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This paper considers the use of bioinspired functionally graded structures in the design of dental multi-layers that are more resistant to sub-surface crack nucleation. Unlike existing dental crown restorations that give rise to high stress concentration, the functionally graded layers (between crown materials and the joins that attach them to dentin) are shown to promote significant reductions in stress and improvements in the critical crack size. Special inspiration is drawn from the low stress concentrations associated with the graded distributions in the dentin-enamel-junction (DEJ). The implications of such functionally graded structures are also discussed for the design of dental restorations.

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This work was initiated to explore the possibility of preparing porous scaffold, using microwave energy under vacuum technique. The hypothesis was that microwave energy under vacuum may promote effective cross-linking of the biopolymers during drying as well as to lead desirable physical characteristics of composites for hard tissue-like bone regeneration. Three different percentages of hydroxyapatite (HA) was reinforced with gelatin—starch polymer network to prepare porous scaffolds. EDS result of the prepared scaffold composite showed that Ca/P ratio of the HA phase was the same for all the HA percentages, 1.7, which is slightly higher than the standard value of 1.67. FTIR results showed the existence of a carbonate group along with the peaks of phosphate groups and hydroxyls, the functional group of HA. The scaffold composite obtained by microwave energy under vacuum technique had good mechanical and structural properties, which showed a promising potential for bone-substitution applications.

The fatigue life of K3XF instruments under water is longer than it is for K3XF instruments in air. There was no work-hardening effect on K3XF instruments subjected to the fatigue process.

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Patterned bioceramic coatings may find potential applications in orthopedic implants and biosensors. In this study, various hydroxyapatite (HA) patterns were created on silicon and titanium substrates. Electrophoretic deposition technique was used together with surface patterning of the cathode specimen. When gold/palladium patterns (hexagons, spherical dots, etc.) were created on the cathode surface, HA colloidal particles in ethanol would preferentially deposit on the gold-coated area and form patterns. When silicon, instead of gold, was evaporated onto a conducting cathode surface, HA mainly deposited on the exposed area of the substrate. Detailed mechanisms for forming HA patterns may involve local concentration of the electric field when a second metal is patterned on the cathode. The difference in electric field across the two metals on the cathode also enhances HA patterning through an electrohydrodynamic process. This study demonstrated the possibility and flexibility of electrophoretic deposition in patterning charged particles onto a substrate.