Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences (Mashhad, Iran).
Oral and Maxillofacial Diseases Research Center, School of Dentistry, Mashhad University of Medical Sciences (Mashhad, Iran).
Dental Press J Orthod. 2024 Sep 2;29(4):e242416. doi: 10.1590/2177-6709.29.4.e242416.oar. eCollection 2024.
This study aimed to assess root volumes of maxillary canines and adjacent lateral incisors in patients with unilateral maxillary canine impaction.
This cross-sectional study was performed on cone-beam computed tomography (CBCT) scans of 100 patients (49 females and 51 males) with unilateral maxillary canine impaction. The images were loaded in Planmeca Romexis Viewer, and root layers between the cementoenamel junction and apex were reconstructed at 600-µm intervals. At each layer, the root boundary was marked, and finally, the root volume was calculated by multiplying the layers' area by the thickness of 600 µm. The root size of canines and lateral incisors was compared between the impaction and normal eruption sides.
Sixty-two patients showed buccal canine impaction, and 38 presented palatal impaction. The mean root volume of canines on the impaction side was significantly greater than that on the normal eruption side; either the tooth was buccally or palatally impacted (p<0.001). The lateral incisors on the side of buccally-impacted canines showed a significantly smaller root volume than that of the contralateral side (p<0.001). However, there was no significant difference in the root size of lateral incisors between the two sides in cases presenting palatal canine impaction (p=0.177).
The difference in root volume of canines between the two sides can serve as an indicator of canine impaction. The reduction in the root size of the lateral incisor on the side of the buccally impacted canine may be due to root resorption created by pressure from the canine's crown.
本研究旨在评估单侧上颌尖牙阻生患者上颌尖牙和相邻侧切牙的根体积。
本横断面研究纳入了 100 名单侧上颌尖牙阻生患者（49 名女性和 51 名男性）的锥形束 CT（CBCT）扫描。将图像加载到 Planmeca Romexis Viewer 中，以 600μm 的间隔重建牙骨质-釉质交界处和根尖之间的根层。在每个层面上，标记根边界，最后通过将层面积乘以 600μm 的厚度来计算根体积。比较了尖牙和侧切牙在阻生侧和正常萌出侧的根大小。
62 名患者表现为颊侧尖牙阻生，38 名患者表现为腭侧尖牙阻生。阻生侧尖牙的平均根体积明显大于正常萌出侧；无论牙齿是颊侧还是腭侧阻生（p<0.001）。颊侧阻生尖牙侧的侧切牙根体积明显小于对侧（p<0.001）。然而，在腭侧尖牙阻生的情况下，两侧侧切牙的根大小无显著差异（p=0.177）。
两侧尖牙根体积的差异可作为尖牙阻生的指标。由于来自尖牙冠的压力导致颊侧阻生尖牙侧侧切牙的根吸收，可能导致侧切牙根体积减小。
