Yan Bin, Sun Zongyang, Fields Henry, Wang Lin
School of Computer Science and Engineering, Southeast University, Nanjing, China and Department of Orthodontics, Institute of Stomatology, Nanjing Medical University, Nanjing, China.
Division of Orthodontics, College of Dentistry, Ohio State University, Columbus, USA.
Orthod Fr. 2015 Jun;86(2):169-79. doi: 10.1051/orthodfr/2015014. Epub 2015 Jun 26.
Our objectives were to investigate the prevalence, resorption location and extent, and potential risk factors for impacted canine-associated root resorption (ICARR) in Chinese patients, who, unlike white patients, have predominantly buccal maxillary canine impactions.
Pretreatment cone-beam computed tomography scans of 170 Chinese subjects (ages, 12-30 years; mean, 14.5 years) with impacted maxillary canines (101 buccal and 69 palatal impactions) and 170 age- and sex-matched subjects without impactions were used. All cone-beam computed tomography records were evaluated in software programs by 1 rater. The prevalence, location, and extent of ICARR at the maxillary lateral incisor, central incisor, and first premolar were analyzed. To identify risk factors for ICARR, the subjects with impacted canine were divided into 2 groups (with and without root resorption). Measurements of 10 variables were individually compared between the groups and then tested together by using binary logistic regressions for each tooth.
Compared with the control subjects and the side of nonimpaction, root resorption was significantly more prevalent in the canine-impaction subjects and the side of impaction (P\0.01), with overall prevalence rates of 27%, 18% and 10% at the maxillary lateral incisor, the central incisor, and the first premolar, respectively. Predominantly affecting the apical third of all teeth, ICARR, if present, reached the pulp of the maxillary lateral incisor, the central incisor, and the first premolar at rates of 36%, 57%, and 0%, respectively. Individually, variables reflecting the proximity to the impacted maxillary canine had different measurements (P\0.05) between the impaction sites (maxillary quadrants) with and without root resorption for each tooth, whereas the canine development stage factor was only significant for the maxillary central and lateral incisors. No significant difference of ICARR prevalence was found between subjects with buccal and palatal impactions. Combined, the contact relationship was the dominant predictor for ICARR at all teeth, with "in contact" (\1 mm separation) having the largest and most significant increase of root resorption likelihood compared with "out of contact" ($1 mm separation); odds ratios were 9.9, 3.7 and 5.9 for the maxillary lateral incisor, the central incisor, and the first premolar, respectively.
Maxillary canine impaction increases the risk of root resorption at adjacent teeth (incisors and first premolars). Physical proximity (\1 mm) between the impacted canine and an adjacent root is the most important predictor for root resorption, and this characteristic is largely similar in Chinese patients to that in white people.
我们的目的是调查中国患者中与阻生尖牙相关的牙根吸收（ICARR）的患病率、吸收位置和程度以及潜在风险因素。与白人患者不同，中国患者的上颌尖牙阻生主要为颊侧阻生。
使用170名中国受试者（年龄12 - 30岁，平均14.5岁）的上颌阻生尖牙（101例颊侧阻生和69例腭侧阻生）的治疗前锥形束计算机断层扫描（CBCT）图像，以及170名年龄和性别匹配的无牙阻生受试者的CBCT图像。所有CBCT记录由1名评估者在软件程序中进行评估。分析上颌侧切牙、中切牙和第一前磨牙处ICARR的患病率、位置和程度。为了确定ICARR的风险因素，将阻生尖牙的受试者分为两组（有牙根吸收和无牙根吸收）。对10个变量的测量值在两组之间进行单独比较，然后通过对每颗牙齿进行二元逻辑回归分析进行综合检验。
与对照组和未阻生侧相比，阻生尖牙受试者及阻生侧的牙根吸收明显更普遍（P<0.01），在上颌侧切牙、中切牙和第一前磨牙处的总体患病率分别为27%、18%和10%。ICARR主要影响所有牙齿的根尖三分之一，若存在，其累及上颌侧切牙、中切牙和第一前磨牙牙髓的比例分别为36%、57%和0%。对于每颗牙齿，反映与上颌阻生尖牙接近程度的各个变量在有牙根吸收和无牙根吸收的阻生部位（上颌象限）之间有不同的测量值（P<0.05），而尖牙发育阶段因素仅对上颌中切牙和侧切牙有显著影响。颊侧阻生和腭侧阻生的受试者之间ICARR患病率无显著差异。综合来看，接触关系是所有牙齿ICARR的主要预测因素，与“不接触”（间隙≥1mm）相比，“接触”（间隙<1mm）时牙根吸收可能性的增加最大且最显著；上颌侧切牙、中切牙和第一前磨牙的优势比分别为9.9、3.7和5.
