Dental Casting Investment
Dental Casting Technique
Calcium Sulfate
Differential Thermal Analysis
Reducing Agents
Gold Alloys
Boron
Dental Alloys
Corrosion
Chromium Alloys
Corrosion Casting
Silver
Materials Testing
Dental Care
Students, Dental
Casts, Surgical
Dental Caries
Inlay Casting Wax
Effects of magnesia and potassium sulfate on gypsum-bonded alumina dental investment for high-fusing casting. (1/63)
The purpose of this study was to improve the characteristics of gypsum-bonded alumina investments using magnesia and potassium sulfate as chemical additives. Magnesia content improved fluidity, delayed setting reaction, increased green strength, and decreased setting expansion, when mixed with distilled water. When the investment was mixed with potassium sulfate, the setting time and setting expansion were reduced, and the thermal expansion increased, however, the green strength decreased. Therefore, the investment with a small amount of magnesia mixed with potassium sulfate was considered a suitable composition, having adequate setting behavior, enough green strength and sufficient compensate expansion for casting. (+info)Evaluation of a reproduction technique for the study of the enamel composite/bracket base area. (2/63)
The objective of the study was to evaluate a reproduction method that would enable the study of the enamel/ bracket/composite interface in vivo, and consisted of in vitro assessment of two different impression materials to compare reproduction of brackets bonded to extracted teeth followed by in vivo assessment of the superior material. In vitro standard edgewise brackets were bonded to two extracted teeth and impressions were taken using two different types of low viscosity silicone-based impression materials. A medium viscosity silicone impression material was used to support the original impression. Three impressions of both the gingival and occlusal aspect of the bracket base region were obtained using each of the impression materials. Replicas were then prepared for SEM viewing and these compared to SEMs of the real teeth for reproduction of detail. A 3-point Reproducibility Index was used to compare the SEM photographs of the comparable replicas. One impression material was clearly superior to the other and produced an acceptably accurate representation of the true clinical situation in three out of four samples. This material also performed well in the in vivo situation. The technique described is satisfactory for the production and analysis of SEM pictures of the enamel/composite/ bracket base interface in vivo. (+info)Study of resin-bonded calcia investment: Part 1. Setting time and compressive strength. (3/63)
This study was carried out to develop a new titanium casting investment consisting of calcia as the refractory material and a cold-curing resin system as the binder. The setting time of the investment was investigated under different N,N-dimethyl-p-toluidine (DMPT) contents in methyl methacrylate monomer (MMA) and benzoyl peroxide (BPO) contents in calcia without any sintering agent. The effects of the sintering agents, which were calcium fluoride (CaF2) and calcium chloride (CaCl2), on the compressive strength of the investments were investigated at room temperature before and after heating to two different temperatures. The shortest setting time (68 minutes) of the investment was obtained at 0.37 DMPT/BPO (1.5 vol% /1.0 mass%) ratio by mass. The highest strength (16.5 MPa) was obtained from the investment which contained 2 mass% CaF2 and was heated to 1,100 degrees C. It was found that the developed calcia investment containing 2 mass% CaF2 has a possibility for use in titanium castings. (+info)Fit and dimensional changes of cast CP titanium crowns fabricated using sintered molds. (4/63)
The present study was undertaken to evaluate the clinical applicability of cast CP titanium crowns fabricated with sintered molds. To this end, the dimensional changes and accuracy of fit of cast CP titanium crowns, manufactured under varying mold firing temperatures, were examined. Molds were fired at 7 temperatures. The outer height of the crown and outer width of the occlusal surface decreased under all sets of firing conditions. The outer width of the cervical part tended to increase at firing temperatures of 1,200, 1,300 and 1,400 degrees C. The inner widths of the occlusal surface and cervical part tended to increase under all sets of firing conditions. In the analysis of the fit of crowns, floating (gained latitude) was observed under all sets of conditions. However, the amount of floating was significantly smaller when the firing temperature was 1,200, 1,300 or 1,400 degrees C than when it was 800, 900, 1,000 or 1,100 degrees C. (+info)Interfacial oxidations of pure titanium and titanium alloys with investments. (5/63)
External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface. (+info)Labor reduction for mold preparation of a commercial titanium cast denture system using a heat-shock method. (6/63)
The purpose of this study was to investigate the application of a heat-shock method to fabricate titanium cast plates. Duplications of a maxillary model were prepared using DM under different firing schedules. Molds with patterns on the duplications were made by an outer investment (D), followed by heat shock at 850 degrees C. Duplications heat shocked at 850 degrees C after 30 min from mixing exploded within a few minutes. This explosion was successfully avoided by a drying procedure prior to the heat-shock. The molds were available for the heat shock at 850 degrees C when the duplicate models were prepared by firing either using the conventional method and the heat shock above method described. Therefore, we could reduce the preparation time from about 16 hr with the conventional method to about 10 hr at the longest with the heat-shock method. These results suggested that the heat-shock method was labor-saving for fabricating titanium cast denture plates when controlling preliminary conditions prior to use. (+info)Experimental ammonia-free phosphate-bonded investments using Mg(H2PO4)2. (7/63)
