Kulshrestha Rohit S, Tandon Ragni, Chandra Pratik
Department of Orthodontics, Saraswati Dental College, Lucknow, Uttar Pradesh, India.
J Orthod Sci. 2015 Jan-Mar;4(1):1-8. doi: 10.4103/2278-0203.149608.
Canine retraction is a very important step in treatment of patients with crowding, or first premolar extraction cases. In severe crowding cases until, the canines have been distilized to relive the crowding, space to correctly align the incisors will not be available. Correct positioning of the canines after retraction is of great importance for the function, stability, and esthetics. The aim of this systematic review was to examine, in an evidence-based way, which kinds of canine retraction methods/techniques are most effective and which have the least side effects. A literature survey was performed by applying the Medline Database (Entrez PubMed) and Science Direct database covering the period from 1985 to 2014, to find out efficient ways to accomplish canine retraction. Randomized controlled trials (RCTs), prospective and retrospective controlled studies, and clinical trials were included. Two reviewers selected and extracted the data independently and assessed the quality of the retrieved studies. The search strategy resulted in 324 articles, of which 22 met the inclusion criteria. Due to the vast heterogeneity in study methods, the scientific evidence was too weak to evaluate retraction efficiency during space closure. The data so far reviewed proved that elastomeric power chains, elastic threads, magnets, NiTi coil springs, corticotomies, distraction osteogenesis, and laser therapy, all are able to provide optimum rate of tooth movements. All the methods were nearly similar to each other for retraction of canines Most of the techniques lead to anchorage loss in various amounts depending on the methods used. Most of the studies had serious problems with small sample size, confounding factors, lack of method error analysis, and no blinding in measurements. To obtain reliable scientific evidence, controlled RCT's with sufficient sample sizes are needed to determine which method/technique is the most effective in the respective retraction situation. Further studies should also consider patient acceptance and cost analysis as well as implants and minor surgeries for canine retraction.
犬齿后移是治疗牙列拥挤患者或拔除第一前磨牙病例的一个非常重要的步骤。在严重牙列拥挤病例中，直到犬齿被远中移动以解除拥挤，才会有空间来正确排齐切牙。犬齿后移后的正确定位对功能、稳定性和美观非常重要。本系统评价的目的是以循证医学的方式研究哪种犬齿后移方法/技术最有效且副作用最小。通过应用1985年至2014年期间的Medline数据库（Entrez PubMed）和ScienceDirect数据库进行文献检索，以找出实现犬齿后移的有效方法。纳入随机对照试验（RCT）、前瞻性和回顾性对照研究以及临床试验。两名评价者独立选择和提取数据，并评估检索到的研究的质量。检索策略共得到324篇文章，其中22篇符合纳入标准。由于研究方法存在巨大异质性，科学证据太薄弱，无法评估间隙关闭期间的后移效率。目前所回顾的数据证明，弹力链、弹力线、磁铁、镍钛螺旋弹簧、皮质切开术、牵张成骨术和激光治疗，都能够提供最佳的牙齿移动速率。所有方法在犬齿后移方面彼此几乎相似。大多数技术会根据所使用的方法导致不同程度的支抗丧失。大多数研究存在样本量小、混杂因素、缺乏方法误差分析以及测量未设盲等严重问题。为了获得可靠的科学证据，需要有足够样本量的对照RCT来确定在各自的后移情况下哪种方法/技术最有效。进一步的研究还应考虑患者的接受程度和成本分析，以及用于犬齿后移的种植体和小型手术。
