无托槽隐形矫治技术与固定矫治技术尖牙远中移动的有限元对比分析

目的通过对无托槽隐形矫治技术与固定矫治技术中远中移动尖牙过程的生物力学特点进行比较分析,深入探讨无托槽隐形矫治技术中牙齿移动的生物力学规律。方法建立下颌双侧第一前磨牙拔除的三维有限元模型,模拟无托槽隐形矫治器载荷和固定矫治器载荷,比较两种载荷作用下牙齿及牙周膜的平均主应力和Von Mises应力的变化,以及牙齿旋转中心的变化。结果模拟无托槽隐形矫治器载荷时下牙齿及牙周膜的平均主应力和Von Mises应力均小于固定矫治器载荷,同时,牙齿旋转中心更接近根尖。结论两种矫治技术均使尖牙产生倾斜移动,但使用无托槽隐形矫治技术尖牙的旋转中心更接近根尖,且应力分布更为合理。     

有关正畸牙移动力学作用的研究进展

正畸治疗通过对牙齿施加矫治力使牙齿移动.近年来,随着新材料新技术应用,正畸的加力方式在改变,正畸的治疗理念在改变.本文将矫治和矫形力学研究进展,以及新材料新技术包括自锁托槽、微种植体、手术辅助正畸和无托槽隐形矫治等影响矫治力学的研究进展作一综述.     

改良无托槽隐形矫治器压低过长磨牙辅助种植修复的临床研究

目的 评价应用改良无托槽隐形矫治器压低过长磨牙辅助种植修复治疗的有效性.方法 本研究包括25名种植修复前正畸患者,平均年龄39.2±10.1岁.样本人群总计41颗过长磨牙需正畸压低治疗,其中上颌第一磨牙21颗,上颌第二磨牙16颗,下颌第一磨牙1颗,下颌第二磨牙3颗.完善牙周治疗并达到健康牙周状况.所有患者均接受了无托槽数字化隐形矫治器(IROK隐形矫治系统,西安恒惠科技有限公司)治疗.为了使压低磨牙的力量有更好的贮存和释放形式,我们改良设计了无托槽隐形矫治器压低牙齿的结构形式.过长磨牙压低治疗前后分别拍摄头颅侧位定位片,并进行头影测量的分析比较.结果 25名患者的41颗过长磨牙均取得良好的正畸压低治疗效果,压低治疗的平均时间7.4±2.3个月.21颗过长上颌第一磨牙和16颗过长上颌第二磨牙,相对于腭平面,分别平均压低3.3 mm(P＜0.001)和2.8 mm(P＜0.001).相对于下颌平面,3颗过长下颌第二磨牙平均压低2.7mm,一颗过长下颌第一磨牙治疗后压低3.5 mm.磨牙压低治疗后未见明显根吸收.结论 应用改良无托槽数字化隐形矫治器压低过长磨牙,是一种有效的辅助种植修复的正畸治疗方法.     

无托槽隐形矫治技术在拔牙临界病例非拔牙治疗中的应用研究进展

正畸拔牙临界病例的治疗设计错综复杂,不同的矫治技术采用的设计方案有所不同。随着医疗新技术的不断发展,无托槽隐形矫治器得以推广,其移动牙齿的效能不断被证实。有专家提出无托槽隐形矫治技术相对于传统唇侧固定矫治技术在拔牙临界病例的非拔牙治疗中显示出优势。该文就无托槽隐形矫治技术三维方向移动牙齿的特点进行回顾与展望,总结分析此技术在拔牙临界病例非拔牙治疗设计中移动牙齿的优势,从而为正畸拔牙临界病例的治疗设计提供参考。     

舌向整体移位设计量对隐形矫治力影响的研究

目的 利用传感器芯片对不同移位设计量的隐形矫治器所产生的矫治力进行测量,探讨移位设计量对隐形矫治力及其衰减的影响,为临床正畸矫治设计提供参考.方法 选用厚度1.0mm的热压膜材料（Erkodent,德国）压制右上中切牙舌向移位设计量分别为0.2、0.3、0.4、0.5和0.6mm的隐形矫治器,利用隐形矫治微型测力系统测量矫治器产生的矫治力并观察其在2周内的衰减情况.结果 移位设计量为0.2、0.3、0.4、0.5、0.6mm的矫治器所产生的矫治力的平均值分别为8.047、9.250、10.189、11.821、12.247N.在矫治器戴入的最初8h矫治力衰减迅速,之后衰减缓慢直至第4天起矫治力维持在较为平稳的水平.结论 随矫治器移位设计量的增加,隐形矫治器产生的矫治力也相应增加.推荐上中切牙舌向整体移动的移位量设计不应超过0.5mm.患者在佩戴每副矫治器的最初4天应尽量全天佩戴.     

