犬关系是识别前牙错合的关键参考,也是评估上颌美学区植入前骨形态的重要意义。本研究旨在比较I类和III类犬类之间上颌中切牙相关测量值(牙槽骨厚度和牙齿矢状角)的差异,并进一步探讨基于锥形束计算机断层扫描(CBCT)数据在上颌前直接植入的危险因素。
收集107例患者(54例具有I类犬关系,53例具有III类犬关系)的CBCT数字成像和医学通信(DICOM)文件,并记录中根牙槽骨厚度(中根颊厚度/MBT;腭/MPT),在中矢状观察平面上测量被检查侧上颌中切牙的顶端区域(顶端颊厚度/ABT;pa/APT)和矢状角(SA)。建立了基于I类或III类犬关系的描述性统计分析和测量值的频率分布。使用Fisher精确检验进行统计分析,独立样本t检验和Pearson相关性检验,显著性水平设置为p<0.05。
上颌中切牙MPT的频率分布,ABT,APT和SA在I类和III类犬关系之间显示出显着差异(分别为p=0.030、0.024、0.000和0.000)。MPT(2.48±0.88mmvs.3.01±1.04mm,p=0.005),APT(6.79±1.65mmvs.8.47±1.93mm,p=0.000)和SA(12.23±5.62°vs.16.42±4.49°,p=0.000)在具有III类犬关系的患者中明显较小。此外,SA与APT呈较强的正相关(R=0.723,p=0.000),与ABT呈中等负相关(R=-0.554,p=0.000)。
在有III类犬关系的人群中,与I类关系相比,上颌中切牙的唇倾斜程度明显更高,并且在顶点处的pal骨板更薄。临床医生应避免在最初突出的上颌切牙的部位立即植入时发生pal穿孔。
Canine relationship is a key reference identifying anterior malocclusion and an important implication for evaluating preimplantation bone morphology at maxillary esthetic zone. This study aimed to compare the differences of maxillary central incisor-related measurements (alveolar bone thickness and tooth sagittal angulation) between Class I and Class III canine relationship and further explore the risk factors for immediate implant placement in the anterior maxilla based on cone beam computed tomography (CBCT) data.
CBCT digital imaging and communications in medicine (DICOM) files of 107 patients (54 with Class I canine relationship and 53 with Class III canine relationship) were collected and the alveolar bone thickness at mid-root (mid-root buccal thickness/MBT; palatal/MPT), apical regions (apical buccal thickness/ABT; palatal/APT) and sagittal angulation (SA) of the maxillary central incisor at the examined side were measured on the mid-sagittal observation plane. Descriptive statistical analysis and frequency distributions of the measurements based on Class I or Class III canine relationship were established. Statistical analyses were performed using Fisher\'s exact test, independent samples t test and Pearson correlation test with the significance level set at p < 0.05.
The frequency distributions of maxillary central incisors\' MPT, ABT, APT and SA showed significant differences between Class I and Class III canine relationships (p = 0.030, 0.024, 0.000 and 0.000, respectively). MPT (2.48 ± 0.88 mm vs. 3.01 ± 1.04 mm, p = 0.005), APT (6.79 ± 1.65 mm vs. 8.47 ± 1.93 mm, p = 0.000) and SA (12.23 ± 5.62° vs. 16.42 ± 4.49°, p = 0.000) were significantly smaller in patients with Class III canine relationship. Moreover, SA showed a strong positive correlation with APT (R = 0.723, p = 0.000) and a moderate negative correlation with ABT (R = - 0.554, p = 0.000).
In populations with Class III canine relationship, maxillary central incisors were significantly more labially inclined and have a thinner palatal bone plate at the apex compared with Class I relationship. Clinicians should avoid palatal perforation during immediate implantation at sites of originally protrusive maxillary incisors.