Polymerization contraction stress in thin resin composite layers as a function of layer thickness.

Objectives: In the present study, the effect of layer thickness on the curing stress in thin resin composite layers was investigated. Since the value of the contraction stress is dependent on the compliance of the measuring equipment (especially for thin films), a method to determine the compliance of the test apparatus was tested.

Methods: A chemically initiated resin composite (Clearfil F2, Kuraray) was inserted between two sandblasted and silane-coated stainless steel discs in a tensilometer.

Influence of compliance of the substrate materials on polymerization contraction stress in thin resin composite layers.

The present study determined in a laboratory set-up the influence of compliance of the substrate material on polymerisation contraction stress for various thicknesses of bonded dental resin composite films. When the compliance of the tensilometer set-up was increased from 0.029 micron MPa-1 to 0.

Tensile strength of thin resin composite layers as a function of layer thickness.

As a rule, cast restorations do not allow for free curing contraction of the resin composite luting cement. In a rigid situation, the resulting contraction stress is inversely proportional to the resin layer thickness. Adhesive technology has demonstrated, however, that thin joints may be considerably stronger than thicker ones.

The growth hormone (GH) response to GH-releasing peptide (His-DTrp-Ala-Trp-DPhe-Lys-NH2), GH-releasing hormone, and thyrotropin-releasing hormone in acromegaly.

In patients with acromegaly, GH-producing pituitary tumors release GH in response to specific stimuli such as GH-releasing hormone (GHRH) and are also responsive to a variety of nonspecific stimuli, such as TRH or GnRH, and may exhibit paradoxical responses to glucose and dopamine. In healthy humans, the synthetic peptide GH-releasing peptide (GHRP) (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) releases GH by a putative mechanism of action that is independent of GHRH. How these tumors respond to GHRP is not well characterized.

The dependence of shrinkage stress reduction on porosity concentration in thin resin layers.

The development of polymerization contraction stress was determined as a function of the surface area of porosity, so that the contribution of voids in resin composite to stress relief could be investigated. Experiments were carried out on 200-microns-thick layers of resin bonded from wall to wall in a restrained condition. The resin samples were divided into three groups: Group A was without porosity, group B contained a small number of pores, and group C contained a large number of pores in comparison with group B.