Invisalign矫治器牙齿移动效率的研究进展

无托槽隐形矫治器通过一系列透明的、可自行摘戴的透明塑料牙套来实现牙齿排齐,纠正错牙合畸形。但在矫治过程中,牙齿实际移位量与预期移位量间相比存在"滞后性",从而涉及矫治效率问题。本文就Invisalign矫治器在各种类型牙齿移动(伸长、压低、扭转、倾斜、扩弓、推磨牙向后等)中的效率进行综述,为临床医生选择合适的Invisalign病例以及设计无托槽隐形矫治方案提供指导。     

无托槽隐形矫治对非拔牙病例矫治疗效的临床研究

目的：应用美国正畸专科医师委员会OGS（Objective Grading System）客观评分系统,对无托槽隐形矫治器临床矫正效果进行评价。方法：选择60例20～25岁非拔牙矫治的错颌畸形患者,随机分成两组,实验组采用无托槽隐形矫治器,对照组采用自锁托槽矫治器。用ABO测量尺对矫治完成后的石膏牙模型和全景片分别进行测量,测量参数包括：牙齿排列整齐程度、邻牙边缘嵴高度差值、颊舌向倾斜度差值、矢状向咬合关系差值、咬合接触紧密度、覆盖异常程度、邻面接触紧密度及牙根成角。评分结果输入SPSS13．0统计软件包进行分析。结果：除上下后牙颊舌向倾斜角及咬合接触两项有统计学差异外,其余指标均无统计学差异。结论：无托槽隐形矫治器对错殆畸形非拔牙矫治病例临床矫治效果可达到自锁托槽矫治器矫治的效果。     

无托槽隐形矫治技术附件的临床粘结技巧

无托槽隐形矫治技术是近年来随着计算机技术、三维重建技术与工程制造技术的发展而出现的一种新型正畸矫治技术,为正畸医生提供了一种新的正畸理念和治疗手段[1-2]。在隐形矫治技术的临床应用中,附件的粘结是非常重要的环节和步骤,它直接影响到牙齿移动的效率和矫治目标的实现[3]。目前无托槽矫治技术的临床研究不断丰富,但有关粘结附件的临床操作技术未见文献报道。     

国产无托槽隐形矫治技术的临床应用初探

目的 将我国自主研发的无托槽隐形矫治技术应用于口腔正畸临床,探讨该矫治器的临床应用情况、存在的问题以及应用前景.方法 选取41例较简单的错(牙合)畸形患者,主要包括牙列间隙、牙列拥挤以及牙周病止畸治疗,应用国产无托槽隐形矫治技术进行正畸治疗.通过层析扫描建立数字化三维牙颌模型,通过激光快速成形技术加工无托槽隐形矫治器,根据治疗方案,为每例患者设计10～40副矫治器.患者每2～3周更换一副矫治器,矫治后评估疗效.结果 所有病例均完成矫治并取得良好的矫治效果,矫治后牙列排齐、无间隙、前牙覆(牙合)覆盖正常,矫治疗程6～25个月,平均18个月.结论 目前,国产无托槽隐形矫治技术仅町矫治相对简单的错(牙合)畸形,并以其透明、美观、舒适、卫生等优点,而具有良好的临床应用前景.     

国产无托槽隐形矫治技术的临床应用

目的:在临床应用国产无托槽隐形矫治技术,总结经验,使该技术更好地满足临床医生和患者的需求.方法:按照隐形矫治矫治技术的矫治特点选择10例病例进行隐形矫治.根据国产隐形矫治技术的临床应用矫治过程准备术前资料、制定矫治方案、计算机矫治过程模拟、制作隐形矫治器、佩戴并按时复诊.结果:所有病例治疗后均取得良好疗效,患者对矫治效果满意.治疗后牙列排列整齐.平均矫治疗程13.2个月.全口曲面断层片未见齿槽骨及牙根吸收.结论:无托槽隐形矫治技术具有美观,舒适,卫生及复诊次数少等特点,在合理选择适应症的条件下,能满足临床医生和患者的矫治需求.     

