Chen Yu, Liu Dongxu
Department of Stomatology, School of Medicine, Xiamen University, Xiamen, China.
Department of Orthodontics, School and Hospital of Stomatology, Shandong University & Shandong Provincial Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, No 44-1, Wenhua Xi Rd, Jinan City, 250012, Shandong Province, China.
Head Face Med. 2020 Jul 27;16(1):16. doi: 10.1186/s13005-020-00229-z.
Bialveolar protrusion is one of the most common chief complaints from the Asian orthodontic patients. Typical orthodontic treatment includes extraction of the bimaxillary premolars and en mass retraction of anterior tooth with maximum anchorage by placing miniscrews. However, excessive pursuit of profile improvement by retraction and intrusion of anterior teeth may result in root resorption, alveolar bone loss, even dehiscence. Thus this retrospective, analytical study was to evaluate the root resorption of anterior teeth after miniscrew assisted en mass retraction in adult bialveolar protrusion patients.
Thirty six adult patients with bimaxillary protrusion had four first premolars extracted, and then miniscrews were placed to provide anchorage. CBCT scans were performed before (T1) and posttreatment (T2). A new improvement project introduced for 3D CBCT registration assessment of root morphology. The paired t-test was used to compare changes from T1 to T2. The relationship between the root resorption and the movement of anterior teeth were assessed by Pearson correlation coefficient analysis.
The significant differences were only found in apical third of root and the largest resorption in apical third of the root is always noted in the palatal and distal sectors. Significant correlations were observed in the loss of root in distal and palatal sectors, the root length and volume decrease with the amount of anterior teeth retraction and intrusion.
The new 3D registration assessment of root morphology will be helpful for the clinicians. Pursuit of large retraction and intrusion leads to obvious anterior teeth root resorption.
双颌前突是亚洲正畸患者最常见的主诉之一。典型的正畸治疗包括拔除双颌前磨牙，并通过植入微螺钉以最大支抗整体内收前牙。然而，过度追求通过前牙的内收和压低来改善侧貌可能会导致牙根吸收、牙槽骨丧失，甚至牙槽骨裂开。因此，这项回顾性分析研究旨在评估微螺钉辅助下成年双颌前突患者整体内收前牙后前牙的牙根吸收情况。
36例成年双颌前突患者拔除了四颗第一前磨牙，然后植入微螺钉以提供支抗。在治疗前（T1）和治疗后（T2）进行CBCT扫描。引入了一个新的改进方案用于对牙根形态进行三维CBCT配准评估。采用配对t检验比较T1到T2的变化。通过Pearson相关系数分析评估牙根吸收与前牙移动之间的关系。
仅在牙根根尖三分之一处发现显著差异，且根尖三分之一处最大吸收总是出现在腭侧和远中区域。在远中及腭侧牙根吸收、牙根长度和体积随前牙内收和压低量的减少之间观察到显著相关性。
新的牙根形态三维配准评估对临床医生有帮助。追求大量的内收和压低会导致明显的前牙牙根吸收。
