植入深度与扫描杆长度对下颌后牙区单牙种植修复数字化印模精度的影响

Influence of implant depth and scanning rod length on accuracy of digital impression for mandibular posterior single-tooth implant restoration

目的体外研究不同植入深度的种植体以及相同植入深度下,不同长度扫描杆的使用对口内数字化印模精度的影响。方法将右下颌第1磨牙(46)缺失的5个标准牙列石膏模型制备出植入深度分别为龈下0、1、3、5、7 mm的就位道,将ITI RC及ITI RC H11型号的扫描杆与替代体连接后置入就位道进行扫描。使用三维牙齿扫描仪获得参考数据,使用数字化口内扫描仪对每种模型进行10次扫描,获得实验数据。通过3D分析软件Geomagic Wrap 2021进行模型数据的对比分析,测试相应模型的精密度与准确度。对植入深度不同的5组数据进行单因素方差分析,并采用LSD检验进行成对比较;对植入深度相同扫描杆长度不同的两对数据进行配对t检验。结果各组间精密度差异无统计学意义(P>0.05)。不同植入深度下的印模准确度:龈下1 mm组准确度为66.81±2.45μm,表现最佳,高于其他组(P<0.05)。龈下0 mm组准确度为95.60±3.04μm,低于龈下1和3 mm组(P<0.05)。从龈下1 mm开始,扫描的准确度随深度的加深逐渐降低(P<0.05)。相同植入深度不同扫描杆长度的印模准确度:在龈下5和7 mm组使用延长的扫描杆后,扫描准确度均有所提高(P<0.05)。结论种植体植入深度对数字化口内扫描精度具有影响,大体趋势为随植入深度的增加扫描精度逐渐降低,在植入深度较深时,可通过使用长度更长的扫描杆以提升扫描精度。

Objective To study the influence of implant depth and scanning rod lengths on the accuracy of digital impression for single-tooth implant restoration of the mandibular posterior teeth.Methods Five standard dental cast models with missing right mandibular first molar(46)were prepared with the subgingival implant depths of 0,1,3,5 and 7 mm.ITI RC and ITI RC H11 scanning rods were connected to the replacement body and placed into the seating tract for scanning.The reference data were obtained using a 3D dental scanner,and the experimental data were obtained by 10 scans of each model using a digitized intraoral scanner.Geomagic Wrap 2021 was used to analyze the model data to test the trueness and precision of the models.Results The trueness did not differ significantly among the groups(P>0.05).The implant depth of 1 mm achieved the highest impression precision(66.81±2.45μm),and the depth of 0 mm resulted in a significantly lower precision(95.60±3.04μm)than the depth of 1 and 3 mm.Starting from the subgingival depth of 1 mm,the precision of the scan decreased progressively with the increase of the implant depth.At the subgingival implant depth of 5 or 7 mm,the use of an extended rod significantly improved the scan precision.Conclusion For single-tooth implant restoration of the mandibular posterior teeth,the implant depth can substantially affect the accuracy of digital impression,which decreases as the implant depth increases.For a deep implant,the use of a longer scanning rod can improve the scanning accuracy.