牙弓腭侧生理性肌力测量系统及测量方法的建立

目的 建立适应口腔实际环境的牙弓腭侧生理性肌力测量系统,探索肌力在固有口腔分布的测量方法。 方法 根据一名个别正常〖HT5”,7”SS〗牙〖KG-*3〗合成年女性口腔的尺寸定制厚仅0.1 mm的薄膜压阻式传感器,研制数据采集装置和PC端压力显示软件,组成测量系统,经标定和测试后用该系统对其口腔主要生理状态下上牙弓腭侧5个位点的肌力进行测量,并验证系统和方法的可行性。 结果 建立了适应口腔实际环境的牙弓腭侧生理性肌力测量系统,实现了主要生理状态下个体上牙弓腭侧肌力的测量,证实该系统和方法的操作一致性较好。 结论 新建立的牙弓腭侧生理性肌力测量系统适应口腔实际环境,测量方法具有一定的可行性, 应用前景良好。     

不同Ⅱ类牵引模式对无托槽隐形矫治磨牙远移作用的比较：三维有限元研究

目的:构建隐形矫治器上颌磨牙远移中两种Ⅱ类牵引的生物力学研究模型,分析矫治体系在不同加力模式、不同牵引力大小作用下的初始位移及应力分布特点,为该技术的临床应用提供参考。方法:建立隐形矫治推上颌磨牙向远中及两种Ⅱ类牵引模式(牙套加力组与牙齿加力组)的三维有限元模型,采用非线性有限元法分析2种不同加力方式及5种不同载荷(100 g、150 g、200 g、250 g、300 g)下的牙齿移动方式、牙套形变、牙周膜应力分布等,比较其增强前牙支抗效果的异同。结果:不同力值不同加力方法下所有组Ⅱ类牵引均可以使前牙内收,抵抗磨牙远中移动过程造成的前牙支抗丧失,但其牙齿应力分布、牙套形变效果不同：牙齿加力组集中在直接受力的尖牙上,分布不均匀;牙套加力组分布更均匀,随距尖牙距离由近到远逐渐减小,但总体大小较牙齿加力组大。牙周膜等效应力除300 g牙套加力组[(2.87×10 -2) MPa]过大外,其余各组均在牙周膜可承受范围内。 结论:100 g的Ⅱ类牵引即可抵抗磨牙远移反作用力造成的前牙支抗丧失,300 g牙套加力作用下的牙周膜受力过大,尽量避免使用。     

不同Ⅱ类牵引模式对无托槽隐形矫治磨牙远移作用的比较：三维有限元研究

目的:构建隐形矫治器上颌磨牙远移中两种Ⅱ类牵引的生物力学研究模型,分析矫治体系在不同加力模式、不同牵引力大小作用下的初始位移及应力分布特点,为该技术的临床应用提供参考。方法:建立隐形矫治推上颌磨牙向远中及两种Ⅱ类牵引模式(牙套加力组与牙齿加力组)的三维有限元模型,采用非线性有限元法分析2种不同加力方式及5种不同载荷(100 g、150 g、200 g、250 g、300 g)下的牙齿移动方式、牙套形变、牙周膜应力分布等,比较其增强前牙支抗效果的异同。结果:不同力值不同加力方法下所有组Ⅱ类牵引均可以使前牙内收,抵抗磨牙远中移动过程造成的前牙支抗丧失,但其牙齿应力分布、牙套形变效果不同：牙齿加力组集中在直接受力的尖牙上,分布不均匀;牙套加力组分布更均匀,随距尖牙距离由近到远逐渐减小,但总体大小较牙齿加力组大。牙周膜等效应力除300 g牙套加力组[(2.87×10 -2) MPa]过大外,其余各组均在牙周膜可承受范围内。 结论:100 g的Ⅱ类牵引即可抵抗磨牙远移反作用力造成的前牙支抗丧失,300 g牙套加力作用下的牙周膜受力过大,尽量避免使用。     

Initial force systems during bodily tooth movement with plastic aligners and composite attachments: A three-dimensional finite element analysis

