Characterization of the elastic and viscoelastic properties of dentin by a nanoindentation creep test.

Dentin is the main supporting structure of teeth, but its mechanical properties may be adversely affected by pathological demineralization. The purposes of this study were to develop a quantitative approach to characterize the viscoelastic properties of dentin after de- and re-mineralization, and to examine the elastic properties using a nanoindentation creep test. Dentin specimens were prepared to receive both micro- and nano-indentation tests at wet and dry states.

Riboflavin-ultraviolet-A-induced collagen cross-linking treatments in improving dentin bonding.

Objectives: To evaluate the collagen cross-linkers, riboflavin-ultraviolet-A (RF/UVA) and glutaraldehyde, with regard to their efficacy in cross-linking the dentinal collagen and improving dentin bonding.

Methods: Glutaraldehyde and different RF/UVA protocols (0.1%RF/1-minUV, 0.

A new method for determining the strain energy release rate of an interface via force-depth data of nanoindentation tests.

Indentation forces, including constant rate and oscillating mode, were applied to SiO(2)/Si and diamond-like carbon (DLC)/Si specimens. A two-stage behavior was exhibited in the force-depth results after delamination occurred. When the depth was smaller than the threshold value, a linear load-depth relationship was exhibited because the debonded film was suspended over the substrate.

Characteristics of water strider legs in hydrodynamic situations.

This study investigated the forces and the cross-section images of a water strider's leg through experimental observations. In the vertical direction, the spring coefficients were found to be 0.6 N/m for the leg and 0.

Adhesion forces and contact angles of water strider legs.

This study investigated the adhesion (pull-off) force and contact angles of a water strider's leg. During hydrostatic experiments, the adhesion force was found to be 2 dyn. The image of a cross section of a live leg contacted with a deformed water surface provided the contact angle of 168.

Initial and adhesive contact between a diamond indenter and polydimethylsiloxane.

Detailed observations for the initial and adhesive contact of polydimethylsiloxane indentations with sharp indenters are proposed and discussed in this study. In dry experiments, the load-depth results revealed an almost reversible feature, which indicated elastic deformation. Significant initial penetration depths, created during the finding surface process, were found.