Schubert Michael, Proff Peter, Kirschneck Christian
Department of Orthodontics, University Medical Centre of Regensburg, Germany.
Eur J Orthod. 2018 Nov 30;40(6):597-607. doi: 10.1093/ejo/cjy028.
BACKGROUND/OBJECTIVE: Orthodontic alignment of impacted upper canines is desirable for functional and aesthetic reasons, but time-consuming and difficult. Estimated treatment time is thus an important factor in treatment planning, its predictability based on hitherto available two-dimensional radiological measurements, however, quite limited (max. 39.1-42%). We thus aimed to improve treatment time prognosis of palatally impacted upper canines based on a three-dimensional quantification of eruption path length in baseline cone-beam computed tomographical (CBCT) diagnostic data.
Baseline CBCT and orthopantomogram (OPT) data and treatment times of 30 adolescent non-syndromic/cleft orthodontic patients with an unilaterally palatally impacted upper canine, aligned by fixed orthodontic non-extraction traction treatment (closed eruption), were retrospectively analysed. Eruption path length was quantified by conventional two-dimensional and new three-dimensional methods, correlated with time to canine alignment and a prediction equation derived by linear regression.
CBCT and OPT eruption path length and time to canine alignment did not show significant gender, age, or impaction side differences, but CBCT methods a distinct correlation (r = 0.856/0.844, P < 0.001) and high concordance [Lin's concordance correlation coefficient (CCC) = 0.9438]. Linear regression yielded a predictability (r2 × 100%) of time to canine alignment from eruption path length of 73.3 per cent (CBCT trigonometry), 71.3 per cent (CBCT-simplified), and 50.0 per cent (OPT), respectively.
The proposed model for treatment time prediction is only valid for eruption path lengths up to 8 mm. In some cases of canines being defined as impacted, these may have had the potential of spontaneous eruption. Possible inter-individual differences have to be considered.
Treatment time prediction for alignment of impacted upper canines can be achieved at an improved certainty of up to 73.3 per cent by the proposed CBCT methods for quantifying eruption path length compared to OPT measurements. Due to absence of gender, age, and impaction side differences, the derived regression formula should be universally usable in non-syndromic/cleft adolescents with palatally impacted upper canines.
背景/目的：出于功能和美观的原因，对上颌阻生尖牙进行正畸排齐是很有必要的，但耗时且困难。因此，估计的治疗时间是治疗计划中的一个重要因素，然而，基于目前可用的二维放射学测量方法，其可预测性相当有限（最高39.1%-42%）。因此，我们旨在通过对基线锥形束计算机断层扫描（CBCT）诊断数据中的萌出路径长度进行三维量化，来改善腭侧阻生上颌尖牙的治疗时间预后。
回顾性分析了30例青少年非综合征/非腭裂正畸患者的基线CBCT和曲面断层片（OPT）数据以及治疗时间，这些患者单侧腭侧阻生上颌尖牙，通过固定正畸非拔牙牵引治疗（闭合萌出）进行排齐。通过传统二维方法和新的三维方法对萌出路径长度进行量化，并与尖牙排齐时间相关联，通过线性回归得出预测方程。
CBCT和OPT的萌出路径长度以及尖牙排齐时间在性别、年龄或阻生侧方面均未显示出显著差异，但CBCT方法具有明显的相关性（r = 0.856/0.844，P < 0.001）和高度一致性[林氏一致性相关系数（CCC）= 0.9438]。线性回归得出，根据萌出路径长度预测尖牙排齐时间的可预测性（r2×100%）分别为73.3%（CBCT三角测量法）、71.3%（CBCT简化法）和50.0%（OPT）。
所提出的治疗时间预测模型仅适用于萌出路径长度达8mm的情况。在一些被定义为阻生的尖牙病例中，这些尖牙可能具有自发萌出的潜力。必须考虑个体间可能存在的差异。
与OPT测量相比，通过所提出的CBCT方法量化萌出路径长度，对上颌阻生尖牙排齐的治疗时间预测可达到更高的确定性，最高可达73.3%。由于不存在性别、年龄和阻生侧差异，所推导的回归公式应普遍适用于非综合征/非腭裂的腭侧阻生上颌尖牙青少年患者。