Objective:To describe, using a three-dimensional finite element (FE) model, the initial force system generated during bodily movement of upper canines with plastic aligners with and without composite attachments.Materials and Methods:A CAD model of an upper right canine, its alveolar bone and periodontal ligament, thermoformed plastic aligner, and two light-cured composite attachments were constructed. A FE model was used to analyze the effects of imposing a distal movement condition of 0.15 mm on the aligner (simulating the mechanics used to produce a distal bodily movement) with and without composite attachments.Results:In terms of tension and compression stress distribution, without composite attachments a compression area in the cervical third of the distal root surface and a tension area in the apical third of the mesial surface were observed. With composite attachments, uniform compression areas in the distal root surface and uniform tension area in the mesial root surface were observed. Compression areas in the active surfaces of the composite attachments were also observed. In terms of movement patterns, an uncontrolled distal inclination, with rotation axis between the middle and cervical root thirds, was observed without composite attachment. Distal bodily movement (translation) was observed with composite attachment.Conclusions:In a three-dimensional FE analysis of a plastic aligner system biomechanically supplementary composite attachments generate the force system required to produce bodily tooth movement; the absence of biomechanically supplementary composite attachments favors the undesired inclination of the tooth during the translation movements.     

台阶式垂直闭合曲内收上颌切牙的三维有限元分析

目的 研究台阶式垂直闭合曲在三维空间内对上颌切牙位置的控制作用.方法 选择一名正常 志愿者,对其上颌牙列和牙槽骨进行三维螺旋CT扫描,只对上颌右侧中、侧切牙及牙槽骨进行建模和数据计算,利用Ansys软件生成右侧弓丝-托槽-上颌切牙段及牙周支持组织的三维有限元模型,最后根据镜像对称原理建立弓丝-托槽-上颌切牙段及牙周支持组织的三维有限元模型.模拟台阶式垂直闭合曲在临床上的使用情况加力,分析上颌切牙的位移趋势以及牙周支持组织中的应力分布规律.结果 台阶式垂直闭合曲作用下,上颌中切牙舌向、唇向最大位移分别为5.29×10-2和0.71×10-2 mm;龈向、向最大位移分别为10.47×10-3和10.20×10-3 mm;近中、远中最大位移分别为10.26×10-3和1.63×10-3 mm;侧切牙舌向、唇向最大位移分别为3.31×10-2和0.41×10-2 mm;龈向、向最大位移分别为10.52×10-3 和5.10×10-3 mm;近中、远中最大位移分别为6.29×10-3 和4.64×10-3 mm;二者均表现为舌向、龈向的近似整体移动趋势.中切牙牙齿、牙周膜、牙槽骨的最大应力值分别为31.35、2.52、4.64 MPa;侧切牙牙齿、牙周膜、牙槽骨的最大应力值分别为19.59、1.28、4.12 MPa;二者的应力分布规律相似,牙周膜对应力起缓冲作用.结论 台阶式垂直闭合曲在上颌切牙内收阶段可控制其在三维方向上的位置,对抗"钟摆效应",对临床实践具有一定参考意义.

Abstract：

Objective To investigate the displacement and stress distribution of upper incisors in three-dimensional(3D) space controlled by step-shaped vertical closing loop. Methods The maxillary teeth and alveolar bone of a volunteer with normal occlusion were scanned with 3D spiral CT. Modeling and calculation were only carried out on right upper central incisor, lateral incisor and their alveolar bone in order to simplify the procedures. A 3D finite element model of archwire-brackets-upper incisors and periodontal tissues was developed using Ansys finite element package. Finally, a 3D finite element model of archwire-brackets-upper incisors and periodontal tissues was established based on mirror symmetry principle. The displacement of maxillary incisors and stress distribution in periodontal tissues were analyzed. ResultsWhen step-shaped vertical closing loop was simply drew back 1 mm, the maximum displacement of upper central incisor in labial and lingual direction were 5.29×10-2 and 0.71×10-2 mm; 10.47×10-3 and 10.20×10-3 mm in gingival and occlusal direction, 10.26×10-3 and 1.63×10-3 mm in medial and distal direction; the maximum displacement of upper lateral incisor in labial and lingual direction were 3.31×10-2 and 0.41×10-2 mm, 10.52×10-3 and 5.10×10-3 mm in gingival and occlusal direction, 6.29×10-3 and 4.64×10-3 mm in medial and distal direction, the displacement trend of them were moving lingually and gingivally similar to bodily movement. The stress peach of upper central incisor, periodontal ligament and alveolar bone were 31.35, 2.52 and 4.64 MPa, the stress peach of upper lateral incisor, periodontal ligament and alveolar bone were 19.59, 1.28 and 4.12 Mpa, the stress distribution of them were similar and the periodontal ligament buffered the stress imposed on the tooth. Conclusions The position of upper incisors in 3D space could be controlled by step-shaped vertical closing loop and the pendulum effect could be confronted.     

