in-hospital mortality in patients with acute peritonitis and to develop a warning score system, based on easily recognizable and assessable variables, globally accepted.MethodsThis worldwide multicentre observational study included 153 surgical departments across 56 countries over a 4-month study period between February 1, 2018, and May 31, 2018.ResultsA total of 3137 patients were included, with 1815 (57.9%) men and 1322 (42.1%) women, with a median age of 47years (interquartile range [IQR] 28-66). The overall in-hospital mortality rate was 8.9%, with a median length of stay of 6days (IQR 4-10). Using multivariable logistic regression, independent variables associated with in-hospital mortality were identified: age > 80years, malignancy, severe cardiovascular disease, severe chronic kidney disease, respiratory rate >= 22 breaths/min, systolic blood pressure 4mmol/l. These variables were used to create the PIPAS Severity Score, a bedside early warning score for patients with acute peritonitis. The overall mortality was 2.9% for patients who had scores of 0-1, 22.7% for those who had scores of 2-3, 46.8% for those who had scores of 4-5, and 86.7% for those who have scores of 7-8.ConclusionsThe simple PIPAS Severity Score can be used on a global level and can help clinicians to identify patients at high risk for treatment failure and mortality.Peer reviewe

Dental Metals and Alloys Characterization

Metals and alloys in dentistry have seen remarkable progress due to their biocompatibility and deepen research on the application of advanced technologies to improve surface properties by controlling interactions material - environment in the mouth. Biocompatibility of metals is a consequence of the presence of surface oxide layer. Chemical properties and therefore chemical processes determine precisely this interface oxide layer and not the metal itself. Biocompatibility would be perfect without any biomaterial - tissue interactions and could be assured by a completely inert biomaterial, which does not exist at this time. Titanium and its alloys provide strength, rigidity, and ductility similar to those of other dental alloys. Whereas, pure titanium castings have mechanical properties similar to Type III and Type IV gold alloys, some titanium alloy castings, such as Ti-6Al-4V and Ti-15V, have properties closer to Ni-Cr and Co-Cr castings with the exception of lower modulus. Co-Cr alloys are alloys nenobile group, developed as an alternative to noble alloys, which have become very expensive, inaccessible and limited resources. Modern alloys based on Co-Cr, due to its superior mechanical and costeffective price noble alloys have replaced the classic class IV in technology (metalpolymer) and modern (metal and metal-ceramic composite). Co-Cr alloys have advantages related to high modulus (250GPa) than type IV gold alloys (70-100GPa) but they maintain their rigidity, which means that all items may have minimum thickness metal frame. This article presents a few considerations and results of studies regarding the biological behavior and corrosion resistance of the commercially pure titanium (CP Ti), titanium alloys (e.g. Ti6Al4V), in comparison with other alloys (stainless steel, Co-Cr alloys) used in prosthetic or orthodontic implant technology

Mechanical Properties of Polymer-Based Blanks for Machined Dental Restorations

The tremendous technological and dental material progress led to a progressive advancement of treatment technologies and materials in restorative dentistry and prosthodontics. In this approach, CAD/CAM restorations have proven to be valuable restorative dental materials in both provisional and definitive restoration, owing to multifarious design, improved and highly tunable mechanical, physical and morphological properties. Thus far, the dentistry market offers a wide range of CAD/CAM restorative dental materials with highly sophisticated design and proper characteristics for a particular clinical problem or multiple dentistry purposes. The main goal of this research study was to comparatively investigate the micro-mechanical properties of various CAD/CAM restorations, which are presented on the market and used in clinical dentistry. Among the investigated dental specimens, hybrid ceramic-based CAD/CAM presented the highest micro-mechanical properties, followed by CAD/CAM PMMA-graphene, while the lowest micro-mechanical features were registered for CAD/CAM multilayered PMMA

Influence of Air-Barrier and Curing Light Distance on Conversion and Micro-Hardness of Dental Polymeric Materials

This study aims to assess the conversion degree and hardness behavior of two new commercial dental restorative composites that have been submitted to light curing in different environments (air and glycerin, respectively) at various distances from the light source (1 to 5 mm) and to better understand the influence of the preparation conditions of the restorative materials. Through FT-IR spectrometry, the crosslinking degree of the commercial restorative materials have been investigated and different conversion values were obtained (from ~17% to ~90%) but more importantly, it was shown that the polymerization environment exhibits a significant influence on the crosslinking degree of the resin-based composites especially for obtaining degrees of higher polymerization. Additionally, the mechanical properties of the restorative materials were studied using the nanoindentation technique showing that the nano-hardness behavior is strongly influenced not only by the polymerization lamp position, but also by the chemical structure of the materials and polymerization conditions. Thus, the nanoindentation results showed that the highest nano-hardness values (~0.86 GPa) were obtained in the case of the flowable C3 composite that contains BisEMA and UDMA as a polymerizable organic matrix when crosslinked at 1 mm distance from the curing lamp using glycerin as an oxygen-inhibitor layer