Deng Yaqi, Sun Yannan, Xu Tianmin
Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, 100081, People's Republic of China.
BMC Oral Health. 2018 Jun 27;18(1):116. doi: 10.1186/s12903-018-0579-2.
Orthodontic treatment can result in root resorption (RR). Traditional two-dimensional (2D) data exhibit magnification, deformation and positioning problems. Cone beam computed tomography (CBCT) contains more accurate three-dimensional (3D) information. This study identified and qualified the extent and location of root resorption using cone beam computed tomography (CBCT) after comprehensive orthodontic treatment.
Studies comparing the RR before and after comprehensive orthodontic treatment using CBCT were identified using electronic searches of databases, including Cochrane, PubMed, EMBASE, China National Knowledge Infrastructure (CNKI) and Web of Science, and manual searches in relevant journals and the reference lists of the included studies until Oct 25, 2017. The extraction of data and the risk of bias evaluation were conducted by two investigators independently. The methodological quality of the included studies was assessed using the methodological index for non-randomized studies (MINORS). Studies that reported the length and volume of teeth were used for quantitative analyses.
Twelve studies were included in the meta-analysis. The length of all teeth after intervention was significantly shorter than that before treatment (MD = 0.80, 95% CI 0.56, 1.03, P < 0.00001). The sequence of RR from heaviest to lightest was maxillary lateral incisors, maxillary central incisors, mandibular anterior teeth, and maxillary canines. Studies were divided into two subgroups based on the use of tooth extraction. Root shortening after treatment was observed in both groups, and extraction caused more root resorption than was observed in the non-extraction group.
There were different degrees of root resorption after orthodontics, but it was clinically acceptable. Root resorption established in CBCT research was less serious and more accurate than that observed in the two-dimensional research. Current evidence suggests that root length and volume were reduced after orthodontic treatment. The order of the amount of RR was maxillary lateral incisors, maxillary central incisors and mandibular anterior teeth. Most of the articles were complicated by different confounding factors. Therefore, more high-quality clinical trials are needed to determine the risk factors of root resorption and optimal protocols for treatment and to draw more reliable conclusions.
正畸治疗可导致牙根吸收（RR）。传统的二维（2D）数据存在放大、变形和定位问题。锥形束计算机断层扫描（CBCT）包含更准确的三维（3D）信息。本研究使用锥形束计算机断层扫描（CBCT）确定并量化了综合正畸治疗后牙根吸收的程度和位置。
通过对包括Cochrane、PubMed、EMBASE、中国知网（CNKI）和科学网在内的数据库进行电子检索，并对手动检索相关期刊及纳入研究的参考文献列表，直至2017年10月25日，以识别使用CBCT比较综合正畸治疗前后RR的研究。数据提取和偏倚风险评估由两名研究人员独立进行。使用非随机研究方法学指标（MINORS）评估纳入研究的方法学质量。报告牙齿长度和体积的研究用于定量分析。
12项研究纳入荟萃分析。干预后所有牙齿的长度均显著短于治疗前（MD = 0.80，95%CI 0.56，1.03，P < 0.00001）。RR从最重到最轻的顺序为上颌侧切牙、上颌中切牙、下颌前牙和上颌尖牙。根据拔牙情况将研究分为两个亚组。两组治疗后均观察到牙根缩短，且拔牙组比非拔牙组引起更多的牙根吸收。
正畸治疗后存在不同程度的牙根吸收，但在临床上是可接受的。CBCT研究中确定的牙根吸收比二维研究中观察到的情况较轻且更准确。当前证据表明正畸治疗后牙根长度和体积减小。RR量的顺序为上颌侧切牙、上颌中切牙和下颌前牙。大多数文章受到不同混杂因素的影响。因此，需要更多高质量临床试验来确定牙根吸收的危险因素和最佳治疗方案，以得出更可靠结论。