Forces and moments delivered by the PET-G aligner to a maxillary central incisor for palatal tipping and intrusion

Objective:To evaluate the effect of material thickness and width of the gingival edge on the forces and moments delivered by aligners prepared from Duran foil (PET-G) to a maxillary incisor during tipping and intrusion.Materials and Methods:Aligners prepared from PET-G of three material thicknesses (0.5, 0.625, and 0.75 mm) and three widths of gingival edges (0–1, 3–4, and 6–7 mm) were investigated during incisor palatal tipping and intrusion of 0.5 mm each. Forces and moments were measured with a six-component measuring device. The influence of aligner thickness and aligner extend on the force and moment development were tested for statistical significance (P < .05).Results:The F_x and F_z forces produced during palatal tipping and intrusion by the 0.75-mm aligner material was significantly higher than those produced by the 0.5-mm-thick material (P = .005 and P = .047, respectively). There was no statistical difference between aligner thickness of 0.5 and 0.625 mm and between 0.625 and 0.75 mm. The same behavior was observed for the palatal moment (M_y). The F_x and F_z forces produced during palatal tipping and intrusion by the aligner with an extension of 0–1 mm edge was significantly lower than that of the aligner with a larger extension (3–4 mm edge: P = .003; 6–7 mm: P = .001). However, there was no statistical difference between aligners with a 3–4-mm and a 6-mm edge. The same behavior was observed for the palatal moment (M_y).Conclusions:The forces and moments exerted by the PET-G aligner on teeth vary, depending on the material thickness, width of the aligner edge, and direction of tooth movement.     

Forces and moments generated by aligner‐type appliances for orthodontic tooth movement: A systematic review and meta‐analysis

The aim of this review was to systematically appraise the evidence on aligner mechanics and forces and moments generated across difference types of aligners. In vitro‐ laboratory studies for model simulated tooth movement with aligners. Database searches within Medline via Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS via BIREME Virtual Health Library. Unpublished literature was also searched in Open Grey, ClinicalTrials.gov ( www.clinicaltrials.gov ), the National Research Register ( www.controlled-trials.com ) and Center for Open Science (Open Science Framework), using the terms “aligner” AND “orthodontic”. Risk of bias assessment was based on the Cochrane Risk of Bias tool. Random effects meta‐analyses were conducted. A total of 447 studies were identified through electronic search and after careful consideration of pre‐ defined eligibility criteria, 13 deemed eligible for inclusion, while 2 were included in the quantitative synthesis. When palatal tipping of the upper central incisor through PET‐G aligners was considered, aligner thickness of 0.5, 0.625 or 0.75 mm was not associated with a significantly different moment to force (M/F) ratio, given a common gingival edge width of 3‐4 mm. Aligner thickness does not appear to possess a significant role in forces and moments generated by clear aligners under specific settings, while the most commonly examined tooth movements are tipping and rotation. The findings of this review may be applicable to certain conditions in laboratory settings.     

基于牙弓形态大小发育的青少年隐形矫治

青少年牙弓形态大小的发育具有特定的规律，正常的牙弓形态大小是正常咬合发育的基础之一。全面深入地分析颅颌面的形态和结构，可完善青少年错牙合畸形的临床矫治方案。文章就牙弓形态大小对咬合关系影响的临床理论在错牙合畸形矫治中的应用，探讨青少年隐形矫治技术的特点，总结其应用的发展规律，拟更有效地开展青少年错牙合畸形的隐形矫治工作，推动青少年错牙合畸形早期阻断及综合矫治的发展，提高青少年错牙合畸形隐形矫治技术的水平。