OBJECTIVES The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. MATERIAL AND METHODS Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implan...

This study evaluated the contributions of locomotive loading and estrogen to the development of diaphysis of rat femur. A randomized 2x2 study design was used. Altogether, 70 female Sprague-Dawley rats were used, of which 10 were euthanized at entry. Of the remaining rats, 16 served as controls, and the rest, 44, underwent a unilateral sciatic neurectomy. The effect of estrogen was removed by o...

Bone research has been re-directed in the 1990s by three revolutions: firstly the recognition that bones respond to changes in their mechanical environment in a dose-dependent way; secondly by the idea that these changes in bone size can be understood as self-adaptation to variant forces by a servo-control mechanism (mechanostat theory); and thirdly by the proposition that muscles ‘enslave’ bon...

In this study we present a new three-dimensional (3D) model to study effects of mechanical loading on tendon/ligament formation in vitro. The model mimics a functional periodontal ligament (PDL), which anchors dental roots to the jaw bone and transfers the axial load of mastication to the jaw bone. A collagen gel containing human PDL fibroblasts was seeded in a PDL space between an artificial r...

Arteries are modeled, within the framework of nonlinear elasticity, as incompressible two-layer cylindrical structures that are residually stressed through differential growth. These structures are loaded by an axial force, internal pressure and have nonlinear, anisotropic, hyperelastic response to stresses. Parameters for this model are directly related to experimental observations. The possib...

PURPOSE To measure the effect of extension, flexion, lateral bending, and axial rotation loads applied to the spine on the anatomic relationship of the spinal nerves in the neural foramen to the ligamentum flavum and the intervertebral disk, anc to determine the effect of disk degeneration on the response to loading. METHODS Cadaveric lumbar motion segments were examined with CT and MR imagin...

In this research, softening and ratcheting behaviors of Ck20 alloy steel cylindrical shells were studied under displacement-control and force-control cyclic axial loading and the behavior of hysteresis curves of specimens was also investigated. Experimental tests were performed by a servo-hydraulic INSTRON 8802 machine. The mechanical properties of specimens were determined according to ASTM E8...

STUDY DESIGN For this study, 43 asymptomatic individuals underwent magnetic resonance imaging of the lumbar spine in both supine psoas-relaxed position and supine axial compression in extension. The change in dural cross-sectional area between positions at each disc level was calculated. OBJECTIVES To evaluate the effect of axial loading on asymptomatic individuals, as compared with the effec...