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PubMed2005

Embryogenesis of the rat telencephalon--a morphologic and stereologic analysis.

Comparative researches of borderline between telencephalon neuroepithelium and its surrounding mesenchyme in successive early developing stages lack in literature. The aim of this investigation was to carry out systematic morphologic and stereologic analyses of rat telencephalon in early developmental stages. We analysed semithin (1 microm) serial sections of rat embryonic brain from the 12th (E12) to the 15th (E15) day of gestation. The surface densities (SV) of an external mesenchymal surface, an internal mesenchymal surface and a neuroepithelial (ventricular) surface were examined stereologically and compared. The surface density of the external mesenchymal surface was the biggest at E12 (4,05 mm-1) and the least at E15 (1,87 mm-1)-p<0,0005. The surface density of the internal mesenchymal surface was the biggest at E12 (4,02 mm-1) and the least at E15 (2,69 mm-1)-p<0,0005. The surface density of the internal neuroepithelial surface was the biggest at E12 (3,31 mm-1) and the least at E15 (2,01 mm-1)-p<<0,0005. Our stereological examines give objective numerical proof of significant morphogenetic changes in telencephalon shape described by morphologic analyses. The major advantage of stereological methods is the possibility to carry out the estimation procedures in specified, well-defined brain regions or layers.

Animals↗
PubMed1989

The effectiveness of two sonic and two ultrasonic scaler tips in furcations.

This study compared the effectiveness of two sonic and two ultrasonic scaler tips on artificial calculus removal from the furcations of mandibular first and second molars. Twenty-four extracted mandibular molars were cleaned and randomly assigned to one of four treatment groups. Teeth were split buccal lingually, artificial calculus was placed in the furcation areas, and the teeth were photographed with a stereo camera. Teeth were reconnected with bonding material and mounted in a typodont with simulated gingiva and attached to a dental chair. Teeth were instrumented with either a Cavitron TFI10 tip, Cavitron EWPP tip, Titan-S Universal tip, or Titan-S Sickle tip by a licensed dental hygienist until each tooth was judged calculus free to the touch with a CH3 explorer. Time for each instrumentation period was recorded. Following instrumentation, the teeth were again split and photographed. Stereophotogrammetry was used to produce tracings of the teeth with initial calculus and remaining calculus. Pre-instrumentation and post-instrumentation amounts of calculus on the surface area were computed using the Bioquant system. A two factor analysis of variance was conducted followed with a Newman-Keuls Multiple Comparison Technique to test for within and between differences. Significant differences (P less than or equal to 0.01) were found between pre- and post-amounts of calculus for all tips. No significant differences (P less than or equal to 0.05) were found between the four instrument tips with respect to percentage of furcation surface with calculus remaining. No differences were found between tips with regard to the time required to clean the test surfaces.

Dental Calculus↗
PubMed1994

Migration of acetabular components, inserted with and without cement, in one-stage bilateral hip arthroplasty. A controlled, randomized study using roentgenstereophotogrammetric analysis.

Twenty-one patients who had primary osteoarthrosis were managed with a bilateral total hip arthroplasty with insertion of a Charnley femoral component. In each patient, one hip was randomly allocated to have a Harris-Galante acetabular component inserted without cement, and the contralateral hip was treated with an all-polyethylene Charnley acetabular component fixed with cement. The clinical result was satisfactory in all patients. All forty-two hips were followed, with respect to migration of the acetabular component, with use of roentgenstereophotogrammetric analysis for a median of twenty-seven months (range, twenty-three to forty-nine months). Each patient served as his or her own control. Maximum migration in any direction was 1.7 and 2.1 millimeters, and maximum rotation was 2.2 and 2.0 degrees for the Harris-Galante and Charnley acetabular components, respectively. There was no significant difference in migration between the two designs of acetabular components (p = 0.98, p = 0.75, and p = 0.06 for the transverse, longitudinal, and sagittal axes, respectively). However, the Harris-Galante acetabular components rotated significantly more than the Charnley acetabular components around two of the three axes (p = 0.008, p = 0.08, and p = 0.03 for the transverse, longitudinal, and sagittal axes, respectively). The Charnley hip implant has been used clinically for a long time, with successful results. Comparison of new designs of implants with the Charnley prosthesis is therefore important. Roentgenstereophotogrammetric analysis provides a potential for detection of problems with fixation at an early stage rather than after long-term follow-up. No major difference in terms of skeletal fixation was found between the two designs of components after short to medium-term follow-up.

Acetabulum↗
PubMed1994

Mechanical behavior of the human lumbar and lumbosacral spine as shown by three-dimensional load-displacement curves.

The lumbar region is a frequent site of spinal disorders, including low-back pain, and of spinal trauma. Clinical studies have established that abnormal intervertebral motions occur in some patients who have low-back pain. A knowledge of normal spinal movements, with all of the inherent complexities, is needed as a baseline. The present study documents the complete three-dimensional elastic physical properties of each lumbar intervertebral level from the level between the first and second lumbar vertebrae through the level between the fifth lumbar and first sacral vertebrae. Nine whole fresh-frozen human cadaveric lumbar-spine specimens were used. Pure moments of flexion-extension, bilateral axial torque, and bilateral lateral bending were applied, and three-dimensional intervertebral motions were determined with use of stereophotogrammetry. The motions were presented in the form of a set of six load-displacement curves, quantitating intervertebral rotations and translations. The curves were found to be non-linear, and the motions were coupled. The ranges of motion were found to compare favorably with reported values from in vivo studies.

Adult↗
PubMed1994

Micromotion of femoral stems in total hip arthroplasty. A randomized study of cemented, hydroxyapatite-coated, and porous-coated stems with roentgen stereophotogrammetric analysis.

