口内数字化印模的重复性研究

Repetitive study of digital impressions in the mouth Study of zirconia crowns fabricated by stereolithography method

目的研究口内数字化印模的重复性以评价其扫描精度。方法选取2018年3月在上海市第九人民医院经过完善根管治疗的1例上颌中切牙患者,确认该例患者的基牙符合全瓷单冠治疗适应症并同意接受全瓷单冠修复治疗。口内组为口内数字化扫描仪重复扫描预备后基牙,口外组为口外扫描仪重复扫描石膏模型(由硅橡胶印模翻制而来)。每组分别进行10次光固化立体造型术(Stereolithography,STL),以第1次扫描得到的STL图像为参考,得到9个匹配图像,对2组18份色斑图报告进行偏差分析报告,分析2组扫描仪多次扫描的重复性和精度。结果 2组共得到18份偏差分析报告,口内组的统计分析结果中的3D average deviation和3D standard deviation值明显高于口外组,进一步统计2组的平均扫描距离数据,提示口外扫描的重复性和精度优于口内扫描(P<0.05);由匹配图像与色斑图报告,提示绿的区域表示扫描重复性好,灰色区域表示不融合,有偏差,提示口内扫描与口外扫描偏差最大部位集中于切端。结论口外扫描重复性较内口扫描好,虽然口内扫描在切断有偏差,但也在临床应用的可接受范围,值得临床推广使用。

Objective To investigate the repeatability of digital impressions in the mouth so as to evaluate its scanning accuracy. Methods A patient undergoing complete root canal treatment was selected in our hospital in March 2018. the patient′s abutment conformed to the all-ceramic single crown treatment indication was confirmed and agreed to accept the all-ceramic single crown. Repair treatment. The intraoral group repeatedly scans the prepared abutment for the intraoral digital scanner, and the extraoral group repeatedly scans the plaster model(transformed from the silicone rubber impression) for the extraoral scanner. Each group was subjected to 10 times of photo-curing stereosynthesis(STL), and the STL images obtained from the first scan were used as control. Nine matching images were obtained, and the deviation analysis of 18 sets of stain map reports was performed to analyze the repeatability and accuracy of multiple scans of the two group scanner. Results A total of 18 deviation analysis reports were obtained in the two groups. The 3 D average deviation and 3 D standard deviation values in the statistical analysis of the intraoral group were significantly higher than those in the extraoral group. The average scan distance data of the two groups were further statistically reported, indicating the repeatability and accuracy of the extraoral scan. It is significantly better than intraoral scan(P<0.05);it is reported by matching image and stain diagram, the green area indicates that the scan repeatability is good, the gray area indicates no fusion, there is deviation, and the maximum deviation between the intraoral scan and the extraoral scan is concentrated on the cut end. Conclusion The extraoral scan repeatability was better than the internal port scan. Although the intraoral scan was biased in the cut, it could be also acceptable in clinical applications and thus is worthy of clinical promotion.