EFFECT OF MANDIBULAR POSITION ON CRANIOSKELETAL GROWTH

目标是在这种快速生长的哺乳动物身上开发一种动物模型， 这只兔子正在适应下颌骨的内侧移位 休息的姿势。其目的是确定不对称的影响 休息位置对颅骨和下颌骨生长的影响 这一系统的重塑以及与之互补的变化 神经肌肉系统。下颌骨的静止姿势将会改变 通过将类似的磁极磁铁放置在 下颌和上颌门牙产生一致的侧移。 第一个具体目标将决定改变 下颌骨静止位置对等高线内骨密度的影响 头骨。颅骨变化将通过研究骨骼来确定 用计算机断层扫描评估密度分布，其中 骨骼的密度轮廓被图形化地勾勒和量化， 在计算机断层扫描中测量的密度参数分布 显示数字(CT)，并重新格式化轴向切片以进行比较 左右两边。第二个具体目标将决定效果 改变下颌静止姿势对这一生长模式的影响 快速生长的哺乳动物。将确定增长模式 通过数字化和测量角度和长度的变化来进行射线摄影 解剖部位和金属植入标记的侧方和 头颅后正位片。这种方法将需要建立 金属种植技术与下颌上颌骨的评估 变化的技术类似于以前在灵长类动物中使用的技术。 第三个具体目标将决定改变 下颌静息姿势对静息肌电水平和咀嚼的影响 颞肌、翼骨内侧、外侧和咬肌的形态 肌肉。将细丝电极放置在下颌肌内 那只清醒的、被轻轻束缚住的兔子。计算机的统计分析 断层扫描、头影测量和肌肉活动数据将由 将给定侧的相同测量值在控件和 实验动物，以及评估测量中的变化 在生长的早期阶段。

The objective is to develop an animal model in the rapidly growing mammal, the rabbit, which is adapting to a mediolateral shift in the mandibular resting posture. The purpose is to determine the effect of the asymmetric rest position on the growth of the cranioskeleton and mandible, the remodeling of this system and the complementary changes in the neuromuscular system. The resting posture of the mandible will be altered mediolaterally by placing similar pole magnets at inclines on the mandibular and maxillary incisors to produce a consistent lateral shift. The first specific aim will determine the effects of changing the mandibular resting position on the contour of bone density within the cranioskeleton. Cranioskeletal changes will be determined by studying bone density distributions assessed with computed tomography in which the density contour of the bone is graphically outlined and quantified, the distribution of density parameters as measured in computed tomography numbers (CT) is displayed and the axial slices are reformatted to compare left and right sides. The second specific aim will determine the effects of changing mandibular resting posture on the growth patterns of this rapidly growing mammal. Growth patterns will be determined radiographically by digitizing and measuring changes in angles and lengths of anatomical sites and metal implanted markers from lateral and postero-anterior cephalograms. This approach will require establishing the techniques of metal implants and assessing mandibular and maxillary changes with techniques similar to those previously used in the primate. The third specific aim will determine the effect of changing the mandibular resting posture on the resting EMG level and the masticatory patterns of the temporalis, medial and lateral pterygoids and masseter muscles. Fine wire electrodes will be placed in the mandibular muscles of the awake, gently restrained rabbit. Statistical analyses of the computer tomography, cephalometric and muscle activity data will be carried out by comparing the same measurement for a given side between the control and experimental animals, as well as evaluating the change in the measurement during the early growth period.