【作者】 赵弘；

【导师】 刘洪臣； 顾晓明；

【作者基本信息】 中国人民解放军军医进修学院 ， 口腔正畸学， 2010， 博士

【摘要】 支抗控制一直是正畸医生在正畸临床中所面临的巨大挑战,支抗控制的优劣决定着正畸治疗是否成功。传统的方法包括口内、口外增强支抗两部分,口内增强支抗常发生支抗丢失,口外增强支抗需要依赖患者合作。传统支抗手段需要依赖患者合作,近年来牙种植体、微钛板、支抗种植钉等作为骨性支抗手段在口腔正畸中的应用逐渐增多,因为这些支抗手段不需要依赖患者合作,同时能获得理想的矫治效果。与牙种植体等骨性支抗相比,支抗种植钉显著的优点是：植入部位的选择较灵活,易于放置和取出、术后不适感较轻、价格低廉、不需等待骨整合、依靠骨面与钉体之间的机械嵌合可以即刻负载。支抗种植钉可用于内收前牙、压低磨牙、将磨牙向近中或远中移动、采用非手术手段矫治骨性开(?)、矫正(?)平面歪斜、可以移动整个牙列向同一方向、向近中或者远中等。支抗种植钉在某种程度上正在改变正畸治疗的矫治设计和矫治技术,它丰富了支抗的方法论,拓展了传统正畸治疗的适应证。但研究报道支抗种植钉技术在使用过程中成功率为70%～91%,为提高支抗种植钉的成功率,使其有效地发挥骨性支抗作用,了解与其稳定性相关的因素是十分重要的。本研究分为三个部分,第一部分为临床研究,选择错(?)患者48人(男性18例,女性30例,平均年龄23.2±6.5岁),植入微型种植钉的总数量为152枚,微型种植钉的负载期为10个月,分析影响微型种植钉成功率的因素。结论为：针对使用微型种植钉的患者,维持好的口腔卫生、对于骨皮质较薄的患者采取谨慎设计、防止微型种植钉周围组织肿胀,以提高微型种植钉植入的成功率。第二部分为基础研究,选取32名成年人(男16人,女16人,平均年龄30.1岁,年龄范围21-44岁),用CBCT评价上颌骨齿槽嵴的颊腭侧、下颌骨齿槽嵴颊侧骨皮质厚度、硬腭部骨质厚度,为临床医生选择合适的植入部位、植入术式提供引导,以期获得良好的初始稳定性,提高支抗种植钉的临床成功率。结论为：1.上下颌骨的骨皮质厚度无性别差异,左右侧对称,下颌骨的骨皮质厚度厚于上颌骨,上颌骨颊侧的骨皮质厚度厚于腭侧。2.下颌骨颊侧骨皮质最厚处位于下颌第一磨牙远中,上颌第一磨牙近中颊侧骨皮质最厚,上颌骨腭侧骨皮质最厚处位于上颌第一、第二双尖牙之间。3.男女硬腭部骨质厚度在位于腭中缝及邻近腭中缝的两侧有显著性差异。成人硬腭部骨质厚度从前向后逐渐递减。4.成人硬腭部骨质厚度最厚处位于腭中缝及硬腭水平部的外缘,而两者之间的骨质厚度较低。第三部分为基础研究,通过建立简单的颌骨及支抗种植钉的三维有限元模型,在不同的骨皮质厚度为0.5mm～3mm和不同的植入角度30°～90°下分别植入支抗种植钉(直径1.6mm、长8mm),探讨不同骨皮质厚度和不同植入角度对支抗种植钉应力分布的影响及位移变化。主要结论为：临床植入支抗种植钉时应该避开骨皮质较薄的区域,植入区域骨皮质厚度应≥1mm。避免过陡的植入角度,当植入角度为70°时支抗种植钉的位移最小,可获得较好的初始稳定性。更多还原

【Abstract】 Anchorage control, a major challenge faced by orthodontists at clinical practice, decides the success of orthodontic treatment. There have been many attempts to devise suitable anchorage methods, including intraoral and extraoral appliances. All intraoral appliances, however, show some lose of anchorage. Extraoral appliances do not provide reliable anchorage without patient compliance. While traditional means of anchorage control depends much on patients’cooperation, the treatment effect was influenced by how well patients cooperated when being treated. When using skeletal anchorage such as osseous dental implants, onplants miniplates, miniscrews, clicians can expect reliable anchorage without patient compliance. Compared with bone-borne anchorage like dental implants, miniplates, and onplants, miniscrews show their great distinction in the following aspects:small size, easy placement and removel, low cost, good access to various to various placement sites, minimal discomfort, and immediate loading with the mechanical interdigitation at the bone-minicrew interface. Miniscrews are used in anterior retraction, molar intrusion to correct an open-bite, controlling vertical dimension, molar distalization, molar protraction, and canting correction, or even moving the entire dentition in the same direction. Because they provide an excellent alternative to traditional compliance-dependent, miniscrews have expended the scope of the traditional orthodontic treatment. According to the literature, the success rates of the miniscrews under orthodontic loading vary between 70%-91%, the aims of this study were to evaluate the factors that affect the stability of miniscrews.This study was divided into three parts, in the first part of this study, Forty-eight malocclusional patients (18 males,30 females, mean age was 23.2±6.5 years old) with a total 152 miniscrews were examined. The miniscrew’s success rates during a 10-month period of force application were determined according to 11 clinical variables. The purpose of this study was to evaluate the success rates and find factors affecting the clinical success of miniscrew used as orthodontic anchorage.The conclusions were as follows:To improve the success rate of miniscrews, the thickness of buccal cortical bone in subjects with a high mandibuar plane angle should be examined carefully, good oral hygiene should be maintained, inflammation around the miniscrews must be controlled.In the second part of this study,32 nonorthodontic adults with nomal occlusion (16 males and 16 females, and their age ranged from 21 to 44 years with 30.1 years as the mean age) were used to investigate the cortical bone thickness by CBCT. Cortical bone thicknesses were measured at various sites in the buccal and palatal aspects of maxillary alveolar bone, in the buccal aspect of mandible alveolar bone, and in the hard palate. The purpose of this study was to provide guidelines for miniscrew placement to enhance the success rate of miniscrew. The conclusions were drawn as follo wings:1. This study found out that cortical bone thickness showed no significant difference between males and females and between the left and right sides in both maxilla and mandible, cortical bone thickness in the mandible is thicker than in the maxilla, buccal cortical bone thickness in the maxilla is thicker than cortical bone thickness in the palate side.2. The thickest site at buccal cortical bone in the mandible is mesial to the second molar. The thickest site of the buccal cortical bone in the maxilla is mesial to the first molar. The thickest site at palatal cortical bone in the maxilla is the site mesial to the second premolar.3. The bone thickness of the hard palate was found have significant differences between males and females at midsaggital suture and its proximity. It showed decreased gradually from anterior part to the posterior part.4. The thicknest bone of the hard palate was located at midsaggital suture and lateral border of the hard palate.In the three part of this study, the three dimensional element models of bone and miniscrew (1.6×8mm) were build up, they were designed with different cortical bone thickness from 0.5mm to 3mm and different insert angle from 30°to 90°(to the long axis of the tooth). The purpose of this study was to analyze the impact of cortical bone thickness and insert angle on primary stability of orthodontic miniscrews. The conclusions were as follows:To achieve the best primary stability, the miniscrew should place in an area with cortical bone thickness>lmm, an insertion angle 70°is advisable. Very oblique insertion angle (<30°) will result in reduced primary stability.更多还原