In previous study, we found that Mg(H2PO4)2 instead of NH4H2PO4 was available as a binder material for phosphate-bonded investments and possibly could be used to develop the phosphate-bonded investment without ammonia gas release. The purpose of the present study was to develop the experimental ammonia-free phosphate-bonded investments by investigating suitable refractories. Mg(H2PO4)2.nH2O and MgO were prepared as a binder. Cristobalite and quartz were selected as refractories. The power ratio of MgO/Mg(H2PO4)2.nH2O was set constant at 1.2 according to our previous findings. Fundamental properties of dental investment such as strength, manipulation and expansion were evaluated. Using cristobalite as the refractory material, further investigations were performed. The refractory/binder ratio was definitely effective. The increase of this ratio led to low mold strength and large mold expansion. The present findings suggested that C5 was desirable for dental investment. (+info)Study of resin-bonded calcia investment: part 2. Effect of titanium content on the dimensional change of the investment. (8/63)
In the present study, titanium powder was chosen as an expanding agent of an experimentally prepared resin-bonded calcia investment. The effect of Ti content on the dimensional change was investigated. In addition, the effects of the heating rate and heating temperature on the dimensional change of the investment were investigated during setting and after heating. The expansion increased with Ti content and the highest expansion (1.57%+/-0.58) was obtained at 10 mass% Ti. The highest expansion was obtained at 900 degrees C for 30 min heating and was independent of the heating rate. These findings mean that the titanium powder in the calcia investment oxidized sufficiently at that heating condition. It was found that the developed resin-bonded calcia investment was able to compensate for casting shrinkage of pure titanium by adding some Ti powder to the investment. (+info)Dental casting investment is a material used in the production of dental restorations, such as crowns and bridges, through the process of lost-wax casting. It is typically made of a gypsum-based substance that is poured into a mold containing a wax pattern of the desired restoration. Once the investment hardens, the mold is heated in a furnace to melt out the wax, leaving behind a cavity in the shape of the restoration. The molten metal alloy is then introduced into this cavity, and after it cools and solidifies, the investment is removed, revealing the finished restoration.
The dental casting technique is a method used in dentistry to create accurate replicas or reproductions of teeth and oral structures. This process typically involves the following steps:
1. Making an impression: A dental professional takes an impression of the patient's teeth and oral structures using a special material, such as alginate or polyvinyl siloxane. The impression material captures the precise shape and contours of the teeth and surrounding tissues.
2. Pouring the cast: The impression is then filled with a casting material, such as gypsum-based stone, which hardens to form a positive model or replica of the teeth and oral structures. This model is called a dental cast or die.
3. Examining and modifying the cast: The dental cast can be used for various purposes, such as analyzing the patient's bite, planning treatment, fabricating dental appliances, or creating study models for teaching or research purposes. Dental professionals may also modify the cast to simulate various conditions or treatments.
4. Replicating the process: In some cases, multiple casts may be made from a single impression, allowing dental professionals to create identical replicas of the patient's teeth and oral structures. This can be useful for comparing changes over time, creating duplicate appliances, or sharing information with other dental professionals involved in the patient's care.
The dental casting technique is an essential part of many dental procedures, as it enables dentists to accurately assess, plan, and implement treatments based on the unique characteristics of each patient's oral structures.
Calcium sulfate is an inorganic compound with the chemical formula CaSO4. It is a white, odorless, and tasteless solid that is insoluble in alcohol but soluble in water. Calcium sulfate is commonly found in nature as the mineral gypsum, which is used in various industrial applications such as plaster, wallboard, and cement.
In the medical field, calcium sulfate may be used as a component of some pharmaceutical products or as a surgical material. For example, it can be used as a bone void filler to promote healing after bone fractures or surgeries. Calcium sulfate is also used in some dental materials and medical devices.
It's important to note that while calcium sulfate has various industrial and medical uses, it should not be taken as a dietary supplement or medication without the guidance of a healthcare professional.
