Mechanical Physical Properties

Mechanical Physical Properties

Maxiofacial Elastomers

Maxillofacial prosthetic devices are those that replace missing facial structures lost to head and neck cancer, such as replacement eyes, ears and noses. These materials are time consuming to fabricate, costly to the patient and deteriorate rapidly during usage. A long-term research goal is to isolate and study the role of several environmental factors responsible for this degradation and to eventually identify mechanisms that are responsible. Present research is focusing on why the color and mechanical properties of these biomaterials can change in response to exposure to ultraviolet light. This research is important in the development of more durable maxillofacial prosthetic materials, which is particularly relevant since the long-term survival rate for most head and neck cancers has dramatically increased in the past twenty years.

Marginal Adaptation of Dental Restorations

Since the resin-based indirect inlay systems exhibit polymerization shrinkage, it is likely that marginal gaps may occur in various locations of the cavity preparation. The size of the marginal gap interface may be significant due to the fact that the resin luting agents will disintegrate and wear much more rapidly than tooth structure or the restorative material. This disintegration may result in marginal staining and voids that cause restoration fracture or recurrent caries. The location and size of marginal gaps may be dependent on cavity preparation width and depth, and may also be dependent on the material type. The goal of this research is to compare the marginal adaptation of composite and ceramic inlay systems versus gold castings. Interface thickness measurements will be made at various locations of the cavity preparation. Correlation with clinical performance data will be the ultimate goal of this laboratory research.


Research has identified microleakage as a significant problem associated with restorative materials. Microleakage can result in secondary caries, tooth discoloration and pulpal irritation. Several studies have investigated the use of dentin bond agents as a liner with dental amalgam and have produced varying results with regard to minimizing microleakage. Adhesive resin liners may be used as dentin bond agents alone or in combination with viscous resin liners. The goal of this research is to discover whether using dentin bond agents alone as an amalgam alloy liner is sufficient to inhibit microleakage, or whether the use the viscous liner component as recommended by manufacturers is necessary.