口内扫描仪用于长牙列的准确性及重复性研究

A study on accuracy and repeatability of intraoral optical scanner used for long dentition

目的采用新的区段划分法研究口内扫描仪扫描长牙列的重复性及准确性。方法8位志愿者制取硅橡胶印模,灌注超硬石膏模型,用窗口扫描仪扫描模型获得虚拟模型Ri,口内扫描仪扫描模型4次得到虚拟模型TiA、TiB、TiC、TiD。将窗口扫描数据模型Ri和口内扫描数据模型TiA的牙列分成从右到左4个区段:右侧后牙,右侧前牙,左侧前牙和左侧后牙,按顺序记为第一、第二、第三、第四区段。对两组模型的第一区段进行全局注册,再依次对两组光学扫描牙列的4个区段行三维偏差分析;Ri与TiB、TiC、TiD之间也进行相同比较。口内扫描数据TiA、TiB、TiC、TiD两两之间进行同样操作以研究口内扫描仪的重复性。结果准确性研究中4个区段虚拟模型偏差的均值按上述顺序依次为:(0.017±0.004)mm、(0.050±0.015)mm、(0.109±0.040)mm和(0.193±0.067)mm,任意两个区段的虚拟模型偏差均存在差异(P<0.05)。重复性研究中4个区段的虚拟模型偏差均值依次为:(0.011±0.008)mm、(0.027±0.012)mm、(0.064±0.038)mm和(0.127±0.077)mm,4个区段两两之间的虚拟模型偏差差异均具有统计学意义(P<0.05)。结论口内扫描仪用于长牙列扫描时,其准确性和重复性均有所欠缺。

Objectives The aim of this study was to investigate the precision and accuracy of inraoral scanner by making use of a novel method based on dividing a model into four sections.Methods Silicone rubber impressions were taken from eight volunteers and gypsum models were casted.A 3D scanner and an intraoral scanner were used to scan the models respectively,and the intraoral scanner was used to scan the models four times to obtain five sets of virtual models named TiA,TiB,TiC,TiD(from intraoral scanner)and Ri(from 3D scanner).Dentition of Ri and TiA was divided into four segments:right posterior teeth,right anterior teeth,left anterior teeth and left posterior teeth,which were named as the first,the second,the third and the fourth sections in sequence.Global registration was applied for the first section of the two models.Deviation analysis was performed on the four sections of the virtual dentition.The values of TiB,TiC and TiD were also compared with the Ri value in the same way.The same procedure was also carried out for comparison among TiA,TiB,TiC,TiD to study the precision of intraoral scanner.Results The model deviation distances of the four sections obtained in the accuracy study was as follows:(0.017±0.004)mm,(0.050±0.015)mm,(0.109±0.040)mm,(0.193±0.067)mm.The differences in the model deviation between the four sections were significant different(P<0.05).The model deviation distances obtained from the precisi on analysis on the four sections was as follows:(0.011±0.008)mm,(0.027±0.012)mm,(0.064±0.038)mm,(0.127±0.077)mm.And there was a significant difference in the model deviation between each two sections of the four sections(P<0.05).Conclusions When intraoral scanners are used for impressions of multiple sections,the accuracy and precision need to be improved.