Differential Thermal Analysis (DTA) is a technique used in thermoanalysis to study the physical and chemical changes that occur in a material as it is heated or cooled. It measures the difference in temperature between a sample and a reference material, both of which are subjected to the same temperature program.
In DTA, the sample and reference material are placed in separate but identical holders, and the temperature of the reference material is kept constant while the temperature of the sample is increased or decreased at a controlled rate. As the sample undergoes physical or chemical changes, such as phase transitions or chemical reactions, it absorbs or releases heat, causing its temperature to change relative to the reference material.
The DTA curve plots the temperature difference between the sample and the reference material against time or temperature. The resulting curve provides information about the thermal behavior of the sample, including any endothermic or exothermic reactions that occur as it is heated or cooled. Endothermic reactions, which require heat input, are indicated by a negative deflection in the DTA curve, while exothermic reactions, which release heat, are indicated by a positive deflection.
DTA is widely used in materials science, chemistry, and physics to study the thermal properties of materials, including their phase transitions, melting points, crystallization behavior, and chemical stability. It can also be used to identify unknown materials or to characterize the purity of a sample.
A reducing agent, in the context of biochemistry and medicine, is a substance that donates electrons to another molecule, thereby reducing it. This process is known as reduction, which is the opposite of oxidation. Reducing agents are often used in chemical reactions to reduce the oxidation state of other compounds. In medical terms, reducing agents may be used in various treatments and therapies, such as wound healing and antioxidant defense systems, where they help protect cells from damage caused by free radicals and other reactive oxygen species. Examples of reducing agents include ascorbic acid (vitamin C), glutathione, and certain enzymes like NADPH-dependent reductases.
Gold alloys are not strictly a medical term, but they are often used in medical applications, particularly in the field of dentistry. Therefore, I will provide both a general definition and a dental-specific definition for clarity.
A gold alloy is a mixture of different metals, where gold is the primary component. The other metals are added to modify the properties of gold, such as its hardness, melting point, or color. These alloys can contain varying amounts of gold, ranging from 30% to 75%, depending on their intended use.
In dentistry, gold alloys refer to a specific type of alloy used for dental restorations like crowns, inlays, and onlays. These alloys typically contain between 60% and 90% gold, along with other metals such as silver, copper, and sometimes palladium or zinc. The high gold content ensures excellent biocompatibility, corrosion resistance, and durability, making these alloys a popular choice for dental applications. Additionally, their malleability allows for precise shaping and adjustment during the fabrication process.
Boron is a chemical element with the symbol B and atomic number 5. It is a metalloid that is light-colored, hard, and highly resistant to corrosion. In its crystalline form, boron is nearly as hard as diamond.
In medicine, boron compounds have been studied for their potential therapeutic uses, particularly in the treatment of cancer. For example, boron neutron capture therapy (BNCT) is a type of radiation therapy that involves the use of boron-containing compounds to selectively deliver radiation to cancer cells.
Boron is also an essential micronutrient for plants and some animals, including humans. However, excessive exposure to boron can be toxic to humans and other organisms. Therefore, it is important to maintain appropriate levels of boron in the body and environment.
Dental alloys are materials made by combining two or more metals to be used in dental restorations, such as crowns, bridges, fillings, and orthodontic appliances. These alloys can be classified into three main categories based on their composition:
1. Precious Alloys: Predominantly composed of precious metals like gold, platinum, palladium, and silver. They are highly corrosion-resistant, biocompatible, and durable, making them suitable for long-term use in dental restorations. Common examples include high noble (gold) alloys and noble alloys.
2. Base Metal Alloys: Contain primarily non-precious metals like nickel, chromium, cobalt, and beryllium. They are more affordable than precious alloys but may cause allergic reactions or sensitivities in some patients. Common examples include nickel-chromium alloys and cobalt-chromium alloys.
3. Castable Glass Ionomer Alloys: A combination of glass ionomer cement (GIC) powder and metal liquid, which can be cast into various dental restorations. They have the advantage of being both strong and adhesive to tooth structure but may not be as durable as other alloy types.
Each type of dental alloy has its unique properties and applications, depending on the specific clinical situation and patient needs. Dental professionals consider factors like cost, biocompatibility, mechanical properties, and esthetics when selecting an appropriate alloy for a dental restoration.
