Biomedical subjects

Michael K Shrout

Publications and source records attributed to Michael K Shrout.

4 recordsLinked to original sources

PubMed2004

An evaluation of the origin of trabecular bone patterns using visual and digital image analysis.

OBJECTIVE: The purpose of this research project was to investigate the origin of the anatomical structures interpreted as trabecula bone on dental radiographic images. STUDY DESIGN: Mandible sections were cut sagitally into halves. Trabecular bone was removed from each section in 4 stages. Following each stage, standardized radiographs were made, using CDR direct digital equipment. Trabecular bone in the resulting digital images was measured with 4 methods: (1) mean gray level; (2) the fractal dimension of the basic images; and, following morphological image processing, (3) counting the number of trabecular ends, intercepts, and segments (EIS) and (4) performing fractal analyses of the skeletonized images. Additionally, human visual interpretation of the collected images was conducted through a written examination. Repeated measures analysis of variance (ANOVA) was used to test for changes in measurements attributable to bone removal. RESULTS: Repeated measures ANOVA indicated that the use of gray levels, fractal dimension, and morphologic operations quantifying using EIS or fractal analysis had similar performance and resulted in significant changes in measurements following bone removal ( P < .05). Visual differences were not always apparent between each stage of bone reduction. Radiometric and morphologic analysis showed measurable differences between stages. CONCLUSIONS: These results imply that the inner trabecula, the junctional trabecula, and the actual cortical housing all contribute to some extent to the radiograph, although changes in the radiographic architecture are not always clinically detectible.

Absorptiometry, Photon↗

PubMed2003

Digital image analysis of cadaver mandibular trabecular bone patterns.

BACKGROUND: The purpose of this study was to investigate the source of radiographic trabecular patterns by removing trabecular bone in four sequential steps from six cadaver mandible sections, radiographing the sections after each removal, and using four digital-image analysis methods to quantify any resulting changes to the radiographs. METHODS: Mandible sections were cut sagittally into halves. Trabecular bone was removed from each section in four stages. Following each stage, standardized radiographs were taken, using direct digital equipment. Trabecular bone in the resulting digital images was measured with four methods. Mean gray level values (method 1) and cumulative percent histograms (method 2) were calculated from the raw data. Morphological image processing was used to skeletonize the trabecular structure, which was quantified by counting the number of trabecular ends and segments in the skeletonized images (method 3) and performing fractal analyses of the skeletonized images (method 4). Repeated measures analysis of variance (ANOVA) was used to test for changes in measurements attributable to bone removal. RESULTS: Repeated measures ANOVA indicated that the use of gray levels, cumulative percent histograms, and morphologic operators resulted in highly significant changes in measurements following bone removal (P < 0.01). Ends and segments demonstrated similar performance, with changes highly significant over time (P < 0.01). Fractal analysis also resulted in highly significant changes over time (P < 0.01). CONCLUSIONS: The analyses performed in this study demonstrated consistent image differences following the four steps of bone removal. These differences appeared whether light, cancellous bone or heavier endosteal bone was removed. These findings indicate that trabecular and endosteal bone combine to form the structure that most dentists identify as trabeculae on intraoral radiographs.

Analysis of Variance↗

PubMed2002

The pattern of alveolar crest height change in healthy postmenopausal women after 3 years of hormone/estrogen replacement therapy.

BACKGROUND: The loss of ovarian function at menopause is associated with loss of postcranial and oral bone. Hormone/estrogen replacement therapy (HRT/ERT) has a positive effect on both postcranial and oral bone. The objective of the study was to determine if the positive effect of HRT/ERT on alveolar crest height (ACH) is generalized or site specific. METHODS: The sample consisted of 49 women who completed a 3-year, HRT/ERT prospective study. Cemento-enamel junction distances (ACH) were measured on digitized images of bitewing radiographs. Lumbar spine and proximal femur bone mineral densities (BMDs) were determined with dual-energy x-ray absorptiometric scans. Measurements were made at baseline and at the end of year 3. For the 3-year study period, mean change in ACH was determined for each patient. In addition, the sites with the greatest, second and third greatest ACH changes were determined for each patient. Correlations between changes in ACH (as determined by the various methods) and postcranial BMD were determined. RESULTS: Mean ACH changes had an average correlation (r) of -0.24 with femoral and lumbar spine BMDs. Although the largest site-specific change in ACH resulted in a mean correlation of -0.21, the correlations for the second and third largest changes in ACH dropped to -0.15 and -0.12. Overall, the correlations for site-specific changes were substantively smaller than those for generalized change. CONCLUSIONS: The data of this study indicate that ACH change attributable to HRT/ERT is generalized rather than site specific. Studies of the effect of HRT/ERT on ACH should employ multiple measurements to minimize measurement errors associated with site-specific measurements.

Absorptiometry, Photon↗

PubMed2002

Treatment planning processes in dental schools.

Treatment planning is a critical aspect of clinical education in the dental school curriculum. It is surprising, therefore, that so little attention has been given to this subject in the dental literature. The importance of treatment planning is reinforced in the standards and the tests that clearly present methods and necessity for treatment planning. However, there is minimal evidence about how these treatment planning courses have been evaluated, how they were incorporated into the curriculum, or how they have been integrated into treatment planning in the academic clinical setting. The purpose of this study was to survey and profile current treatment planning processes in U.S. dental schools. A questionnaire consisting of twenty-nine items relating to treatment plan preparation, process, and outcomes was mailed to fifty-four U.S. dental schools. The primary topics included patient assignments, treatment planning, plan sequencing, plan presentation, informed consent, and plan modifications. Forty-seven of the fifty-four U.S. dental schools (87 percent) completed and returned the surveys. Profiling the treatment planning process in dental schools reveals many similarities. Typically, the schools screen patients prior to assignment to students and expect the student diagnostician to complete the planning process as well as comprehensive care. The patient's welfare is the primary determinant of the content of the plan in 92 percent of U.S. dental schools. Secondly, though current accreditation standards are concentrated on competencies, the treatment plans are influenced by quantitative requirements. Third, the plan is usually completed during the second patient visit after screening. Fourth, the approaches vary among the schools when a multidisciplinary or complex treatment plan is appropriate. Some depend on a panel of experts, whereas others do not have interactive planning with specialists. A significant number of schools decentralize treatment planning and delegate part of the plan to disciplines or group practice leaders. Fifth, the treatment plans and treatment risks are presented in accordance with the intent of the accreditation guidelines; however, fewer than half the schools explain the risk of procedures to patients at the time of plan presentation. Finally, plans change frequently, but the modifications are generally considered to be minor.

Academic Medical Centers↗