The fixation of the femoral stem in a total hip arthroplasty was studied in sixty patients (sixty-four hips) with use of roentgen stereophotogrammetric analysis. The hips were randomly stratified on the basis of the age, sex, and weight of the patient; the roentgenographic quality of the bone; and the reason for the operation (primary or secondary osteoarthrosis). The hips were then randomly assigned to one of three types of fixation of the femoral component: insertion with cement, hydroxyapatite coating, or porous coating. Examinations with roentgen stereophotogrammetry were done as long as two years after the operation. Micromotion of the prostheses was evaluated in terms of subsidence or proximal migration and rotations and translations of the proximal-lateral (shoulder) and distal (tip) parts of the prostheses. The clinical results at the two-year follow-up evaluation did not differ significantly between the groups with regard to the Harris hip score or the pain score (p > 0.05 for both; Wilcoxon rank-sum test). There were small or no differences in rotations and micromotions of the shoulder and the tip of the prostheses. Increased subsidence of 0.1 to 0.2 millimeter was recorded for the cemented and the porous-coated prostheses (p = 0.002 and p = 0.02, respectively; Wilcoxon rank-sum test). Thus, proximal hydroxyapatite coating seems to enhance the early fixation of the stem. Conventional roentgenography revealed an increased number of radiodense lines surrounding the porous-coated prostheses. Distal hypertrophy of the femoral cortex was found mainly around the hydroxyapatite-coated prostheses. Proximal resorption of bone and heterotopic ossification occurred to approximately the same extent regardless of the type of fixation used.

Adult↗
PubMed1998

The effect of hydroxyapatite on the micromotion of total knee prostheses. A prospective, randomized, double-blind study.

A prospective, randomized, double-blind study was performed to evaluate three different means of fixing tibial components during total knee arthroplasty. Eleven components fixed with cement, ten hydroxyapatite-coated components fixed without cement, and ten noncoated components fixed without cement were studied. A posterior cruciate ligament-retaining total condylar implant was used. Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period. There were no significant differences among the patients with regard to age (mean [and standard deviation], 68 +/- 11.6 years), body-mass index (mean, 23 +/- 2.8 kilograms per square meter), or stage of osteoarthrosis (mean, 4 +/- 2.4 according to the classification system of Ahlback and 5 +/- 0.6 according to that of Larsen et al.). The diagnosis was osteoarthrosis in five knees, and it was rheumatoid arthritis in twenty-six. The clinical scores were similar among the study groups. According to the system of the Knee Society, the mean preoperative functional score was 10 +/- 2.9 points and the mean preoperative knee score was 24 +/- 3.2 points. At the two-year follow-up evaluation, these scores were 41 +/- 8.3 and 79 +/- 3.2 points, respectively. A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement (p < 0.001, analysis of variance). The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis (subsidence) throughout the follow-up period than did the noncoated components fixed without cement. At the two-year follow-up evaluation, the subsidence of the noncoated components was -0.73 +/- 0.924 millimeter, the subsidence of the cemented components was -0.05 +/- 0.109 millimeter, and the subsidence of the hydroxyapatite-coated components was -0.06 +/- 0.169 millimeter. The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis (p < 0.001, analysis of variance) and the sagittal axis (p < 0.001, analysis of variance) compared with the noncoated components. In conclusion, micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement. Therefore, hydroxyapatite, a biological mediator, may be necessary for the adequate fixation of tibial components when cement is not used.

Aged↗
PubMed1975

Computer-assisted thyroidal technetium uptake measurement using a short pinhole-to-surface distance.

The close pinhole view of the thyroid presents some important measurement problems. Possible errors due to gland, neck and set-up geometry are accentuated due to the effects of the inverse square law, and care is needed to control these. The nonuniform response inherent in the use of the pinhole collimator has a significant effect, but with computer processing this is readily eliminated. ENR subtraction may become difficult in certain circumstances, as insufficient "background areas" may be viewed, but it has been shown that the use of a "universal" (for the particular system) ENR subtraction may give, if anything, more accurate results. With these precautions in use, important errors will be of the same order of magnitude as those involved in more distant views, and may thus be kept within the realms of clinical significance. On the other hand, considerable improvements in both resolution and sensitivity make the use of the closer view an asset to both the research laboratory and the small department involved mainly in routine service work.

Computers↗
PubMed2007

Trunk inclination, pelvic tilt and pelvic rotation in relation to the craniofacial morphology in adults.

OBJECTIVE: To relate the differences in the posture of patients with different craniofacial morphologies. SUBJECTS AND METHODS: Fifty-three adult patients with Class II and III malformations were examined by cephalometric analysis and rasterstereography. The facial depth, maxillary position, mandibular plane angle, inner gonial angle, facial axis, and lower facial height were evaluated and classified into a basal distal-mesial group and a horizontal-vertical group by means of threshold parameters. Analyzing the results of the rasterstereography, the spine's lateral perpendicular deviation, the pelvic tilt, and the pelvic rotation were calculated by means of mathematical algorithms on the basis of the three-dimensional spine profile. To determine the statistically significant correlations between the studied parameters, the t-test was applied in groups with a normal distribution, and the Mann-Whitney U-test was used in the cases of abnormally distributed variables (significance level P < .05). RESULTS: Statistically significant differences (P < .05) in pelvic torsion were documented with respect to the facial axis and facial depth. Moreover, the differences (P < .05) between patients with a skeletal horizontal-vertical facial axis and patients with a basal distal-mesial position for the facial depth could be determined for the pelvic torsion. CONCLUSIONS: As a clinical consequence of the results, an extension of the interdisciplinary concepts within the sense of an orthopedic examination can be considered for patients undergoing a combined orthodontic-operative therapy.

Adult↗