Search results for "cortical bone"
showing 10 items of 69 documents
Ameloblastic fibro-odontoma: A conservative surgical approach
2009
Ameloblastic fibro-odontoma (AFO) is a rare benign mixed odontogenic tumor that occurs predominantly in children and young adults with no gender predilection and anatomic site, usually appearing as a painless swelling. We present a case of an 11-year-old non-Caucasian boy complaining of large painless isolated swelling in the right mandibular body. Intraoral examination revealed a tumoral mass with cortical bone expansion, covered by normal mucosa measuring 4.0 x 2.0 cm, located on both the lingual and buccal surfaces of the right body of the mandible, with displacement of the neighboring teeth. Panoramic radiography revealed an expansile, radiolucent and well circumscribed lesion with scat…
Anatomic site evaluation of the palatal bone for temporary orthodontic anchorage devices.
2008
: Objectives: The aim of the present study was to assess the micromorphologic characteristics of the palatal bone from an implantologic standpoint. Materials and Methods: The material consisted of tissue blocks of autopsy material from 22 subjects (18 males, three females) between 18 and 63 years of age. The specimens comprised the anterior median palatal region from 5 to 10 mm behind the incisive foramen. They were prepared in the transversal plane according to ground thin-section technology. The midpalatal area as well as an area of 3 mm bilateral to the midline were assessed, and a classification of quantitative palatal bone availability was developed. Results: The findings could be divi…
Age-dependence of bone material quality shown by the measurement of frequency of resonance in the ulna
1994
In women before and after the age of peak bone mass, identical values of bone mineral density (BMD) can be obtained. However, there is a much higher incidence of osteoporotic fractures in older women. We investigated whether a deterioration of bone material quality with increasing age might contribute to this phenomenon. Material properties of bone tissue can be characterized by the modulus of elasticity, which is correlated to the square of sound transmission velocity. In this study, sound transmission velocity was determined in cortical bone by measuring the frequency of resonance in the ulna in the direction of the bone's longitudinal axis and correcting the values by multiplying by ulna…
The internal calcar septum and its contact with the virtual stem in THR: a computer tomographic evaluation.
2003
The internal calcar septum is a ridge of cortical bone protruding from the inner cortical wall of the proximal femur into the medullary canal. It extends from the lesser trochanter into the femoral neck and narrows the femoral cavity in its dorsal third. This region is essential for THR stability, but the degree of contact between the septum and standard THR implants has never been studied. We obtained CT scans of 50 arthrotic hip joints from patients requiring THR. Virtual stems (50 straight/wedge-shaped and 50 anatomic stems) were placed in CT images of the femora using a PC-based preoperative planning unit. The dimensions of the septum, degree and location of contact between the septum a…
Cortical bone thickening in Type A posterior atlas arch defects: experimental report.
2017
Abstract Background Context To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. Purpose To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. Study Design Micro-computed tomography (CT) study on cadaveric atlas vertebrae. Methods We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. Results The micro-CT study revealed significant differences in cortica…
LOAD SUPPORT OF FRC CYLINDERS UNDER COMPRESSION
2000
ABSTRACT The purpose of this research is to look for the optimum structure applied FRC for load support by considering the biomimetic design. For example, cortical bone is made of FRC structures for load support in living bones. Making a start of analysis, the osteon being an structural unit of cortical bone was modelled in filament-wound (FW) cylinder. The first approximation of cortical bone was represented by the densest arrangement of the cylinders to focus on compressive behaviour of osteons. E-glass/epoxy cylinders were applied to specimens. Static compression tests were carried out to evaluate these models. On the osteon model, the smaller ply angle to the longitudinal direction gave…
Architecture in cortical bone and ultrasound transmission velocity
1993
The square of ultrasound transmission velocity in a material is correlated to the modulus of elasticity, which is an indicator of its mechanical properties. This might make the measurement of ultrasound transmission velocity useful in the noninvasive diagnosis of bone diseases. Bone, however, is not an isotropic material but is architecturally structured. The aim of our study was to investigate and especially to quantify the influence of architecture in cortical bone on ultrasound transmission velocity. Twenty-two rectangular, flat specimens of cortical bone were prepared from diaphysis of fresh pig radius. Ultrasound transmission velocity was measured parallel and perpendicular to directio…
Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation
2010
Background Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component.Method Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm2) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry.Results 6 years postoperatively, cancellous BD had decreased by as much as 41%…
Effect of platform switching on the peri-implant bone: A finite element study
2015
Background: There exists a relation between the presence and location of the micro-gap and the loss of peri-implant bone. Several authors have shown that the treatments based on the use of platform switching result in less peri-implant bone loss and an increased tissue stability. The purpose of this study was to analyse the effect of the platform switching on the distribution of stresses on the peri-implant bone using the finite element method. Material and Methods: A realistic 3D full-mandible finite element model representing cortical bone and trabecular bone was used to study the distribution of the stress on the bone induced by an implant of diameter 4.1 mm. Two abutments were modelled.…
Atlases with Arcuate Foramen Present Cortical Bone Thickening That May Contribute to Lower Fracture Risk.
2018
To date, no information about the cortical bone microstructural properties in atlas vertebrae with arcuate foramen has been reported. As a result, we aimed to test in an experimental model if there is a cortical bone thickening in an atlas vertebra which has an arcuate foramen that may play a protective role against bone fracture.We analyzed by means of micro-computed tomography the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry atlas vertebrae with arcuate foramen and without arcuate foramen. We also reviewed a case series of 31 posterior atlas arch fractures to correlate the possible presence in t…