Corrosion is a process of deterioration or damage to a material, usually a metal, caused by chemical reactions with its environment. In the medical context, corrosion may refer to the breakdown and destruction of living tissue due to exposure to harsh substances or environmental conditions. This can occur in various parts of the body, such as the skin, mouth, or gastrointestinal tract, and can be caused by factors like acid reflux, infection, or exposure to chemicals.
In the case of medical devices made of metal, corrosion can also refer to the degradation of the device due to chemical reactions with bodily fluids or tissues. This can compromise the function and safety of the device, potentially leading to complications or failure. Therefore, understanding and preventing corrosion is an important consideration in the design and use of medical devices made of metal.
I'm sorry for any confusion, but "investments" is not a term that has a specific medical definition. It is an economic and financial term that refers to the allocation of resources, usually money, with the expectation of receiving future returns or benefits. This could include purchasing stocks, bonds, real estate, or other assets with the goal of generating income or appreciating in value over time.
If you have any questions related to medical terminology or health-related concepts, I'd be happy to help!
Chromium alloys are materials made by combining chromium with other metals, such as nickel, cobalt, or iron. The addition of chromium to these alloys enhances their properties, making them resistant to corrosion and high temperatures. These alloys have a wide range of applications in various industries, including automotive, aerospace, and medical devices.
Chromium alloys can be classified into two main categories: stainless steels and superalloys. Stainless steels are alloys that contain at least 10.5% chromium by weight, which forms a passive oxide layer on the surface of the material, protecting it from corrosion. Superalloys, on the other hand, are high-performance alloys designed to operate in extreme environments, such as jet engines and gas turbines. They contain significant amounts of chromium, along with other elements like nickel, cobalt, and molybdenum.
Chromium alloys have several medical applications due to their excellent properties. For instance, they are used in surgical instruments, dental implants, and orthopedic devices because of their resistance to corrosion and biocompatibility. Additionally, some chromium alloys exhibit superelasticity, a property that allows them to return to their original shape after being deformed, making them suitable for use in stents and other medical devices that require flexibility and durability.
Corrosion casting is a specialized technique used in anatomy and pathology to create detailed casts or molds of biological specimens, particularly vascular systems. This method is also known as "acid etching" or "corrosive casting." Here's the medical definition:
Corrosion casting is a process that involves injecting a special resin or plastic material into the vasculature or other hollow structures of a biological specimen, such as an organ or tissue. The injected material thoroughly fills the cavity and then hardens once it has set. After hardening, the surrounding tissues are corroded or dissolved using strong acids or bases, leaving behind only the cast or mold of the internal structures.
This technique results in a detailed three-dimensional representation of the complex internal networks, like blood vessels, which can be used for further study, research, and education. Corrosion casting is particularly useful in visualizing the intricate branching patterns and structural relationships within these systems.
I'm sorry for any confusion, but "Silver" is not a medical term. It is a chemical element with the symbol Ag and atomic number 47. Silver is a soft, white, lustrous transition metal that occurs in its pure, free form (native silver) as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite.
In the medical field, silver compounds have been used for their antimicrobial properties. For example, silver sulfadiazine is a common topical cream used to prevent or treat wound infections. Colloidal silver, a suspension of silver particles in a liquid, has also been promoted as a dietary supplement and alternative treatment for various conditions, but its effectiveness and safety are not well-established.
I'm happy to help! However, I must clarify that "materials testing" is not a medical term per se. It is a term used in various fields, including engineering and materials science, to describe the process of subjecting materials to different tests to evaluate their properties and performance under various conditions.
In the context of medical devices or implants, materials testing may refer to the evaluation of the physical and mechanical properties of materials used in their construction. These tests can include assessments of strength, durability, biocompatibility, and other factors that are critical to ensuring the safety and efficacy of medical devices.
Medical device manufacturers must comply with regulatory standards for materials testing to ensure that their products meet specific requirements for performance, safety, and quality. These standards may vary depending on the type of device, its intended use, and the country or region in which it will be marketed and sold.
Dental care refers to the practice of maintaining and improving the oral health of the teeth and gums. It involves regular check-ups, cleanings, and treatments by dental professionals such as dentists, hygienists, and dental assistants. Dental care also includes personal habits and practices, such as brushing and flossing, that help prevent tooth decay and gum disease.
Regular dental care is important for preventing common dental problems like cavities, gingivitis, and periodontal disease. It can also help detect early signs of more serious health issues, such as oral cancer or diabetes, which can have symptoms that appear in the mouth.
Dental care may involve a range of treatments, from routine cleanings and fillings to more complex procedures like root canals, crowns, bridges, and implants. Dental professionals use various tools and techniques to diagnose and treat dental problems, including X-rays, dental impressions, and local anesthesia.
