Evaluation of Canine Retraction Strategies

描述(申请人提供)：这个跨学科(数值工程建模、台式和临床实验)项目的长期目标是提高正畸治疗的可预测性。可预见性将减少医源性副作用、必要的纠正、就诊和治疗时间--所有这些都有利于临床医生和患者。这项拟议的研究集中于两种最常用的治疗策略(平移和倾斜加牙根矫正)，这是一种常见的临床程序。三维(3D)临床正畸负荷系统将被控制；基于牙齿移动理论的临床结果将被预测；治疗时间、牙齿移动和牙根吸收方面的实际临床结果将使用新开发的技术进行量化。将监测局部炎症和骨质量所反映的生物反应。此外，还将评估基因分型对临床结果的影响。主要目的是(1)通过比较治疗时间和伴随的副作用来定量评估两种常用的、但在哲学上不同的正畸加载方式，以及(2)确定生物学因素对临床结果的作用。假设是：(H-1)直接翻译路径(策略1)比间接模式(策略2)需要更少的治疗时间；(H-2)策略1产生更低的应力集中；(H-3)更低应力集中的策略将减少与压力相关的副作用，如牙根吸收和炎症反应；以及(H-4)IL-12等位基因对两种策略的治疗时间的影响相似，因此与两种治疗机制的差异相比，作用不显著。具体目标(SA)是：SA-1使用我们以前开发的正畸力测试仪(OFT)来表征和量化治疗策略的机制。SA-2根据临床印模模型和康伯束CT(CBCT)图像评估的3D牙齿位移来量化临床结果。SA-3直接将治疗策略机制与临床结果联系起来。SA-4开发了一种使用CBCT数据量化正畸相关的牙根吸收和牙齿形态的方法。SA-5计算骨、牙髓和牙根的力学环境，并确定牙齿阻力中心的位置。SA-6使用校准的正畸加载系统治疗患者，并量化由此产生的牙齿位移和生物反应。这项研究的结果将为哪种策略更优越提供明确的证据。它们还将提供对减少医源性副作用的方法的洞察，以及为优化治疗而进行必要的循证权衡。有了这些知识，未来的正畸用具将被设计成减少副作用和治疗时间。此外，这些结果将为优化其他正畸治疗的创新机制提供基础。 公共卫生相关性：该项目将对同一患者的两种常用治疗策略进行临床评估。治疗时间和副作用，包括牙根吸收，都将被量化。这个项目的相关性在于，它将在临床上确定更好的策略和改进方向。

DESCRIPTION (provided by applicant): The long-term goal of this interdisciplinary (numerical engineering modeling, bench-top and clinical experiments) project is to improve the predictability of orthodontic treatment. Predictability will produce reductions in iatrogenic side effects, needed corrections, office visits, and treatment time - all to benefit clinician and patient. The proposed study focuses on the two most used treatment strategies (translation vs. tipping with root correction) for canine retraction, a frequent clinical procedure. The three dimensional (3D) clinical orthodontic load systems will be controlled; the clinical outcomes based on tooth movement theory will be predicted; and the actual clinical outcomes in terms of treatment time, tooth movement, and root resorption will be quantified using newly developed technologies. Biological responses as reflected by local inflammation and bone quality will be monitored. Furthermore, the effect of genotype on clinical outcomes will also be evaluated. The main objectives are to (1) quantitatively evaluate two commonly used, but philosophically divergent, well-controlled orthodontic loading modalities by comparing treatment times and their attendant side effects, and (2) identify the roles of biological factors on the clinical outcomes. The hypotheses are: (H-1) the direct translation path (Strategy 1) needs less treatment time than the indirect pattern (Strategy 2); (H-2) Strategy 1 produces lower stress concentrations; (H-3) the strategy with the lower stress concentration will produce reduced stress-related side effects such as root resorption and inflammatory responses; and (H-4) IL- 12 Allele affects the treatment time of both strategies in a similar way, thus playing an insignificant role in comparison to the differences in the two treatment mechanics. The specific aims (SA) are: SA-1 Characterize and quantify the mechanics of the treatment strategies using our previously developed orthodontic force tester (OFT). SA-2 Quantify the clinical outcomes in terms of 3D tooth displacements assessed from casts of clinical impressions and Conebeam CT (CBCT) images. SA-3 Directly associate treatment strategy mechanics with the clinical outcome. SA-4 Develop a method to quantify orthodontics-associated root resorption and tooth morphology using CBCT data. SA-5 Calculate the mechanical environment in bone, PDL, and root and determine the location of the tooth's center of resistance. SA-6 Treat patients with calibrated orthodontic load systems and quantify the resulting tooth displacements and biological responses. The outcomes of this study will provide clear evidence as to which strategy is superior. They will also provide insight into ways of reducing iatrogenic side effects and into the necessary evidence-based trade-offs for optimized treatment. With the knowledge gained, future orthodontic appliances will be designed to reduce side effects and treatment time. Furthermore, these results will provide a foundation for innovative mechanics that optimize other orthodontic treatments. PUBLIC HEALTH RELEVANCE: The project will clinically evaluate two commonly used treatment strategies on the same patient. Both treatment time and side effects including root resorption will be quantified. The relevance of this project is that it will clinically identify the superior strategy and the directions for improvement.