Biological Behavior and Corrosion of Prosthetic and Orthodontic Titanium Implants

Titanium and its alloys are used in dentistry for implants because of their unique combination of chemical, physical, and biological properties. For dental implants, biocompatibility depends on mechanical and corrosion/degradation properties of the material, tissue, and host factors. Corrosion can severely limit the fatigue life and ultimate strength of the material leading to mechanical failure of the dental materials. 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. 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) by comparation with other alloys (stainless steel orthodontic mini implants for example, fig.) used in prosthetic or orthodontic implant technology. The goal of the study is to determinate the main parameters (factors) and the way they affect (integrity, stability) the utilisation performance of the stainless steel orthodontic mini implants

Experimental Research on Heating Behavior of Some Steels During Hot Metallurgical Processing

The heating of steel semi-products in view of hot rolling process or heat treatments is achieved at the large scale in propulsion ovens for the increase of their deformability and to improving mechanical characteristics of finite products. The main heating defects (oxidation and decarburation, overgrown grain size of steels) represent processes of alteration of the superficial layers or the decrease of the physical and mechanical characteristics of the finished products. This paper presents the results of experimental researches on the oxidation susceptibility, variation of the depth of the decarburized layer and the susceptibility to overheat of two ship steel grades (A36 and E36 grade), during the heating for the hot metallurgical processing of the semi-products. It is the deepening of the researches about heating behavior of naval steels with different chemical compositions

Research on the Influence of Chemical Composition and Structural Condition on the Properties of High-Resistance Naval Steel Flat Rolled Products

The performance achieved in the manufacture of large ships and components of special characteristics requires the use of quality metallic materials with physico-chemical and mechanical characteristics able to satisfy the quality conditions specified in the product standards for a safety operation. The category of flat rolled products widely used in naval industry includes the high-strength sheet steel whose characteristics depend on the correlation of the chemical composition with the thermal and / or the thermo-mechanical processing in order to obtain the prescriptions imposed by the naval regulations. The paper presents some of the experimental results obtained by a laboratory scale research program for the study of the influence of the thermal and / or thermomechanical treatment parameters on the use characteristics of the highstrength naval steel sheet while ensuring the constancy of these characteristics in the manufacturing. The evaluation of the physical-mechanical properties and the interpretation of the experimental results obtained have as reference similar properties obtained from conventional thermal processing or even from the state of rolling as the state of the product delivery

Research on the Behaviour of the Tooth - Crown Assemblies Made of Different Metal Materials in Solutions Simulating the Oral Environment

One of the basic principles of restorative dentistry is the conservation of the hard dental structure, while satisfying both aesthetic and functional requirements. Complying with this principle will minimize the harmful effects caused by the diversity of works and materials. There are numerous studies that aim to determine the behavior of different types of materials in the complex environment of the oral cavity, but a small number are those that relate to the changes that occur in the underlying dental hard tissues represented by dental abutments. Experiments were performed on extracted teeth prepared by grinding. On the polished abutments, crowns of three alloy types were made, namely: Cr- Co, Cr-Ni, and copper alloys. The crowns were cemented onto the abutments with a glass ionomer cement and subsequently immersed and maintained in solutions simulating the specific conditions of an oral environment (also called artificial saliva) of the type: Ringer Fusayama-Mayer  and citric acid. After a period of six months, the ablation of crowns was achieved and comments were made on the changes in the abutments and also in the crown envelopes

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

Study of Heat Treatment Influence on Aluminum - Based Alloy ATN-Si10Cu4

This work presents the experimental results concerning the behavior on heat treatment of on aluminum based alloy. The laboratory level experiments achieved on samples of ATN-Si10Cu4 (4145 series) alloy illustrate the variation of properties depending on the variation of heat treatment technological parameters specific to different heat treatment. We have experimented more variants of heat treatment in order to establish the optimal variant treatment. The samples were characterized by HB hardness and microstructure analysis

Surface Tension of Liquid Copper in Dilute Oxygen Concentrations

The studies of this paper regarding the influence of low oxygen contents on the liquid copper surface tension had as base „sessile drop” method and the determination of the oxygen content using calculation ratio where partial pressure of the oxygen is in equilibrium with the melt in a gaseous atmosphere. The surface tension of the liquid copper, with very low oxygen contents has been studied at various temperatures (1373, 1423, 1473, 1523 and 1573 K)

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

The Laboratory Experiments Regarding the Intercritical Heat Treatments Applied on the Low - Alloyed Steel

The paper presents the research results regarding the influence of the intercritical thermal treatments carried out on some hypoeutectoid steel castings. The purpose of this research at the laboratory scale is to measure the effect of the thermal treatment which precedes the intercritical thermal treatment as well as to establish the optimum experimental variant in order to replace the classical thermal treatments

Study of the Inclusions from the Oriented Grains Silicon Steels and their Influence on the Texture

The paper presents experimental results concerning the inhibitor phases generation by microalloying elements utilization. It was made experiments on three silicon steel charges. It was observed that the inhibitor phases have a strong influence on steel sheet structure and its texture. So these phases can by considered like “texture nucleus”