Zheng Changhong, Li Lei
（ 610041） State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Sichuan Da Xue Xue Bao Yi Xue Ban. 2025 May 20;56(3):778-784. doi: 10.12182/20250560603.
To evaluate the accuracy of conventional impression techniques, intraoral scanning, and two stereophotogrammetry systems (PIC and ICam4D) for complete-arch implant restorations, and to analyze the influence of varying interimplant distance and implant angulation on the accuracy of each impression method.
A total of 6 edentulous maxillary all-on-four casts were fabricated with varying posterior implant parameters, including anterior-posterior (A-P) distances of 20 mm and 35 mm and distal implant angulations of 0°, 15°, and 25°. Impressions were obtained using conventional impression techniques, intraoral scanning, and two stereophotogrammetry systems (PIC and ICam4D). The three-dimensional deviations of the impression techniques were measured using reverse-engineering software to evaluate trueness and precision.
The accuracy of intraoral scanning technology exhibited a declining trend with increasing A-P distance and implant angulation. The maximum deviations in trueness and precision were observed in the posterior region with an A-P distance of 35 mm and a distal implant angulation of 25°, measuring (76.90 ± 43.32) μm and (99.43 ± 74.39) μm, respectively. The conventional impression techniques exhibited stable performance, with mean accuracy deviation values consistently falling below 50 μm. The ICam4D stereophotogrammetry system exhibited the highest precision across all conditions ( < 0.05). The maximum precision deviation for PIC system occurred in the right anterior region with an A-P distance of 20 mm and a distal implant angulation of 15° ([28.10 ± 18.73] μm), while the maximum trueness deviations for both PIC and ICam4D were observed in the anterior region with an A-P distance of 20 mm and a distal implant angulation of 25°, measuring (62.63 ±9.40) μm and (83.61 ± 1.76) μm, respectively. The PIC system showed better overall trueness than ICam4D did when distal implant angles were ≥ 15° ( < 0.05).
For complete-arch implant rehabilitation, the accuracy of different impression methods varies depending on implant-related factors. The inter-implant distance and angulation were critical determinants of accuracy for intraoral scanning, whereas conventional impression techniques and the two stereophotogrammetry systems exhibited no clear correlation with these parameters.
评估传统印模技术、口内扫描以及两种立体摄影测量系统（PIC和ICam4D）用于全牙弓种植修复的准确性，并分析种植体间距离和种植体角度变化对每种印模方法准确性的影响。
制作6个无牙上颌全口四颗种植体的模型，其种植体后段参数各异，包括前后（A-P）距离为20mm和35mm，以及远中种植体角度为0°、15°和25°。使用传统印模技术、口内扫描以及两种立体摄影测量系统（PIC和ICam4D）获取印模。采用逆向工程软件测量印模技术的三维偏差，以评估准确性和精确性。
口内扫描技术的准确性随A-P距离和种植体角度增加呈下降趋势。在A-P距离为35mm且远中种植体角度为25°的后牙区域观察到准确性和精确性的最大偏差，分别为（76.90±43.32）μm和（99.43±74.39）μm。传统印模技术表现稳定，平均准确性偏差值始终低于50μm。ICam4D立体摄影测量系统在所有条件下均表现出最高的精确性（<0.05）。PIC系统的最大精确性偏差出现在A-P距离为20mm且远中种植体角度为15°的右前牙区域（[28.10±18.73]μm），而PIC和ICam4D的最大准确性偏差均出现在A-P距离为20mm且远中种植体角度为25°的前牙区域，分别为（62.63±9.40）μm和（83.61±1.76）μm。当远中种植体角度≥15°时，PIC系统的总体准确性优于ICam4D（<0.05）。
对于全牙弓种植修复，不同印模方法的准确性因种植相关因素而异。种植体间距离和角度是口内扫描准确性的关键决定因素，而传统印模技术和两种立体摄影测量系统与这些参数无明显相关性。
