Yusuke Hamada^1,*; Yoshiatsu Tanaka²; Vinicius Dutra³; Brandi Herron¹; Wei-Shao Lin⁴

¹Department of Periodontology, Indiana University School of Dentistry, Indianapolis, United States; ²Private Practice, Hokkaido, Japan; ³Department of Oral Pathology, Medicine, and Radiology, Indiana University School Dentistry; ⁴Department of Prosthodontics, Indiana University School of Dentistry, Indianapolis, United States

Background: Cone-beam computed tomography (CBCT) has been widely used for treatment planning for implant dentistry. To achieve ideal outcomes for immediate implant placement, the presence of buccal bone plays important role. An average labial bone thickness in the maxillary anterior area was reported as 0.8 mm, and the detection of this thickness with CBCT is still challenging. Voxel sizes and the size of field of view might affect to detect the thin objects.

Aim/Hypothesis: The primary aim of this study was to analyze the accuracy of CBCT measurements with three different voxel sizes to histological sections in maxillary anterior teeth. We hypothesized that the smaller voxel size has higher accuracy to detect the buccal bone thickness compared with larger voxel sizes.

Material and Methods: The buccal bone thickness at 3, 5, and 7 mm from the reference notches were measured on cross-sectional images with the CBCT and histomorphometric images. Prior to the actual measurements, inter-intra examiner calibrations were conducted, and intraclass correlation coefficients (ICC) reached >0.9. The agreement of measurements between CBCT and histomorphometric images was assessed by Bland-Altman plots and ICC. The average buccal thickness of each method was investigated and compared to the average histology measurement with paired t-tests. Specificity and sensitivity of buccal bone detections were calculated and analyzed for all groups.

Results: A total of 30 teeth with 90 sites were included in this study. Agreement between the CBCT and histology did not exceed more than 0.8 in all groups. Group 1 and 2 demonstrated ICC values of 0.71 and 0.72, respectively. However, ICC of Group 3 to histology reduced to 0.6. (Table 1) The mean and standard error of buccal bone thickness with histology was 0.40 ± 0.05 mm, Group 1 was 0.52 ± 0.05 mm, Group 2 was 0.39 ± 0.05 mm, Group 3 was 0.36 ± 0.06 mm. The difference between only Group 1 and histology revealed statistically significant difference (p < 0.001) (Figure 1). Sensitivity and specificity of buccal bone detection with Group 1 was 75.4% and 65.5%, Group 2 was 59.0% and 72.4%, and Group 3 showed 39.3% and 79.3%, respectively. The accuracy of buccal bone detection decreased from 72.2% with Group 1 to 52.2% with Group 3 (Table 2).

Conclusion and Clinical implications: Voxel sizes of 0.25 mm and 0.3 mm showed higher accuracy of buccal bone thickness measurements compared with the voxel size of 0.4 mm. Decrease in CBCT voxel size showed an increase in sensitivity while an increase in CBCT voxel size showed an increase in specificity. Accuracy of buccal bone detection decreased with voxel size of 0.4 mm compared with 0.25 and 0.3 mm.

Disclosure of Interest: None Declared

Keywords: accuracy, CBCT, histology

Yusuke Hamada ^1,* ; 田中义压² ; 维尼修斯·杜特拉³ ; 布兰迪赫伦¹ ; 林伟少⁴

¹美国印第安纳波利斯印第安纳大学牙科学院牙周病学系；²日本北海道私人执业；³印第安纳大学牙科学院口腔病理学、医学和放射学系；⁴美国印第安纳波利斯印第安纳大学牙科学院口腔修复系

背景：锥形束计算机断层扫描 (CBCT) 已广泛用于种植牙的治疗计划。为了实现即刻种植体植入的理想结果，颊侧骨的存在起着重要作用。据报道，上颌前区的平均唇骨厚度为 0.8 毫米，使用 CBCT 检测该厚度仍然具有挑战性。体素大小和视野大小可能会影响检测薄物体。

目的/假设：本研究的主要目的是分析三种不同体素大小的 CBCT 测量对上颌前牙组织切片的准确性。我们假设与较大的体素尺寸相比，较小的体素尺寸在检测颊骨厚度方面具有更高的准确性。

材料和方法：使用 CBCT 和组织形态测量图像在横截面图像上测量距参考切口 3、5 和 7 毫米处的颊骨厚度。在实际测量之前，进行了内部检查员校准，并且组内相关系数（ICC）达到> 0.9。CBCT 和组织形态测量图像之间的测量一致性通过 Bland-Altman 图和 ICC 进行评估。研究了每种方法的平均颊侧厚度，并与配对 t 检验的平均组织学测量值进行了比较。计算和分析所有组的颊侧骨检测的特异性和敏感性。

结果：本研究共纳入 30 颗牙齿，共 90 个部位。在所有组中，CBCT 和组织学之间的一致性不超过 0.8。第 1 组和第 2 组的 ICC 值分别为 0.71 和 0.72。然而，第 3 组对组织学的 ICC 降低到 0.6。（表 1）颊侧骨厚度与组织学的平均值和标准误差为 0.40 ± 0.05 mm，第 1 组为 0.52 ± 0.05 mm，第 2 组为 0.39 ± 0.05 mm，第 3 组为 0.36 ± 0.06 mm。仅第 1 组和组织学之间的差异显示出统计学上的显着差异 ( p< 0.001)（图 1）。第一组颊骨检测的灵敏度和特异性分别为 75.4% 和 65.5%，第二组为 59.0% 和 72.4%，第三组分别为 39.3% 和 79.3%。颊侧骨检测的准确性从第 1 组的 72.2% 下降到第 3 组的 52.2%（表 2）。

结论和临床意义：与 0.4 mm 的体素尺寸相比，0.25 mm 和 0.3 mm 的体素尺寸显示出更高的颊侧骨厚度测量精度。CBCT 体素大小的减小表明敏感性增加，而 CBCT 体素大小的增加表明特异性增加。与 0.25 和 0.3 毫米相比，体素大小为 0.4 毫米时，颊侧骨检测的准确性降低。

利益披露：无申报

关键词：准确性，CBCT，组织学