Overall, dental care is a critical component of overall health and wellness, as poor oral health has been linked to a range of systemic health issues, including heart disease, stroke, and respiratory infections.
Dental education refers to the process of teaching, training, and learning in the field of dentistry. It involves a curriculum of academic and clinical instruction that prepares students to become licensed dental professionals, such as dentists, dental hygienists, and dental assistants. Dental education typically takes place in accredited dental schools or programs and includes classroom study, laboratory work, and supervised clinical experience. The goal of dental education is to provide students with the knowledge, skills, and values necessary to deliver high-quality oral health care to patients and promote overall health and wellness.
"Schools, Dental" is not a recognized medical term or concept. It seems that there might be some confusion in the terminology used. If you are referring to "Dental Schools," they are educational institutions that offer professional training programs in dentistry, leading to a degree in dental surgery (DDS) or dental medicine (DMD).
If you meant something else, please clarify the term or concept, and I would be happy to provide more information.
I'm happy to help! However, I believe there may be a slight misunderstanding in your question. "Students, Dental" is not a medical term or definition. Instead, it likely refers to individuals who are studying to become dental professionals, such as dentists, dental hygienists, or dental assistants.
If you're looking for information about dental education or the field of dentistry, I would be happy to provide some resources or answer any questions you may have!
Surgical casts are medical devices used to immobilize and protect injured body parts, typically fractured or broken bones, during the healing process. They are usually made of plaster or fiberglass materials that harden when wet and conform to the shape of the affected area once applied. The purpose of a surgical cast is to restrict movement and provide stability to the injured site, allowing for proper alignment and healing of the bones.
The casting process involves first aligning the broken bone fragments into their correct positions, often through manual manipulation or surgical intervention. Once aligned, the cast material is applied in layers, with each layer being allowed to dry before adding the next. This creates a rigid structure that encases and supports the injured area. The cast must be kept dry during the healing process to prevent it from becoming weakened or damaged.
Surgical casts come in various shapes and sizes depending on the location and severity of the injury. They may also include additional components such as padding, Velcro straps, or window openings to allow for regular monitoring of the skin and underlying tissue. In some cases, removable splints or functional braces may be used instead of traditional casts, providing similar support while allowing for limited movement and easier adjustments.
It is essential to follow proper care instructions when wearing a surgical cast, including elevating the injured limb, avoiding excessive weight-bearing, and monitoring for signs of complications such as swelling, numbness, or infection. Regular check-ups with a healthcare provider are necessary to ensure proper healing and adjust the cast if needed.
Dental caries, also known as tooth decay or cavities, refers to the damage or breakdown of the hard tissues of the teeth (enamel, dentin, and cementum) due to the activity of acid-producing bacteria. These bacteria ferment sugars from food and drinks, producing acids that dissolve and weaken the tooth structure, leading to cavities.
The process of dental caries development involves several stages:
1. Demineralization: The acidic environment created by bacterial activity causes minerals (calcium and phosphate) to be lost from the tooth surface, making it weaker and more susceptible to decay.
2. Formation of a white spot lesion: As demineralization progresses, a chalky white area appears on the tooth surface, indicating early caries development.
3. Cavity formation: If left untreated, the demineralization process continues, leading to the breakdown and loss of tooth structure, resulting in a cavity or hole in the tooth.
4. Infection and pulp involvement: As the decay progresses deeper into the tooth, it can reach the dental pulp (the soft tissue containing nerves and blood vessels), causing infection, inflammation, and potentially leading to toothache, abscess, or even tooth loss.
Preventing dental caries involves maintaining good oral hygiene, reducing sugar intake, using fluoride toothpaste and mouthwash, and having regular dental check-ups and cleanings. Early detection and treatment of dental caries can help prevent further progression and more severe complications.
"Inlay casting wax" is not a medical term per se, but rather a term used in the field of dentistry, specifically in dental prosthetics. It refers to a type of wax that is used during the fabrication of dental restorations such as crowns, bridges, and inlays/onlays.
The inlay casting wax is used to create a positive model or pattern of the prepared tooth and the surrounding teeth. The wax pattern is then invested in a refractory material and burned out in a high-temperature oven, leaving behind a mold cavity that can be filled with precious metal alloys (such as gold) or other materials to create the final restoration.
Therefore, while not a medical definition per se, it's important to note that "Inlay casting wax" is a term used in dental technology and prosthodontics for creating custom-made dental restorations.