Browsing by Subject "Bone Density"

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    On the Relationship between Condylar Cortication and Mandibular Growth Activity
    (2021-07) Sharp, John
    Introduction: Mandibular growth prediction is central to orthodontics, yet little is known of the condylar bone density that accompanies this growth. Aims: To determine the bilateral symmetry of condylar cortical (CC), condylar trabecular (CT) and otic capsule (OC) grey values (GVs). To determine the relationship between condylar and OC GVs with age. To determine the relationship between three-dimensional mandibular growth and age. To determine the relationship between condylar cortication and mandibular growth activity. Methods: Mandibular growth rate was measured on CBCTs of orthodontically treated adolescents and young adults. OC, CC, and CT GVs were collected, and a bone density ratio calculated. Results: Significant differences exist in bilateral CC and OC GVs. CC, CT, and OC GVs significantly vary with age. Intercondylar width and mandibular growth rate significantly vary with age. Condylar cortication significantly predicts mandibular growth rate. Conclusions: A novel method to assess mandibular growth activity is introduced.
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    Volumetric bone mineral density and bone strength based on sport in elite female and male athletes.
    (2009-08) Bruininks, Brett Douglas
    Introduction: 1 in 2 women and 1 in 4 men will suffer from osteoporosis and/or osteoporotic fracture in their lifetime. Osteoporosis is a condition characterized by low bone mass and bone structural deterioration, which leads to a decrease in bone strength and an increase in fracture susceptibility. Physical activity is a critical element for building a strong skeletal structure and offsetting bone fragility in later life. Thus, there is interest in identifying activities that are osteogenic. Purpose: To investigate differences in bone mineral density (BMD) and bone strength in elite male and female athletes. Methods: A total 160 elite collegiate (18-25 years) ice hockey (male=19, female=21), swimming (male=13, female=17), soccer (female=15), and running (male=19, female=22) athletes and non-active controls (male=15, female=19) were studied. Areal (aBMD) and volumetric (vBMD) bone mineral densities and bone strength were assessed via dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Results: Part 1: Females in the weight-bearing sports, soccer and ice hockey, were associated with the highest adjusted total body and lumbar spine aBMD compared to swimmers and controls. At the distal tibia, the soccer group demonstrated significantly greater trabecular vBMD and bone strength index compared to all other groups. At the distal radius, ice hockey players were associated with greater bone strength index compared to swimmers and controls. There were no differences between the soccer and ice hockey groups in any of the tibia measurements. Part 2: Gender differences were found in relation to bone strength of the tibia between elite male and female athletes. Males in weight-bearing sports (ice hockey and running) had greater section modulus, strength strain index at the tibial shaft and tibial mid-shaft compared to their female counterparts. No differences were evident between males and females of the nonweight bearing swimming group. Summary: Weight-bearing sports such as hockey, soccer, and running are beneficial activities to enhance bone mass and strength in males and females. In these populations, skeletal adaptations appear to be influenced by their loading environment. However, in the weight-bearing sports, males had greater bone strength at all sites compared to females. This is congruent with findings from the general non-active population. Even after adjustments the differences existed. Strength differences may help explain the discrepancies in fracture rates between males and females.