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Abstract：
BACKGROUND: This 20-year retrospective study aimed to evaluate the treatment methods used in patients with impacted maxillary permanent canines and to determine the occurrence of ankylotic and resorptive processes and their association with potential risk factors.
METHODS: The cohort consisted of 351 consecutive Caucasian patients (120 males and 231 females, mean age 18.4 and 19.9 years, respectively) with 420 impacted maxillary permanent canines. CT and CBCT findings were subsequently confirmed during surgery. Statistical analyses were performed by the generalized linear models, Pearson x2 and Fisher exact tests using the statistical programs R and Statistica v. 14.
RESULTS: A total of 273 (65.0%) impacted canines were aligned in the dental arch by orthodontic traction after surgical exposure, this treatment was predominant in patients under 20 years of age. Surgical extraction was performed in 115 (27.2%) impacted canines and was more common in older patients. Ankylotic changes were recorded in 61 (14.5%) impacted canines. The probability of ankylosis increased with age, particularly after the patient\'s 20th year of life (p < 0.001). Patients were 1.2% likely to develop ankylosis at age 15 years, 4.3% at age 20 years, 14.1% at age 25 years, and 96.8% at age 45 years. Invasive cervical root resorption (ICRR) was found in 8 (1.9%) canines. In 4 canines (1.0%), root ankylosis in addition to ICRR was observed. In contrast to ankylosis, whose frequency of occurrence increased with age, the occurrence of ICRR resulting from PDL damage during surgery was more typical in younger patients. Canines in a high position above the root apices of the adjacent teeth, with a horizontal inclination of the longitudinal axis, with the crown located deep in the center of the alveolar bone and with labiopalatal position, should be considered critically impacted canines with a high risk to failure of orthodontic traction.
CONCLUSIONS: In conclusion, the treatment of impacted canines depends mainly on the age of the patient, and the position and inclination of the longitudinal axis of the impacted tooth. To select an adequate treatment method, we recommend CBCT examination, which allows a precise analysis of the position of impacted canines.
METHODS: The cohort consisted of 351 consecutive Caucasian patients (120 males and 231 females, mean age 18.4 and 19.9 years, respectively) with 420 impacted maxillary permanent canines. CT and CBCT findings were subsequently confirmed during surgery. Statistical analyses were performed by the generalized linear models, Pearson x2 and Fisher exact tests using the statistical programs R and Statistica v. 14.
RESULTS: A total of 273 (65.0%) impacted canines were aligned in the dental arch by orthodontic traction after surgical exposure, this treatment was predominant in patients under 20 years of age. Surgical extraction was performed in 115 (27.2%) impacted canines and was more common in older patients. Ankylotic changes were recorded in 61 (14.5%) impacted canines. The probability of ankylosis increased with age, particularly after the patient\'s 20th year of life (p < 0.001). Patients were 1.2% likely to develop ankylosis at age 15 years, 4.3% at age 20 years, 14.1% at age 25 years, and 96.8% at age 45 years. Invasive cervical root resorption (ICRR) was found in 8 (1.9%) canines. In 4 canines (1.0%), root ankylosis in addition to ICRR was observed. In contrast to ankylosis, whose frequency of occurrence increased with age, the occurrence of ICRR resulting from PDL damage during surgery was more typical in younger patients. Canines in a high position above the root apices of the adjacent teeth, with a horizontal inclination of the longitudinal axis, with the crown located deep in the center of the alveolar bone and with labiopalatal position, should be considered critically impacted canines with a high risk to failure of orthodontic traction.
CONCLUSIONS: In conclusion, the treatment of impacted canines depends mainly on the age of the patient, and the position and inclination of the longitudinal axis of the impacted tooth. To select an adequate treatment method, we recommend CBCT examination, which allows a precise analysis of the position of impacted canines.
摘要：
背景：这项为期20年的回顾性研究旨在评估上颌恒牙阻生患者的治疗方法，并确定强直和吸收过程的发生及其与潜在危险因素的关系。
方法：该队列包括351名连续的白种人患者（120名男性和231名女性，平均年龄18.4和19.9岁，分别）与420个受影响的上颌永久性犬齿。随后在手术期间证实了CT和CBCT的发现。通过广义线性模型进行统计分析，使用统计程序R和Statisticav.14的Pearsonx2和Fisher精确检验。
结果：手术暴露后，通过正畸牵引在牙弓中对齐了总共273只（65.0％）受影响的犬齿，这种治疗在20岁以下的患者中占主导地位.在115例（27.2％）受影响的犬科动物中进行了手术拔除，在老年患者中更为常见。在61只（14.5％）受影响的犬科动物中记录了Ankylotic变化。强直的概率随着年龄的增长而增加,特别是在患者20岁后（p<0.001）。1.2%的患者在15岁时可能发生强直，4.3%在20岁时，25岁时14.1%，45岁时为96.8%。在8只（1.9％）犬中发现了侵入性宫颈根吸收（ICRR）。在4只犬中（1.0％），除ICRR外，还观察到根强直。与强直相反，其发生频率随着年龄的增长而增加，手术期间PDL损伤导致的ICRR的发生在年轻患者中更为典型.犬齿位于相邻牙齿根尖上方的高位置，纵轴水平倾斜，牙冠位于牙槽骨的中心深处，并具有唇瓣位置，应被认为是严重受累的犬科动物，其正畸牵引失败的风险很高。
结论：结论：患犬的治疗主要取决于患者的年龄，以及受撞击牙齿的纵向轴线的位置和倾斜度。为了选择适当的治疗方法，我们推荐CBCT检查,这可以精确分析受影响的犬科动物的位置。
方法：该队列包括351名连续的白种人患者（120名男性和231名女性，平均年龄18.4和19.9岁，分别）与420个受影响的上颌永久性犬齿。随后在手术期间证实了CT和CBCT的发现。通过广义线性模型进行统计分析，使用统计程序R和Statisticav.14的Pearsonx2和Fisher精确检验。
结果：手术暴露后，通过正畸牵引在牙弓中对齐了总共273只（65.0％）受影响的犬齿，这种治疗在20岁以下的患者中占主导地位.在115例（27.2％）受影响的犬科动物中进行了手术拔除，在老年患者中更为常见。在61只（14.5％）受影响的犬科动物中记录了Ankylotic变化。强直的概率随着年龄的增长而增加,特别是在患者20岁后（p<0.001）。1.2%的患者在15岁时可能发生强直，4.3%在20岁时，25岁时14.1%，45岁时为96.8%。在8只（1.9％）犬中发现了侵入性宫颈根吸收（ICRR）。在4只犬中（1.0％），除ICRR外，还观察到根强直。与强直相反，其发生频率随着年龄的增长而增加，手术期间PDL损伤导致的ICRR的发生在年轻患者中更为典型.犬齿位于相邻牙齿根尖上方的高位置，纵轴水平倾斜，牙冠位于牙槽骨的中心深处，并具有唇瓣位置，应被认为是严重受累的犬科动物，其正畸牵引失败的风险很高。
结论：结论：患犬的治疗主要取决于患者的年龄，以及受撞击牙齿的纵向轴线的位置和倾斜度。为了选择适当的治疗方法，我们推荐CBCT检查,这可以精确分析受影响的犬科动物的位置。
