Structure-Property Relationships in Dental Polymers and Composites
Biomaterials
A biomaterial is any material, natural or man-made, that comprises whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function. In this way, biomaterials are contributing to longer, higher quality lives.
Hip replacement component parts. The image below demonstrates one example: hip joint replacement. Determination of the position of the shaft of a hip joint prosthesis in the femur at a planning station of the operating robot is shown. Corresponding to this planning, the milling of the cavitation for the shaft is done during the operation (so that one will have a tailored fit). 
Whereas current medical implants are engineered to be biologically inert, the goal of tissue engineering is to utilize our understanding of tissue repair processes to design advanced medical devices that promote regeneration.
Structure-Property Relationships in Dental Polymers and Composites
Objective
To develop and characterize novel dental resins and composites that exhibit high conversion, low shrinkage, strong mechanical properties and enhanced durability.The properties of these composites are determined in large part by the filler-resin interface and the degree of filler dispersion. The challenge is to develop suitable metrologies for determining structure-property relationships for the nano-sized filler phases and the interfacial phases formed by resin-filler interactions.
PB1000-650 Polyurethane-based Biomedical Elastomer
Hardness, Shore D / 65 - 75 / 65 - 75 / ASTM D2240
Tensile Strength, Ultimate / 44.8MPa / 6500psi / ASTM D412
Elongation at Break / 350% / 350% / ASTM D412
Modulus of Elasticity / 0.0365GPa / 5.3ksi / at 100%; ASTM D412
Subcategory: Ceramic; Natural Biomaterial; Oxide, Other
Univ of Mich. – materials site
Mechanical properties of biological materials
special considerations needed for tensile testing biological soft tissue (e.g., ligament and tendon) compared to traditional engineering materials (e.g., aluminum and steel). Young’s modulus (E), the slope of the elastic portion of the stress-strain curve, is a quantity often used to asses a material’s stiffness. The linear elastic assumption makes the determination of E relatively straightforward as it can be assessed anywhere along the initial linear portion of the curve. Due to the un-crimping of collagen fibers and elasticity of elastin, the initial portion of a biological sample stress-strain curve has a high deformation/low force characteristic known as the toe region.
unlike traditional materials this region is non-linear.
Chemical Composition - Degradation of the phosphorus-nitrogen backbone yields the biologically compatible hydrolysis products phosphate and ammonia. Even though most polyphosphazenes are stable to moisture, considerable effort has been focused on the synthesis of polymers which erode at biological pH to innocuous products.
Thermal Conductivity
The thermal conductivity of a substance is the quantity of heat in cal/sec passing through a body 1 cm thick with a cross section of 1 sq. cm when the temperature difference between the hot and cold sides of the body is 1 deg. C.