Abstract：
OBJECTIVE: To evaluate the performance of low-dose cone beam computed tomography (CBCT) protocols with regard to linear bone measurements in the posterior mandible for implant planning compared with higher dose protocols.
METHODS: Forty-two edentulous posterior sites in human cadaveric mandibles were imaged in three CBCT scanners using three or four protocols with varying exposure parameters to achieve lower dose. Co-registration was performed to generate sagittal and cross-sectional image sections representative of the implant site. Three observers measured bone height, from the alveolar crest to the mandibular canal, and width, three mm from the top of the alveolar crest. Intra- and interobserver reproducibility were assessed for the cases rated as nonmeasurable as well as for completed measurements. The measurements were analyzed using paired t-tests for differences among the CBCT protocols and the frequency distribution of nonmeasurable cases with a Pearson Chi-square test.
RESULTS: Reproducibility for registering nonmeasurable cases varied among observers; however, no consistent significant differences were found in the frequency distribution of these cases among observers, units, and protocols. Intraclass correlation coefficients (ICC) were >0.9 for all measurements of bone height and width. Mean differences of <0.5 mm were found regardless of protocol; however, one observer did in some cases produce larger differences.
CONCLUSIONS: Linear bone measurements did not differ significantly and could be performed with excellent reliability, using low-dose CBCT protocols compared with standard and high-resolution ones. Varying approaches for rating nonmeasurable cases were found, indicating differences in diagnostic strategies related to implant planning among observers.
METHODS: Forty-two edentulous posterior sites in human cadaveric mandibles were imaged in three CBCT scanners using three or four protocols with varying exposure parameters to achieve lower dose. Co-registration was performed to generate sagittal and cross-sectional image sections representative of the implant site. Three observers measured bone height, from the alveolar crest to the mandibular canal, and width, three mm from the top of the alveolar crest. Intra- and interobserver reproducibility were assessed for the cases rated as nonmeasurable as well as for completed measurements. The measurements were analyzed using paired t-tests for differences among the CBCT protocols and the frequency distribution of nonmeasurable cases with a Pearson Chi-square test.
RESULTS: Reproducibility for registering nonmeasurable cases varied among observers; however, no consistent significant differences were found in the frequency distribution of these cases among observers, units, and protocols. Intraclass correlation coefficients (ICC) were >0.9 for all measurements of bone height and width. Mean differences of <0.5 mm were found regardless of protocol; however, one observer did in some cases produce larger differences.
CONCLUSIONS: Linear bone measurements did not differ significantly and could be performed with excellent reliability, using low-dose CBCT protocols compared with standard and high-resolution ones. Varying approaches for rating nonmeasurable cases were found, indicating differences in diagnostic strategies related to implant planning among observers.
摘要：
目的：评估低剂量锥形束计算机断层扫描（CBCT）方案在用于植入计划的后下颌骨线性骨测量方面的性能，与高剂量方案相比。
方法：使用三种或四种不同暴露参数的方案，在三种CBCT扫描仪中对人类尸体下颌骨的42个无牙颌后部部位进行成像，以达到较低的剂量。进行配准以产生代表植入部位的矢状和横截面图像切片。三个观察者测量了骨骼高度，从牙槽嵴到下颌管，和宽度，从牙槽脊顶部3毫米。对于被评为不可测量的病例以及已完成的测量，评估了观察者内部和观察者之间的可重复性。使用配对t检验分析CBCT方案之间的差异以及Pearson卡方检验不可测量病例的频率分布。
结果：记录不可测量病例的可重复性因观察者而异；然而，这些病例在观察者之间的频率分布没有发现一致的显著差异，units,和协议。对于骨高度和骨宽度的所有测量值,组内相关系数(ICC)>0.9。无论协议如何，均发现<0.5mm的平均差异；然而，在某些情况下，一个观察者确实产生了更大的差异。
结论：线性骨测量没有显着差异，可以以出色的可靠性进行，与标准和高分辨率方案相比，使用低剂量CBCT方案。发现了对不可测量病例进行评级的不同方法，表明观察者之间与植入物计划相关的诊断策略的差异。
方法：使用三种或四种不同暴露参数的方案，在三种CBCT扫描仪中对人类尸体下颌骨的42个无牙颌后部部位进行成像，以达到较低的剂量。进行配准以产生代表植入部位的矢状和横截面图像切片。三个观察者测量了骨骼高度，从牙槽嵴到下颌管，和宽度，从牙槽脊顶部3毫米。对于被评为不可测量的病例以及已完成的测量，评估了观察者内部和观察者之间的可重复性。使用配对t检验分析CBCT方案之间的差异以及Pearson卡方检验不可测量病例的频率分布。
结果：记录不可测量病例的可重复性因观察者而异；然而，这些病例在观察者之间的频率分布没有发现一致的显著差异，units,和协议。对于骨高度和骨宽度的所有测量值,组内相关系数(ICC)>0.9。无论协议如何，均发现<0.5mm的平均差异；然而，在某些情况下，一个观察者确实产生了更大的差异。
结论：线性骨测量没有显着差异，可以以出色的可靠性进行，与标准和高分辨率方案相比，使用低剂量CBCT方案。发现了对不可测量病例进行评级的不同方法，表明观察者之间与植入物计划相关的诊断策略的差异。
