Dental applications biomaterials

Gheysen G., Ducheyne R, Hench L.L., and de Meester P. 1983. Bioglass composites a potential material for dental application. Biomaterials 4 81-84. 

Biomaterials are synthetic and naturally occurring materials that are foreign to the body but are used to replace a diseased organ or tissue or augment or assist a partially functioning organ or tissue. Cardiovascular, orthopedic, and dental applications are some of the most common areas in which biomaterials are employed. 

The only wide-range application and commercialisation area of fluoride-containing biomaterials concern ionomer glasses for dental applications. The improved biological effect of these compounds is related to a slow release of active fluoride ions in biological fluids and the direct effect of fluoride ions on mineralised biological tissues. 

Biomaterials for Dental Applications a. Acylgermane-containing polymers... 

One great advantage with phosphate bonded ceramics in biomaterial or dental applications is the phosphate ions in their structure. Bones contain calcium phosphate, and hence phosphate bonded ceramics are generally biocompatible with bones. While chemically bonded calcium phosphate ceramics have been difficult to produce, magnesium and zinc based phosphate bonded ceramics have been more easily synthesized and used as structural and dental cements. 

Table 19.1 summarizes some of the existing usage of polymeric biomaterials in a variety of implantable prostheses for cardiovascular, orthopedic, ophthalmologic, and dental applications. 

In recent years, dental research has been focused on dental implants and artificial teeth rooted in a patient s jaw allowing for a permanent denture, as alternatives to bridges or false teeth. A wide array of materials including polymers such as UHMWPE, PTFE, and PET have been used in many types of existing dental implants [54,119]. Porous polymeric surfaces are now designed to facilitate bone integration [54], Other dental applications of polymeric biomaterials have been for the development of a dental bridge, meant as a partial denture or false teeth. In extreme cases, removable dentures fabricated from PMMA are used to overcome the loss of all teeth [203]. 

The situation with regard to glass-ceramics for restorative dental applications is different. These materials must also fulfill the standards for biomaterial use, such as compatibility with the oral environment. Bioactivity on the surface of the dental restoration, however, must not occur. More importantly, the surface properties of the glass-ceramics, such as shade, translucency, toughness, and wear, must correspond to those of natural teeth. Even higher standards are placed on the chemical durability of the material compared with that of natural teeth, since cavities should not occur in the new glass-ceramics. 

These desired applications determine the main requirements to be fiilfilled in the development of glass-ceramics for dental applications. The main objective is to produce a new biomaterial, the properties of which correspond to those of natural teeth. The most important properties are mechanical properties, biochemical compatibility with the oral environment, and a degree of translucency, shade, opalescence, and fluorescence similar to that of natural teeth. An abrasion resistance similar to that of natural teeth must also be achieved. The new biomaterial must demonstrate higher chemical durability than natural teeth, to prevent it from being susceptible to decay. 

A biomaterial is essentially a material that is used and adapted for a medical application [1], Biomaterials can have a benign function, such as being used for a heart valve, or may be bioactive and used for a more interactive purpose such as hydroxyapatite (HA)-coated hip implants [2-5]. Biomaterials are also used every day in dental applications, surgery, and drug delivery (a construct with impregnated pharmaceutical products can be placed into the body, which permits the prolonged release of a drug over an extended period of time) [6-10], The type of material used is also dependent on the anticipated mode of applications, the need for surface functionalization, and the need of the cell types of interest in terms of porosity. 

One of the most useful zirconium-based materials is zirconia, Zr02-Zirconia may be found in a variety of phases (i.e., cubic, orthorhombic), exhibits exceptional resistance to fracturing, and is highly chemically inert. Zirconia is an excellent refractory material and has found many applications in high-heat environments. The hardness and high chemical stability of zirconia make this material well suited for dental applications [1,2]. Ceramic biomaterials based on zirconia have gained popularity in a variety of appHcations [3], such as knee and hip replacements, and are noted for their durability [4]. Cubic zirconia is also used in jewelry. 

The past 10 years have been characterized by an explosion in the field of materials science. It cannot be denied that scientists all over the world exdted by the development of smart polymers, composites, and systems invest effort in studying them in potential biomedical appUcations. The term Smart defines a material or system having the ability of adapting itself to external stimulus by a number of ways, for example, shape shifting. The most known nonpolymer biomaterial is the shape memory alloys, such as NiTinol, with many dental applications [111]. Smart polymers are still under development [112, 113], some are already commercially available as in the case of smart polyurethanes (DiAPLEX ) by Mitsui Polymers. Recently, a cardiology product has been released in the market featuring smart characteristics. The discussion is about a cardiology stent dilated with the help of a balloon made from smart shape memory polyurethane as described in a 2002 US patent, and placed inside the blocked arteries of a patient [114]. 

Given that the structural building blocks of the tooth are essentially composed of polymeric constituents, it is no surprise that the progress of dentistry and dental biomaterials would seek to approximate the polymeric composition of the natural tooth [7], Interestingly, however, it was not until the mid 1900s that polymeric materials emerged as an alternative material for dental applications [8],... 

Ordering behaviors and age-hardening in experimental AnCn-Zn pseudobinary alloys for dental applications, S. H. Seol, T. Shiraishi, Y. Tanaka, E. Mima, K. Hisatsnne, and H. I. Kim, Biomaterials, 2002, 23(24), 4873-9. 

The arrangement of the revised and expanded Chapters in this volume differs considerably from the original order in the symposium in an attempt to make the book more consistent in its development of this broad topic. Basically these thirty five papers have been grouped into four categories (1) General Biomaterial Applications of Polymers, (2) Cardiovascular Applications of Polymers, (3) Applications of Polymers in Medication and (4) Dental Applications of Polymers. Frequently there is some overlap of the information in one section with that in another section. This is unavoidable and even desirable to an extent. Very often a material used in one application could also have utility in a totally different area. 

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